view2d.c

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. 
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2008 Blender Foundation.
 * All rights reserved.
 * 
 * Contributor(s): Blender Foundation, Joshua Leung
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <float.h>
#include <limits.h>
#include <math.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_scene_types.h"
#include "DNA_userdef_types.h"

#include "BLI_blenlib.h"
#include "BLI_utildefines.h"

#include "BKE_context.h"
#include "BKE_screen.h"
#include "BKE_global.h"


#include "WM_api.h"

#include "BIF_gl.h"

#include "BLF_api.h"

#include "ED_anim_api.h"
#include "ED_screen.h"

#include "UI_interface.h"
#include "UI_view2d.h"

#include "interface_intern.h"

/* *********************************************************************** */

/* XXX still unresolved: scrolls hide/unhide vs region mask handling */
/* XXX there's V2D_SCROLL_HORIZONTAL_HIDE and V2D_SCROLL_HORIZONTAL_FULLR ... */

/* helper to allow scrollbars to dynamically hide
 *  - returns a copy of the scrollbar settings with the flags to display 
 *    horizontal/vertical scrollbars removed
 *  - input scroll value is the v2d->scroll var
 *  - hide flags are set per region at drawtime
 */
static int view2d_scroll_mapped(int scroll)
{
    if(scroll & V2D_SCROLL_HORIZONTAL_HIDE)
        scroll &= ~(V2D_SCROLL_HORIZONTAL);
    if(scroll & V2D_SCROLL_VERTICAL_HIDE)
        scroll &= ~(V2D_SCROLL_VERTICAL);
    return scroll;
}

/* called each time cur changes, to dynamically update masks */
static void view2d_masks(View2D *v2d)
{
    int scroll;
    
    /* mask - view frame */
    v2d->mask.xmin= v2d->mask.ymin= 0;
    v2d->mask.xmax= v2d->winx - 1;  /* -1 yes! masks are pixels */
    v2d->mask.ymax= v2d->winy - 1;

#if 0
    // XXX see above
    v2d->scroll &= ~(V2D_SCROLL_HORIZONTAL_HIDE|V2D_SCROLL_VERTICAL_HIDE);
    /* check size if: */
    if (v2d->scroll & V2D_SCROLL_HORIZONTAL)
        if(!(v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL))
            if (v2d->tot.xmax-v2d->tot.xmin <= v2d->cur.xmax-v2d->cur.xmin)
                v2d->scroll |= V2D_SCROLL_HORIZONTAL_HIDE;
    if (v2d->scroll & V2D_SCROLL_VERTICAL)
        if(!(v2d->scroll & V2D_SCROLL_SCALE_VERTICAL))
            if (v2d->tot.ymax-v2d->tot.ymin <= v2d->cur.ymax-v2d->cur.ymin)
                v2d->scroll |= V2D_SCROLL_VERTICAL_HIDE;
#endif
    scroll= view2d_scroll_mapped(v2d->scroll);
    
    /* scrollers shrink mask area, but should be based off regionsize 
     *  - they can only be on one to two edges of the region they define
     *  - if they overlap, they must not occupy the corners (which are reserved for other widgets)
     */
    if (scroll) {
        /* vertical scroller */
        if (scroll & V2D_SCROLL_LEFT) {
            /* on left-hand edge of region */
            v2d->vert= v2d->mask;
            v2d->vert.xmax= V2D_SCROLL_WIDTH;
            v2d->mask.xmin= v2d->vert.xmax + 1;
        }
        else if (scroll & V2D_SCROLL_RIGHT) {
            /* on right-hand edge of region */
            v2d->vert= v2d->mask;
            v2d->vert.xmax++; /* one pixel extra... was leaving a minor gap... */
            v2d->vert.xmin= v2d->vert.xmax - V2D_SCROLL_WIDTH;
            v2d->mask.xmax= v2d->vert.xmin - 1;
        }
        
        /* horizontal scroller */
        if (scroll & (V2D_SCROLL_BOTTOM|V2D_SCROLL_BOTTOM_O)) {
            /* on bottom edge of region (V2D_SCROLL_BOTTOM_O is outliner, the other is for standard) */
            v2d->hor= v2d->mask;
            v2d->hor.ymax= V2D_SCROLL_HEIGHT;
            v2d->mask.ymin= v2d->hor.ymax + 1;
        }
        else if (scroll & V2D_SCROLL_TOP) {
            /* on upper edge of region */
            v2d->hor= v2d->mask;
            v2d->hor.ymin= v2d->hor.ymax - V2D_SCROLL_HEIGHT;
            v2d->mask.ymax= v2d->hor.ymin - 1;
        }
        
        /* adjust vertical scroller if there's a horizontal scroller, to leave corner free */
        if (scroll & V2D_SCROLL_VERTICAL) {
            /* just set y min/max for vertical scroller to y min/max of mask as appropriate */
            if (scroll & (V2D_SCROLL_BOTTOM|V2D_SCROLL_BOTTOM_O)) {
                /* on bottom edge of region (V2D_SCROLL_BOTTOM_O is outliner, the other is for standard) */
                v2d->vert.ymin= v2d->mask.ymin;
            }
            else if (scroll & V2D_SCROLL_TOP) {
                /* on upper edge of region */
                v2d->vert.ymax= v2d->mask.ymax;
            }
        }
    }
    
}

/* Refresh and Validation */

/* Initialise all relevant View2D data (including view rects if first time) and/or refresh mask sizes after view resize
 *  - for some of these presets, it is expected that the region will have defined some
 *    additional settings necessary for the customisation of the 2D viewport to its requirements
 *  - this function should only be called from region init() callbacks, where it is expected that
 *    this is called before UI_view2d_size_update(), as this one checks that the rects are properly initialised. 
 */
void UI_view2d_region_reinit(View2D *v2d, short type, int winx, int winy)
{
    short tot_changed= 0, init= 0;
    uiStyle *style= UI_GetStyle();

    /* initialise data if there is a need for such */
    if ((v2d->flag & V2D_IS_INITIALISED) == 0) {
        /* set initialised flag so that View2D doesn't get reinitialised next time again */
        v2d->flag |= V2D_IS_INITIALISED;

        init= 1;
        
        /* see eView2D_CommonViewTypes in UI_view2d.h for available view presets */
        switch (type) {
            /* 'standard view' - optimum setup for 'standard' view behaviour,
             *  that should be used new views as basis for their
             *  own unique View2D settings, which should be used instead of this in most cases...
             */
            case V2D_COMMONVIEW_STANDARD:
            {
                /* for now, aspect ratio should be maintained, and zoom is clamped within sane default limits */
                v2d->keepzoom= (V2D_KEEPASPECT|V2D_LIMITZOOM);
                v2d->minzoom= 0.01f;
                v2d->maxzoom= 1000.0f;
                
                /* tot rect and cur should be same size, and aligned using 'standard' OpenGL coordinates for now 
                 *  - region can resize 'tot' later to fit other data
                 *  - keeptot is only within bounds, as strict locking is not that critical
                 *  - view is aligned for (0,0) -> (winx-1, winy-1) setup
                 */
                v2d->align= (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                v2d->keeptot= V2D_KEEPTOT_BOUNDS;
                
                v2d->tot.xmin= v2d->tot.ymin= 0.0f;
                v2d->tot.xmax= (float)(winx - 1);
                v2d->tot.ymax= (float)(winy - 1);
                
                v2d->cur= v2d->tot;
                
                /* scrollers - should we have these by default? */
                // XXX for now, we don't override this, or set it either!
            }
                break;
            
            /* 'list/channel view' - zoom, aspect ratio, and alignment restrictions are set here */
            case V2D_COMMONVIEW_LIST:
            {
                /* zoom + aspect ratio are locked */
                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                v2d->minzoom= v2d->maxzoom= 1.0f;
                
                /* tot rect has strictly regulated placement, and must only occur in +/- quadrant */
                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_POS_Y);
                v2d->keeptot = V2D_KEEPTOT_STRICT;
                tot_changed= 1;
                
                /* scroller settings are currently not set here... that is left for regions... */
            }
                break;
                
            /* 'stack view' - practically the same as list/channel view, except is located in the pos y half instead. 
             *  zoom, aspect ratio, and alignment restrictions are set here */
            case V2D_COMMONVIEW_STACK:
            {
                /* zoom + aspect ratio are locked */
                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                v2d->minzoom= v2d->maxzoom= 1.0f;
                
                /* tot rect has strictly regulated placement, and must only occur in +/+ quadrant */
                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                v2d->keeptot = V2D_KEEPTOT_STRICT;
                tot_changed= 1;
                
                /* scroller settings are currently not set here... that is left for regions... */
            }
                break;
                
            /* 'header' regions - zoom, aspect ratio, alignment, and panning restrictions are set here */
            case V2D_COMMONVIEW_HEADER:
            {
                /* zoom + aspect ratio are locked */
                v2d->keepzoom = (V2D_LOCKZOOM_X|V2D_LOCKZOOM_Y|V2D_LIMITZOOM|V2D_KEEPASPECT);
                v2d->minzoom= v2d->maxzoom= 1.0f;
                v2d->min[0]= v2d->max[0]= (float)(winx-1);
                v2d->min[1]= v2d->max[1]= (float)(winy-1);
                
                /* tot rect has strictly regulated placement, and must only occur in +/+ quadrant */
                v2d->align = (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_NEG_Y);
                v2d->keeptot = V2D_KEEPTOT_STRICT;
                tot_changed= 1;
                
                /* panning in y-axis is prohibited */
                v2d->keepofs= V2D_LOCKOFS_Y;
                
                /* absolutely no scrollers allowed */
                v2d->scroll= 0;
                
            }
                break;
            
            /* panels view, with horizontal/vertical align */
            case V2D_COMMONVIEW_PANELS_UI:
            {
                float panelzoom= (style) ? style->panelzoom : 1.0f;
                
                /* for now, aspect ratio should be maintained, and zoom is clamped within sane default limits */
                v2d->keepzoom= (V2D_KEEPASPECT|V2D_LIMITZOOM|V2D_KEEPZOOM);
                v2d->minzoom= 0.5f;
                v2d->maxzoom= 2.0f;
                //tot_changed= 1;
                
                v2d->align= (V2D_ALIGN_NO_NEG_X|V2D_ALIGN_NO_POS_Y);
                v2d->keeptot= V2D_KEEPTOT_BOUNDS;
                
                v2d->scroll |= (V2D_SCROLL_RIGHT|V2D_SCROLL_BOTTOM);
                v2d->scroll |= V2D_SCROLL_HORIZONTAL_HIDE;
                v2d->scroll &= ~V2D_SCROLL_VERTICAL_HIDE;

                v2d->tot.xmin= 0.0f;
                v2d->tot.xmax= winx;
                
                v2d->tot.ymax= 0.0f;
                v2d->tot.ymin= -winy;
                
                v2d->cur.xmin= 0.0f;
                /* bad workaround for keeping zoom level with scrollers */
                v2d->cur.xmax= (winx - V2D_SCROLL_WIDTH)*panelzoom;
                
                v2d->cur.ymax= 0.0f;
                v2d->cur.ymin= (-winy)*panelzoom;
            }
                break;
                
                /* other view types are completely defined using their own settings already */
            default:
                /* we don't do anything here, as settings should be fine, but just make sure that rect */
                break;  
        }
    }
    
    /* store view size */
    v2d->winx= winx;
    v2d->winy= winy;
    
    /* set masks */
    view2d_masks(v2d);
    
    /* set 'tot' rect before setting cur? */
    if (tot_changed) 
        UI_view2d_totRect_set_resize(v2d, winx, winy, !init);
    else
        UI_view2d_curRect_validate_resize(v2d, !init);
}

/* Ensure View2D rects remain in a viable configuration 
 *  - cur is not allowed to be: larger than max, smaller than min, or outside of tot
 */
// XXX pre2.5 -> this used to be called  test_view2d()
void UI_view2d_curRect_validate_resize(View2D *v2d, int resize)
{
    float totwidth, totheight, curwidth, curheight, width, height;
    float winx, winy;
    rctf *cur, *tot;
    
    /* use mask as size of region that View2D resides in, as it takes into account scrollbars already  */
    winx= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
    winy= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);
    
    /* get pointers to rcts for less typing */
    cur= &v2d->cur;
    tot= &v2d->tot;
    
    /* we must satisfy the following constraints (in decreasing order of importance):
     *  - alignment restrictions are respected
     *  - cur must not fall outside of tot
     *  - axis locks (zoom and offset) must be maintained
     *  - zoom must not be excessive (check either sizes or zoom values)
     *  - aspect ratio should be respected (NOTE: this is quite closely realted to zoom too)
     */
    
    /* Step 1: if keepzoom, adjust the sizes of the rects only
     *  - firstly, we calculate the sizes of the rects
     *  - curwidth and curheight are saved as reference... modify width and height values here
     */
    totwidth= tot->xmax - tot->xmin;
    totheight= tot->ymax - tot->ymin;
    curwidth= width= cur->xmax - cur->xmin;
    curheight= height= cur->ymax - cur->ymin;
    
    /* if zoom is locked, size on the appropriate axis is reset to mask size */
    if (v2d->keepzoom & V2D_LOCKZOOM_X)
        width= winx;
    if (v2d->keepzoom & V2D_LOCKZOOM_Y)
        height= winy;
        
    /* values used to divide, so make it safe 
     * NOTE: width and height must use FLT_MIN instead of 1, otherwise it is impossible to
     *      get enough resolution in Graph Editor for editing some curves
     */
    if(width < FLT_MIN) width= 1;
    if(height < FLT_MIN) height= 1;
    if(winx < 1) winx= 1;
    if(winy < 1) winy= 1;
    
    /* V2D_LIMITZOOM indicates that zoom level should be preserved when the window size changes */
    if (resize && (v2d->keepzoom & V2D_KEEPZOOM)) {
        float zoom, oldzoom;

        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
            zoom= winx / width;
            oldzoom= v2d->oldwinx / curwidth;

            if(oldzoom != zoom)
                width *= zoom/oldzoom;
        }

        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
            zoom= winy / height;
            oldzoom= v2d->oldwiny / curheight;

            if(oldzoom != zoom)
                height *= zoom/oldzoom;
        }
    }
    /* keepzoom (V2D_LIMITZOOM set), indicates that zoom level on each axis must not exceed limits 
     * NOTE: in general, it is not expected that the lock-zoom will be used in conjunction with this
     */
    else if (v2d->keepzoom & V2D_LIMITZOOM) {
        float zoom, fac;
        
        /* check if excessive zoom on x-axis */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
            zoom= winx / width;
            if ((zoom < v2d->minzoom) || (zoom > v2d->maxzoom)) {
                fac= (zoom < v2d->minzoom) ? (zoom / v2d->minzoom) : (zoom / v2d->maxzoom);
                width *= fac;
            }
        }
        
        /* check if excessive zoom on y-axis */
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
            zoom= winy / height;
            if ((zoom < v2d->minzoom) || (zoom > v2d->maxzoom)) {
                fac= (zoom < v2d->minzoom) ? (zoom / v2d->minzoom) : (zoom / v2d->maxzoom);
                height *= fac;
            }
        }
    }
    else {
        /* make sure sizes don't exceed that of the min/max sizes (even though we're not doing zoom clamping) */
        CLAMP(width, v2d->min[0], v2d->max[0]);
        CLAMP(height, v2d->min[1], v2d->max[1]);
    }
    
    /* check if we should restore aspect ratio (if view size changed) */
    if (v2d->keepzoom & V2D_KEEPASPECT) {
        short do_x=0, do_y=0, do_cur /* , do_win */ /* UNUSED */;
        float /* curRatio, */ /* UNUSED */ winRatio;
        
        /* when a window edge changes, the aspect ratio can't be used to
         * find which is the best new 'cur' rect. thats why it stores 'old' 
         */
        if (winx != v2d->oldwinx) do_x= 1;
        if (winy != v2d->oldwiny) do_y= 1;
        
        /* curRatio= height / width; */ /* UNUSED */
        winRatio= winy / winx;
        
        /* both sizes change (area/region maximised)  */
        if (do_x == do_y) {
            if (do_x && do_y) {
                /* here is 1,1 case, so all others must be 0,0 */
                if (ABS(winx - v2d->oldwinx) > ABS(winy - v2d->oldwiny)) do_y= 0;
                else do_x= 0;
            }
            else if (winRatio > 1.0f) do_x= 0; 
            else do_x= 1;
        }
        do_cur= do_x;
        /* do_win= do_y; */ /* UNUSED */
        
        if (do_cur) {
            if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winx != v2d->oldwinx)) {
                /* special exception for Outliner (and later channel-lists):
                 *  - The view may be moved left to avoid contents being pushed out of view when view shrinks. 
                 *  - The keeptot code will make sure cur->xmin will not be less than tot->xmin (which cannot be allowed)
                 *  - width is not adjusted for changed ratios here...
                 */
                if (winx < v2d->oldwinx) {
                    float temp = v2d->oldwinx - winx;
                    
                    cur->xmin -= temp;
                    cur->xmax -= temp;
                    
                    /* width does not get modified, as keepaspect here is just set to make 
                     * sure visible area adjusts to changing view shape! 
                     */
                }
            }
            else {
                /* portrait window: correct for x */
                width= height / winRatio;
            }
        }
        else {
            if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winy != v2d->oldwiny)) {
                /* special exception for Outliner (and later channel-lists):
                 *  - Currently, no actions need to be taken here...
                 */

                if (winy < v2d->oldwiny) {
                    float temp = v2d->oldwiny - winy;
                    
                    cur->ymin += temp;
                    cur->ymax += temp;
                }

            }
            else {
                /* landscape window: correct for y */
                height = width * winRatio;
            }
        }
        
        /* store region size for next time */
        v2d->oldwinx= (short)winx; 
        v2d->oldwiny= (short)winy;
    }
    
    /* Step 2: apply new sizes to cur rect, but need to take into account alignment settings here... */
    if ((width != curwidth) || (height != curheight)) {
        float temp, dh;
        
        /* resize from centerpoint, unless otherwise specified */
        if (width != curwidth) {
            if (v2d->keepofs & V2D_LOCKOFS_X) {
                cur->xmax += width - (cur->xmax - cur->xmin);
            }
            else if (v2d->keepofs & V2D_KEEPOFS_X) {
                if(v2d->align & V2D_ALIGN_NO_POS_X)
                    cur->xmin -= width - (cur->xmax - cur->xmin);
                else
                    cur->xmax += width - (cur->xmax - cur->xmin);
            }
            else {
                temp= (cur->xmax + cur->xmin) * 0.5f;
                dh= width * 0.5f;
                
                cur->xmin = temp - dh;
                cur->xmax = temp + dh;
            }
        }
        if (height != curheight) {
            if (v2d->keepofs & V2D_LOCKOFS_Y) {
                cur->ymax += height - (cur->ymax - cur->ymin);
            }
            else if (v2d->keepofs & V2D_KEEPOFS_Y) {
                if(v2d->align & V2D_ALIGN_NO_POS_Y)
                    cur->ymin -= height - (cur->ymax - cur->ymin);
                else
                    cur->ymax += height - (cur->ymax - cur->ymin);
            }
            else {
                temp= (cur->ymax + cur->ymin) * 0.5f;
                dh= height * 0.5f;
                
                cur->ymin = temp - dh;
                cur->ymax = temp + dh;
            }
        }
    }
    
    /* Step 3: adjust so that it doesn't fall outside of bounds of 'tot' */
    if (v2d->keeptot) {
        float temp, diff;
        
        /* recalculate extents of cur */
        curwidth= cur->xmax - cur->xmin;
        curheight= cur->ymax - cur->ymin;
        
        /* width */
        if ( (curwidth > totwidth) && !(v2d->keepzoom & (V2D_KEEPZOOM|V2D_LOCKZOOM_X|V2D_LIMITZOOM)) ) {
            /* if zoom doesn't have to be maintained, just clamp edges */
            if (cur->xmin < tot->xmin) cur->xmin= tot->xmin;
            if (cur->xmax > tot->xmax) cur->xmax= tot->xmax;
        }
        else if (v2d->keeptot == V2D_KEEPTOT_STRICT) {
            /* This is an exception for the outliner (and later channel-lists, headers) 
             *  - must clamp within tot rect (absolutely no excuses)
             *  --> therefore, cur->xmin must not be less than tot->xmin
             */
            if (cur->xmin < tot->xmin) {
                /* move cur across so that it sits at minimum of tot */
                temp= tot->xmin - cur->xmin;
                
                cur->xmin += temp;
                cur->xmax += temp;
            }
            else if (cur->xmax > tot->xmax) {
                /* - only offset by difference of cur-xmax and tot-xmax if that would not move 
                 *  cur-xmin to lie past tot-xmin
                 * - otherwise, simply shift to tot-xmin???
                 */
                temp= cur->xmax - tot->xmax;
                
                if ((cur->xmin - temp) < tot->xmin) {
                    /* only offset by difference from cur-min and tot-min */
                    temp= cur->xmin - tot->xmin;
                    
                    cur->xmin -= temp;
                    cur->xmax -= temp;
                }
                else {
                    cur->xmin -= temp;
                    cur->xmax -= temp;
                }
            }
        }
        else {
            /* This here occurs when:
             *  - width too big, but maintaining zoom (i.e. widths cannot be changed)
             *  - width is OK, but need to check if outside of boundaries
             * 
             * So, resolution is to just shift view by the gap between the extremities.
             * We favour moving the 'minimum' across, as that's origin for most things
             * (XXX - in the past, max was favoured... if there are bugs, swap!)
             */
            if ((cur->xmin < tot->xmin) && (cur->xmax > tot->xmax)) {
                /* outside boundaries on both sides, so take middle-point of tot, and place in balanced way */
                temp= (tot->xmax + tot->xmin) * 0.5f;
                diff= curheight * 0.5f;
                
                cur->xmin= temp - diff;
                cur->xmax= temp + diff;
            }
            else if (cur->xmin < tot->xmin) {
                /* move cur across so that it sits at minimum of tot */
                temp= tot->xmin - cur->xmin;
                
                cur->xmin += temp;
                cur->xmax += temp;
            }
            else if (cur->xmax > tot->xmax) {
                /* - only offset by difference of cur-xmax and tot-xmax if that would not move 
                 *  cur-xmin to lie past tot-xmin
                 * - otherwise, simply shift to tot-xmin???
                 */
                temp= cur->xmax - tot->xmax;
                
                if ((cur->xmin - temp) < tot->xmin) {
                    /* only offset by difference from cur-min and tot-min */
                    temp= cur->xmin - tot->xmin;
                    
                    cur->xmin -= temp;
                    cur->xmax -= temp;
                }
                else {
                    cur->xmin -= temp;
                    cur->xmax -= temp;
                }
            }
        }
        
        /* height */
        if ( (curheight > totheight) && !(v2d->keepzoom & (V2D_KEEPZOOM|V2D_LOCKZOOM_Y|V2D_LIMITZOOM)) ) {
            /* if zoom doesn't have to be maintained, just clamp edges */
            if (cur->ymin < tot->ymin) cur->ymin= tot->ymin;
            if (cur->ymax > tot->ymax) cur->ymax= tot->ymax;
        }
        else {
            /* This here occurs when:
             *  - height too big, but maintaining zoom (i.e. heights cannot be changed)
             *  - height is OK, but need to check if outside of boundaries
             * 
             * So, resolution is to just shift view by the gap between the extremities.
             * We favour moving the 'minimum' across, as that's origin for most things
             */
            if ((cur->ymin < tot->ymin) && (cur->ymax > tot->ymax)) {
                /* outside boundaries on both sides, so take middle-point of tot, and place in balanced way */
                temp= (tot->ymax + tot->ymin) * 0.5f;
                diff= curheight * 0.5f;
                
                cur->ymin= temp - diff;
                cur->ymax= temp + diff;
            }
            else if (cur->ymin < tot->ymin) {
                /* there's still space remaining, so shift up */
                temp= tot->ymin - cur->ymin;
                
                cur->ymin += temp;
                cur->ymax += temp;
            }
            else if (cur->ymax > tot->ymax) {
                /* there's still space remaining, so shift down */
                temp= cur->ymax - tot->ymax;
                
                cur->ymin -= temp;
                cur->ymax -= temp;
            }
        }
    }
    
    /* Step 4: Make sure alignment restrictions are respected */
    if (v2d->align) {
        /* If alignment flags are set (but keeptot is not), they must still be respected, as although
         * they don't specify any particular bounds to stay within, they do define ranges which are 
         * invalid.
         *
         * Here, we only check to make sure that on each axis, the 'cur' rect doesn't stray into these 
         * invalid zones, otherwise we offset.
         */
        
        /* handle width - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
            /* width is in negative-x half */
            if (v2d->cur.xmax > 0) {
                v2d->cur.xmin -= v2d->cur.xmax;
                v2d->cur.xmax= 0.0f;
            }
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
            /* width is in positive-x half */
            if (v2d->cur.xmin < 0) {
                v2d->cur.xmax -= v2d->cur.xmin;
                v2d->cur.xmin = 0.0f;
            }
        }
        
        /* handle height - posx and negx flags are mutually exclusive, so watch out */
        if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
            /* height is in negative-y half */
            if (v2d->cur.ymax > 0) {
                v2d->cur.ymin -= v2d->cur.ymax;
                v2d->cur.ymax = 0.0f;
            }
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
            /* height is in positive-y half */
            if (v2d->cur.ymin < 0) {
                v2d->cur.ymax -= v2d->cur.ymin;
                v2d->cur.ymin = 0.0f;
            }
        }
    }
    
    /* set masks */
    view2d_masks(v2d);
}

void UI_view2d_curRect_validate(View2D *v2d)
{
    UI_view2d_curRect_validate_resize(v2d, 0);
}

/* ------------------ */

/* Called by menus to activate it, or by view2d operators to make sure 'related' views stay in synchrony */
void UI_view2d_sync(bScreen *screen, ScrArea *area, View2D *v2dcur, int flag)
{
    ScrArea *sa;
    ARegion *ar;
    
    /* don't continue if no view syncing to be done */
    if ((v2dcur->flag & (V2D_VIEWSYNC_SCREEN_TIME|V2D_VIEWSYNC_AREA_VERTICAL)) == 0)
        return;
        
    /* check if doing within area syncing (i.e. channels/vertical) */
    if ((v2dcur->flag & V2D_VIEWSYNC_AREA_VERTICAL) && (area)) {
        for (ar= area->regionbase.first; ar; ar= ar->next) {
            /* don't operate on self */
            if (v2dcur != &ar->v2d) {
                /* only if view has vertical locks enabled */
                if (ar->v2d.flag & V2D_VIEWSYNC_AREA_VERTICAL) {
                    if (flag == V2D_LOCK_COPY) {
                        /* other views with locks on must copy active */
                        ar->v2d.cur.ymin= v2dcur->cur.ymin;
                        ar->v2d.cur.ymax= v2dcur->cur.ymax;
                    }
                    else { /* V2D_LOCK_SET */
                        /* active must copy others */
                        v2dcur->cur.ymin= ar->v2d.cur.ymin;
                        v2dcur->cur.ymax= ar->v2d.cur.ymax;
                    }
                    
                    /* region possibly changed, so refresh */
                    ED_region_tag_redraw(ar);
                }
            }
        }
    }
    
    /* check if doing whole screen syncing (i.e. time/horizontal) */
    if ((v2dcur->flag & V2D_VIEWSYNC_SCREEN_TIME) && (screen)) {
        for (sa= screen->areabase.first; sa; sa= sa->next) {
            for (ar= sa->regionbase.first; ar; ar= ar->next) {
                /* don't operate on self */
                if (v2dcur != &ar->v2d) {
                    /* only if view has horizontal locks enabled */
                    if (ar->v2d.flag & V2D_VIEWSYNC_SCREEN_TIME) {
                        if (flag == V2D_LOCK_COPY) {
                            /* other views with locks on must copy active */
                            ar->v2d.cur.xmin= v2dcur->cur.xmin;
                            ar->v2d.cur.xmax= v2dcur->cur.xmax;
                        }
                        else { /* V2D_LOCK_SET */
                            /* active must copy others */
                            v2dcur->cur.xmin= ar->v2d.cur.xmin;
                            v2dcur->cur.xmax= ar->v2d.cur.xmax;
                        }
                        
                        /* region possibly changed, so refresh */
                        ED_region_tag_redraw(ar);
                    }
                }
            }
        }
    }
}


/* Restore 'cur' rect to standard orientation (i.e. optimal maximum view of tot) 
 * This does not take into account if zooming the view on an axis will improve the view (if allowed)
 */
void UI_view2d_curRect_reset (View2D *v2d)
{
    float width, height;
    
    /* assume width and height of 'cur' rect by default, should be same size as mask */
    width= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
    height= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);
    
    /* handle width - posx and negx flags are mutually exclusive, so watch out */
    if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
        /* width is in negative-x half */
        v2d->cur.xmin= (float)-width;
        v2d->cur.xmax= 0.0f;
    }
    else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
        /* width is in positive-x half */
        v2d->cur.xmin= 0.0f;
        v2d->cur.xmax= (float)width;
    }
    else {
        /* width is centered around x==0 */
        const float dx= (float)width / 2.0f;
        
        v2d->cur.xmin= -dx;
        v2d->cur.xmax= dx;
    }
    
    /* handle height - posx and negx flags are mutually exclusive, so watch out */
    if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
        /* height is in negative-y half */
        v2d->cur.ymin= (float)-height;
        v2d->cur.ymax= 0.0f;
    }
    else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
        /* height is in positive-y half */
        v2d->cur.ymin= 0.0f;
        v2d->cur.ymax= (float)height;
    }
    else {
        /* height is centered around y==0 */
        const float dy= (float)height / 2.0f;
        
        v2d->cur.ymin= -dy;
        v2d->cur.ymax= dy;
    }
}

/* ------------------ */

/* Change the size of the maximum viewable area (i.e. 'tot' rect) */
void UI_view2d_totRect_set_resize (View2D *v2d, int width, int height, int resize)
{
    int scroll= view2d_scroll_mapped(v2d->scroll);
    
    /* don't do anything if either value is 0 */
    width= abs(width);
    height= abs(height);
    
    /* hrumf! */
    /* XXX: there are work arounds for this in the panel and file browse code. */
    if(scroll & V2D_SCROLL_HORIZONTAL) 
        width -= V2D_SCROLL_WIDTH;
    if(scroll & V2D_SCROLL_VERTICAL) 
        height -= V2D_SCROLL_HEIGHT;
    
    if (ELEM3(0, v2d, width, height)) {
        if (G.f & G_DEBUG)
            printf("Error: View2D totRect set exiting: v2d=%p width=%d height=%d \n", (void *)v2d, width, height); // XXX temp debug info
        return;
    }
    
    /* handle width - posx and negx flags are mutually exclusive, so watch out */
    if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
        /* width is in negative-x half */
        v2d->tot.xmin= (float)-width;
        v2d->tot.xmax= 0.0f;
    }
    else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
        /* width is in positive-x half */
        v2d->tot.xmin= 0.0f;
        v2d->tot.xmax= (float)width;
    }
    else {
        /* width is centered around x==0 */
        const float dx= (float)width / 2.0f;
        
        v2d->tot.xmin= -dx;
        v2d->tot.xmax= dx;
    }
    
    /* handle height - posx and negx flags are mutually exclusive, so watch out */
    if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
        /* height is in negative-y half */
        v2d->tot.ymin= (float)-height;
        v2d->tot.ymax= 0.0f;
    }
    else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
        /* height is in positive-y half */
        v2d->tot.ymin= 0.0f;
        v2d->tot.ymax= (float)height;
    }
    else {
        /* height is centered around y==0 */
        const float dy= (float)height / 2.0f;
        
        v2d->tot.ymin= -dy;
        v2d->tot.ymax= dy;
    }
    
    /* make sure that 'cur' rect is in a valid state as a result of these changes */
    UI_view2d_curRect_validate_resize(v2d, resize);
}

void UI_view2d_totRect_set(View2D *v2d, int width, int height)
{
    UI_view2d_totRect_set_resize(v2d, width, height, 0);
}

int UI_view2d_tab_set(View2D *v2d, int tab)
{
    float default_offset[2]= {0.0f, 0.0f};
    float *offset, *new_offset;
    int changed= 0;

    /* if tab changed, change offset */
    if(tab != v2d->tab_cur && v2d->tab_offset) {
        if(tab < v2d->tab_num)
            offset= &v2d->tab_offset[tab*2];
        else
            offset= default_offset;

        v2d->cur.xmax += offset[0] - v2d->cur.xmin;
        v2d->cur.xmin= offset[0];

        v2d->cur.ymin += offset[1] - v2d->cur.ymax;
        v2d->cur.ymax= offset[1];

        /* validation should happen in subsequent totRect_set */

        changed= 1;
    }

    /* resize array if needed */
    if(tab >= v2d->tab_num) {
        new_offset= MEM_callocN(sizeof(float)*(tab+1)*2, "view2d tab offset");

        if(v2d->tab_offset) {
            memcpy(new_offset, v2d->tab_offset, sizeof(float)*v2d->tab_num*2);
            MEM_freeN(v2d->tab_offset);
        }

        v2d->tab_offset= new_offset;
        v2d->tab_num= tab+1;
    }

    /* set current tab and offset */
    v2d->tab_cur= tab;
    v2d->tab_offset[2*tab+0]= v2d->cur.xmin;
    v2d->tab_offset[2*tab+1]= v2d->cur.ymax;

    return changed;
}

/* *********************************************************************** */
/* View Matrix Setup */

/* mapping function to ensure 'cur' draws extended over the area where sliders are */
static void view2d_map_cur_using_mask(View2D *v2d, rctf *curmasked)
{
    *curmasked= v2d->cur;
    
    if (view2d_scroll_mapped(v2d->scroll)) {
        float dx= (v2d->cur.xmax-v2d->cur.xmin)/((float)(v2d->mask.xmax-v2d->mask.xmin+1));
        float dy= (v2d->cur.ymax-v2d->cur.ymin)/((float)(v2d->mask.ymax-v2d->mask.ymin+1));
        
        if (v2d->mask.xmin != 0)
            curmasked->xmin -= dx*(float)v2d->mask.xmin;
        if (v2d->mask.xmax+1 != v2d->winx)
            curmasked->xmax += dx*(float)(v2d->winx - v2d->mask.xmax-1);
        
        if (v2d->mask.ymin != 0)
            curmasked->ymin -= dy*(float)v2d->mask.ymin;
        if (v2d->mask.ymax+1 != v2d->winy)
            curmasked->ymax += dy*(float)(v2d->winy - v2d->mask.ymax-1);
        
    }
}

/* Set view matrices to use 'cur' rect as viewing frame for View2D drawing */
void UI_view2d_view_ortho(View2D *v2d)
{
    rctf curmasked;
    float xofs, yofs;
    
    /* pixel offsets (-0.375f) are needed to get 1:1 correspondance with pixels for smooth UI drawing, 
     * but only applied where requsted
     */
    /* XXX brecht: instead of zero at least use a tiny offset, otherwise
     * pixel rounding is effectively random due to float inaccuracy */
    xofs= 0.001f*(v2d->cur.xmax - v2d->cur.xmin)/(v2d->mask.xmax - v2d->mask.xmin);
    yofs= 0.001f*(v2d->cur.ymax - v2d->cur.ymin)/(v2d->mask.ymax - v2d->mask.ymin);
    
    /* apply mask-based adjustments to cur rect (due to scrollers), to eliminate scaling artifacts */
    view2d_map_cur_using_mask(v2d, &curmasked);
    
    curmasked.xmin-= xofs; curmasked.xmax-=xofs;
    curmasked.ymin-= yofs; curmasked.ymax-=yofs;
    
    /* XXX ton: this flag set by outliner, for icons */
    if(v2d->flag & V2D_PIXELOFS_X) {
        curmasked.xmin= floorf(curmasked.xmin) - 0.001f;
        curmasked.xmax= floorf(curmasked.xmax) - 0.001f;
    }
    if(v2d->flag & V2D_PIXELOFS_Y) {
        curmasked.ymin= floorf(curmasked.ymin) - 0.001f;
        curmasked.ymax= floorf(curmasked.ymax) - 0.001f;
    }
    
    /* set matrix on all appropriate axes */
    wmOrtho2(curmasked.xmin-xofs, curmasked.xmax-xofs, curmasked.ymin-yofs, curmasked.ymax-yofs);

    /* XXX is this necessary? */
    glLoadIdentity();
}

/* Set view matrices to only use one axis of 'cur' only
 *  - xaxis     = if non-zero, only use cur x-axis, otherwise use cur-yaxis (mostly this will be used for x)
 */
void UI_view2d_view_orthoSpecial(ARegion *ar, View2D *v2d, short xaxis)
{
    rctf curmasked;
    float xofs, yofs;
    
    /* pixel offsets (-0.375f) are needed to get 1:1 correspondance with pixels for smooth UI drawing, 
     * but only applied where requsted
     */
    /* XXX temp (ton) */
    xofs= 0.0f; // (v2d->flag & V2D_PIXELOFS_X) ? 0.375f : 0.0f;
    yofs= 0.0f; // (v2d->flag & V2D_PIXELOFS_Y) ? 0.375f : 0.0f;
    
    /* apply mask-based adjustments to cur rect (due to scrollers), to eliminate scaling artifacts */
    view2d_map_cur_using_mask(v2d, &curmasked);
    
    /* only set matrix with 'cur' coordinates on relevant axes */
    if (xaxis)
        wmOrtho2(curmasked.xmin-xofs, curmasked.xmax-xofs, -yofs, ar->winy-yofs);
    else
        wmOrtho2(-xofs, ar->winx-xofs, curmasked.ymin-yofs, curmasked.ymax-yofs);
        
    /* XXX is this necessary? */
    glLoadIdentity();
} 


/* Restore view matrices after drawing */
void UI_view2d_view_restore(const bContext *C)
{
    ARegion *ar= CTX_wm_region(C);
    int width= ar->winrct.xmax-ar->winrct.xmin+1;
    int height= ar->winrct.ymax-ar->winrct.ymin+1;
    
    wmOrtho2(0.0f, (float)width, 0.0f, (float)height);
    glLoadIdentity();
    
    //  ED_region_pixelspace(CTX_wm_region(C));
}

/* *********************************************************************** */
/* Gridlines */

/* View2DGrid is typedef'd in UI_view2d.h */
struct View2DGrid {
    float dx, dy;           /* stepsize (in pixels) between gridlines */
    float startx, starty;   /* initial coordinates to start drawing grid from */
    int powerx, powery;     /* step as power of 10 */
};

/* --------------- */

/* try to write step as a power of 10 */
static void step_to_grid(float *step, int *power, int unit)
{
    const float loga= (float)log10(*step);
    float rem;
    
    *power= (int)(loga);
    
    rem= loga - (*power);
    rem= (float)pow(10.0, rem);
    
    if (loga < 0.0f) {
        if (rem < 0.2f) rem= 0.2f;
        else if(rem < 0.5f) rem= 0.5f;
        else rem= 1.0f;
        
        *step= rem * (float)pow(10.0, (*power));
        
        /* for frames, we want 1.0 frame intervals only */
        if (unit == V2D_UNIT_FRAMES) {
            rem = 1.0f;
            *step = 2.0f; /* use 2 since there are grid lines drawn in between, this way to get 1 line per frane */
        }
        
        /* prevents printing 1.0 2.0 3.0 etc */
        if (rem == 1.0f) (*power)++;    
    }
    else {
        if (rem < 2.0f) rem= 2.0f;
        else if(rem < 5.0f) rem= 5.0f;
        else rem= 10.0f;
        
        *step= rem * (float)pow(10.0, (*power));
        
        (*power)++;
        /* prevents printing 1.0, 2.0, 3.0, etc. */
        if (rem == 10.0f) (*power)++;   
    }
}

/* Intialise settings necessary for drawing gridlines in a 2d-view 
 *  - Currently, will return pointer to View2DGrid struct that needs to 
 *    be freed with UI_view2d_grid_free()
 *  - Is used for scrollbar drawing too (for units drawing)
 *  - Units + clamping args will be checked, to make sure they are valid values that can be used
 *    so it is very possible that we won't return grid at all!
 *  
 *  - xunits,yunits = V2D_UNIT_*  grid steps in seconds or frames 
 *  - xclamp,yclamp = V2D_CLAMP_* only show whole-number intervals
 *  - winx          = width of region we're drawing to, note: not used but keeping for completeness.
 *  - winy          = height of region we're drawing into
 */
View2DGrid *UI_view2d_grid_calc(Scene *scene, View2D *v2d, short xunits, short xclamp, short yunits, short yclamp, int UNUSED(winx), int winy)
{

    View2DGrid *grid;
    float space, pixels, seconddiv;
    
    /* check that there are at least some workable args */
    if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) && ELEM(V2D_ARG_DUMMY, yunits, yclamp))
        return NULL;
    
    /* grid here is allocated... */
    grid= MEM_callocN(sizeof(View2DGrid), "View2DGrid");
    
    /* rule: gridstep is minimal GRIDSTEP pixels */
    if (xunits == V2D_UNIT_SECONDS) {
        seconddiv= (float)(0.01 * FPS);
    }
    else {
        seconddiv= 1.0f;
    }
    
    /* calculate x-axis grid scale (only if both args are valid) */
    if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) == 0) {
        space= v2d->cur.xmax - v2d->cur.xmin;
        pixels= (float)(v2d->mask.xmax - v2d->mask.xmin);
        
        if(pixels!=0.0f) {
            grid->dx= (U.v2d_min_gridsize * space) / (seconddiv * pixels);
            step_to_grid(&grid->dx, &grid->powerx, xunits);
            grid->dx *= seconddiv;
        }
        
        if (xclamp == V2D_GRID_CLAMP) {
            if (grid->dx < 0.1f) grid->dx= 0.1f;
            grid->powerx-= 2;
            if (grid->powerx < -2) grid->powerx= -2;
        }
    }
    
    /* calculate y-axis grid scale (only if both args are valid) */
    if (ELEM(V2D_ARG_DUMMY, yunits, yclamp) == 0) {
        space= v2d->cur.ymax - v2d->cur.ymin;
        pixels= (float)winy;
        
        grid->dy= U.v2d_min_gridsize * space / pixels;
        step_to_grid(&grid->dy, &grid->powery, yunits);
        
        if (yclamp == V2D_GRID_CLAMP) {
            if (grid->dy < 1.0f) grid->dy= 1.0f;
            if (grid->powery < 1) grid->powery= 1;
        }
    }
    
    /* calculate start position */
    if (ELEM(V2D_ARG_DUMMY, xunits, xclamp) == 0) {
        grid->startx= seconddiv*(v2d->cur.xmin/seconddiv - (float)fmod(v2d->cur.xmin/seconddiv, grid->dx/seconddiv));
        if (v2d->cur.xmin < 0.0f) grid->startx-= grid->dx;
    }
    else
        grid->startx= v2d->cur.xmin;
        
    if (ELEM(V2D_ARG_DUMMY, yunits, yclamp) == 0) {
        grid->starty= (v2d->cur.ymin - (float)fmod(v2d->cur.ymin, grid->dy));
        if (v2d->cur.ymin < 0.0f) grid->starty-= grid->dy;
    }
    else
        grid->starty= v2d->cur.ymin;
    
    return grid;
}

/* Draw gridlines in the given 2d-region */
void UI_view2d_grid_draw(View2D *v2d, View2DGrid *grid, int flag)
{
    float vec1[2], vec2[2];
    int a, step;
    
    /* check for grid first, as it may not exist */
    if (grid == NULL)
        return;
    
    /* vertical lines */
    if (flag & V2D_VERTICAL_LINES) {
        /* initialise initial settings */
        vec1[0]= vec2[0]= grid->startx;
        vec1[1]= grid->starty;
        vec2[1]= v2d->cur.ymax;
        
        /* minor gridlines */
        step= (v2d->mask.xmax - v2d->mask.xmin + 1) / U.v2d_min_gridsize;
        UI_ThemeColor(TH_GRID);
        
        for (a=0; a<step; a++) {
            glBegin(GL_LINE_STRIP);
                glVertex2fv(vec1); 
                glVertex2fv(vec2);
            glEnd();
            
            vec2[0]= vec1[0]+= grid->dx;
        }
        
        /* major gridlines */
        vec2[0]= vec1[0]-= 0.5f*grid->dx;
        UI_ThemeColorShade(TH_GRID, 16);
        
        step++;
        for (a=0; a<=step; a++) {
            glBegin(GL_LINE_STRIP);
                glVertex2fv(vec1); 
                glVertex2fv(vec2);
            glEnd();
            
            vec2[0]= vec1[0]-= grid->dx;
        }
    }
    
    /* horizontal lines */
    if (flag & V2D_HORIZONTAL_LINES) {
        /* only major gridlines */
        vec1[1]= vec2[1]= grid->starty;
        vec1[0]= grid->startx;
        vec2[0]= v2d->cur.xmax;
        
        step= (v2d->mask.ymax - v2d->mask.ymin + 1) / U.v2d_min_gridsize;
        
        UI_ThemeColor(TH_GRID);
        for (a=0; a<=step; a++) {
            glBegin(GL_LINE_STRIP);
                glVertex2fv(vec1); 
                glVertex2fv(vec2);
            glEnd();
            
            vec2[1]= vec1[1]+= grid->dy;
        }
        
        /* fine grid lines */
        vec2[1]= vec1[1]-= 0.5f*grid->dy;
        step++;
        
        if (flag & V2D_HORIZONTAL_FINELINES) { 
            UI_ThemeColorShade(TH_GRID, 16);
            for (a=0; a<step; a++) {
                glBegin(GL_LINE_STRIP);
                    glVertex2fv(vec1); 
                    glVertex2fv(vec2);
                glEnd();
                
                vec2[1]= vec1[1]-= grid->dy;
            }
        }
    }
    
    /* Axes are drawn as darker lines */
    UI_ThemeColorShade(TH_GRID, -50);
    
    /* horizontal axis */
    if (flag & V2D_HORIZONTAL_AXIS) {
        vec1[0]= v2d->cur.xmin;
        vec2[0]= v2d->cur.xmax;
        vec1[1]= vec2[1]= 0.0f;
        
        glBegin(GL_LINE_STRIP);
            glVertex2fv(vec1);
            glVertex2fv(vec2);
        glEnd();
    }
    
    /* vertical axis */
    if (flag & V2D_VERTICAL_AXIS) {
        vec1[1]= v2d->cur.ymin;
        vec2[1]= v2d->cur.ymax;
        vec1[0]= vec2[0]= 0.0f;
        
        glBegin(GL_LINE_STRIP);
            glVertex2fv(vec1); 
            glVertex2fv(vec2);
        glEnd();
    }
}

/* Draw a constant grid in given 2d-region */
void UI_view2d_constant_grid_draw(View2D *v2d)
{
    float start, step= 25.0f;

    UI_ThemeColorShade(TH_BACK, -10);
    
    start= v2d->cur.xmin - (float)fmod(v2d->cur.xmin, step);
    
    glBegin(GL_LINES);
    for(; start<v2d->cur.xmax; start+=step) {
        glVertex2f(start, v2d->cur.ymin);
        glVertex2f(start, v2d->cur.ymax);
    }

    start= v2d->cur.ymin - (float)fmod(v2d->cur.ymin, step);
    for(; start<v2d->cur.ymax; start+=step) {
        glVertex2f(v2d->cur.xmin, start);
        glVertex2f(v2d->cur.xmax, start);
    }
    
    /* X and Y axis */
    UI_ThemeColorShade(TH_BACK, -18);
    glVertex2f(0.0f, v2d->cur.ymin);
    glVertex2f(0.0f, v2d->cur.ymax);
    glVertex2f(v2d->cur.xmin, 0.0f);
    glVertex2f(v2d->cur.xmax, 0.0f);
    
    glEnd();
}

/* the price we pay for not exposting structs :( */
void UI_view2d_grid_size(View2DGrid *grid, float *r_dx, float *r_dy)
{
    *r_dx= grid->dx;
    *r_dy= grid->dy;
}

/* free temporary memory used for drawing grid */
void UI_view2d_grid_free(View2DGrid *grid)
{
    /* only free if there's a grid */
    if (grid)
        MEM_freeN(grid);
}

/* *********************************************************************** */
/* Scrollers */

/* View2DScrollers is typedef'd in UI_view2d.h 
 * WARNING: the start of this struct must not change, as view2d_ops.c uses this too. 
 *         For now, we don't need to have a separate (internal) header for structs like this...
 */
struct View2DScrollers {
        /* focus bubbles */
    int vert_min, vert_max; /* vertical scrollbar */
    int hor_min, hor_max;   /* horizontal scrollbar */
    
    rcti hor, vert;         /* exact size of slider backdrop */
    int horfull, vertfull;  /* set if sliders are full, we don't draw them */
    
    /* scales */
    View2DGrid *grid;       /* grid for coordinate drawing */
    short xunits, xclamp;   /* units and clamping options for x-axis */
    short yunits, yclamp;   /* units and clamping options for y-axis */
};

/* Calculate relevant scroller properties */
View2DScrollers *UI_view2d_scrollers_calc(const bContext *C, View2D *v2d, short xunits, short xclamp, short yunits, short yclamp)
{
    View2DScrollers *scrollers;
    rcti vert, hor;
    float fac1, fac2, totsize, scrollsize;
    int scroll= view2d_scroll_mapped(v2d->scroll);
    
    /* scrollers is allocated here... */
    scrollers= MEM_callocN(sizeof(View2DScrollers), "View2DScrollers");
    
    vert= v2d->vert;
    hor= v2d->hor;
    
    /* slider rects need to be smaller than region */
    hor.xmin+=4;
    hor.xmax-=4;
    if (scroll & V2D_SCROLL_BOTTOM)
        hor.ymin+=4;
    else
        hor.ymax-=4;
    
    if (scroll & V2D_SCROLL_LEFT)
        vert.xmin+=4;
    else
        vert.xmax-=4;
    vert.ymin+=4;
    vert.ymax-=4;
    
    CLAMP(vert.ymin, vert.ymin, vert.ymax-V2D_SCROLLER_HANDLE_SIZE);
    CLAMP(hor.xmin, hor.xmin, hor.xmax-V2D_SCROLLER_HANDLE_SIZE);
    
    /* store in scrollers, used for drawing */
    scrollers->vert= vert;
    scrollers->hor= hor;
    
    /* scroller 'buttons':
     *  - These should always remain within the visible region of the scrollbar
     *  - They represent the region of 'tot' that is visible in 'cur'
     */
    
    /* horizontal scrollers */
    if (scroll & V2D_SCROLL_HORIZONTAL) {
        /* scroller 'button' extents */
        totsize= v2d->tot.xmax - v2d->tot.xmin;
        scrollsize= (float)(hor.xmax - hor.xmin);
        if(totsize==0.0f) totsize = 1.0f; /* avoid divide by zero */
        
        fac1= (v2d->cur.xmin - v2d->tot.xmin) / totsize;
        if(fac1<=0.0f)
            scrollers->hor_min= hor.xmin;
        else
            scrollers->hor_min= (int)(hor.xmin + (fac1 * scrollsize));
        
        fac2= (v2d->cur.xmax - v2d->tot.xmin) / totsize;
        if(fac2>=1.0f)
            scrollers->hor_max= hor.xmax;
        else
            scrollers->hor_max= (int)(hor.xmin + (fac2 * scrollsize));
        
        /* prevent inverted sliders */
        if (scrollers->hor_min > scrollers->hor_max) 
            scrollers->hor_min= scrollers->hor_max;
        /* prevent sliders from being too small, and disappearing */
        if ((scrollers->hor_max - scrollers->hor_min) < V2D_SCROLLER_HANDLE_SIZE) {
            scrollers->hor_max= scrollers->hor_min + V2D_SCROLLER_HANDLE_SIZE;

            CLAMP(scrollers->hor_max, hor.xmin+V2D_SCROLLER_HANDLE_SIZE, hor.xmax);
            CLAMP(scrollers->hor_min, hor.xmin, hor.xmax-V2D_SCROLLER_HANDLE_SIZE);
        }
        
        /* check whether sliders can disappear due to the full-range being used */
        if(v2d->keeptot) {
            if ((fac1 <= 0.0f) && (fac2 >= 1.0f)) { 
                v2d->scroll |= V2D_SCROLL_HORIZONTAL_FULLR;
                scrollers->horfull= 1;
            }
            else    
                v2d->scroll &= ~V2D_SCROLL_HORIZONTAL_FULLR;
        }
    }
    
    /* vertical scrollers */
    if (scroll & V2D_SCROLL_VERTICAL) {
        /* scroller 'button' extents */
        totsize= v2d->tot.ymax - v2d->tot.ymin;
        scrollsize= (float)(vert.ymax - vert.ymin);
        if(totsize==0.0f) totsize = 1.0f; /* avoid divide by zero */
        
        fac1= (v2d->cur.ymin- v2d->tot.ymin) / totsize;
        if(fac1<=0.0f)
            scrollers->vert_min= vert.ymin;
        else
            scrollers->vert_min= (int)(vert.ymin + (fac1 * scrollsize));
        
        fac2= (v2d->cur.ymax - v2d->tot.ymin) / totsize;
        if(fac2>=1.0f)
            scrollers->vert_max= vert.ymax;
        else
            scrollers->vert_max= (int)(vert.ymin + (fac2 * scrollsize));
        
        /* prevent inverted sliders */
        if (scrollers->vert_min > scrollers->vert_max) 
            scrollers->vert_min= scrollers->vert_max;
        /* prevent sliders from being too small, and disappearing */
        if ((scrollers->vert_max - scrollers->vert_min) < V2D_SCROLLER_HANDLE_SIZE) {
            
            scrollers->vert_max= scrollers->vert_min + V2D_SCROLLER_HANDLE_SIZE;
            
            CLAMP(scrollers->vert_max, vert.ymin+V2D_SCROLLER_HANDLE_SIZE, vert.ymax);
            CLAMP(scrollers->vert_min, vert.ymin, vert.ymax-V2D_SCROLLER_HANDLE_SIZE);
        }

        /* check whether sliders can disappear due to the full-range being used */
        if(v2d->keeptot) {
            if ((fac1 <= 0.0f) && (fac2 >= 1.0f)) { 
                v2d->scroll |= V2D_SCROLL_VERTICAL_FULLR;
                scrollers->vertfull= 1;
            }
            else    
                v2d->scroll &= ~V2D_SCROLL_VERTICAL_FULLR;
        }
    }
    
    /* grid markings on scrollbars */
    if (scroll & (V2D_SCROLL_SCALE_HORIZONTAL|V2D_SCROLL_SCALE_VERTICAL)) {
        /* store clamping */
        scrollers->xclamp= xclamp;
        scrollers->xunits= xunits;
        scrollers->yclamp= yclamp;
        scrollers->yunits= yunits;
        
        scrollers->grid= UI_view2d_grid_calc(CTX_data_scene(C), v2d, xunits, xclamp, yunits, yclamp, (hor.xmax - hor.xmin), (vert.ymax - vert.ymin));
    }
    
    /* return scrollers */
    return scrollers;
}

/* Print scale marking along a time scrollbar */
static void scroll_printstr(Scene *scene, float x, float y, float val, int power, short unit, char dir)
{
    int len;
    char timecode_str[32];
    
    /* adjust the scale unit to work ok */
    if (dir == 'v') {
        /* here we bump up the power by factor of 10, as 
         * rotation values (hence 'degrees') are divided by 10 to 
         * be able to show the curves at the same time
         */
        if (ELEM(unit, V2D_UNIT_DEGREES, V2D_UNIT_TIME)) {
            power += 1;
            val *= 10;
        }
    }
    
    /* get string to print */
    ANIM_timecode_string_from_frame(timecode_str, scene, power, (unit == V2D_UNIT_SECONDS), val);
    
    /* get length of string, and adjust printing location to fit it into the horizontal scrollbar */
    len= strlen(timecode_str);
    if (dir == 'h') {
        /* seconds/timecode display has slightly longer strings... */
        if (unit == V2D_UNIT_SECONDS)
            x-= 3*len;
        else
            x-= 4*len;
    }
    
    /* Add degree sympbol to end of string for vertical scrollbar? */
    if ((dir == 'v') && (unit == V2D_UNIT_DEGREES)) {
        timecode_str[len]= 186;
        timecode_str[len+1]= 0;
    }
    
    /* draw it */
    BLF_draw_default_ascii(x, y, 0.0f, timecode_str, sizeof(timecode_str));
}

/* Draw scrollbars in the given 2d-region */
void UI_view2d_scrollers_draw(const bContext *C, View2D *v2d, View2DScrollers *vs)
{
    Scene *scene= CTX_data_scene(C);
    rcti vert, hor;
    int scroll= view2d_scroll_mapped(v2d->scroll);
    
    /* make copies of rects for less typing */
    vert= vs->vert;
    hor= vs->hor;
    
    /* horizontal scrollbar */
    if (scroll & V2D_SCROLL_HORIZONTAL) {
        /* only draw scrollbar when it doesn't fill the entire space */
        if(vs->horfull==0) {
            bTheme *btheme= UI_GetTheme();
            uiWidgetColors wcol= btheme->tui.wcol_scroll;
            rcti slider;
            int state;
            
            slider.xmin= vs->hor_min;
            slider.xmax= vs->hor_max;
            slider.ymin= hor.ymin;
            slider.ymax= hor.ymax;
            
            state= (v2d->scroll_ui & V2D_SCROLL_H_ACTIVE)?UI_SCROLL_PRESSED:0;
            
            /* show zoom handles if:
             *  - zooming on x-axis is allowed (no scroll otherwise)
             *  - slider bubble is large enough (no overdraw confusion)
             *  - scale is shown on the scroller 
             *    (workaround to make sure that button windows don't show these, 
             *      and only the time-grids with their zoomability can do so)
             */
            if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0 && 
                (v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL) &&
                (slider.xmax - slider.xmin > V2D_SCROLLER_HANDLE_SIZE))
            {
                state |= UI_SCROLL_ARROWS;
            }
            
            UI_ThemeColor(TH_BACK);
            glRecti(v2d->hor.xmin, v2d->hor.ymin, v2d->hor.xmax, v2d->hor.ymax);
            
            uiWidgetScrollDraw(&wcol, &hor, &slider, state);
        }
        
        /* scale indicators */
        if ((scroll & V2D_SCROLL_SCALE_HORIZONTAL) && (vs->grid)) {
            View2DGrid *grid= vs->grid;
            float fac, dfac, fac2, val;
            
            /* the numbers: convert grid->startx and -dx to scroll coordinates 
             *  - fac is x-coordinate to draw to
             *  - dfac is gap between scale markings
             */
            fac= (grid->startx - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
            fac= (float)hor.xmin + fac*(hor.xmax - hor.xmin);
            
            dfac= (grid->dx) / (v2d->cur.xmax - v2d->cur.xmin);
            dfac= dfac * (hor.xmax - hor.xmin);
            
            /* set starting value, and text color */
            UI_ThemeColor(TH_TEXT);
            val= grid->startx;
            
            /* if we're clamping to whole numbers only, make sure entries won't be repeated */
            if (vs->xclamp == V2D_GRID_CLAMP) {
                while (grid->dx < 0.9999f) {
                    grid->dx *= 2.0f;
                    dfac *= 2.0f;
                }
            }
            if (vs->xunits == V2D_UNIT_FRAMES)
                grid->powerx= 1;
            
            /* draw numbers in the appropriate range */
            if (dfac > 0.0f) {
                float h= 2.0f+(float)(hor.ymin);
                
                for (; fac < hor.xmax-10; fac+=dfac, val+=grid->dx) {
                    
                    /* make prints look nicer for scrollers */
                    if(fac < hor.xmin+10)
                        continue;
                    
                    switch (vs->xunits) {                           
                        case V2D_UNIT_FRAMES:       /* frames (as whole numbers)*/
                            scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_FRAMES, 'h');
                            break;
                            
                        case V2D_UNIT_FRAMESCALE:   /* frames (not always as whole numbers) */
                            scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_FRAMESCALE, 'h');
                            break;
                        
                        case V2D_UNIT_SECONDS:      /* seconds */
                            fac2= val/(float)FPS;
                            scroll_printstr(scene, fac, h, fac2, grid->powerx, V2D_UNIT_SECONDS, 'h');
                            break;
                            
                        case V2D_UNIT_SECONDSSEQ:   /* seconds with special calculations (only used for sequencer only) */
                        {
                            float time;
                            
                            fac2= val/(float)FPS;
                            time= (float)floor(fac2);
                            fac2= fac2-time;
                            
                            scroll_printstr(scene, fac, h, time+(float)FPS*fac2/100.0f, grid->powerx, V2D_UNIT_SECONDSSEQ, 'h');
                        }
                            break;
                            
                        case V2D_UNIT_DEGREES:      /* Graph Editor for rotation Drivers */
                            /* HACK: although we're drawing horizontal, we make this draw as 'vertical', just to get degree signs */
                            scroll_printstr(scene, fac, h, val, grid->powerx, V2D_UNIT_DEGREES, 'v');
                            break;
                    }
                }
            }
        }
    }
    
    /* vertical scrollbar */
    if (scroll & V2D_SCROLL_VERTICAL) {
        /* only draw scrollbar when it doesn't fill the entire space */
        if(vs->vertfull==0) {
            bTheme *btheme= UI_GetTheme();
            uiWidgetColors wcol= btheme->tui.wcol_scroll;
            rcti slider;
            int state;
            
            slider.xmin= vert.xmin;
            slider.xmax= vert.xmax;
            slider.ymin= vs->vert_min;
            slider.ymax= vs->vert_max;
            
            state= (v2d->scroll_ui & V2D_SCROLL_V_ACTIVE)?UI_SCROLL_PRESSED:0;
            
            /* show zoom handles if:
             *  - zooming on y-axis is allowed (no scroll otherwise)
             *  - slider bubble is large enough (no overdraw confusion)
             *  - scale is shown on the scroller 
             *    (workaround to make sure that button windows don't show these, 
             *      and only the time-grids with their zoomability can do so)
             */
            if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0 && 
                (v2d->scroll & V2D_SCROLL_SCALE_VERTICAL) &&
                (slider.ymax - slider.ymin > V2D_SCROLLER_HANDLE_SIZE))
            {
                state |= UI_SCROLL_ARROWS;
            }
                
            UI_ThemeColor(TH_BACK);
            glRecti(v2d->vert.xmin, v2d->vert.ymin, v2d->vert.xmax, v2d->vert.ymax);
            
            uiWidgetScrollDraw(&wcol, &vert, &slider, state);
        }
        
        
        /* scale indiators */
        if ((scroll & V2D_SCROLL_SCALE_VERTICAL) && (vs->grid)) {
            View2DGrid *grid= vs->grid;
            float fac, dfac, val;
            
            /* the numbers: convert grid->starty and dy to scroll coordinates 
             *  - fac is y-coordinate to draw to
             *  - dfac is gap between scale markings
             *  - these involve a correction for horizontal scrollbar
             *    NOTE: it's assumed that that scrollbar is there if this is involved!
             */
            fac= (grid->starty- v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
            fac= vert.ymin + fac*(vert.ymax - vert.ymin);
            
            dfac= (grid->dy) / (v2d->cur.ymax - v2d->cur.ymin);
            dfac= dfac * (vert.ymax - vert.ymin);
            
            /* set starting value, and text color */
            UI_ThemeColor(TH_TEXT);
            val= grid->starty;
            
            /* if vertical clamping (to whole numbers) is used (i.e. in Sequencer), apply correction */
            if (vs->yclamp == V2D_GRID_CLAMP)
                fac += 0.5f * dfac;
                
            /* draw vertical steps */
            if (dfac > 0.0f) {
                
                BLF_rotation_default(90.0f);
                BLF_enable_default(BLF_ROTATION);

                for (; fac < vert.ymax-10; fac+= dfac, val += grid->dy) {
                    
                    /* make prints look nicer for scrollers */
                    if(fac < vert.ymin+10)
                        continue;
                    
                    scroll_printstr(scene, (float)(vert.xmax)-2.0f, fac, val, grid->powery, vs->yunits, 'v');
                }
                
                BLF_disable_default(BLF_ROTATION);
            }
        }   
    }
    
}

/* free temporary memory used for drawing scrollers */
void UI_view2d_scrollers_free(View2DScrollers *scrollers)
{
    /* need to free grid as well... */
    if (scrollers->grid) MEM_freeN(scrollers->grid);
    MEM_freeN(scrollers);
}

/* *********************************************************************** */
/* List View Utilities */

/* Get the view-coordinates of the nominated cell 
 *  - columnwidth, rowheight    = size of each 'cell'
 *  - startx, starty            = coordinates (in 'tot' rect space) that the list starts from
 *                            This should be (0,0) for most views. However, for those where the starting row was offsetted
 *                            (like for Animation Editor channel lists, to make the first entry more visible), these will be 
 *                            the min-coordinates of the first item.
 *  - column, row               = the 2d-corodinates (in 2D-view / 'tot' rect space) the cell exists at
 *  - rect                  = coordinates of the cell (passed as single var instead of 4 separate, as it's more useful this way)
 */
void UI_view2d_listview_cell_to_view(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, int column, int row, rctf *rect)
{
    /* sanity checks */
    if ELEM(NULL, v2d, rect)
        return;
    if ((columnwidth <= 0) && (rowheight <= 0)) {
        rect->xmin= rect->xmax= 0.0f;
        rect->ymin= rect->ymax= 0.0f;
        return;
    }
    
    /* x-coordinates */
    rect->xmin= startx + (float)(columnwidth * column);
    rect->xmax= startx + (float)(columnwidth * (column + 1));
    
    if ((v2d->align & V2D_ALIGN_NO_POS_X) && !(v2d->align & V2D_ALIGN_NO_NEG_X)) {
        /* simply negate the values for the coordinates if in negative half */
        rect->xmin = -rect->xmin;
        rect->xmax = -rect->xmax;
    }
    
    /* y-coordinates */
    rect->ymin= starty + (float)(rowheight * row);
    rect->ymax= starty + (float)(rowheight * (row + 1));
    
    if ((v2d->align & V2D_ALIGN_NO_POS_Y) && !(v2d->align & V2D_ALIGN_NO_NEG_Y)) {
        /* simply negate the values for the coordinates if in negative half */
        rect->ymin = -rect->ymin;
        rect->ymax = -rect->ymax;
    }
}

/* Get the 'cell' (row, column) that the given 2D-view coordinates (i.e. in 'tot' rect space) lie in.
 *  - columnwidth, rowheight    = size of each 'cell'
 *  - startx, starty            = coordinates (in 'tot' rect space) that the list starts from
 *                            This should be (0,0) for most views. However, for those where the starting row was offsetted
 *                            (like for Animation Editor channel lists, to make the first entry more visible), these will be 
 *                            the min-coordinates of the first item.
 *  - viewx, viewy          = 2D-coordinates (in 2D-view / 'tot' rect space) to get the cell for
 *  - column, row               = the 'coordinates' of the relevant 'cell'
 */
void UI_view2d_listview_view_to_cell(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, 
                        float viewx, float viewy, int *column, int *row)
{
    /* adjust view coordinates to be all positive ints, corrected for the start offset */
    const int x= (int)(floorf(fabsf(viewx) + 0.5f) - startx);
    const int y= (int)(floorf(fabsf(viewy) + 0.5f) - starty);
    
    /* sizes must not be negative */
    if ( (v2d == NULL) || ((columnwidth <= 0) && (rowheight <= 0)) ) {
        if (column) *column= 0;
        if (row) *row= 0;
        
        return;
    }
    
    /* get column */
    if ((column) && (columnwidth > 0))
        *column= x / columnwidth;
    else if (column)
        *column= 0;
    
    /* get row */
    if ((row) && (rowheight > 0))
        *row= y / rowheight;
    else if (row)
        *row= 0;
}

/* Get the 'extreme' (min/max) column and row indices which are visible within the 'cur' rect 
 *  - columnwidth, rowheight    = size of each 'cell'
 *  - startx, starty            = coordinates that the list starts from, which should be (0,0) for most views
 *  - column/row_min/max        = the starting and ending column/row indices
 */
void UI_view2d_listview_visible_cells(View2D *v2d, short columnwidth, short rowheight, float startx, float starty, 
                        int *column_min, int *column_max, int *row_min, int *row_max)
{
    /* using 'cur' rect coordinates, call the cell-getting function to get the cells for this */
    if (v2d) {
        /* min */
        UI_view2d_listview_view_to_cell(v2d, columnwidth, rowheight, startx, starty, 
                    v2d->cur.xmin, v2d->cur.ymin, column_min, row_min);
                    
        /* max*/
        UI_view2d_listview_view_to_cell(v2d, columnwidth, rowheight, startx, starty, 
                    v2d->cur.xmax, v2d->cur.ymax, column_max, row_max);
    }
}

/* *********************************************************************** */
/* Coordinate Conversions */

/* Convert from screen/region space to 2d-View space 
 *  
 *  - x,y           = coordinates to convert
 *  - viewx,viewy       = resultant coordinates
 */
void UI_view2d_region_to_view(View2D *v2d, int x, int y, float *viewx, float *viewy)
{
    float div, ofs;

    if (viewx) {
        div= (float)(v2d->mask.xmax - v2d->mask.xmin);
        ofs= (float)v2d->mask.xmin;
        
        *viewx= v2d->cur.xmin + (v2d->cur.xmax-v2d->cur.xmin) * ((float)x - ofs) / div;
    }

    if (viewy) {
        div= (float)(v2d->mask.ymax - v2d->mask.ymin);
        ofs= (float)v2d->mask.ymin;
        
        *viewy= v2d->cur.ymin + (v2d->cur.ymax - v2d->cur.ymin) * ((float)y - ofs) / div;
    }
}

/* Convert from 2d-View space to screen/region space
 *  - Coordinates are clamped to lie within bounds of region
 *
 *  - x,y               = coordinates to convert
 *  - regionx,regiony   = resultant coordinates 
 */
void UI_view2d_view_to_region(View2D *v2d, float x, float y, int *regionx, int *regiony)
{
    /* set initial value in case coordinate lies outside of bounds */
    if (regionx)
        *regionx= V2D_IS_CLIPPED;
    if (regiony)
        *regiony= V2D_IS_CLIPPED;
    
    /* express given coordinates as proportional values */
    x= (x - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
    y= (y - v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
    
    /* check if values are within bounds */
    if ((x>=0.0f) && (x<=1.0f) && (y>=0.0f) && (y<=1.0f)) {
        if (regionx)
            *regionx= (int)(v2d->mask.xmin + x*(v2d->mask.xmax-v2d->mask.xmin));
        if (regiony)
            *regiony= (int)(v2d->mask.ymin + y*(v2d->mask.ymax-v2d->mask.ymin));
    }
}

/* Convert from 2d-view space to screen/region space
 *  - Coordinates are NOT clamped to lie within bounds of region
 *
 *  - x,y               = coordinates to convert
 *  - regionx,regiony   = resultant coordinates 
 */
void UI_view2d_to_region_no_clip(View2D *v2d, float x, float y, int *regionx, int *regiony)
{
    /* step 1: express given coordinates as proportional values */
    x= (x - v2d->cur.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
    y= (y - v2d->cur.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
    
    /* step 2: convert proportional distances to screen coordinates  */
    x= v2d->mask.xmin + x*(v2d->mask.xmax - v2d->mask.xmin);
    y= v2d->mask.ymin + y*(v2d->mask.ymax - v2d->mask.ymin);
    
    /* although we don't clamp to lie within region bounds, we must avoid exceeding size of ints */
    if (regionx) {
        if (x < INT_MIN) *regionx= INT_MIN;
        else if(x > INT_MAX) *regionx= INT_MAX;
        else *regionx= (int)x;
    }
    if (regiony) {
        if (y < INT_MIN) *regiony= INT_MIN;
        else if(y > INT_MAX) *regiony= INT_MAX;
        else *regiony= (int)y;
    }
}

/* *********************************************************************** */
/* Utilities */

/* View2D data by default resides in region, so get from region stored in context */
View2D *UI_view2d_fromcontext(const bContext *C)
{
    ScrArea *area= CTX_wm_area(C);
    ARegion *region= CTX_wm_region(C);

    if (area == NULL) return NULL;
    if (region == NULL) return NULL;
    return &(region->v2d);
}

/* same as above, but it returns regionwindow. Utility for pulldowns or buttons */
View2D *UI_view2d_fromcontext_rwin(const bContext *C)
{
    ScrArea *sa= CTX_wm_area(C);
    ARegion *region= CTX_wm_region(C);

    if (sa == NULL) return NULL;
    if (region == NULL) return NULL;
    if (region->regiontype!=RGN_TYPE_WINDOW) {
        ARegion *ar= BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
        return ar ? &(ar->v2d) : NULL;
    }
    return &(region->v2d);
}


/* Calculate the scale per-axis of the drawing-area
 *  - Is used to inverse correct drawing of icons, etc. that need to follow view 
 *    but not be affected by scale
 *
 *  - x,y   = scale on each axis
 */
void UI_view2d_getscale(View2D *v2d, float *x, float *y) 
{
    if (x) *x = (v2d->mask.xmax - v2d->mask.xmin) / (v2d->cur.xmax - v2d->cur.xmin);
    if (y) *y = (v2d->mask.ymax - v2d->mask.ymin) / (v2d->cur.ymax - v2d->cur.ymin);
}

/* Check if mouse is within scrollers
 *  - Returns appropriate code for match
 *      'h' = in horizontal scroller
 *      'v' = in vertical scroller
 *      0 = not in scroller
 *  
 *  - x,y   = mouse coordinates in screen (not region) space
 */
short UI_view2d_mouse_in_scrollers (const bContext *C, View2D *v2d, int x, int y)
{
    ARegion *ar= CTX_wm_region(C);
    int co[2];
    int scroll= view2d_scroll_mapped(v2d->scroll);
    
    /* clamp x,y to region-coordinates first */
    co[0]= x - ar->winrct.xmin;
    co[1]= y - ar->winrct.ymin;
    
    /* check if within scrollbars */
    if (scroll & V2D_SCROLL_HORIZONTAL) {
        if (IN_2D_HORIZ_SCROLL(v2d, co)) return 'h';
    }
    if (scroll & V2D_SCROLL_VERTICAL) {
        if (IN_2D_VERT_SCROLL(v2d, co)) return 'v';
    }   
    
    /* not found */
    return 0;
}

/* ******************* view2d text drawing cache ******************** */

/* assumes caches are used correctly, so for time being no local storage in v2d */
static ListBase strings= {NULL, NULL};

typedef struct View2DString {
    struct View2DString *next, *prev;
    union {
        unsigned char ub[4];
        int pack;
    } col;
    int mval[2];
    rcti rect;
} View2DString;


void UI_view2d_text_cache_add(View2D *v2d, float x, float y, const char *str, const char col[4])
{
    int mval[2];
    
    UI_view2d_view_to_region(v2d, x, y, mval, mval+1);
    
    if(mval[0]!=V2D_IS_CLIPPED && mval[1]!=V2D_IS_CLIPPED) {
        int len= strlen(str)+1;
        /* use calloc, rect has to be zeroe'd */
        View2DString *v2s= MEM_callocN(sizeof(View2DString)+len, "View2DString");
        char *v2s_str= (char *)(v2s+1);
        memcpy(v2s_str, str, len);

        BLI_addtail(&strings, v2s);
        v2s->col.pack= *((int *)col);
        v2s->mval[0]= mval[0];
        v2s->mval[1]= mval[1];
    }
}

/* no clip (yet) */
void UI_view2d_text_cache_rectf(View2D *v2d, rctf *rect, const char *str, const char col[4])
{
    int len= strlen(str)+1;
    View2DString *v2s= MEM_callocN(sizeof(View2DString)+len, "View2DString");
    char *v2s_str= (char *)(v2s+1);
    memcpy(v2s_str, str, len);

    UI_view2d_to_region_no_clip(v2d, rect->xmin, rect->ymin, &v2s->rect.xmin, &v2s->rect.ymin);
    UI_view2d_to_region_no_clip(v2d, rect->xmax, rect->ymax, &v2s->rect.xmax, &v2s->rect.ymax);

    v2s->col.pack= *((int *)col);
    v2s->mval[0]= v2s->rect.xmin;
    v2s->mval[1]= v2s->rect.ymin;

    BLI_addtail(&strings, v2s);
}


void UI_view2d_text_cache_draw(ARegion *ar)
{
    View2DString *v2s;
    int col_pack_prev= 0;
    
    // glMatrixMode(GL_PROJECTION);
    // glPushMatrix();
    // glMatrixMode(GL_MODELVIEW);
    // glPushMatrix();
    ED_region_pixelspace(ar);
    
    for(v2s= strings.first; v2s; v2s= v2s->next) {
        const char *str= (const char *)(v2s+1);
        int xofs=0, yofs;

        yofs= ceil( 0.5f*(v2s->rect.ymax - v2s->rect.ymin - BLF_height_default("28")));
        if(yofs<1) yofs= 1;

        if(col_pack_prev != v2s->col.pack) {
            glColor3ubv(v2s->col.ub);
            col_pack_prev= v2s->col.pack;
        }

        if(v2s->rect.xmin >= v2s->rect.xmax)
            BLF_draw_default((float)v2s->mval[0]+xofs, (float)v2s->mval[1]+yofs, 0.0, str, BLF_DRAW_STR_DUMMY_MAX);
        else {
            BLF_clipping_default(v2s->rect.xmin-4, v2s->rect.ymin-4, v2s->rect.xmax+4, v2s->rect.ymax+4);
            BLF_enable_default(BLF_CLIPPING);
            BLF_draw_default(v2s->rect.xmin+xofs, v2s->rect.ymin+yofs, 0.0f, str, BLF_DRAW_STR_DUMMY_MAX);
            BLF_disable_default(BLF_CLIPPING);
        }
    }
    
    // glMatrixMode(GL_PROJECTION);
    // glPopMatrix();
    // glMatrixMode(GL_MODELVIEW);
    // glPopMatrix();
    
    if(strings.first) 
        BLI_freelistN(&strings);
}


/* ******************************************************** */