view2d_ops.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 <math.h>

#include "MEM_guardedalloc.h"

#include "DNA_userdef_types.h"

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

#include "BKE_context.h"

#include "RNA_access.h"
#include "RNA_define.h"

#include "WM_api.h"
#include "WM_types.h"


#include "ED_screen.h"

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

#include "PIL_time.h" /* USER_ZOOM_CONT */

static int view2d_poll(bContext *C)
{
    ARegion *ar= CTX_wm_region(C);

    return (ar != NULL) && (ar->v2d.flag & V2D_IS_INITIALISED);
}

/* ********************************************************* */
/* VIEW PANNING OPERATOR                                 */

/*  This group of operators come in several forms:
 *      1) Modal 'dragging' with MMB - where movement of mouse dictates amount to pan view by
 *      2) Scrollwheel 'steps' - rolling mousewheel by one step moves view by predefined amount
 *
 *  In order to make sure this works, each operator must define the following RNA-Operator Props:
 *      deltax, deltay  - define how much to move view by (relative to zoom-correction factor)
 */

/* ------------------ Shared 'core' stuff ---------------------- */
 
/* temp customdata for operator */
typedef struct v2dViewPanData {
    bScreen *sc;            /* screen where view pan was initiated */
    ScrArea *sa;            /* area where view pan was initiated */
    ARegion *ar;            /* region where view pan was initiated */
    View2D *v2d;            /* view2d we're operating in */
    
    float facx, facy;       /* amount to move view relative to zoom */
    
        /* options for version 1 */
    int startx, starty;     /* mouse x/y values in window when operator was initiated */
    int lastx, lasty;       /* previous x/y values of mouse in window */
    int invoke_event;       /* event starting pan, for modal exit */
    
    short in_scroller;      /* for MMB in scrollers (old feature in past, but now not that useful) */
} v2dViewPanData;
 
/* initialise panning customdata */
static int view_pan_init(bContext *C, wmOperator *op)
{
    ARegion *ar= CTX_wm_region(C);
    v2dViewPanData *vpd;
    View2D *v2d;
    float winx, winy;
    
    /* regions now have v2d-data by default, so check for region */
    if (ar == NULL)
        return 0;
        
    /* check if panning is allowed at all */
    v2d= &ar->v2d;
    if ((v2d->keepofs & V2D_LOCKOFS_X) && (v2d->keepofs & V2D_LOCKOFS_Y))
        return 0;
    
    /* set custom-data for operator */
    vpd= MEM_callocN(sizeof(v2dViewPanData), "v2dViewPanData");
    op->customdata= vpd;
    
    /* set pointers to owners */
    vpd->sc= CTX_wm_screen(C);
    vpd->sa= CTX_wm_area(C);
    vpd->v2d= v2d;
    vpd->ar = ar;
    
    /* calculate translation factor - based on size of view */
    winx= (float)(ar->winrct.xmax - ar->winrct.xmin + 1);
    winy= (float)(ar->winrct.ymax - ar->winrct.ymin + 1);
    vpd->facx= (v2d->cur.xmax - v2d->cur.xmin) / winx;
    vpd->facy= (v2d->cur.ymax - v2d->cur.ymin) / winy;
    
    return 1;
}

/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_pan_apply(wmOperator *op)
{
    v2dViewPanData *vpd= op->customdata;
    View2D *v2d= vpd->v2d;
    float dx, dy;
    
    /* calculate amount to move view by */
    dx= vpd->facx * (float)RNA_int_get(op->ptr, "deltax");
    dy= vpd->facy * (float)RNA_int_get(op->ptr, "deltay");
    
    /* only move view on an axis if change is allowed */
    if ((v2d->keepofs & V2D_LOCKOFS_X)==0) {
        v2d->cur.xmin += dx;
        v2d->cur.xmax += dx;
    }
    if ((v2d->keepofs & V2D_LOCKOFS_Y)==0) {
        v2d->cur.ymin += dy;
        v2d->cur.ymax += dy;
    }
    
    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);
    
    /* request updates to be done... */
    ED_region_tag_redraw(vpd->ar);
    
    UI_view2d_sync(vpd->sc, vpd->sa, v2d, V2D_LOCK_COPY);
    
    /* exceptions */
    if (vpd->sa->spacetype==SPACE_OUTLINER) {
        /* don't rebuild full tree, since we're just changing our view */
        SpaceOops *soops= vpd->sa->spacedata.first;
        soops->storeflag |= SO_TREESTORE_REDRAW;
    }
}

/* cleanup temp customdata  */
static void view_pan_exit(wmOperator *op)
{
    if (op->customdata) {
        MEM_freeN(op->customdata);
        op->customdata= NULL;               
    }
} 
 
/* ------------------ Modal Drag Version (1) ---------------------- */

/* for 'redo' only, with no user input */
static int view_pan_exec(bContext *C, wmOperator *op)
{
    if (!view_pan_init(C, op))
        return OPERATOR_CANCELLED;
    
    view_pan_apply(op);
    view_pan_exit(op);
    return OPERATOR_FINISHED;
}

/* set up modal operator and relevant settings */
static int view_pan_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
    wmWindow *window= CTX_wm_window(C);
    v2dViewPanData *vpd;
    View2D *v2d;
    
    /* set up customdata */
    if (!view_pan_init(C, op))
        return OPERATOR_PASS_THROUGH;
    
    vpd= op->customdata;
    v2d= vpd->v2d;
    
    /* set initial settings */
    vpd->startx= vpd->lastx= event->x;
    vpd->starty= vpd->lasty= event->y;
    vpd->invoke_event= event->type;
    
    if (event->type == MOUSEPAN) {
        RNA_int_set(op->ptr, "deltax", event->prevx - event->x);
        RNA_int_set(op->ptr, "deltay", event->prevy - event->y);
        
        view_pan_apply(op);
        view_pan_exit(op);
        return OPERATOR_FINISHED;
    }
    
    RNA_int_set(op->ptr, "deltax", 0);
    RNA_int_set(op->ptr, "deltay", 0);
    
    if (v2d->keepofs & V2D_LOCKOFS_X)
        WM_cursor_modal(window, BC_NS_SCROLLCURSOR);
    else if (v2d->keepofs & V2D_LOCKOFS_Y)
        WM_cursor_modal(window, BC_EW_SCROLLCURSOR);
    else
        WM_cursor_modal(window, BC_NSEW_SCROLLCURSOR);
    
    /* add temp handler */
    WM_event_add_modal_handler(C, op);

    return OPERATOR_RUNNING_MODAL;
}

/* handle user input - calculations of mouse-movement need to be done here, not in the apply callback! */
static int view_pan_modal(bContext *C, wmOperator *op, wmEvent *event)
{
    v2dViewPanData *vpd= op->customdata;
    
    /* execute the events */
    switch (event->type) {
        case MOUSEMOVE:
        {
            /* calculate new delta transform, then store mouse-coordinates for next-time */
            RNA_int_set(op->ptr, "deltax", (vpd->lastx - event->x));
            RNA_int_set(op->ptr, "deltay", (vpd->lasty - event->y));
            
            vpd->lastx= event->x;
            vpd->lasty= event->y;
            
            view_pan_apply(op);
        }
            break;
        /* XXX - Mode switching isn't implemented. See comments in 36818.
         * switch to zoom *
        case LEFTMOUSE:
            if (event->val==KM_PRESS) {
                * calculate overall delta mouse-movement for redo *
                RNA_int_set(op->ptr, "deltax", (vpd->startx - vpd->lastx));
                RNA_int_set(op->ptr, "deltay", (vpd->starty - vpd->lasty));
                
                view_pan_exit(op);
                WM_cursor_restore(CTX_wm_window(C));
                WM_operator_name_call(C, "VIEW2D_OT_zoom", WM_OP_INVOKE_DEFAULT, NULL);
                return OPERATOR_FINISHED;
            }*/
            
        default:
            if (event->type == vpd->invoke_event || event->type==ESCKEY) {
                if (event->val==KM_RELEASE) {
                    /* calculate overall delta mouse-movement for redo */
                    RNA_int_set(op->ptr, "deltax", (vpd->startx - vpd->lastx));
                    RNA_int_set(op->ptr, "deltay", (vpd->starty - vpd->lasty));
                    
                    view_pan_exit(op);
                    WM_cursor_restore(CTX_wm_window(C));
                    
                    return OPERATOR_FINISHED;
                }
            }
            break;
    }

    return OPERATOR_RUNNING_MODAL;
}

static int view_pan_cancel(bContext *UNUSED(C), wmOperator *op)
{
    view_pan_exit(op);
    return OPERATOR_CANCELLED;
}

static void VIEW2D_OT_pan(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Pan View";
    ot->description= "Pan the view";
    ot->idname= "VIEW2D_OT_pan";
    
    /* api callbacks */
    ot->exec= view_pan_exec;
    ot->invoke= view_pan_invoke;
    ot->modal= view_pan_modal;
    ot->cancel= view_pan_cancel;
    
    /* operator is modal */
    ot->flag= OPTYPE_BLOCKING|OPTYPE_GRAB_POINTER;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}

/* ------------------ Scrollwheel Versions (2) ---------------------- */

/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollright_exec(bContext *C, wmOperator *op)
{
    v2dViewPanData *vpd;
    
    /* initialise default settings (and validate if ok to run) */
    if (!view_pan_init(C, op))
        return OPERATOR_PASS_THROUGH;
        
    /* also, check if can pan in horizontal axis */
    vpd= op->customdata;
    if (vpd->v2d->keepofs & V2D_LOCKOFS_X) {
        view_pan_exit(op);
        return OPERATOR_PASS_THROUGH;
    }
    
    /* set RNA-Props - only movement in positive x-direction */
    RNA_int_set(op->ptr, "deltax", 20);
    RNA_int_set(op->ptr, "deltay", 0);
    
    /* apply movement, then we're done */
    view_pan_apply(op);
    view_pan_exit(op);
    
    return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_right(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Scroll Right";
    ot->description= "Scroll the view right";
    ot->idname= "VIEW2D_OT_scroll_right";
    
    /* api callbacks */
    ot->exec= view_scrollright_exec;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}



/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollleft_exec(bContext *C, wmOperator *op)
{
    v2dViewPanData *vpd;
    
    /* initialise default settings (and validate if ok to run) */
    if (!view_pan_init(C, op))
        return OPERATOR_PASS_THROUGH;
        
    /* also, check if can pan in horizontal axis */
    vpd= op->customdata;
    if (vpd->v2d->keepofs & V2D_LOCKOFS_X) {
        view_pan_exit(op);
        return OPERATOR_PASS_THROUGH;
    }
    
    /* set RNA-Props - only movement in negative x-direction */
    RNA_int_set(op->ptr, "deltax", -20);
    RNA_int_set(op->ptr, "deltay", 0);
    
    /* apply movement, then we're done */
    view_pan_apply(op);
    view_pan_exit(op);
    
    return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_left(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Scroll Left";
    ot->description= "Scroll the view left";
    ot->idname= "VIEW2D_OT_scroll_left";
    
    /* api callbacks */
    ot->exec= view_scrollleft_exec;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
}


/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrolldown_exec(bContext *C, wmOperator *op)
{
    v2dViewPanData *vpd;
    
    /* initialise default settings (and validate if ok to run) */
    if (!view_pan_init(C, op))
        return OPERATOR_PASS_THROUGH;
        
    /* also, check if can pan in vertical axis */
    vpd= op->customdata;
    if (vpd->v2d->keepofs & V2D_LOCKOFS_Y) {
        view_pan_exit(op);
        return OPERATOR_PASS_THROUGH;
    }
    
    /* set RNA-Props */
    RNA_int_set(op->ptr, "deltax", 0);
    RNA_int_set(op->ptr, "deltay", -40);
    
    if(RNA_boolean_get(op->ptr, "page")) {
        ARegion *ar= CTX_wm_region(C);
        RNA_int_set(op->ptr, "deltay", ar->v2d.mask.ymin - ar->v2d.mask.ymax);
    }
    
    /* apply movement, then we're done */
    view_pan_apply(op);
    view_pan_exit(op);
    
    return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_down(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Scroll Down";
    ot->description= "Scroll the view down";
    ot->idname= "VIEW2D_OT_scroll_down";
    
    /* api callbacks */
    ot->exec= view_scrolldown_exec;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
    RNA_def_boolean(ot->srna, "page", 0, "Page", "Scroll down one page");
}



/* this operator only needs this single callback, where it callsthe view_pan_*() methods */
static int view_scrollup_exec(bContext *C, wmOperator *op)
{
    v2dViewPanData *vpd;
    
    /* initialise default settings (and validate if ok to run) */
    if (!view_pan_init(C, op))
        return OPERATOR_PASS_THROUGH;
        
    /* also, check if can pan in vertical axis */
    vpd= op->customdata;
    if (vpd->v2d->keepofs & V2D_LOCKOFS_Y) {
        view_pan_exit(op);
        return OPERATOR_PASS_THROUGH;
    }
    
    /* set RNA-Props */
    RNA_int_set(op->ptr, "deltax", 0);
    RNA_int_set(op->ptr, "deltay", 40);
    
    if(RNA_boolean_get(op->ptr, "page")) {
        ARegion *ar= CTX_wm_region(C);
        RNA_int_set(op->ptr, "deltay", ar->v2d.mask.ymax - ar->v2d.mask.ymin);
    }
    
    /* apply movement, then we're done */
    view_pan_apply(op);
    view_pan_exit(op);
    
    return OPERATOR_FINISHED;
}

static void VIEW2D_OT_scroll_up(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Scroll Up";
    ot->description= "Scroll the view up";
    ot->idname= "VIEW2D_OT_scroll_up";
    
    /* api callbacks */
    ot->exec= view_scrollup_exec;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_int(ot->srna, "deltax", 0, INT_MIN, INT_MAX, "Delta X", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "deltay", 0, INT_MIN, INT_MAX, "Delta Y", "", INT_MIN, INT_MAX);
    RNA_def_boolean(ot->srna, "page", 0, "Page", "Scroll up one page");
}

/* ********************************************************* */
/* SINGLE-STEP VIEW ZOOMING OPERATOR                         */

/*  This group of operators come in several forms:
 *      1) Scrollwheel 'steps' - rolling mousewheel by one step zooms view by predefined amount
 *      2) Scrollwheel 'steps' + alt + ctrl/shift - zooms view on one axis only (ctrl=x, shift=y)  // XXX this could be implemented...
 *      3) Pad +/- Keys - pressing each key moves the zooms the view by a predefined amount
 *
 *  In order to make sure this works, each operator must define the following RNA-Operator Props:
 *      zoomfacx, zoomfacy  - These two zoom factors allow for non-uniform scaling.
 *                            It is safe to scale by 0, as these factors are used to determine
 *                            amount to enlarge 'cur' by
 */

/* ------------------ 'Shared' stuff ------------------------ */

/* temp customdata for operator */
typedef struct v2dViewZoomData {
    View2D *v2d;            /* view2d we're operating in */
    ARegion *ar;

    /* needed for continuous zoom */
    wmTimer *timer;
    double timer_lastdraw;

    int lastx, lasty;       /* previous x/y values of mouse in window */
    int invoke_event;       /* event type that invoked, for modal exits */
    float dx, dy;           /* running tally of previous delta values (for obtaining final zoom) */
    float mx_2d, my_2d;     /* initial mouse location in v2d coords */
} v2dViewZoomData;


/* initialise panning customdata */
static int view_zoomdrag_init(bContext *C, wmOperator *op)
{
    ARegion *ar= CTX_wm_region(C);
    v2dViewZoomData *vzd;
    View2D *v2d;
    
    /* regions now have v2d-data by default, so check for region */
    if (ar == NULL)
        return 0;
    v2d= &ar->v2d;
    
    /* check that 2d-view is zoomable */
    if ((v2d->keepzoom & V2D_LOCKZOOM_X) && (v2d->keepzoom & V2D_LOCKZOOM_Y))
        return 0;
    
    /* set custom-data for operator */
    vzd= MEM_callocN(sizeof(v2dViewZoomData), "v2dViewZoomData");
    op->customdata= vzd;
    
    /* set pointers to owners */
    vzd->v2d= v2d;
    vzd->ar = ar;
    
    return 1;
}

/* check if step-zoom can be applied */
static int view_zoom_poll(bContext *C)
{
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d;
    
    /* check if there's a region in context to work with */
    if (ar == NULL)
        return 0;
    v2d= &ar->v2d;
    
    /* check that 2d-view is zoomable */
    if ((v2d->keepzoom & V2D_LOCKZOOM_X) && (v2d->keepzoom & V2D_LOCKZOOM_Y))
        return 0;
        
    /* view is zoomable */
    return 1;
}
 
/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_zoomstep_apply(bContext *C, wmOperator *op)
{
    v2dViewZoomData *vzd= op->customdata;
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d= &ar->v2d;
    float dx, dy, facx, facy;
    
    /* calculate amount to move view by, ensuring symmetry so the
     * old zoom level is restored after zooming back the same amount 
     */
    facx= RNA_float_get(op->ptr, "zoomfacx");
    facy= RNA_float_get(op->ptr, "zoomfacy");

    if (facx >= 0.0f) {
        dx= (v2d->cur.xmax - v2d->cur.xmin) * facx;
        dy= (v2d->cur.ymax - v2d->cur.ymin) * facy;
    }
    else {
        dx= ((v2d->cur.xmax - v2d->cur.xmin)/(1.0f + 2.0f*facx)) * facx;
        dy= ((v2d->cur.ymax - v2d->cur.ymin)/(1.0f + 2.0f*facy)) * facy;
    }

    /* only resize view on an axis if change is allowed */
    if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
        if (v2d->keepofs & V2D_LOCKOFS_X) {
            v2d->cur.xmax -= 2*dx;
        }
        else if (v2d->keepofs & V2D_KEEPOFS_X) {
            if (v2d->align & V2D_ALIGN_NO_POS_X)
                v2d->cur.xmin += 2*dx;
            else
                v2d->cur.xmax -= 2*dx;
        }
        else {
            if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                float mval_fac = (vzd->mx_2d - v2d->cur.xmin) / (v2d->cur.xmax-v2d->cur.xmin);
                float mval_faci = 1.0f - mval_fac;
                float ofs= (mval_fac * dx) - (mval_faci * dx);
                
                v2d->cur.xmin += ofs + dx;
                v2d->cur.xmax += ofs - dx;
            }
            else {
                v2d->cur.xmin += dx;
                v2d->cur.xmax -= dx;
            }
        }
    }
    if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
        if (v2d->keepofs & V2D_LOCKOFS_Y) {
            v2d->cur.ymax -= 2*dy;
        }
        else if (v2d->keepofs & V2D_KEEPOFS_Y) {
            if (v2d->align & V2D_ALIGN_NO_POS_Y)
                v2d->cur.ymin += 2*dy;
            else
                v2d->cur.ymax -= 2*dy;
        }
        else {
            if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                float mval_fac = (vzd->my_2d - v2d->cur.ymin) / (v2d->cur.ymax-v2d->cur.ymin);
                float mval_faci = 1.0f - mval_fac;
                float ofs= (mval_fac * dy) - (mval_faci * dy);
                
                v2d->cur.ymin += ofs + dy;
                v2d->cur.ymax += ofs - dy;
            } 
            else {
                v2d->cur.ymin += dy;
                v2d->cur.ymax -= dy;
            }
        }
    }

    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);

    /* request updates to be done... */
    ED_region_tag_redraw(vzd->ar);
    UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* --------------- Individual Operators ------------------- */

/* cleanup temp customdata  */
static void view_zoomstep_exit(wmOperator *op)
{
    if (op->customdata) {
        MEM_freeN(op->customdata);
        op->customdata= NULL;               
    }
}

/* this operator only needs this single callback, where it calls the view_zoom_*() methods */
static int view_zoomin_exec(bContext *C, wmOperator *op)
{
    /* check that there's an active region, as View2D data resides there */
    if (!view_zoom_poll(C))
        return OPERATOR_PASS_THROUGH;
    
    /* set RNA-Props - zooming in by uniform factor */
    RNA_float_set(op->ptr, "zoomfacx", 0.0375f);
    RNA_float_set(op->ptr, "zoomfacy", 0.0375f);
    
    /* apply movement, then we're done */
    view_zoomstep_apply(C, op);
    
    view_zoomstep_exit(op);
    
    return OPERATOR_FINISHED;
}

static int view_zoomin_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
    v2dViewZoomData *vzd;
    
    if (!view_zoomdrag_init(C, op))
        return OPERATOR_PASS_THROUGH;
    
    vzd= op->customdata;
    
    if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
        ARegion *ar= CTX_wm_region(C);
        
        /* store initial mouse position (in view space) */
        UI_view2d_region_to_view(&ar->v2d, 
                event->mval[0], event->mval[1],
                &vzd->mx_2d, &vzd->my_2d);
    }
    
    return view_zoomin_exec(C, op);
}

static void VIEW2D_OT_zoom_in(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Zoom In";
    ot->description= "Zoom in the view";
    ot->idname= "VIEW2D_OT_zoom_in";
    
    /* api callbacks */
    ot->invoke= view_zoomin_invoke;
//  ot->exec= view_zoomin_exec;  // XXX, needs view_zoomdrag_init called first.
    ot->poll= view_zoom_poll;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_float(ot->srna, "zoomfacx", 0, -FLT_MAX, FLT_MAX, "Zoom Factor X", "", -FLT_MAX, FLT_MAX);
    RNA_def_float(ot->srna, "zoomfacy", 0, -FLT_MAX, FLT_MAX, "Zoom Factor Y", "", -FLT_MAX, FLT_MAX);
}
    
/* this operator only needs this single callback, where it callsthe view_zoom_*() methods */
static int view_zoomout_exec(bContext *C, wmOperator *op)
{
    /* check that there's an active region, as View2D data resides there */
    if (!view_zoom_poll(C))
        return OPERATOR_PASS_THROUGH;
    
    /* set RNA-Props - zooming in by uniform factor */
    RNA_float_set(op->ptr, "zoomfacx", -0.0375f);
    RNA_float_set(op->ptr, "zoomfacy", -0.0375f);
    
    /* apply movement, then we're done */
    view_zoomstep_apply(C, op);

    view_zoomstep_exit(op);
    
    return OPERATOR_FINISHED;
}

static int view_zoomout_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
    v2dViewZoomData *vzd;
    
    if (!view_zoomdrag_init(C, op))
        return OPERATOR_PASS_THROUGH;

    vzd= op->customdata;
    
    if(U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
        ARegion *ar= CTX_wm_region(C);
        
        /* store initial mouse position (in view space) */
        UI_view2d_region_to_view(&ar->v2d, 
                event->mval[0], event->mval[1],
                &vzd->mx_2d, &vzd->my_2d);
    }
    
    return view_zoomout_exec(C, op);
}

static void VIEW2D_OT_zoom_out(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Zoom Out";
    ot->description= "Zoom out the view";
    ot->idname= "VIEW2D_OT_zoom_out";
    
    /* api callbacks */
    ot->invoke= view_zoomout_invoke;
//  ot->exec= view_zoomout_exec; // XXX, needs view_zoomdrag_init called first.
    ot->poll= view_zoom_poll;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_float(ot->srna, "zoomfacx", 0, -FLT_MAX, FLT_MAX, "Zoom Factor X", "", -FLT_MAX, FLT_MAX);
    RNA_def_float(ot->srna, "zoomfacy", 0, -FLT_MAX, FLT_MAX, "Zoom Factor Y", "", -FLT_MAX, FLT_MAX);
}

/* ********************************************************* */
/* DRAG-ZOOM OPERATOR                                    */

/*  MMB Drag - allows non-uniform scaling by dragging mouse
 *
 *  In order to make sure this works, each operator must define the following RNA-Operator Props:
 *      deltax, deltay  - amounts to add to each side of the 'cur' rect
 */

/* apply transform to view (i.e. adjust 'cur' rect) */
static void view_zoomdrag_apply(bContext *C, wmOperator *op)
{
    v2dViewZoomData *vzd= op->customdata;
    View2D *v2d= vzd->v2d;
    float dx, dy;
    
    /* get amount to move view by */
    dx= RNA_float_get(op->ptr, "deltax");
    dy= RNA_float_get(op->ptr, "deltay");

    /* continous zoom shouldn't move that fast... */
    if (U.viewzoom == USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
        double time= PIL_check_seconds_timer();
        float time_step= (float)(time - vzd->timer_lastdraw);

        dx *= time_step * 0.5f;
        dy *= time_step * 0.5f;
        
        vzd->timer_lastdraw= time;
    }

    /* only move view on an axis if change is allowed */
    if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
        if (v2d->keepofs & V2D_LOCKOFS_X) {
            v2d->cur.xmax -= 2*dx;
        }
        else {
            if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                float mval_fac = (vzd->mx_2d - v2d->cur.xmin) / (v2d->cur.xmax-v2d->cur.xmin);
                float mval_faci = 1.0f - mval_fac;
                float ofs= (mval_fac * dx) - (mval_faci * dx);
                
                v2d->cur.xmin += ofs + dx;
                v2d->cur.xmax += ofs - dx;
            }
            else {
                v2d->cur.xmin += dx;
                v2d->cur.xmax -= dx;
            }
        }
    }
    if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
        if (v2d->keepofs & V2D_LOCKOFS_Y) {
            v2d->cur.ymax -= 2*dy;
        }
        else {
            if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
                float mval_fac = (vzd->my_2d - v2d->cur.ymin) / (v2d->cur.ymax-v2d->cur.ymin);
                float mval_faci = 1.0f - mval_fac;
                float ofs= (mval_fac * dy) - (mval_faci * dy);
                
                v2d->cur.ymin += ofs + dy;
                v2d->cur.ymax += ofs - dy;
            }
            else {
                v2d->cur.ymin += dy;
                v2d->cur.ymax -= dy;
            }
        }
    }
    
    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);
    
    /* request updates to be done... */
    ED_region_tag_redraw(vzd->ar);
    UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* cleanup temp customdata  */
static void view_zoomdrag_exit(bContext *C, wmOperator *op)
{
    if (op->customdata) {
        v2dViewZoomData *vzd= op->customdata;
        
        if(vzd->timer)
            WM_event_remove_timer(CTX_wm_manager(C), CTX_wm_window(C), vzd->timer);
        
        MEM_freeN(op->customdata);
        op->customdata= NULL;               
    }
} 

static int view_zoomdrag_cancel(bContext *C, wmOperator *op)
{
    view_zoomdrag_exit(C, op);

    return OPERATOR_CANCELLED;
}

/* for 'redo' only, with no user input */
static int view_zoomdrag_exec(bContext *C, wmOperator *op)
{
    if (!view_zoomdrag_init(C, op))
        return OPERATOR_PASS_THROUGH;
    
    view_zoomdrag_apply(C, op);
    view_zoomdrag_exit(C, op);
    return OPERATOR_FINISHED;
}

/* set up modal operator and relevant settings */
static int view_zoomdrag_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
    wmWindow *window= CTX_wm_window(C);
    v2dViewZoomData *vzd;
    View2D *v2d;
    
    /* set up customdata */
    if (!view_zoomdrag_init(C, op))
        return OPERATOR_PASS_THROUGH;
    
    vzd= op->customdata;
    v2d= vzd->v2d;
    
    if (event->type == MOUSEZOOM) {
        float dx, dy, fac;
        
        vzd->lastx= event->prevx;
        vzd->lasty= event->prevy;
        
        /* As we have only 1D information (magnify value), feed both axes
         * with magnify information that is stored in x axis 
         */
        fac= 0.01f * (event->x - event->prevx);
        dx= fac * (v2d->cur.xmax - v2d->cur.xmin) / 10.0f;
        dy= fac * (v2d->cur.ymax - v2d->cur.ymin) / 10.0f;

        RNA_float_set(op->ptr, "deltax", dx);
        RNA_float_set(op->ptr, "deltay", dy);
        
        view_zoomdrag_apply(C, op);
        view_zoomdrag_exit(C, op);
        return OPERATOR_FINISHED;
    }   
    
    /* set initial settings */
    vzd->lastx= event->x;
    vzd->lasty= event->y;
    RNA_float_set(op->ptr, "deltax", 0);
    RNA_float_set(op->ptr, "deltay", 0);
    
    /* for modal exit test */
    vzd->invoke_event= event->type;
    
    if (U.uiflag & USER_ZOOM_TO_MOUSEPOS) {
        ARegion *ar= CTX_wm_region(C);
        
        /* store initial mouse position (in view space) */
        UI_view2d_region_to_view(&ar->v2d, 
                event->mval[0], event->mval[1],
                &vzd->mx_2d, &vzd->my_2d);
    }

    if (v2d->keepofs & V2D_LOCKOFS_X)
        WM_cursor_modal(window, BC_NS_SCROLLCURSOR);
    else if (v2d->keepofs & V2D_LOCKOFS_Y)
        WM_cursor_modal(window, BC_EW_SCROLLCURSOR);
    else
        WM_cursor_modal(window, BC_NSEW_SCROLLCURSOR);
    
    /* add temp handler */
    WM_event_add_modal_handler(C, op);

    if (U.viewzoom == USER_ZOOM_CONT) {
        /* needs a timer to continue redrawing */
        vzd->timer= WM_event_add_timer(CTX_wm_manager(C), CTX_wm_window(C), TIMER, 0.01f);
        vzd->timer_lastdraw= PIL_check_seconds_timer();
    }

    return OPERATOR_RUNNING_MODAL;
}

/* handle user input - calculations of mouse-movement need to be done here, not in the apply callback! */
static int view_zoomdrag_modal(bContext *C, wmOperator *op, wmEvent *event)
{
    v2dViewZoomData *vzd= op->customdata;
    View2D *v2d= vzd->v2d;
    
    /* execute the events */
    if (event->type == TIMER && event->customdata == vzd->timer) {
        view_zoomdrag_apply(C, op);
    }
    else if(event->type == MOUSEMOVE) {
        float dx, dy;
        
        /* calculate new delta transform, based on zooming mode */
        if (U.viewzoom == USER_ZOOM_SCALE) {
            /* 'scale' zooming */
            float dist;
            
            /* x-axis transform */
            dist = (v2d->mask.xmax - v2d->mask.xmin) / 2.0f;
            dx= 1.0f - (fabsf(vzd->lastx - dist) + 2.0f) / (fabsf(event->x - dist) + 2.0f);
            dx*= 0.5f * (v2d->cur.xmax - v2d->cur.xmin);
            
            /* y-axis transform */
            dist = (v2d->mask.ymax - v2d->mask.ymin) / 2.0f;
            dy= 1.0f - (fabsf(vzd->lasty - dist) + 2.0f) / (fabsf(event->y - dist) + 2.0f);
            dy*= 0.5f * (v2d->cur.ymax - v2d->cur.ymin);
        }
        else {
            /* 'continuous' or 'dolly' */
            float fac;
            
            /* x-axis transform */
            fac= 0.01f * (event->x - vzd->lastx);
            dx= fac * (v2d->cur.xmax - v2d->cur.xmin);
            
            /* y-axis transform */
            fac= 0.01f * (event->y - vzd->lasty);
            dy= fac * (v2d->cur.ymax - v2d->cur.ymin);
#if 0
            /* continous zoom shouldn't move that fast... */
            if (U.viewzoom == USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
                double time= PIL_check_seconds_timer();
                float time_step= (float)(time - vzd->timer_lastdraw);

                dx /= (0.1f / time_step);
                dy /= (0.1f / time_step);
                
                vzd->timer_lastdraw= time;
            }
#endif
        }
        
        /* set transform amount, and add current deltas to stored total delta (for redo) */
        RNA_float_set(op->ptr, "deltax", dx);
        RNA_float_set(op->ptr, "deltay", dy);
        vzd->dx += dx;
        vzd->dy += dy;
        
        /* store mouse coordinates for next time, if not doing continuous zoom
         *  - continuous zoom only depends on distance of mouse to starting point to determine rate of change
         */
        if (U.viewzoom != USER_ZOOM_CONT) { // XXX store this setting as RNA prop?
            vzd->lastx= event->x;
            vzd->lasty= event->y;
        }
        
        /* apply zooming */
        view_zoomdrag_apply(C, op);
    } 
    else if (event->type == vzd->invoke_event || event->type==ESCKEY) {
        if (event->val == KM_RELEASE) {
            
            /* for redo, store the overall deltas - need to respect zoom-locks here... */
            if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0)
                RNA_float_set(op->ptr, "deltax", vzd->dx);
            else
                RNA_float_set(op->ptr, "deltax", 0);
                
            if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0)
                RNA_float_set(op->ptr, "deltay", vzd->dy);
            else
                RNA_float_set(op->ptr, "deltay", 0);
            
            /* free customdata */
            view_zoomdrag_exit(C, op);
            WM_cursor_restore(CTX_wm_window(C));
            
            return OPERATOR_FINISHED;
        }
    }

    return OPERATOR_RUNNING_MODAL;
}

static void VIEW2D_OT_zoom(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Zoom 2D View";
    ot->description= "Zoom in/out the view";
    ot->idname= "VIEW2D_OT_zoom";
    
    /* api callbacks */
    ot->exec= view_zoomdrag_exec;
    ot->invoke= view_zoomdrag_invoke;
    ot->modal= view_zoomdrag_modal;
    ot->cancel= view_zoomdrag_cancel;
    
    ot->poll= view_zoom_poll;
    
    /* operator is repeatable */
    // ot->flag= OPTYPE_BLOCKING;
    
    /* rna - must keep these in sync with the other operators */
    RNA_def_float(ot->srna, "deltax", 0, -FLT_MAX, FLT_MAX, "Delta X", "", -FLT_MAX, FLT_MAX);
    RNA_def_float(ot->srna, "deltay", 0, -FLT_MAX, FLT_MAX, "Delta Y", "", -FLT_MAX, FLT_MAX);
}

/* ********************************************************* */
/* BORDER-ZOOM */

/* The user defines a rect using standard borderselect tools, and we use this rect to 
 * define the new zoom-level of the view in the following ways:
 *  1) LEFTMOUSE - zoom in to view
 *  2) RIGHTMOUSE - zoom out of view
 *
 * Currently, these key mappings are hardcoded, but it shouldn't be too important to
 * have custom keymappings for this...
 */
 
static int view_borderzoom_exec(bContext *C, wmOperator *op)
{
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d= &ar->v2d;
    rctf rect;
    int gesture_mode;
    
    /* convert coordinates of rect to 'tot' rect coordinates */
    UI_view2d_region_to_view(v2d, RNA_int_get(op->ptr, "xmin"), RNA_int_get(op->ptr, "ymin"), &rect.xmin, &rect.ymin);
    UI_view2d_region_to_view(v2d, RNA_int_get(op->ptr, "xmax"), RNA_int_get(op->ptr, "ymax"), &rect.xmax, &rect.ymax);
    
    /* check if zooming in/out view */
    gesture_mode= RNA_int_get(op->ptr, "gesture_mode");
    
    if (gesture_mode == GESTURE_MODAL_IN) {
        /* zoom in: 
         *  - 'cur' rect will be defined by the coordinates of the border region 
         *  - just set the 'cur' rect to have the same coordinates as the border region
         *    if zoom is allowed to be changed
         */
        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
            v2d->cur.xmin= rect.xmin;
            v2d->cur.xmax= rect.xmax;
        }
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
            v2d->cur.ymin= rect.ymin;
            v2d->cur.ymax= rect.ymax;
        }
    }
    else /* if (gesture_mode == GESTURE_MODAL_OUT) */ {
        /* zoom out:
         *  - the current 'cur' rect coordinates are going to end upwhere the 'rect' ones are, 
         *    but the 'cur' rect coordinates will need to be adjusted to take in more of the view
         *  - calculate zoom factor, and adjust using center-point
         */
        float zoom, center, size;
        
        // TODO: is this zoom factor calculation valid? It seems to produce same results everytime...
        if ((v2d->keepzoom & V2D_LOCKZOOM_X)==0) {
            size= (v2d->cur.xmax - v2d->cur.xmin);
            zoom= size / (rect.xmax - rect.xmin);
            center= (v2d->cur.xmax + v2d->cur.xmin) * 0.5f;
            
            v2d->cur.xmin= center - (size * zoom);
            v2d->cur.xmax= center + (size * zoom);
        }
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y)==0) {
            size= (v2d->cur.ymax - v2d->cur.ymin);
            zoom= size / (rect.ymax - rect.ymin);
            center= (v2d->cur.ymax + v2d->cur.ymin) * 0.5f;
            
            v2d->cur.ymin= center - (size * zoom);
            v2d->cur.ymax= center + (size * zoom);
        }
    }
    
    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);
    
    /* request updates to be done... */
    ED_region_tag_redraw(ar);
    UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
    
    return OPERATOR_FINISHED;
} 

static void VIEW2D_OT_zoom_border(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Zoom to Border";
    ot->description= "Zoom in the view to the nearest item contained in the border";
    ot->idname= "VIEW2D_OT_zoom_border";
    
    /* api callbacks */
    ot->invoke= WM_border_select_invoke;
    ot->exec= view_borderzoom_exec;
    ot->modal= WM_border_select_modal;
    ot->cancel= WM_border_select_cancel;
    
    ot->poll= view_zoom_poll;
    
    /* rna */
    RNA_def_int(ot->srna, "gesture_mode", 0, INT_MIN, INT_MAX, "Gesture Mode", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "xmin", 0, INT_MIN, INT_MAX, "X Min", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "xmax", 0, INT_MIN, INT_MAX, "X Max", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "ymin", 0, INT_MIN, INT_MAX, "Y Min", "", INT_MIN, INT_MAX);
    RNA_def_int(ot->srna, "ymax", 0, INT_MIN, INT_MAX, "Y Max", "", INT_MIN, INT_MAX);
}

/* ********************************************************* */
/* SCROLLERS */

/*  Scrollers should behave in the following ways, when clicked on with LMB (and dragged):
 *      1) 'Handles' on end of 'bubble' - when the axis that the scroller represents is zoomable, 
 *          enlarge 'cur' rect on the relevant side 
 *      2) 'Bubble'/'bar' - just drag, and bar should move with mouse (view pans opposite)
 *
 *  In order to make sure this works, each operator must define the following RNA-Operator Props:
 *      deltax, deltay  - define how much to move view by (relative to zoom-correction factor)
 */

/* customdata for scroller-invoke data */
typedef struct v2dScrollerMove {
    View2D *v2d;            /* View2D data that this operation affects */
    ARegion *ar;            /* region that the scroller is in */
    
    short scroller;         /* scroller that mouse is in ('h' or 'v') */
    short zone;             /* -1 is min zoomer, 0 is bar, 1 is max zoomer */ // XXX find some way to provide visual feedback of this (active color?)
    
    float fac;              /* view adjustment factor, based on size of region */
    float delta;            /* amount moved by mouse on axis of interest */
    
    float scrollbarwidth;   /* width of the scrollbar itself, used for page up/down clicks */
    int scrollbar_orig;      /* initial location of scrollbar x/y, mouse relative */
    
    int lastx, lasty;       /* previous mouse coordinates (in screen coordinates) for determining movement */
} v2dScrollerMove;


/* View2DScrollers is typedef'd in UI_view2d.h 
 * This is a CUT DOWN VERSION of the 'real' version, which is defined in view2d.c, as we only need focus bubble info
 * WARNING: the start of this struct must not change, so that it stays in sync with the 'real' version
 *         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 */
};

/* quick enum for vsm->zone (scroller handles) */
enum {
    SCROLLHANDLE_MIN= -1,
    SCROLLHANDLE_BAR,
    SCROLLHANDLE_MAX,
    SCROLLHANDLE_MIN_OUTSIDE,
    SCROLLHANDLE_MAX_OUTSIDE
} /*eV2DScrollerHandle_Zone*/;

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

/* check if mouse is within scroller handle 
 *  - mouse         =   relevant mouse coordinate in region space
 *  - sc_min, sc_max    =   extents of scroller 'groove' (potential available space for scroller)
 *  - sh_min, sh_max    =   positions of scrollbar handles
 */
static short mouse_in_scroller_handle(int mouse, int sc_min, int sc_max, int sh_min, int sh_max)
{
    short in_min, in_max, in_bar, out_min, out_max, in_view=1;
    
    /* firstly, check if 
     *  - 'bubble' fills entire scroller 
     *  - 'bubble' completely out of view on either side 
     */
    if ((sh_min <= sc_min) && (sh_max >= sc_max)) in_view= 0;
    if (sh_min == sh_max) {
        if (sh_min <= sc_min) in_view= 0;
        if (sh_max >= sc_max) in_view= 0;
    }
    else {
        if (sh_max <= sc_min) in_view= 0;
        if (sh_min >= sc_max) in_view= 0;
    }
    
    
    if (in_view == 0) {
        return SCROLLHANDLE_BAR;
    }
    
    /* check if mouse is in or past either handle */
    // TODO: check if these extents are still valid or not
    in_max= ( (mouse >= (sh_max - V2D_SCROLLER_HANDLE_SIZE)) && (mouse <= (sh_max + V2D_SCROLLER_HANDLE_SIZE)) );
    in_min= ( (mouse <= (sh_min + V2D_SCROLLER_HANDLE_SIZE)) && (mouse >= (sh_min - V2D_SCROLLER_HANDLE_SIZE)) );
    in_bar= ( (mouse < (sh_max - V2D_SCROLLER_HANDLE_SIZE)) && (mouse > (sh_min + V2D_SCROLLER_HANDLE_SIZE)) );
    out_min= mouse < (sh_min - V2D_SCROLLER_HANDLE_SIZE);
    out_max= mouse > (sh_max + V2D_SCROLLER_HANDLE_SIZE);
    
    if (in_bar)
        return SCROLLHANDLE_BAR;
    else if (in_max)
        return SCROLLHANDLE_MAX;
    else if (in_min)
        return SCROLLHANDLE_MIN;
    else if (out_min)
        return SCROLLHANDLE_MIN_OUTSIDE;              
    else if (out_max)
        return SCROLLHANDLE_MAX_OUTSIDE;
    
    /* unlikely to happen, though we just cover it in case */
    return SCROLLHANDLE_BAR;
} 

/* initialise customdata for scroller manipulation operator */
static void scroller_activate_init(bContext *C, wmOperator *op, wmEvent *event, short in_scroller)
{
    v2dScrollerMove *vsm;
    View2DScrollers *scrollers;
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d= &ar->v2d;
    float mask_size;
    
    /* set custom-data for operator */
    vsm= MEM_callocN(sizeof(v2dScrollerMove), "v2dScrollerMove");
    op->customdata= vsm;
    
    /* set general data */
    vsm->v2d= v2d;
    vsm->ar= ar;
    vsm->scroller= in_scroller;

    /* store mouse-coordinates, and convert mouse/screen coordinates to region coordinates */
    vsm->lastx = event->x;
    vsm->lasty = event->y;
    /* 'zone' depends on where mouse is relative to bubble 
     *  - zooming must be allowed on this axis, otherwise, default to pan
     */
    scrollers= UI_view2d_scrollers_calc(C, v2d, V2D_ARG_DUMMY, V2D_ARG_DUMMY, V2D_ARG_DUMMY, V2D_ARG_DUMMY);


    if (in_scroller == 'h') {
        /* horizontal scroller - calculate adjustment factor first */
        mask_size= (float)(v2d->hor.xmax - v2d->hor.xmin);
        vsm->fac= (v2d->tot.xmax - v2d->tot.xmin) / mask_size;
        
        /* get 'zone' (i.e. which part of scroller is activated) */
        vsm->zone= mouse_in_scroller_handle(event->mval[0], v2d->hor.xmin, v2d->hor.xmax, scrollers->hor_min, scrollers->hor_max);
        
        if ((v2d->keepzoom & V2D_LOCKZOOM_X) && ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
            /* default to scroll, as handles not usable */
            vsm->zone= SCROLLHANDLE_BAR;
        }

        vsm->scrollbarwidth = scrollers->hor_max - scrollers->hor_min;
        vsm->scrollbar_orig = ((scrollers->hor_max + scrollers->hor_min) / 2) + ar->winrct.xmin;
    }
    else {
        /* vertical scroller - calculate adjustment factor first */
        mask_size= (float)(v2d->vert.ymax - v2d->vert.ymin);
        vsm->fac= (v2d->tot.ymax - v2d->tot.ymin) / mask_size;
        
        /* get 'zone' (i.e. which part of scroller is activated) */
        vsm->zone= mouse_in_scroller_handle(event->mval[1], v2d->vert.ymin, v2d->vert.ymax, scrollers->vert_min, scrollers->vert_max);
            
        if ((v2d->keepzoom & V2D_LOCKZOOM_Y) && ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
            /* default to scroll, as handles not usable */
            vsm->zone= SCROLLHANDLE_BAR;
        }
        
        vsm->scrollbarwidth = scrollers->vert_max - scrollers->vert_min;
        vsm->scrollbar_orig = ((scrollers->vert_max + scrollers->vert_min) / 2) +  + ar->winrct.ymin;
    }
    
    UI_view2d_scrollers_free(scrollers);
    ED_region_tag_redraw(ar);
}

/* cleanup temp customdata  */
static void scroller_activate_exit(bContext *C, wmOperator *op)
{
    if (op->customdata) {
        v2dScrollerMove *vsm= op->customdata;

        vsm->v2d->scroll_ui &= ~(V2D_SCROLL_H_ACTIVE|V2D_SCROLL_V_ACTIVE);
        
        MEM_freeN(op->customdata);
        op->customdata= NULL;       
        
        ED_region_tag_redraw(CTX_wm_region(C));
    }
}

static int scroller_activate_cancel(bContext *C, wmOperator *op)
{
    scroller_activate_exit(C, op);

    return OPERATOR_CANCELLED;
}

/* apply transform to view (i.e. adjust 'cur' rect) */
static void scroller_activate_apply(bContext *C, wmOperator *op)
{
    v2dScrollerMove *vsm= op->customdata;
    View2D *v2d= vsm->v2d;
    float temp;
    
    /* calculate amount to move view by */
    temp= vsm->fac * vsm->delta;
    
    /* type of movement */
    switch (vsm->zone) {
        case SCROLLHANDLE_MIN:
            /* only expand view on axis if zoom is allowed */
            if ((vsm->scroller == 'h') && !(v2d->keepzoom & V2D_LOCKZOOM_X))
                v2d->cur.xmin -= temp;
            if ((vsm->scroller == 'v') && !(v2d->keepzoom & V2D_LOCKZOOM_Y))
                v2d->cur.ymin -= temp;
            break;
            
        case SCROLLHANDLE_MAX:
            
            /* only expand view on axis if zoom is allowed */
            if ((vsm->scroller == 'h') && !(v2d->keepzoom & V2D_LOCKZOOM_X))
                v2d->cur.xmax += temp;
            if ((vsm->scroller == 'v') && !(v2d->keepzoom & V2D_LOCKZOOM_Y))
                v2d->cur.ymax += temp;
            break;
            
        case SCROLLHANDLE_MIN_OUTSIDE:
        case SCROLLHANDLE_MAX_OUTSIDE:
        case SCROLLHANDLE_BAR:
        default:
            /* only move view on an axis if panning is allowed */
            if ((vsm->scroller == 'h') && !(v2d->keepofs & V2D_LOCKOFS_X)) {
                v2d->cur.xmin += temp;
                v2d->cur.xmax += temp;
            }
            if ((vsm->scroller == 'v') && !(v2d->keepofs & V2D_LOCKOFS_Y)) {
                v2d->cur.ymin += temp;
                v2d->cur.ymax += temp;
            }
            break;
            
    }
    
    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);
    
    /* request updates to be done... */
    ED_region_tag_redraw(vsm->ar);
    UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
}

/* handle user input for scrollers - calculations of mouse-movement need to be done here, not in the apply callback! */
static int scroller_activate_modal(bContext *C, wmOperator *op, wmEvent *event)
{
    v2dScrollerMove *vsm= op->customdata;
    
    /* execute the events */
    switch (event->type) {
        case MOUSEMOVE:
        {
            /* calculate new delta transform, then store mouse-coordinates for next-time */
            if (ELEM(vsm->zone, SCROLLHANDLE_BAR, SCROLLHANDLE_MAX)) {
                /* if using bar (i.e. 'panning') or 'max' zoom widget */
                switch (vsm->scroller) {
                    case 'h': /* horizontal scroller - so only horizontal movement ('cur' moves opposite to mouse) */
                        vsm->delta= (float)(event->x - vsm->lastx);
                        break;
                    case 'v': /* vertical scroller - so only vertical movement ('cur' moves opposite to mouse) */
                        vsm->delta= (float)(event->y - vsm->lasty);
                        break;
                }
            }
            else if (vsm->zone == SCROLLHANDLE_MIN) {
                /* using 'min' zoom widget */
                switch (vsm->scroller) {
                    case 'h': /* horizontal scroller - so only horizontal movement ('cur' moves with mouse) */
                        vsm->delta= (float)(vsm->lastx - event->x);
                        break;
                    case 'v': /* vertical scroller - so only vertical movement ('cur' moves with to mouse) */
                        vsm->delta= (float)(vsm->lasty - event->y);
                        break;
                }
            }
            
            /* store previous coordinates */
            vsm->lastx= event->x;
            vsm->lasty= event->y;
            
            scroller_activate_apply(C, op);
        }
            break;
            
        case LEFTMOUSE:
        case MIDDLEMOUSE:
            if (event->val==KM_RELEASE) {
                /* single-click was in empty space outside bubble, so scroll by 1 'page' */
                if (ELEM(vsm->zone, SCROLLHANDLE_MIN_OUTSIDE, SCROLLHANDLE_MAX_OUTSIDE)) {
                    if (vsm->zone == SCROLLHANDLE_MIN_OUTSIDE)
                        vsm->delta = -vsm->scrollbarwidth * 0.8f;
                    else if (vsm->zone == SCROLLHANDLE_MAX_OUTSIDE)
                        vsm->delta = vsm->scrollbarwidth * 0.8f;
                    
                    scroller_activate_apply(C, op);
                    scroller_activate_exit(C, op);
                    return OPERATOR_FINISHED;
                }
                
                /* otherwise, end the drag action  */
                if (vsm->lastx || vsm->lasty) {
                    scroller_activate_exit(C, op);
                    return OPERATOR_FINISHED;
                }
            }
            break;

    }

    return OPERATOR_RUNNING_MODAL;
}


/* a click (or click drag in progress) should have occurred, so check if it happened in scrollbar */
static int scroller_activate_invoke(bContext *C, wmOperator *op, wmEvent *event)
{
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d= &ar->v2d;
    short in_scroller= 0;
        
    /* check if mouse in scrollbars, if they're enabled */
    in_scroller= UI_view2d_mouse_in_scrollers(C, v2d, event->x, event->y);
    
    /* if in a scroller, init customdata then set modal handler which will catch mousedown to start doing useful stuff */
    if (in_scroller) {
        v2dScrollerMove *vsm;
        
        /* initialise customdata */
        scroller_activate_init(C, op, event, in_scroller);
        vsm= (v2dScrollerMove *)op->customdata;
        
        /* support for quick jump to location - gtk and qt do this on linux */
        if (event->type == MIDDLEMOUSE) {
            switch (vsm->scroller) {
                case 'h': /* horizontal scroller - so only horizontal movement ('cur' moves opposite to mouse) */
                    vsm->delta= (float)(event->x - vsm->scrollbar_orig);
                    break;
                case 'v': /* vertical scroller - so only vertical movement ('cur' moves opposite to mouse) */
                    vsm->delta= (float)(event->y - vsm->scrollbar_orig);
                    break;
            }
            scroller_activate_apply(C, op);

            vsm->zone= SCROLLHANDLE_BAR;
        }

        /* check if zoom zones are inappropriate (i.e. zoom widgets not shown), so cannot continue
         * NOTE: see view2d.c for latest conditions, and keep this in sync with that
         */
        if (ELEM(vsm->zone, SCROLLHANDLE_MIN, SCROLLHANDLE_MAX)) {
            if ( ((vsm->scroller=='h') && (v2d->scroll & V2D_SCROLL_SCALE_HORIZONTAL)==0) ||
                 ((vsm->scroller=='v') && (v2d->scroll & V2D_SCROLL_SCALE_VERTICAL)==0) )
            {
                /* switch to bar (i.e. no scaling gets handled) */
                vsm->zone= SCROLLHANDLE_BAR;
            }
        }
        
        /* check if zone is inappropriate (i.e. 'bar' but panning is banned), so cannot continue */
        if (vsm->zone == SCROLLHANDLE_BAR) {
            if ( ((vsm->scroller=='h') && (v2d->keepofs & V2D_LOCKOFS_X)) ||
                 ((vsm->scroller=='v') && (v2d->keepofs & V2D_LOCKOFS_Y)) )
            {
                /* free customdata initialised */
                scroller_activate_exit(C, op);
                
                /* can't catch this event for ourselves, so let it go to someone else? */
                return OPERATOR_PASS_THROUGH;
            }           
        }
        
        /* zone is also inappropriate if scroller is not visible... */
        if ( ((vsm->scroller=='h') && (v2d->scroll & (V2D_SCROLL_HORIZONTAL_HIDE|V2D_SCROLL_HORIZONTAL_FULLR))) ||
             ((vsm->scroller=='v') && (v2d->scroll & (V2D_SCROLL_VERTICAL_HIDE|V2D_SCROLL_VERTICAL_FULLR))) )
        {
            /* free customdata initialised */
            scroller_activate_exit(C, op);
                
            /* can't catch this event for ourselves, so let it go to someone else? */
            /* XXX note: if handlers use mask rect to clip input, input will fail for this case */
            return OPERATOR_PASS_THROUGH;
        }
        
        /* activate the scroller */
        if (vsm->scroller=='h')
            v2d->scroll_ui |= V2D_SCROLL_H_ACTIVE;
        else
            v2d->scroll_ui |= V2D_SCROLL_V_ACTIVE;
        
        /* still ok, so can add */
        WM_event_add_modal_handler(C, op);
        return OPERATOR_RUNNING_MODAL;
    }
    else {
        /* not in scroller, so nothing happened... (pass through let's something else catch event) */
        return OPERATOR_PASS_THROUGH;
    }
}

/* LMB-Drag in Scrollers - not repeatable operator! */
static void VIEW2D_OT_scroller_activate(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Scroller Activate";
    ot->description= "Scroll view by mouse click and drag";
    ot->idname= "VIEW2D_OT_scroller_activate";

    /* flags */
    ot->flag= OPTYPE_BLOCKING;
    
    /* api callbacks */
    ot->invoke= scroller_activate_invoke;
    ot->modal= scroller_activate_modal;
    ot->cancel= scroller_activate_cancel;

    ot->poll= view2d_poll;
}

/* ********************************************************* */
/* RESET */

static int reset_exec(bContext *C, wmOperator *UNUSED(op))
{
    uiStyle *style= UI_GetStyle();
    ARegion *ar= CTX_wm_region(C);
    View2D *v2d= &ar->v2d;
    int winx, winy;

    /* zoom 1.0 */
    winx= (float)(v2d->mask.xmax - v2d->mask.xmin + 1);
    winy= (float)(v2d->mask.ymax - v2d->mask.ymin + 1);

    v2d->cur.xmax= v2d->cur.xmin + winx;
    v2d->cur.ymax= v2d->cur.ymin + winy;
    
    /* align */
    if (v2d->align) {
        /* 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)) {
            v2d->cur.xmax= 0.0f;
            v2d->cur.xmin= -winx*style->panelzoom;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_X) && !(v2d->align & V2D_ALIGN_NO_POS_X)) {
            v2d->cur.xmax= winx*style->panelzoom;
            v2d->cur.xmin= 0.0f;
        }

        /* - 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)) {
            v2d->cur.ymax= 0.0f;
            v2d->cur.ymin= -winy*style->panelzoom;
        }
        else if ((v2d->align & V2D_ALIGN_NO_NEG_Y) && !(v2d->align & V2D_ALIGN_NO_POS_Y)) {
            v2d->cur.ymax= winy*style->panelzoom;
            v2d->cur.ymin= 0.0f;
        }
    }

    /* validate that view is in valid configuration after this operation */
    UI_view2d_curRect_validate(v2d);
    
    /* request updates to be done... */
    ED_region_tag_redraw(ar);
    UI_view2d_sync(CTX_wm_screen(C), CTX_wm_area(C), v2d, V2D_LOCK_COPY);
    
    return OPERATOR_FINISHED;
}
 
static void VIEW2D_OT_reset(wmOperatorType *ot)
{
    /* identifiers */
    ot->name= "Reset View";
    ot->description= "Reset the view";
    ot->idname= "VIEW2D_OT_reset";
    
    /* api callbacks */
    ot->exec= reset_exec;
    ot->poll= view2d_poll;
}
 
/* ********************************************************* */
/* Registration */

void UI_view2d_operatortypes(void)
{
    WM_operatortype_append(VIEW2D_OT_pan);
    
    WM_operatortype_append(VIEW2D_OT_scroll_left);
    WM_operatortype_append(VIEW2D_OT_scroll_right);
    WM_operatortype_append(VIEW2D_OT_scroll_up);
    WM_operatortype_append(VIEW2D_OT_scroll_down);
    
    WM_operatortype_append(VIEW2D_OT_zoom_in);
    WM_operatortype_append(VIEW2D_OT_zoom_out);
    
    WM_operatortype_append(VIEW2D_OT_zoom);
    WM_operatortype_append(VIEW2D_OT_zoom_border);
    
    WM_operatortype_append(VIEW2D_OT_scroller_activate);

    WM_operatortype_append(VIEW2D_OT_reset);
}

void UI_view2d_keymap(wmKeyConfig *keyconf)
{
    wmKeyMap *keymap= WM_keymap_find(keyconf, "View2D", 0, 0);
    wmKeyMapItem *kmi;

    /* scrollers */
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", LEFTMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", MIDDLEMOUSE, KM_PRESS, 0, 0);

    /* pan/scroll */
    WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, KM_SHIFT, 0);
    
    WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MOUSEPAN, 0, 0, 0);
    
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", WHEELDOWNMOUSE, KM_PRESS, KM_CTRL, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", WHEELUPMOUSE, KM_PRESS, KM_CTRL, 0);
    
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, KM_SHIFT, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, KM_SHIFT, 0);
    
    /* zoom - single step */
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", WHEELOUTMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", WHEELINMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", PADMINUS, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", PADPLUSKEY, KM_PRESS, 0, 0);
    
    /* scroll up/down - no modifiers, only when zoom fails */
        /* these may fail if zoom is disallowed, in which case they should pass on event */
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, 0, 0);
        /* these may be necessary if vertical scroll is disallowed */
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", WHEELUPMOUSE, KM_PRESS, 0, 0);
    
    /* alternatives for page up/down to scroll */
#if 0 // XXX disabled, since this causes conflicts with hotkeys in animation editors
        /* scroll up/down may fall through to left/right */
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", PAGEDOWNKEY, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", PAGEUPKEY, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", PAGEDOWNKEY, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", PAGEUPKEY, KM_PRESS, 0, 0);
        /* shift for moving view left/right with page up/down */
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_right", PAGEDOWNKEY, KM_PRESS, KM_SHIFT, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_left", PAGEUPKEY, KM_PRESS, KM_SHIFT, 0);
#endif
    
    /* zoom - drag */
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MIDDLEMOUSE, KM_PRESS, KM_CTRL, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MOUSEZOOM, 0, 0, 0);
    
    /* borderzoom - drag */
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_border", BKEY, KM_PRESS, KM_SHIFT, 0);

    /* Alternative keymap for buttons listview */
    keymap= WM_keymap_find(keyconf, "View2D Buttons List", 0, 0);

    WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", LEFTMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroller_activate", MIDDLEMOUSE, KM_PRESS, 0, 0);

    WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MIDDLEMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_pan", MOUSEPAN, 0, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", WHEELDOWNMOUSE, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", WHEELUPMOUSE, KM_PRESS, 0, 0);
    
    kmi = WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_down", PAGEDOWNKEY, KM_PRESS, 0, 0);
    RNA_boolean_set(kmi->ptr, "page", TRUE);
    kmi = WM_keymap_add_item(keymap, "VIEW2D_OT_scroll_up", PAGEUPKEY, KM_PRESS, 0, 0);
    RNA_boolean_set(kmi->ptr, "page", TRUE);
    
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MIDDLEMOUSE, KM_PRESS, KM_CTRL, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom", MOUSEZOOM, 0, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_out", PADMINUS, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_zoom_in", PADPLUSKEY, KM_PRESS, 0, 0);
    WM_keymap_add_item(keymap, "VIEW2D_OT_reset", HOMEKEY, KM_PRESS, 0, 0);
}