interface_panel.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) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * Contributor(s): Blender Foundation, 2003-2009 full recode.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/* a full doc with API notes can be found in bf-blender/trunk/blender/doc/guides/interface_API.txt */
 
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "MEM_guardedalloc.h"

#include "PIL_time.h"

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

#include "BLF_translation.h"

#include "DNA_userdef_types.h"

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

#include "BIF_gl.h"
#include "BIF_glutil.h"

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

#include "ED_screen.h"

#include "UI_interface.h"
#include "UI_resources.h"

#include "interface_intern.h"

/*********************** defines and structs ************************/

#define ANIMATION_TIME      0.30
#define ANIMATION_INTERVAL  0.02

#define PNL_LAST_ADDED      1
#define PNL_ACTIVE          2
#define PNL_WAS_ACTIVE      4
#define PNL_ANIM_ALIGN      8
#define PNL_NEW_ADDED       16
#define PNL_FIRST           32

typedef enum uiHandlePanelState {
    PANEL_STATE_DRAG,
    PANEL_STATE_DRAG_SCALE,
    PANEL_STATE_WAIT_UNTAB,
    PANEL_STATE_ANIMATION,
    PANEL_STATE_EXIT
} uiHandlePanelState;

typedef struct uiHandlePanelData {
    uiHandlePanelState state;

    /* animation */
    wmTimer *animtimer;
    double starttime;

    /* dragging */
    int startx, starty;
    int startofsx, startofsy;
    int startsizex, startsizey;
} uiHandlePanelData;

static void panel_activate_state(const bContext *C, Panel *pa, uiHandlePanelState state);

/*********************** space specific code ************************/
/* temporary code to remove all sbuts stuff from panel code         */

static int panel_aligned(ScrArea *sa, ARegion *ar)
{
    if(sa->spacetype==SPACE_BUTS && ar->regiontype == RGN_TYPE_WINDOW) {
        SpaceButs *sbuts= sa->spacedata.first;
        return sbuts->align;
    }
    else if(sa->spacetype==SPACE_USERPREF && ar->regiontype == RGN_TYPE_WINDOW)
        return BUT_VERTICAL;
    else if(sa->spacetype==SPACE_FILE && ar->regiontype == RGN_TYPE_CHANNELS)
        return BUT_VERTICAL;
    else if(sa->spacetype==SPACE_IMAGE && ar->regiontype == RGN_TYPE_PREVIEW)
        return BUT_VERTICAL; 
    else if(ELEM3(ar->regiontype, RGN_TYPE_UI, RGN_TYPE_TOOLS, RGN_TYPE_TOOL_PROPS))
        return BUT_VERTICAL;
    
    return 0;
}

static int panels_re_align(ScrArea *sa, ARegion *ar, Panel **r_pa)
{
    Panel *pa;
    int active= 0;

    *r_pa= NULL;

    if(sa->spacetype==SPACE_BUTS && ar->regiontype == RGN_TYPE_WINDOW) {
        SpaceButs *sbuts= sa->spacedata.first;

        if(sbuts->align)
            if(sbuts->re_align || sbuts->mainbo!=sbuts->mainb)
                return 1;
    }
    else if(ar->regiontype==RGN_TYPE_UI)
        return 1;
    else if(sa->spacetype==SPACE_IMAGE && ar->regiontype == RGN_TYPE_PREVIEW)
        return 1;
    else if(sa->spacetype==SPACE_FILE && ar->regiontype == RGN_TYPE_CHANNELS)
        return 1;

    /* in case panel is added or disappears */
    for(pa=ar->panels.first; pa; pa=pa->next) {
        if((pa->runtime_flag & PNL_WAS_ACTIVE) && !(pa->runtime_flag & PNL_ACTIVE))
            return 1;
        if(!(pa->runtime_flag & PNL_WAS_ACTIVE) && (pa->runtime_flag & PNL_ACTIVE))
            return 1;
        if(pa->activedata)
            active= 1;
    }

    /* in case we need to do an animation (size changes) */
    for(pa=ar->panels.first; pa; pa=pa->next) {
        if(pa->runtime_flag & PNL_ANIM_ALIGN) {
            if(!active)
                *r_pa= pa;
            return 1;
        }
    }
    
    return 0;
}

/****************************** panels ******************************/

static void ui_panel_copy_offset(Panel *pa, Panel *papar)
{
    /* with respect to sizes... papar is parent */

    pa->ofsx= papar->ofsx;
    pa->ofsy= papar->ofsy + papar->sizey-pa->sizey;
}

Panel *uiBeginPanel(ScrArea *sa, ARegion *ar, uiBlock *block, PanelType *pt, int *open)
{
    Panel *pa, *patab, *palast, *panext;
    char *drawname= pt->label;
    char *idname= pt->idname;
    char *tabname= pt->idname;
    char *hookname= NULL;
    int newpanel;
    int align= panel_aligned(sa, ar);
    
    /* check if Panel exists, then use that one */
    for(pa=ar->panels.first; pa; pa=pa->next)
        if(strncmp(pa->panelname, idname, UI_MAX_NAME_STR)==0)
            if(strncmp(pa->tabname, tabname, UI_MAX_NAME_STR)==0)
                break;
    
    newpanel= (pa == NULL);

    if(!newpanel) {
        pa->type= pt;
    }
    else {
        /* new panel */
        pa= MEM_callocN(sizeof(Panel), "new panel");
        pa->type= pt;
        BLI_strncpy(pa->panelname, idname, UI_MAX_NAME_STR);
        BLI_strncpy(pa->tabname, tabname, UI_MAX_NAME_STR);

        if(pt->flag & PNL_DEFAULT_CLOSED) {
            if(align == BUT_VERTICAL)
                pa->flag |= PNL_CLOSEDY;
            else
                pa->flag |= PNL_CLOSEDX;
        }
    
        pa->ofsx= 0;
        pa->ofsy= 0;
        pa->sizex= 0;
        pa->sizey= 0;
        pa->runtime_flag |= PNL_NEW_ADDED;

        BLI_addtail(&ar->panels, pa);
        
        /* make new Panel tabbed? */
        if(hookname) {
            for(patab= ar->panels.first; patab; patab= patab->next) {
                if((patab->runtime_flag & PNL_ACTIVE) && patab->paneltab==NULL) {
                    if(strncmp(hookname, patab->panelname, UI_MAX_NAME_STR)==0) {
                        if(strncmp(tabname, patab->tabname, UI_MAX_NAME_STR)==0) {
                            pa->paneltab= patab;
                            ui_panel_copy_offset(pa, patab);
                            break;
                        }
                    }
                }
            } 
        }
    }

    BLI_strncpy(pa->drawname, drawname, UI_MAX_NAME_STR);

    /* if a new panel is added, we insert it right after the panel
     * that was last added. this way new panels are inserted in the
     * right place between versions */
    for(palast=ar->panels.first; palast; palast=palast->next)
        if(palast->runtime_flag & PNL_LAST_ADDED)
            break;
    
    if(newpanel) {
        pa->sortorder= (palast)? palast->sortorder+1: 0;

        for(panext=ar->panels.first; panext; panext=panext->next)
            if(panext != pa && panext->sortorder >= pa->sortorder)
                panext->sortorder++;
    }

    if(palast)
        palast->runtime_flag &= ~PNL_LAST_ADDED;

    /* assign to block */
    block->panel= pa;
    pa->runtime_flag |= PNL_ACTIVE|PNL_LAST_ADDED;

    *open= 0;

    if(pa->paneltab) return pa;
    if(pa->flag & PNL_CLOSED) return pa;

    *open= 1;
    
    return pa;
}

void uiEndPanel(uiBlock *block, int width, int height)
{
    Panel *pa= block->panel;

    if(pa->runtime_flag & PNL_NEW_ADDED) {
        pa->runtime_flag &= ~PNL_NEW_ADDED;
        pa->sizex= width;
        pa->sizey= height;
    }
    else {
        /* check if we need to do an animation */
        if(!ELEM(width, 0, pa->sizex) || !ELEM(height, 0, pa->sizey)) {
            pa->runtime_flag |= PNL_ANIM_ALIGN;
            if(height != 0)
                pa->ofsy += pa->sizey-height;
        }

        /* update width/height if non-zero */
        if(width != 0)
            pa->sizex= width;
        if(height != 0)
            pa->sizey= height;
    }
}

static void ui_offset_panel_block(uiBlock *block)
{
    uiStyle *style= UI_GetStyle();
    uiBut *but;
    int ofsy;

    /* compute bounds and offset */
    ui_bounds_block(block);

    ofsy= block->panel->sizey - style->panelspace;

    for(but= block->buttons.first; but; but=but->next) {
        but->y1 += ofsy;
        but->y2 += ofsy;
    }

    block->maxx= block->panel->sizex;
    block->maxy= block->panel->sizey;
    block->minx= block->miny= 0.0;
}

/**************************** drawing *******************************/

/* extern used by previewrender */
#if 0 /*UNUSED 2.5*/
static void uiPanelPush(uiBlock *block)
{
    glPushMatrix(); 

    if(block->panel)
        glTranslatef((float)block->panel->ofsx, (float)block->panel->ofsy, 0.0);
}

static void uiPanelPop(uiBlock *UNUSED(block))
{
    glPopMatrix();
}
#endif

/* triangle 'icon' for panel header */
void UI_DrawTriIcon(float x, float y, char dir)
{
    if(dir=='h') {
        ui_draw_anti_tria( x-3, y-5, x-3, y+5, x+7,y );
    }
    else if(dir=='t') {
        ui_draw_anti_tria( x-5, y-7, x+5, y-7, x, y+3); 
    }
    else { /* 'v' = vertical, down */
        ui_draw_anti_tria( x-5, y+3, x+5, y+3, x, y-7); 
    }
}

/* triangle 'icon' inside rect */
static void ui_draw_tria_rect(rctf *rect, char dir)
{
    if(dir=='h') {
        float half= 0.5f*(rect->ymax - rect->ymin);
        ui_draw_anti_tria(rect->xmin, rect->ymin, rect->xmin, rect->ymax, rect->xmax, rect->ymin+half);
    }
    else {
        float half= 0.5f*(rect->xmax - rect->xmin);
        ui_draw_anti_tria(rect->xmin, rect->ymax, rect->xmax, rect->ymax, rect->xmin+half, rect->ymin);
    }
}

static void ui_draw_anti_x(float x1, float y1, float x2, float y2)
{

    /* set antialias line */
    glEnable(GL_LINE_SMOOTH);
    glEnable(GL_BLEND);

    glLineWidth(2.0);
    
    fdrawline(x1, y1, x2, y2);
    fdrawline(x1, y2, x2, y1);
    
    glLineWidth(1.0);
    
    glDisable(GL_LINE_SMOOTH);
    glDisable(GL_BLEND);
    
}

/* x 'icon' for panel header */
static void ui_draw_x_icon(float x, float y)
{

    ui_draw_anti_x(x, y, x+9.375f, y+9.375f);

}

#define PNL_ICON    UI_UNIT_X  /* could be UI_UNIT_Y too */

static void ui_draw_panel_scalewidget(rcti *rect)
{
    float xmin, xmax, dx;
    float ymin, ymax, dy;
    
    xmin= rect->xmax-PNL_HEADER+2;
    xmax= rect->xmax-3;
    ymin= rect->ymin+3;
    ymax= rect->ymin+PNL_HEADER-2;
        
    dx= 0.5f*(xmax-xmin);
    dy= 0.5f*(ymax-ymin);
    
    glEnable(GL_BLEND);
    glColor4ub(255, 255, 255, 50);
    fdrawline(xmin, ymin, xmax, ymax);
    fdrawline(xmin+dx, ymin, xmax, ymax-dy);
    
    glColor4ub(0, 0, 0, 50);
    fdrawline(xmin, ymin+1, xmax, ymax+1);
    fdrawline(xmin+dx, ymin+1, xmax, ymax-dy+1);
    glDisable(GL_BLEND);
}

static void ui_draw_panel_dragwidget(rctf *rect)
{
    float xmin, xmax, dx;
    float ymin, ymax, dy;
    
    xmin= rect->xmin;
    xmax= rect->xmax;
    ymin= rect->ymin;
    ymax= rect->ymax;
    
    dx= 0.333f*(xmax-xmin);
    dy= 0.333f*(ymax-ymin);
    
    glEnable(GL_BLEND);
    glColor4ub(255, 255, 255, 50);
    fdrawline(xmin, ymax, xmax, ymin);
    fdrawline(xmin+dx, ymax, xmax, ymin+dy);
    fdrawline(xmin+2*dx, ymax, xmax, ymin+2*dy);
    
    glColor4ub(0, 0, 0, 50);
    fdrawline(xmin, ymax+1, xmax, ymin+1);
    fdrawline(xmin+dx, ymax+1, xmax, ymin+dy+1);
    fdrawline(xmin+2*dx, ymax+1, xmax, ymin+2*dy+1);
    glDisable(GL_BLEND);
}


static void ui_draw_aligned_panel_header(uiStyle *style, uiBlock *block, rcti *rect, char dir)
{
    Panel *panel= block->panel;
    rcti hrect;
    int  pnl_icons;
    const char *activename= IFACE_(panel->drawname[0] ? panel->drawname : panel->panelname);

    /* + 0.001f to avoid flirting with float inaccuracy */
    if(panel->control & UI_PNL_CLOSE) pnl_icons=(panel->labelofs+2*PNL_ICON+5)/block->aspect + 0.001f;
    else pnl_icons= (panel->labelofs+PNL_ICON+5)/block->aspect + 0.001f;
    
    /* active tab */
    /* draw text label */
    UI_ThemeColor(TH_TITLE);
    
    hrect= *rect;
    if(dir == 'h') {
        hrect.xmin= rect->xmin+pnl_icons;
        hrect.ymin += 2.0f/block->aspect;
        uiStyleFontDraw(&style->paneltitle, &hrect, activename);
    }
    else {
        /* ignore 'pnl_icons', otherwise the text gets offset horizontally 
         * + 0.001f to avoid flirting with float inaccuracy
         */
        hrect.xmin= rect->xmin + (PNL_ICON+5)/block->aspect + 0.001f;
        uiStyleFontDrawRotated(&style->paneltitle, &hrect, activename);
    }
}

static void rectf_scale(rctf *rect, float scale)
{
    float centx= 0.5f*(rect->xmin+rect->xmax);
    float centy= 0.5f*(rect->ymin+rect->ymax);
    float sizex= 0.5f*scale*(rect->xmax - rect->xmin);
    float sizey= 0.5f*scale*(rect->ymax - rect->ymin);
    
    rect->xmin= centx - sizex;
    rect->xmax= centx + sizex;
    rect->ymin= centy - sizey;
    rect->ymax= centy + sizey;
}

/* panel integrated in buttonswindow, tool/property lists etc */
void ui_draw_aligned_panel(uiStyle *style, uiBlock *block, rcti *rect)
{
    bTheme *btheme= UI_GetTheme();
    Panel *panel= block->panel;
    rcti headrect;
    rctf itemrect;
    int ofsx;
    
    if(panel->paneltab) return;
    if(panel->type && (panel->type->flag & PNL_NO_HEADER)) return;

    /* calculate header rect */
    /* + 0.001f to prevent flicker due to float inaccuracy */
    headrect= *rect;
    headrect.ymin= headrect.ymax;
    headrect.ymax= headrect.ymin + floor(PNL_HEADER/block->aspect + 0.001f);
    
    {
        float minx= rect->xmin;
        float maxx= rect->xmax;
        float y= headrect.ymax;

        glEnable(GL_BLEND);

        if(btheme->tui.panel.show_header) {
            /* draw with background color */
            glEnable(GL_BLEND);
            glColor4ubv((unsigned char*)btheme->tui.panel.header);
            glRectf(minx, headrect.ymin+1, maxx, y);

            fdrawline(minx, y, maxx, y);
            fdrawline(minx, y, maxx, y);
        }
        else if(!(panel->runtime_flag & PNL_FIRST)) {
            /* draw embossed separator */
            minx += 5.0f/block->aspect;
            maxx -= 5.0f/block->aspect;
            
            glColor4f(0.0f, 0.0f, 0.0f, 0.5f);
            fdrawline(minx, y, maxx, y);
            glColor4f(1.0f, 1.0f, 1.0f, 0.25f);
            fdrawline(minx, y-1, maxx, y-1);
            glDisable(GL_BLEND);
        }

        glDisable(GL_BLEND);
    }
    
    /* horizontal title */
    if(!(panel->flag & PNL_CLOSEDX)) {
        ui_draw_aligned_panel_header(style, block, &headrect, 'h');
        
        /* itemrect smaller */  
        itemrect.xmax= headrect.xmax - 5.0f/block->aspect;
        itemrect.xmin= itemrect.xmax - (headrect.ymax-headrect.ymin);
        itemrect.ymin= headrect.ymin;
        itemrect.ymax= headrect.ymax;

        rectf_scale(&itemrect, 0.7f);
        ui_draw_panel_dragwidget(&itemrect);
    }
    
    /* if the panel is minimized vertically:
        * (------)
        */
    if(panel->flag & PNL_CLOSEDY) {
        
    }
    else if(panel->flag & PNL_CLOSEDX) {
        /* draw vertical title */
        ui_draw_aligned_panel_header(style, block, &headrect, 'v');
    }
    /* an open panel */
    else {
        
        /* in some occasions, draw a border */
        if(panel->flag & PNL_SELECT) {
            if(panel->control & UI_PNL_SOLID) uiSetRoundBox(UI_CNR_ALL);
            else uiSetRoundBox(UI_CNR_NONE);
            
            UI_ThemeColorShade(TH_BACK, -120);
            uiRoundRect(0.5f + rect->xmin, 0.5f + rect->ymin, 0.5f + rect->xmax, 0.5f + headrect.ymax+1, 8);
        }
        
        if(panel->control & UI_PNL_SCALE)
            ui_draw_panel_scalewidget(rect);
    }
    
    /* draw optional close icon */
    
    ofsx= 6;
    if(panel->control & UI_PNL_CLOSE) {
        
        UI_ThemeColor(TH_TEXT);
        ui_draw_x_icon(rect->xmin+2+ofsx, rect->ymax+2);
        ofsx= 22;
    }
    
    /* draw collapse icon */
    UI_ThemeColor(TH_TEXT);
    
    /* itemrect smaller */  
    itemrect.xmin= headrect.xmin + 5.0f/block->aspect;
    itemrect.xmax= itemrect.xmin + (headrect.ymax-headrect.ymin);
    itemrect.ymin= headrect.ymin;
    itemrect.ymax= headrect.ymax;
    
    rectf_scale(&itemrect, 0.35f);
    
    if(panel->flag & PNL_CLOSEDY)
        ui_draw_tria_rect(&itemrect, 'h');
    else if(panel->flag & PNL_CLOSEDX)
        ui_draw_tria_rect(&itemrect, 'h');
    else
        ui_draw_tria_rect(&itemrect, 'v');

    (void)ofsx;
}

/************************** panel alignment *************************/

static int get_panel_header(Panel *pa)
{
    if(pa->type && (pa->type->flag & PNL_NO_HEADER))
        return 0;

    return PNL_HEADER;
}

static int get_panel_size_y(Panel *pa)
{
    if(pa->type && (pa->type->flag & PNL_NO_HEADER))
        return pa->sizey;

    return PNL_HEADER + pa->sizey;
}

/* this function is needed because uiBlock and Panel itself dont
change sizey or location when closed */
static int get_panel_real_ofsy(Panel *pa)
{
    if(pa->flag & PNL_CLOSEDY) return pa->ofsy+pa->sizey;
    else if(pa->paneltab && (pa->paneltab->flag & PNL_CLOSEDY)) return pa->ofsy+pa->sizey;
    else if(pa->paneltab) return pa->paneltab->ofsy;
    else return pa->ofsy;
}

static int get_panel_real_ofsx(Panel *pa)
{
    if(pa->flag & PNL_CLOSEDX) return pa->ofsx+get_panel_header(pa);
    else if(pa->paneltab && (pa->paneltab->flag & PNL_CLOSEDX)) return pa->ofsx+get_panel_header(pa);
    else return pa->ofsx+pa->sizex;
}

typedef struct PanelSort {
    Panel *pa, *orig;
} PanelSort;

/* note about sorting;
   the sortorder has a lower value for new panels being added.
   however, that only works to insert a single panel, when more new panels get
   added the coordinates of existing panels and the previously stored to-be-insterted
   panels do not match for sorting */

static int find_leftmost_panel(const void *a1, const void *a2)
{
    const PanelSort *ps1=a1, *ps2=a2;
    
    if(ps1->pa->ofsx > ps2->pa->ofsx) return 1;
    else if(ps1->pa->ofsx < ps2->pa->ofsx) return -1;
    else if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
    else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;

    return 0;
}


static int find_highest_panel(const void *a1, const void *a2)
{
    const PanelSort *ps1=a1, *ps2=a2;
    
    /* stick uppermost header-less panels to the top of the region -
     * prevent them from being sorted */
    if (ps1->pa->sortorder < ps2->pa->sortorder && ps1->pa->type->flag & PNL_NO_HEADER) return -1;
    
    if(ps1->pa->ofsy+ps1->pa->sizey < ps2->pa->ofsy+ps2->pa->sizey) return 1;
    else if(ps1->pa->ofsy+ps1->pa->sizey > ps2->pa->ofsy+ps2->pa->sizey) return -1;
    else if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
    else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;
    
    return 0;
}

static int compare_panel(const void *a1, const void *a2)
{
    const PanelSort *ps1=a1, *ps2=a2;
    
    if(ps1->pa->sortorder > ps2->pa->sortorder) return 1;
    else if(ps1->pa->sortorder < ps2->pa->sortorder) return -1;
    
    return 0;
}

/* this doesnt draw */
/* returns 1 when it did something */
static int uiAlignPanelStep(ScrArea *sa, ARegion *ar, float fac, int drag)
{
    Panel *pa;
    PanelSort *ps, *panelsort, *psnext;
    int a, tot=0, done;
    int align= panel_aligned(sa, ar);
    
    /* count active, not tabbed panels */
    for(pa= ar->panels.first; pa; pa= pa->next)
        if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL)
            tot++;

    if(tot==0) return 0;

    /* extra; change close direction? */
    for(pa= ar->panels.first; pa; pa= pa->next) {
        if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL) {
            if((pa->flag & PNL_CLOSEDX) && (align==BUT_VERTICAL))
                pa->flag ^= PNL_CLOSED;
            else if((pa->flag & PNL_CLOSEDY) && (align==BUT_HORIZONTAL))
                pa->flag ^= PNL_CLOSED;
        }
    }

    /* sort panels */
    panelsort= MEM_callocN(tot*sizeof(PanelSort), "panelsort");
    
    ps= panelsort;
    for(pa= ar->panels.first; pa; pa= pa->next) {
        if((pa->runtime_flag & PNL_ACTIVE) && pa->paneltab==NULL) {
            ps->pa= MEM_dupallocN(pa);
            ps->orig= pa;
            ps++;
        }
    }
    
    if(drag) {
        /* while we are dragging, we sort on location and update sortorder */
        if(align==BUT_VERTICAL) 
            qsort(panelsort, tot, sizeof(PanelSort), find_highest_panel);
        else
            qsort(panelsort, tot, sizeof(PanelSort), find_leftmost_panel);

        for(ps=panelsort, a=0; a<tot; a++, ps++)
            ps->orig->sortorder= a;
    }
    else
        /* otherwise use sortorder */
        qsort(panelsort, tot, sizeof(PanelSort), compare_panel);
    
    /* no smart other default start loc! this keeps switching f5/f6/etc compatible */
    ps= panelsort;
    ps->pa->ofsx= 0;
    ps->pa->ofsy= -get_panel_size_y(ps->pa);

    for(a=0; a<tot-1; a++, ps++) {
        psnext= ps+1;
    
        if(align==BUT_VERTICAL) {
            psnext->pa->ofsx= ps->pa->ofsx;
            psnext->pa->ofsy= get_panel_real_ofsy(ps->pa) - get_panel_size_y(psnext->pa);
        }
        else {
            psnext->pa->ofsx= get_panel_real_ofsx(ps->pa);
            psnext->pa->ofsy= ps->pa->ofsy + get_panel_size_y(ps->pa) - get_panel_size_y(psnext->pa);
        }
    }
    
    /* we interpolate */
    done= 0;
    ps= panelsort;
    for(a=0; a<tot; a++, ps++) {
        if((ps->pa->flag & PNL_SELECT)==0) {
            if((ps->orig->ofsx != ps->pa->ofsx) || (ps->orig->ofsy != ps->pa->ofsy)) {
                ps->orig->ofsx= floorf(0.5f + fac*(float)ps->pa->ofsx + (1.0f-fac)*(float)ps->orig->ofsx);
                ps->orig->ofsy= floorf(0.5f + fac*(float)ps->pa->ofsy + (1.0f-fac)*(float)ps->orig->ofsy);
                done= 1;
            }
        }
    }

    /* copy locations to tabs */
    for(pa= ar->panels.first; pa; pa= pa->next)
        if(pa->paneltab && (pa->runtime_flag & PNL_ACTIVE))
            ui_panel_copy_offset(pa, pa->paneltab);

    /* free panelsort array */
    for(ps= panelsort, a=0; a<tot; a++, ps++)
        MEM_freeN(ps->pa);
    MEM_freeN(panelsort);
    
    return done;
}

static void ui_panels_size(ScrArea *sa, ARegion *ar, int *x, int *y)
{
    Panel *pa;
    int align= panel_aligned(sa, ar);
    int sizex = UI_PANEL_WIDTH;
    int sizey = UI_PANEL_WIDTH;

    /* compute size taken up by panels, for setting in view2d */
    for(pa= ar->panels.first; pa; pa= pa->next) {
        if(pa->runtime_flag & PNL_ACTIVE) {
            int pa_sizex, pa_sizey;

            if(align==BUT_VERTICAL) {
                pa_sizex= pa->ofsx + pa->sizex;
                pa_sizey= get_panel_real_ofsy(pa);
            }
            else {
                pa_sizex= get_panel_real_ofsx(pa) + pa->sizex;
                pa_sizey= pa->ofsy + get_panel_size_y(pa);
            }

            sizex= MAX2(sizex, pa_sizex);
            sizey= MIN2(sizey, pa_sizey);
        }
    }

    *x= sizex;
    *y= sizey;
}

static void ui_do_animate(const bContext *C, Panel *panel)
{
    uiHandlePanelData *data= panel->activedata;
    ScrArea *sa= CTX_wm_area(C);
    ARegion *ar= CTX_wm_region(C);
    float fac;

    fac= (PIL_check_seconds_timer()-data->starttime)/ANIMATION_TIME;
    fac= sqrt(fac);
    fac= MIN2(fac, 1.0f);

    /* for max 1 second, interpolate positions */
    if(uiAlignPanelStep(sa, ar, fac, 0))
        ED_region_tag_redraw(ar);
    else
        fac= 1.0f;

    if(fac >= 1.0f) {
        panel_activate_state(C, panel, PANEL_STATE_EXIT);
        return;
    }
}

void uiBeginPanels(const bContext *UNUSED(C), ARegion *ar)
{
    Panel *pa;
  
      /* set all panels as inactive, so that at the end we know
     * which ones were used */
    for(pa=ar->panels.first; pa; pa=pa->next) {
        if(pa->runtime_flag & PNL_ACTIVE)
            pa->runtime_flag= PNL_WAS_ACTIVE;
        else
            pa->runtime_flag= 0;
    }
}

/* only draws blocks with panels */
void uiEndPanels(const bContext *C, ARegion *ar, int *x, int *y)
{
    ScrArea *sa= CTX_wm_area(C);
    uiBlock *block;
    Panel *panot, *panew, *patest, *pa, *firstpa;
    
    /* offset contents */
    for(block= ar->uiblocks.first; block; block= block->next)
        if(block->active && block->panel)
            ui_offset_panel_block(block);

    /* consistency; are panels not made, whilst they have tabs */
    for(panot= ar->panels.first; panot; panot= panot->next) {
        if((panot->runtime_flag & PNL_ACTIVE)==0) { // not made

            for(panew= ar->panels.first; panew; panew= panew->next) {
                if((panew->runtime_flag & PNL_ACTIVE)) {
                    if(panew->paneltab==panot) { // panew is tab in notmade pa
                        break;
                    }
                }
            }
            /* now panew can become the new parent, check all other tabs */
            if(panew) {
                for(patest= ar->panels.first; patest; patest= patest->next) {
                    if(patest->paneltab == panot) {
                        patest->paneltab= panew;
                    }
                }
                panot->paneltab= panew;
                panew->paneltab= NULL;
                ED_region_tag_redraw(ar); // the buttons panew were not made
            }
        }   
    }

    /* re-align, possibly with animation */
    if(panels_re_align(sa, ar, &pa)) {
        if(pa)
            panel_activate_state(C, pa, PANEL_STATE_ANIMATION);
        else
            uiAlignPanelStep(sa, ar, 1.0, 0);
    }

    /* tag first panel */
    firstpa= NULL;
    for(block= ar->uiblocks.first; block; block=block->next)
        if(block->active && block->panel)
            if(!firstpa || block->panel->sortorder < firstpa->sortorder)
                firstpa= block->panel;
    
    if(firstpa)
        firstpa->runtime_flag |= PNL_FIRST;
    
    /* compute size taken up by panel */
    ui_panels_size(sa, ar, x, y);
}

void uiDrawPanels(const bContext *C, ARegion *ar)
{
    uiBlock *block;

    UI_ThemeClearColor(TH_BACK);
    
    /* draw panels, selected on top */
    for(block= ar->uiblocks.first; block; block=block->next) {
        if(block->active && block->panel && !(block->panel->flag & PNL_SELECT)) {
            uiDrawBlock(C, block);
        }
    }

    for(block= ar->uiblocks.first; block; block=block->next) {
        if(block->active && block->panel && (block->panel->flag & PNL_SELECT)) {
            uiDrawBlock(C, block);
        }
    }
}

/* ------------ panel merging ---------------- */

static void check_panel_overlap(ARegion *ar, Panel *panel)
{
    Panel *pa;

    /* also called with panel==NULL for clear */
    
    for(pa=ar->panels.first; pa; pa=pa->next) {
        pa->flag &= ~PNL_OVERLAP;
        if(panel && (pa != panel)) {
            if(pa->paneltab==NULL && (pa->runtime_flag & PNL_ACTIVE)) {
                float safex= 0.2, safey= 0.2;
                
                if(pa->flag & PNL_CLOSEDX) safex= 0.05;
                else if(pa->flag & PNL_CLOSEDY) safey= 0.05;
                else if(panel->flag & PNL_CLOSEDX) safex= 0.05;
                else if(panel->flag & PNL_CLOSEDY) safey= 0.05;
                
                if(pa->ofsx > panel->ofsx- safex*panel->sizex)
                if(pa->ofsx+pa->sizex < panel->ofsx+ (1.0f+safex)*panel->sizex)
                if(pa->ofsy > panel->ofsy- safey*panel->sizey)
                if(pa->ofsy+pa->sizey < panel->ofsy+ (1.0f+safey)*panel->sizey)
                    pa->flag |= PNL_OVERLAP;
            }
        }
    }
}

/************************ panel dragging ****************************/

static void ui_do_drag(const bContext *C, wmEvent *event, Panel *panel)
{
    uiHandlePanelData *data= panel->activedata;
    ScrArea *sa= CTX_wm_area(C);
    ARegion *ar= CTX_wm_region(C);
    short align= panel_aligned(sa, ar), dx=0, dy=0;
    
    /* first clip for window, no dragging outside */
    if(!BLI_in_rcti(&ar->winrct, event->x, event->y))
        return;

    dx= (event->x-data->startx) & ~(PNL_GRID-1);
    dy= (event->y-data->starty) & ~(PNL_GRID-1);

    dx *= (float)(ar->v2d.cur.xmax - ar->v2d.cur.xmin)/(float)(ar->winrct.xmax - ar->winrct.xmin);
    dy *= (float)(ar->v2d.cur.ymax - ar->v2d.cur.ymin)/(float)(ar->winrct.ymax - ar->winrct.ymin);
    
    if(data->state == PANEL_STATE_DRAG_SCALE) {
        panel->sizex = MAX2(data->startsizex+dx, UI_PANEL_MINX);
        
        if(data->startsizey-dy < UI_PANEL_MINY)
            dy= -UI_PANEL_MINY+data->startsizey;

        panel->sizey= data->startsizey-dy;
        panel->ofsy= data->startofsy+dy;
    }
    else {
        /* reset the panel snapping, to allow dragging away from snapped edges */
        panel->snap = PNL_SNAP_NONE;
        
        panel->ofsx = data->startofsx+dx;
        panel->ofsy = data->startofsy+dy;
        check_panel_overlap(ar, panel);
        
        if(align) uiAlignPanelStep(sa, ar, 0.2, 1);
    }

    ED_region_tag_redraw(ar);
}

/******************* region level panel interaction *****************/


/* this function is supposed to call general window drawing too */
/* also it supposes a block has panel, and isnt a menu */
static void ui_handle_panel_header(const bContext *C, uiBlock *block, int mx, int my, int event)
{
    ScrArea *sa= CTX_wm_area(C);
    ARegion *ar= CTX_wm_region(C);
    Panel *pa;
    int align= panel_aligned(sa, ar), button= 0;

    /* mouse coordinates in panel space! */
    
    /* XXX weak code, currently it assumes layout style for location of widgets */
    
    /* check open/collapsed button */
    if(event==RETKEY)
        button= 1;
    else if(event==AKEY)
        button= 1;
    else if(block->panel->flag & PNL_CLOSEDX) {
        if(my >= block->maxy) button= 1;
    }
    else if(block->panel->control & UI_PNL_CLOSE) {
        /* whole of header can be used to collapse panel (except top-right corner) */
        if(mx <= block->maxx-8-PNL_ICON) button= 2;
        //else if(mx <= block->minx+10+2*PNL_ICON+2) button= 1;
    }
    else if(mx <= block->maxx-PNL_ICON-12) {
        button= 1;
    }
    
    if(button) {
        if(button==2) { // close
            ED_region_tag_redraw(ar);
        }
        else {  // collapse
            if(block->panel->flag & PNL_CLOSED) {
                block->panel->flag &= ~PNL_CLOSED;
                /* snap back up so full panel aligns with screen edge */
                if (block->panel->snap & PNL_SNAP_BOTTOM) 
                    block->panel->ofsy= 0;
            }
            else if(align==BUT_HORIZONTAL) {
                block->panel->flag |= PNL_CLOSEDX;
            }
            else {
                /* snap down to bottom screen edge*/
                block->panel->flag |= PNL_CLOSEDY;
                if (block->panel->snap & PNL_SNAP_BOTTOM) 
                    block->panel->ofsy= -block->panel->sizey;
            }
            
            for(pa= ar->panels.first; pa; pa= pa->next) {
                if(pa->paneltab==block->panel) {
                    if(block->panel->flag & PNL_CLOSED) pa->flag |= PNL_CLOSED;
                    else pa->flag &= ~PNL_CLOSED;
                }
            }
        }

        if(align)
            panel_activate_state(C, block->panel, PANEL_STATE_ANIMATION);
        else
            ED_region_tag_redraw(ar);
    }
    else if(mx <= (block->maxx-PNL_ICON-12)+PNL_ICON+2) {
        panel_activate_state(C, block->panel, PANEL_STATE_DRAG);
    }
}

/* XXX should become modal keymap */
/* AKey is opening/closing panels, independent of button state now */

int ui_handler_panel_region(bContext *C, wmEvent *event)
{
    ARegion *ar= CTX_wm_region(C);
    uiBlock *block;
    Panel *pa;
    int retval, mx, my, inside_header= 0, inside_scale= 0, inside;

    retval= WM_UI_HANDLER_CONTINUE;
    for(block=ar->uiblocks.last; block; block=block->prev) {
        mx= event->x;
        my= event->y;
        ui_window_to_block(ar, block, &mx, &my);

        /* check if inside boundbox */
        inside= 0;
        pa= block->panel;

        if(!pa || pa->paneltab!=NULL)
            continue;
        if(pa->type && pa->type->flag & PNL_NO_HEADER) // XXX - accessed freed panels when scripts reload, need to fix.
            continue;

        if(block->minx <= mx && block->maxx >= mx)
            if(block->miny <= my && block->maxy+PNL_HEADER >= my)
                inside= 1;
        
        if(inside && event->val==KM_PRESS) {
            if(event->type == AKEY && !ELEM4(KM_MOD_FIRST, event->ctrl, event->oskey, event->shift, event->alt)) {
                
                if(pa->flag & PNL_CLOSEDY) {
                    if((block->maxy <= my) && (block->maxy+PNL_HEADER >= my))
                        ui_handle_panel_header(C, block, mx, my, event->type);
                }
                else
                    ui_handle_panel_header(C, block, mx, my, event->type);
                
                continue;
            }
        }
        
        /* on active button, do not handle panels */
        if(ui_button_is_active(ar))
            continue;
        
        if(inside) {
            /* clicked at panel header? */
            if(pa->flag & PNL_CLOSEDX) {
                if(block->minx <= mx && block->minx+PNL_HEADER >= mx) 
                    inside_header= 1;
            }
            else if((block->maxy <= my) && (block->maxy+PNL_HEADER >= my)) {
                inside_header= 1;
            }
            else if(pa->control & UI_PNL_SCALE) {
                if(block->maxx-PNL_HEADER <= mx)
                    if(block->miny+PNL_HEADER >= my)
                        inside_scale= 1;
            }

            if(event->val==KM_PRESS) {
                /* open close on header */
                if(ELEM(event->type, RETKEY, PADENTER)) {
                    if(inside_header) {
                        ui_handle_panel_header(C, block, mx, my, RETKEY);
                        break;
                    }
                }
                else if(event->type == LEFTMOUSE) {
                    if(inside_header) {
                        ui_handle_panel_header(C, block, mx, my, 0);
                        break;
                    }
                    else if(inside_scale && !(pa->flag & PNL_CLOSED)) {
                        panel_activate_state(C, pa, PANEL_STATE_DRAG_SCALE);
                        break;
                    }
                }
                else if(event->type == ESCKEY) {
                    /*XXX 2.50 if(block->handler) {
                        rem_blockhandler(sa, block->handler);
                        ED_region_tag_redraw(ar);
                        retval= WM_UI_HANDLER_BREAK;
                    }*/
                }
                else if(event->type==PADPLUSKEY || event->type==PADMINUS) {
#if 0 // XXX make float panel exception?
                    int zoom=0;
                
                    /* if panel is closed, only zoom if mouse is over the header */
                    if (pa->flag & (PNL_CLOSEDX|PNL_CLOSEDY)) {
                        if (inside_header)
                            zoom=1;
                    }
                    else
                        zoom=1;

                    if(zoom) {
                        ScrArea *sa= CTX_wm_area(C);
                        SpaceLink *sl= sa->spacedata.first;

                        if(sa->spacetype!=SPACE_BUTS) {
                            if(!(pa->control & UI_PNL_SCALE)) {
                                if(event->type==PADPLUSKEY) sl->blockscale+= 0.1;
                                else sl->blockscale-= 0.1;
                                CLAMP(sl->blockscale, 0.6, 1.0);

                                ED_region_tag_redraw(ar);
                                retval= WM_UI_HANDLER_BREAK;
                            }                       
                        }
                    }
#endif
                }
            }
        }
    }

    return retval;
}

/**************** window level modal panel interaction **************/

/* note, this is modal handler and should not swallow events for animation */
static int ui_handler_panel(bContext *C, wmEvent *event, void *userdata)
{
    Panel *panel= userdata;
    uiHandlePanelData *data= panel->activedata;

    /* verify if we can stop */
    if(event->type == LEFTMOUSE && event->val!=KM_PRESS) {
        ScrArea *sa= CTX_wm_area(C);
        ARegion *ar= CTX_wm_region(C);
        int align= panel_aligned(sa, ar);

        if(align)
            panel_activate_state(C, panel, PANEL_STATE_ANIMATION);
        else
            panel_activate_state(C, panel, PANEL_STATE_EXIT);
    }
    else if(event->type == MOUSEMOVE) {
        if(data->state == PANEL_STATE_DRAG)
            ui_do_drag(C, event, panel);
    }
    else if(event->type == TIMER && event->customdata == data->animtimer) {
        if(data->state == PANEL_STATE_ANIMATION)
            ui_do_animate(C, panel);
        else if(data->state == PANEL_STATE_DRAG)
            ui_do_drag(C, event, panel);
    }

    data= panel->activedata;

    if(data && data->state == PANEL_STATE_ANIMATION)
        return WM_UI_HANDLER_CONTINUE;
    else
        return WM_UI_HANDLER_BREAK;
}

static void ui_handler_remove_panel(bContext *C, void *userdata)
{
    Panel *pa= userdata;

    panel_activate_state(C, pa, PANEL_STATE_EXIT);
}

static void panel_activate_state(const bContext *C, Panel *pa, uiHandlePanelState state)
{
    uiHandlePanelData *data= pa->activedata;
    wmWindow *win= CTX_wm_window(C);
    ARegion *ar= CTX_wm_region(C);
    
    if(data && data->state == state)
        return;

    if(state == PANEL_STATE_EXIT || state == PANEL_STATE_ANIMATION) {
        if(data && data->state != PANEL_STATE_ANIMATION) {
            /* XXX:
             *  - the panel tabbing function call below (test_add_new_tabs()) has been commented out
             *    "It is too easy to do by accident when reordering panels, is very hard to control and use, and has no real benefit." - BillRey
             * Aligorith, 2009Sep
             */
            //test_add_new_tabs(ar);   // also copies locations of tabs in dragged panel
            check_panel_overlap(ar, NULL);  // clears
        }

        pa->flag &= ~PNL_SELECT;
    }
    else
        pa->flag |= PNL_SELECT;

    if(data && data->animtimer) {
        WM_event_remove_timer(CTX_wm_manager(C), win, data->animtimer);
        data->animtimer= NULL;
    }

    if(state == PANEL_STATE_EXIT) {
        MEM_freeN(data);
        pa->activedata= NULL;

        WM_event_remove_ui_handler(&win->modalhandlers, ui_handler_panel, ui_handler_remove_panel, pa, 0);
    }
    else {
        if(!data) {
            data= MEM_callocN(sizeof(uiHandlePanelData), "uiHandlePanelData");
            pa->activedata= data;

            WM_event_add_ui_handler(C, &win->modalhandlers, ui_handler_panel, ui_handler_remove_panel, pa);
        }

        if(ELEM(state, PANEL_STATE_ANIMATION, PANEL_STATE_DRAG))
            data->animtimer= WM_event_add_timer(CTX_wm_manager(C), win, TIMER, ANIMATION_INTERVAL);

        data->state= state;
        data->startx= win->eventstate->x;
        data->starty= win->eventstate->y;
        data->startofsx= pa->ofsx;
        data->startofsy= pa->ofsy;
        data->startsizex= pa->sizex;
        data->startsizey= pa->sizey;
        data->starttime= PIL_check_seconds_timer();
    }

    ED_region_tag_redraw(ar);

    /* XXX exception handling, 3d window preview panel */
    /* if(block->drawextra==BIF_view3d_previewdraw)
        BIF_view3d_previewrender_clear(curarea);*/
    
    /* XXX exception handling, 3d window preview panel */
    /* if(block->drawextra==BIF_view3d_previewdraw)
        BIF_view3d_previewrender_signal(curarea, PR_DISPRECT);
    else if(strcmp(block->name, "image_panel_preview")==0)
        image_preview_event(2); */
}