image_draw.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, 2002-2009
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <math.h>
#include <stdlib.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_camera_types.h"
#include "DNA_object_types.h"
#include "DNA_space_types.h"
#include "DNA_scene_types.h"
#include "DNA_screen_types.h"
#include "DNA_brush_types.h"

#include "PIL_time.h"

#include "BLI_math.h"
#include "BLI_threads.h"
#include "BLI_string.h"
#include "BLI_utildefines.h"

#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"

#include "BKE_context.h"
#include "BKE_global.h"
#include "BKE_image.h"
#include "BKE_paint.h"

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

#include "BLF_api.h"

#include "ED_gpencil.h"
#include "ED_image.h"
#include "ED_screen.h"

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


#include "RE_pipeline.h"

#include "image_intern.h"

#define HEADER_HEIGHT 18

static void image_verify_buffer_float(Image *ima, ImBuf *ibuf, int color_manage)
{
    /* detect if we need to redo the curve map.
       ibuf->rect is zero for compositor and render results after change 
       convert to 32 bits always... drawing float rects isnt supported well (atis)
    
       NOTE: if float buffer changes, we have to manually remove the rect
    */

    if(ibuf->rect_float && (ibuf->rect==NULL || (ibuf->userflags & IB_RECT_INVALID)) ) {
        if(color_manage) {
            if(ima && ima->source == IMA_SRC_VIEWER)
                ibuf->profile = IB_PROFILE_LINEAR_RGB;
        }
        else
            ibuf->profile = IB_PROFILE_NONE;

        IMB_rect_from_float(ibuf);
    }
}

static void draw_render_info(Scene *scene, Image *ima, ARegion *ar)
{
    RenderResult *rr;
    
    rr= BKE_image_acquire_renderresult(scene, ima);

    if(rr && rr->text) {
        ED_region_info_draw(ar, rr->text, 1, 0.25);
    }

    BKE_image_release_renderresult(scene, ima);
}

/* used by node view too */
void ED_image_draw_info(ARegion *ar, int color_manage, int channels, int x, int y, const char cp[4], const float fp[4], int *zp, float *zpf)
{
    char str[256];
    float dx= 6;
    /* text colors */
    /* XXX colored text not allowed in Blender UI */
    #if 0
    unsigned char red[3] = {255, 50, 50};
    unsigned char green[3] = {0, 255, 0};
    unsigned char blue[3] = {100, 100, 255};
    #else
    unsigned char red[3] = {255, 255, 255};
    unsigned char green[3] = {255, 255, 255};
    unsigned char blue[3] = {255, 255, 255};
    #endif
    float hue=0, sat=0, val=0, lum=0, u=0, v=0;
    float col[4], finalcol[4];

    glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_BLEND);

    /* noisy, high contrast make impossible to read if lower alpha is used. */
    glColor4ub(0, 0, 0, 190);
    glRecti(0.0, 0.0, ar->winrct.xmax - ar->winrct.xmin + 1, 20);
    glDisable(GL_BLEND);

    BLF_size(blf_mono_font, 11, 72);

    glColor3ub(255, 255, 255);
    BLI_snprintf(str, sizeof(str), "X:%-4d  Y:%-4d |", x, y);
    // UI_DrawString(6, 6, str); // works ok but fixed width is nicer.
    BLF_position(blf_mono_font, dx, 6, 0);
    BLF_draw_ascii(blf_mono_font, str, sizeof(str));
    dx += BLF_width(blf_mono_font, str);

    if(zp) {
        glColor3ub(255, 255, 255);
        BLI_snprintf(str, sizeof(str), " Z:%-.4f |", 0.5f+0.5f*(((float)*zp)/(float)0x7fffffff));
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
    }
    if(zpf) {
        glColor3ub(255, 255, 255);
        BLI_snprintf(str, sizeof(str), " Z:%-.3f |", *zpf);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
    }

    if(channels >= 3) {
        glColor3ubv(red);
        if (fp)
            BLI_snprintf(str, sizeof(str), "  R:%-.4f", fp[0]);
        else if (cp)
            BLI_snprintf(str, sizeof(str), "  R:%-3d", cp[0]);
        else
            BLI_snprintf(str, sizeof(str), "  R:-");
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
        
        glColor3ubv(green);
        if (fp)
            BLI_snprintf(str, sizeof(str), "  G:%-.4f", fp[1]);
        else if (cp)
            BLI_snprintf(str, sizeof(str), "  G:%-3d", cp[1]);
        else
            BLI_snprintf(str, sizeof(str), "  G:-");
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
        
        glColor3ubv(blue);
        if (fp)
            BLI_snprintf(str, sizeof(str), "  B:%-.4f", fp[2]);
        else if (cp)
            BLI_snprintf(str, sizeof(str), "  B:%-3d", cp[2]);
        else
            BLI_snprintf(str, sizeof(str), "  B:-");
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
        
        if(channels == 4) {
            glColor3ub(255, 255, 255);
            if (fp)
                BLI_snprintf(str, sizeof(str), "  A:%-.4f", fp[3]);
            else if (cp)
                BLI_snprintf(str, sizeof(str), "  A:%-3d", cp[3]);
            else
                BLI_snprintf(str, sizeof(str), "- ");
            BLF_position(blf_mono_font, dx, 6, 0);
            BLF_draw_ascii(blf_mono_font, str, sizeof(str));
            dx += BLF_width(blf_mono_font, str);
        }
    }
    
    /* color rectangle */
    if (channels==1) {
        if (fp)
            col[0] = col[1] = col[2] = fp[0];
        else if (cp)
            col[0] = col[1] = col[2] = (float)cp[0]/255.0f;
        else
            col[0] = col[1] = col[2] = 0.0f;
    }
    else if (channels==3) {
        if (fp)
            copy_v3_v3(col, fp);
        else if (cp) {
            col[0] = (float)cp[0]/255.0f;
            col[1] = (float)cp[1]/255.0f;
            col[2] = (float)cp[2]/255.0f;
        }
        else
            zero_v3(col);
    }
    else if (channels==4) {
        if (fp)
            copy_v4_v4(col, fp);
        else if (cp) {
            col[0] = (float)cp[0]/255.0f;
            col[1] = (float)cp[1]/255.0f;
            col[2] = (float)cp[2]/255.0f;
            col[3] = (float)cp[3]/255.0f;
        }
        else
            zero_v4(col);
    }
    if (color_manage) {
        linearrgb_to_srgb_v3_v3(finalcol, col);
        finalcol[3] = col[3];
    }
    else {
        copy_v4_v4(finalcol, col);
    }
    glDisable(GL_BLEND);
    glColor3fv(finalcol);
    dx += 5;
    glBegin(GL_QUADS);
    glVertex2f(dx, 3);
    glVertex2f(dx, 17);
    glVertex2f(dx+30, 17);
    glVertex2f(dx+30, 3);
    glEnd();
    dx += 35;

    glColor3ub(255, 255, 255);
    if(channels == 1) {
        if (fp) {
            rgb_to_hsv(fp[0], fp[0], fp[0], &hue, &sat, &val);
            rgb_to_yuv(fp[0], fp[0], fp[0], &lum, &u, &v);
        }
        else if (cp) {
            rgb_to_hsv((float)cp[0]/255.0f, (float)cp[0]/255.0f, (float)cp[0]/255.0f, &hue, &sat, &val);
            rgb_to_yuv((float)cp[0]/255.0f, (float)cp[0]/255.0f, (float)cp[0]/255.0f, &lum, &u, &v);
        }
        
        BLI_snprintf(str, sizeof(str), "V:%-.4f", val);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);

        BLI_snprintf(str, sizeof(str), "   L:%-.4f", lum);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
    }
    else if(channels >= 3) {
        if (fp) {
            rgb_to_hsv(fp[0], fp[1], fp[2], &hue, &sat, &val);
            rgb_to_yuv(fp[0], fp[1], fp[2], &lum, &u, &v);
        }
        else if (cp) {
            rgb_to_hsv((float)cp[0]/255.0f, (float)cp[1]/255.0f, (float)cp[2]/255.0f, &hue, &sat, &val);
            rgb_to_yuv((float)cp[0]/255.0f, (float)cp[1]/255.0f, (float)cp[2]/255.0f, &lum, &u, &v);
        }

        BLI_snprintf(str, sizeof(str), "H:%-.4f", hue);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);

        BLI_snprintf(str, sizeof(str), "  S:%-.4f", sat);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);

        BLI_snprintf(str, sizeof(str), "  V:%-.4f", val);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);

        BLI_snprintf(str, sizeof(str), "   L:%-.4f", lum);
        BLF_position(blf_mono_font, dx, 6, 0);
        BLF_draw_ascii(blf_mono_font, str, sizeof(str));
        dx += BLF_width(blf_mono_font, str);
    }

    (void)dx;
}

/* image drawing */

static void draw_image_grid(ARegion *ar, float zoomx, float zoomy)
{
    float gridsize, gridstep= 1.0f/32.0f;
    float fac, blendfac;
    int x1, y1, x2, y2;
    
    /* the image is located inside (0,0),(1, 1) as set by view2d */
    UI_ThemeColorShade(TH_BACK, 20);

    UI_view2d_to_region_no_clip(&ar->v2d, 0.0f, 0.0f, &x1, &y1);
    UI_view2d_to_region_no_clip(&ar->v2d, 1.0f, 1.0f, &x2, &y2);
    glRectf(x1, y1, x2, y2);

    /* gridsize adapted to zoom level */
    gridsize= 0.5f*(zoomx+zoomy);
    if(gridsize<=0.0f) return;
    
    if(gridsize<1.0f) {
        while(gridsize<1.0f) {
            gridsize*= 4.0f;
            gridstep*= 4.0f;
        }
    }
    else {
        while(gridsize>=4.0f) {
            gridsize/= 4.0f;
            gridstep/= 4.0f;
        }
    }
    
    /* the fine resolution level */
    blendfac= 0.25f*gridsize - floorf(0.25f*gridsize);
    CLAMP(blendfac, 0.0f, 1.0f);
    UI_ThemeColorShade(TH_BACK, (int)(20.0f*(1.0f-blendfac)));
    
    fac= 0.0f;
    glBegin(GL_LINES);
    while(fac<1.0f) {
        glVertex2f(x1, y1*(1.0f-fac) + y2*fac);
        glVertex2f(x2, y1*(1.0f-fac) + y2*fac);
        glVertex2f(x1*(1.0f-fac) + x2*fac, y1);
        glVertex2f(x1*(1.0f-fac) + x2*fac, y2);
        fac+= gridstep;
    }
    
    /* the large resolution level */
    UI_ThemeColor(TH_BACK);
    
    fac= 0.0f;
    while(fac<1.0f) {
        glVertex2f(x1, y1*(1.0f-fac) + y2*fac);
        glVertex2f(x2, y1*(1.0f-fac) + y2*fac);
        glVertex2f(x1*(1.0f-fac) + x2*fac, y1);
        glVertex2f(x1*(1.0f-fac) + x2*fac, y2);
        fac+= 4.0f*gridstep;
    }
    glEnd();
}

static void sima_draw_alpha_backdrop(float x1, float y1, float xsize, float ysize, float zoomx, float zoomy, unsigned char col1[3], unsigned char col2[3])
{
    GLubyte checker_stipple[32*32/8] =
    {
        255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0,
        255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0,
        255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0,
        255,255,0,0,255,255,0,0,255,255,0,0,255,255,0,0,
        0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255,
        0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255,
        0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255,
        0,0,255,255,0,0,255,255,0,0,255,255,0,0,255,255,
    };
    
    glColor3ubv(col1);
    glRectf(x1, y1, x1 + zoomx*xsize, y1 + zoomy*ysize);
    glColor3ubv(col2);

    glEnable(GL_POLYGON_STIPPLE);
    glPolygonStipple(checker_stipple);
    glRectf(x1, y1, x1 + zoomx*xsize, y1 + zoomy*ysize);
    glDisable(GL_POLYGON_STIPPLE);
}

static void sima_draw_alpha_pixels(float x1, float y1, int rectx, int recty, unsigned int *recti)
{
    
    /* swap bytes, so alpha is most significant one, then just draw it as luminance int */
    if(ENDIAN_ORDER == B_ENDIAN)
        glPixelStorei(GL_UNPACK_SWAP_BYTES, 1);

    glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_LUMINANCE, GL_UNSIGNED_INT, recti);
    glPixelStorei(GL_UNPACK_SWAP_BYTES, 0);
}

static void sima_draw_alpha_pixelsf(float x1, float y1, int rectx, int recty, float *rectf)
{
    float *trectf= MEM_mallocN(rectx*recty*4, "temp");
    int a, b;
    
    for(a= rectx*recty -1, b= 4*a+3; a>=0; a--, b-=4)
        trectf[a]= rectf[b];
    
    glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_LUMINANCE, GL_FLOAT, trectf);
    MEM_freeN(trectf);
    /* ogl trick below is slower... (on ATI 9600) */
//  glColorMask(1, 0, 0, 0);
//  glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_RGBA, GL_FLOAT, rectf+3);
//  glColorMask(0, 1, 0, 0);
//  glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_RGBA, GL_FLOAT, rectf+2);
//  glColorMask(0, 0, 1, 0);
//  glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_RGBA, GL_FLOAT, rectf+1);
//  glColorMask(1, 1, 1, 1);
}

static void sima_draw_zbuf_pixels(float x1, float y1, int rectx, int recty, int *recti)
{
    /* zbuffer values are signed, so we need to shift color range */
    glPixelTransferf(GL_RED_SCALE, 0.5f);
    glPixelTransferf(GL_GREEN_SCALE, 0.5f);
    glPixelTransferf(GL_BLUE_SCALE, 0.5f);
    glPixelTransferf(GL_RED_BIAS, 0.5f);
    glPixelTransferf(GL_GREEN_BIAS, 0.5f);
    glPixelTransferf(GL_BLUE_BIAS, 0.5f);
    
    glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_LUMINANCE, GL_INT, recti);
    
    glPixelTransferf(GL_RED_SCALE, 1.0f);
    glPixelTransferf(GL_GREEN_SCALE, 1.0f);
    glPixelTransferf(GL_BLUE_SCALE, 1.0f);
    glPixelTransferf(GL_RED_BIAS, 0.0f);
    glPixelTransferf(GL_GREEN_BIAS, 0.0f);
    glPixelTransferf(GL_BLUE_BIAS, 0.0f);
}

static void sima_draw_zbuffloat_pixels(Scene *scene, float x1, float y1, int rectx, int recty, float *rect_float)
{
    float bias, scale, *rectf, clipend;
    int a;
    
    if(scene->camera && scene->camera->type==OB_CAMERA) {
        bias= ((Camera *)scene->camera->data)->clipsta;
        clipend= ((Camera *)scene->camera->data)->clipend;
        scale= 1.0f/(clipend-bias);
    }
    else {
        bias= 0.1f;
        scale= 0.01f;
        clipend= 100.0f;
    }
    
    rectf= MEM_mallocN(rectx*recty*4, "temp");
    for(a= rectx*recty -1; a>=0; a--) {
        if(rect_float[a]>clipend)
            rectf[a]= 0.0f;
        else if(rect_float[a]<bias)
            rectf[a]= 1.0f;
        else {
            rectf[a]= 1.0f - (rect_float[a]-bias)*scale;
            rectf[a]*= rectf[a];
        }
    }
    glaDrawPixelsSafe(x1, y1, rectx, recty, rectx, GL_LUMINANCE, GL_FLOAT, rectf);
    
    MEM_freeN(rectf);
}

static void draw_image_buffer(SpaceImage *sima, ARegion *ar, Scene *scene, Image *ima, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
{
    int x, y;
    int color_manage = scene->r.color_mgt_flag & R_COLOR_MANAGEMENT;

    /* set zoom */
    glPixelZoom(zoomx, zoomy);

    /* find window pixel coordinates of origin */
    UI_view2d_to_region_no_clip(&ar->v2d, fx, fy, &x, &y);

    /* this part is generic image display */
    if(sima->flag & SI_SHOW_ALPHA) {
        if(ibuf->rect)
            sima_draw_alpha_pixels(x, y, ibuf->x, ibuf->y, ibuf->rect);
        else if(ibuf->rect_float && ibuf->channels==4)
            sima_draw_alpha_pixelsf(x, y, ibuf->x, ibuf->y, ibuf->rect_float);
    }
    else if(sima->flag & SI_SHOW_ZBUF && (ibuf->zbuf || ibuf->zbuf_float || (ibuf->channels==1))) {
        if(ibuf->zbuf)
            sima_draw_zbuf_pixels(x, y, ibuf->x, ibuf->y, ibuf->zbuf);
        else if(ibuf->zbuf_float)
            sima_draw_zbuffloat_pixels(scene, x, y, ibuf->x, ibuf->y, ibuf->zbuf_float);
        else if(ibuf->channels==1)
            sima_draw_zbuffloat_pixels(scene, x, y, ibuf->x, ibuf->y, ibuf->rect_float);
    }
    else {
        if(sima->flag & SI_USE_ALPHA) {
            unsigned char col1[3]= {100, 100, 100}, col2[3]= {160, 160, 160};
            sima_draw_alpha_backdrop(x, y, ibuf->x, ibuf->y, zoomx, zoomy, col1, col2);

            glEnable(GL_BLEND);
            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
        }

        /* we don't draw floats buffers directly but
         * convert them, and optionally apply curves */
        image_verify_buffer_float(ima, ibuf, color_manage);

        if(ibuf->rect)
            glaDrawPixelsSafe(x, y, ibuf->x, ibuf->y, ibuf->x, GL_RGBA, GL_UNSIGNED_BYTE, ibuf->rect);
        /*else
            glaDrawPixelsSafe(x, y, ibuf->x, ibuf->y, ibuf->x, GL_RGBA, GL_FLOAT, ibuf->rect_float);*/
        
        if(sima->flag & SI_USE_ALPHA)
            glDisable(GL_BLEND);
    }

    /* reset zoom */
    glPixelZoom(1.0f, 1.0f);
}

static unsigned int *get_part_from_ibuf(ImBuf *ibuf, short startx, short starty, short endx, short endy)
{
    unsigned int *rt, *rp, *rectmain;
    short y, heigth, len;

    /* the right offset in rectot */

    rt= ibuf->rect+ (starty*ibuf->x+ startx);

    len= (endx-startx);
    heigth= (endy-starty);

    rp=rectmain= MEM_mallocN(heigth*len*sizeof(int), "rect");
    
    for(y=0; y<heigth; y++) {
        memcpy(rp, rt, len*4);
        rt+= ibuf->x;
        rp+= len;
    }
    return rectmain;
}

static void draw_image_buffer_tiled(SpaceImage *sima, ARegion *ar, Scene *scene, Image *ima, ImBuf *ibuf, float fx, float fy, float zoomx, float zoomy)
{
    unsigned int *rect;
    int dx, dy, sx, sy, x, y;
    int color_manage = scene->r.color_mgt_flag & R_COLOR_MANAGEMENT;

    /* verify valid values, just leave this a while */
    if(ima->xrep<1) return;
    if(ima->yrep<1) return;
    
    glPixelZoom(zoomx, zoomy);

    if(sima->curtile >= ima->xrep*ima->yrep) 
        sima->curtile = ima->xrep*ima->yrep - 1; 
    
    /* create char buffer from float if needed */
    image_verify_buffer_float(ima, ibuf, color_manage);

    /* retrieve part of image buffer */
    dx= ibuf->x/ima->xrep;
    dy= ibuf->y/ima->yrep;
    sx= (sima->curtile % ima->xrep)*dx;
    sy= (sima->curtile / ima->xrep)*dy;
    rect= get_part_from_ibuf(ibuf, sx, sy, sx+dx, sy+dy);
    
    /* draw repeated */
    for(sy=0; sy+dy<=ibuf->y; sy+= dy) {
        for(sx=0; sx+dx<=ibuf->x; sx+= dx) {
            UI_view2d_to_region_no_clip(&ar->v2d, fx + (float)sx/(float)ibuf->x, fy + (float)sy/(float)ibuf->y, &x, &y);

            glaDrawPixelsSafe(x, y, dx, dy, dx, GL_RGBA, GL_UNSIGNED_BYTE, rect);
        }
    }

    glPixelZoom(1.0f, 1.0f);

    MEM_freeN(rect);
}

static void draw_image_buffer_repeated(SpaceImage *sima, ARegion *ar, Scene *scene, Image *ima, ImBuf *ibuf, float zoomx, float zoomy)
{
    const double time_current= PIL_check_seconds_timer();

    const int xmax= ceil(ar->v2d.cur.xmax);
    const int ymax= ceil(ar->v2d.cur.ymax);
    const int xmin= floor(ar->v2d.cur.xmin);
    const int ymin= floor(ar->v2d.cur.ymin);

    int x;

    for(x=xmin; x<xmax; x++) {
        int y;
        for(y=ymin; y<ymax; y++) { 
            if(ima && (ima->tpageflag & IMA_TILES))
                draw_image_buffer_tiled(sima, ar, scene, ima, ibuf, x, y, zoomx, zoomy);
            else
                draw_image_buffer(sima, ar, scene, ima, ibuf, x, y, zoomx, zoomy);

            /* only draw until running out of time */
            if((PIL_check_seconds_timer() - time_current) > 0.25)
                return;
        }
    }
}

/* draw uv edit */

/* draw grease pencil */
void draw_image_grease_pencil(bContext *C, short onlyv2d)
{
    /* draw in View2D space? */
    if (onlyv2d) {
        /* assume that UI_view2d_ortho(C) has been called... */
        SpaceImage *sima= (SpaceImage *)CTX_wm_space_data(C);
        void *lock;
        ImBuf *ibuf= ED_space_image_acquire_buffer(sima, &lock);
        
        /* draw grease-pencil ('image' strokes) */
        //if (sima->flag & SI_DISPGP)
            draw_gpencil_2dimage(C, ibuf);

        ED_space_image_release_buffer(sima, lock);
    }
    else {
        /* assume that UI_view2d_restore(C) has been called... */
        //SpaceImage *sima= (SpaceImage *)CTX_wm_space_data(C);
        
        /* draw grease-pencil ('screen' strokes) */
        //if (sima->flag & SI_DISPGP)
            draw_gpencil_view2d(C, 0);
    }
}

/* XXX becomes WM paint cursor */
#if 0
static void draw_image_view_tool(Scene *scene)
{
    ToolSettings *settings= scene->toolsettings;
    Brush *brush= settings->imapaint.brush;
    int mval[2];
    float radius;
    int draw= 0;

    if(brush) {
        if(settings->imapaint.flag & IMAGEPAINT_DRAWING) {
            if(settings->imapaint.flag & IMAGEPAINT_DRAW_TOOL_DRAWING)
                draw= 1;
        }
        else if(settings->imapaint.flag & IMAGEPAINT_DRAW_TOOL)
            draw= 1;
        
        if(draw) {
            getmouseco_areawin(mval);

            radius= brush_size(brush)*G.sima->zoom;
            fdrawXORcirc(mval[0], mval[1], radius);

            if (brush->innerradius != 1.0) {
                radius *= brush->innerradius;
                fdrawXORcirc(mval[0], mval[1], radius);
            }
        }
    }
}
#endif

static unsigned char *get_alpha_clone_image(Scene *scene, int *width, int *height)
{
    Brush *brush = paint_brush(&scene->toolsettings->imapaint.paint);
    ImBuf *ibuf;
    unsigned int size, alpha;
    unsigned char *rect, *cp;

    if(!brush || !brush->clone.image)
        return NULL;
    
    ibuf= BKE_image_get_ibuf(brush->clone.image, NULL);

    if(!ibuf || !ibuf->rect)
        return NULL;

    rect= MEM_dupallocN(ibuf->rect);
    if(!rect)
        return NULL;

    *width= ibuf->x;
    *height= ibuf->y;

    size= (*width)*(*height);
    alpha= (unsigned char)255*brush->clone.alpha;
    cp= rect;

    while(size-- > 0) {
        cp[3]= alpha;
        cp += 4;
    }

    return rect;
}

static void draw_image_paint_helpers(ARegion *ar, Scene *scene, float zoomx, float zoomy)
{
    Brush *brush;
    int x, y, w, h;
    unsigned char *clonerect;

    brush= paint_brush(&scene->toolsettings->imapaint.paint);

    if(brush && (brush->imagepaint_tool == PAINT_TOOL_CLONE)) {
        /* this is not very efficient, but glDrawPixels doesn't allow
           drawing with alpha */
        clonerect= get_alpha_clone_image(scene, &w, &h);

        if(clonerect) {
            UI_view2d_to_region_no_clip(&ar->v2d, brush->clone.offset[0], brush->clone.offset[1], &x, &y);

            glPixelZoom(zoomx, zoomy);

            glEnable(GL_BLEND);
            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            glaDrawPixelsSafe(x, y, w, h, w, GL_RGBA, GL_UNSIGNED_BYTE, clonerect);
            glDisable(GL_BLEND);

            glPixelZoom(1.0, 1.0);

            MEM_freeN(clonerect);
        }
    }
}

/* draw main image area */

void draw_image_main(SpaceImage *sima, ARegion *ar, Scene *scene)
{
    Image *ima;
    ImBuf *ibuf;
    float zoomx, zoomy;
    int show_viewer, show_render;
    void *lock;

    /* XXX can we do this in refresh? */
#if 0
    what_image(sima);
    
    if(sima->image) {
        ED_image_aspect(sima->image, &xuser_asp, &yuser_asp);
        
        /* UGLY hack? until now iusers worked fine... but for flipbook viewer we need this */
        if(sima->image->type==IMA_TYPE_COMPOSITE) {
            ImageUser *iuser= ntree_get_active_iuser(scene->nodetree);
            if(iuser) {
                BKE_image_user_calc_imanr(iuser, scene->r.cfra, 0);
                sima->iuser= *iuser;
            }
        }
        /* and we check for spare */
        ibuf= ED_space_image_buffer(sima);
    }
#endif

    /* retrieve the image and information about it */
    ima= ED_space_image(sima);
    ED_space_image_zoom(sima, ar, &zoomx, &zoomy);
    ibuf= ED_space_image_acquire_buffer(sima, &lock);

    show_viewer= (ima && ima->source == IMA_SRC_VIEWER);
    show_render= (show_viewer && ima->type == IMA_TYPE_R_RESULT);

    /* draw the image or grid */
    if(ibuf==NULL)
        draw_image_grid(ar, zoomx, zoomy);
    else if(sima->flag & SI_DRAW_TILE)
        draw_image_buffer_repeated(sima, ar, scene, ima, ibuf, zoomx, zoomy);
    else if(ima && (ima->tpageflag & IMA_TILES))
        draw_image_buffer_tiled(sima, ar, scene, ima, ibuf, 0.0f, 0.0, zoomx, zoomy);
    else
        draw_image_buffer(sima, ar, scene, ima, ibuf, 0.0f, 0.0f, zoomx, zoomy);

    /* paint helpers */
    if(sima->flag & SI_DRAWTOOL)
        draw_image_paint_helpers(ar, scene, zoomx, zoomy);


    /* XXX integrate this code */
#if 0
    if(ibuf) {
        float xoffs=0.0f, yoffs= 0.0f;
        
        if(image_preview_active(sa, &xim, &yim)) {
            xoffs= scene->r.disprect.xmin;
            yoffs= scene->r.disprect.ymin;
            glColor3ub(0,0,0);
            calc_image_view(sima, 'f'); 
            myortho2(G.v2d->cur.xmin, G.v2d->cur.xmax, G.v2d->cur.ymin, G.v2d->cur.ymax);
            glRectf(0.0f, 0.0f, 1.0f, 1.0f);
            glLoadIdentity();
        }
    }
#endif

    ED_space_image_release_buffer(sima, lock);

    /* render info */
    if(ima && show_render)
        draw_render_info(scene, ima, ar);
}