gdiplus: Use clipping region in alpha_blend_pixels.

dlls/gdiplus/graphics.c

@@ -359,12 +359,15 @@ static void gdi_alpha_blend(GpGraphics *graphics, INT dst_x, INT dst_y, INT dst_
     }
 }
 
+static GpStatus get_clip_hrgn(GpGraphics *graphics, HRGN *hrgn)
+{
+    return GdipGetRegionHRgn(graphics->clip, graphics, hrgn);
+}
+
 /* Draw non-premultiplied ARGB data to the given graphics object */
-static GpStatus alpha_blend_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
+static GpStatus alpha_blend_bmp_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
     const BYTE *src, INT src_width, INT src_height, INT src_stride)
 {
-    if (graphics->image && graphics->image->type == ImageTypeBitmap)
-    {
     GpBitmap *dst_bitmap = (GpBitmap*)graphics->image;
     INT x, y;
 
@@ -380,14 +383,11 @@ static GpStatus alpha_blend_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
     }
 
     return Ok;
-    }
-    else if (graphics->image && graphics->image->type == ImageTypeMetafile)
-    {
-        ERR("This should not be used for metafiles; fix caller\n");
-        return NotImplemented;
-    }
-    else
-    {
+}
+
+static GpStatus alpha_blend_hdc_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
+    const BYTE *src, INT src_width, INT src_height, INT src_stride)
+{
     HDC hdc;
     HBITMAP hbitmap;
     BITMAPINFOHEADER bih;
@@ -420,7 +420,6 @@ static GpStatus alpha_blend_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
     DeleteObject(hbitmap);
 
     return Ok;
-    }
 }
 
 static GpStatus alpha_blend_pixels_hrgn(GpGraphics *graphics, INT dst_x, INT dst_y,
@@ -433,20 +432,44 @@ static GpStatus alpha_blend_pixels_hrgn(GpGraphics *graphics, INT dst_x, INT dst
         int i, size;
         RGNDATA *rgndata;
         RECT *rects;
+        HRGN hrgn, visible_rgn;
+
+        hrgn = CreateRectRgn(dst_x, dst_y, dst_x + src_width, dst_y + src_height);
+        if (!hrgn)
+            return OutOfMemory;
+
+        stat = get_clip_hrgn(graphics, &visible_rgn);
+        if (stat != Ok)
+        {
+            DeleteObject(hrgn);
+            return stat;
+        }
 
-        size = GetRegionData(hregion, 0, NULL);
+        if (visible_rgn)
+        {
+            CombineRgn(hrgn, hrgn, visible_rgn, RGN_AND);
+            DeleteObject(visible_rgn);
+        }
+
+        if (hregion)
+            CombineRgn(hrgn, hrgn, hregion, RGN_AND);
+
+        size = GetRegionData(hrgn, 0, NULL);
 
         rgndata = GdipAlloc(size);
         if (!rgndata)
+        {
+            DeleteObject(hrgn);
             return OutOfMemory;
+        }
 
-        GetRegionData(hregion, size, rgndata);
+        GetRegionData(hrgn, size, rgndata);
 
         rects = (RECT*)&rgndata->Buffer;
 
         for (i=0; stat == Ok && i<rgndata->rdh.nCount; i++)
         {
-            stat = alpha_blend_pixels(graphics, rects[i].left, rects[i].top,
+            stat = alpha_blend_bmp_pixels(graphics, rects[i].left, rects[i].top,
                 &src[(rects[i].left - dst_x) * 4 + (rects[i].top - dst_y) * src_stride],
                 rects[i].right - rects[i].left, rects[i].bottom - rects[i].top,
                 src_stride);
@@ -454,6 +477,8 @@ static GpStatus alpha_blend_pixels_hrgn(GpGraphics *graphics, INT dst_x, INT dst
 
         GdipFree(rgndata);
 
+        DeleteObject(hrgn);
+
         return stat;
     }
     else if (graphics->image && graphics->image->type == ImageTypeMetafile)
@@ -463,21 +488,39 @@ static GpStatus alpha_blend_pixels_hrgn(GpGraphics *graphics, INT dst_x, INT dst
     }
     else
     {
+        HRGN hrgn;
         int save;
 
+        stat = get_clip_hrgn(graphics, &hrgn);
+
+        if (stat != Ok)
+            return stat;
+
         save = SaveDC(graphics->hdc);
 
+        if (hrgn)
+            ExtSelectClipRgn(graphics->hdc, hrgn, RGN_AND);
+
+        if (hregion)
             ExtSelectClipRgn(graphics->hdc, hregion, RGN_AND);
 
-        stat = alpha_blend_pixels(graphics, dst_x, dst_y, src, src_width,
+        stat = alpha_blend_hdc_pixels(graphics, dst_x, dst_y, src, src_width,
             src_height, src_stride);
 
         RestoreDC(graphics->hdc, save);
 
+        DeleteObject(hrgn);
+
         return stat;
     }
 }
 
+static GpStatus alpha_blend_pixels(GpGraphics *graphics, INT dst_x, INT dst_y,
+    const BYTE *src, INT src_width, INT src_height, INT src_stride)
+{
+    return alpha_blend_pixels_hrgn(graphics, dst_x, dst_y, src, src_width, src_height, src_stride, NULL);
+}
+
 static ARGB blend_colors(ARGB start, ARGB end, REAL position)
 {
     ARGB result=0;