[PATCH v3 0/1] MR3546: gdiplus: move pointer calculation outside inner loop for alpha_blend_bmp_pixels

[Bartosz Kosiorek (＠gang65)]

--
  v3: gdiplus: move pointer calculation outside inner loop to improve performance

https://gitlab.winehq.org/wine/wine/-/merge_requests/3546

[PATCH v3 1/1] gdiplus: move pointer calculation outside inner loop to improve performance

[Bartosz Kosiorek]

From: Bartosz Kosiorek

---
 dlls/gdiplus/graphics.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index e3b5661fd67..a2a9c3db186 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -422,28 +422,27 @@ static GpStatus alpha_blend_bmp_pixels(GpGraphics *graphics, INT dst_x, INT dst_

for (y=0; y<src_height; y++)
     {
+        ARGB *src_color = (ARGB*)(src + src_stride * y);
         for (x=0; x<src_width; x++)
         {
-            ARGB dst_color, src_color;
-            src_color = ((ARGB*)(src + src_stride * y))[x];
-
             if (comp_mode == CompositingModeSourceCopy)
             {
-                if (!(src_color & 0xff000000))
+                if (!(src_color[x] & 0xff000000))
                     GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, 0);
                 else
-                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, src_color);
+                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, src_color[x]);
             }
             else
             {
-                if (!(src_color & 0xff000000))
+                ARGB dst_color;
+                if (!(src_color[x] & 0xff000000))
                     continue;

GdipBitmapGetPixel(dst_bitmap, x+dst_x, y+dst_y, &dst_color);
                 if (fmt & PixelFormatPAlpha)
-                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, color_over_fgpremult(dst_color, src_color));
+                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, color_over_fgpremult(dst_color, src_color[x]));
                 else
-                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, color_over(dst_color, src_color));
+                    GdipBitmapSetPixel(dst_bitmap, x+dst_x, y+dst_y, color_over(dst_color, src_color[x]));
             }
         }
     }

[Nikolay Sivov (＠nsivov)]

On Fri Aug 11 08:34:38 2023 +0000, Bartosz Kosiorek wrote:
> In previous implementation we calculated `src_color` position every time
> (in `for (x` loop):
>         for (x=0; x<src_width; x++)
>         {
>             ARGB dst_color, src_color;
>             src_color = ((ARGB*)(src + src_stride * y))[x];
>
> With new implementation we are calculating `src_color` position only
> once (outside `x` loop), and we just iterating the `src_color++`:
>         ARGB *src_color = ((ARGB*)(src + src_stride * y));
>         for (x=0; x<src_width; x++)
>         {
> ...
>             src_color++;
>         }
>
> It is faster (avoiding not needed multiplications), especially for wide images.

I asked because usually claiming something is faster also needs some performance numbers.

[Bartosz Kosiorek (＠gang65)]

On Fri Aug 11 09:01:05 2023 +0000, Bartosz Kosiorek wrote:
> It seems that Linux32 tests are failing with previous changes.
> Linux64 test were passing.

I have replaced it with array