[PATCH v4 0/2] MR8461: gdiplus: Fix drawing indexed bitmaps with a palette that has alpha.

[Zhiyi Zhang (＠zhiyi)]

--
  v4: gdiplus: Fix drawing indexed bitmaps with a palette that has alpha.
      gdiplus/tests: Test drawing indexed bitmaps with a palette that has alpha.

https://gitlab.winehq.org/wine/wine/-/merge_requests/8461

[PATCH v4 1/2] gdiplus/tests: Test drawing indexed bitmaps with a palette that has alpha.

[Zhiyi Zhang]

From: Zhiyi Zhang

---
 dlls/gdiplus/tests/graphics.c | 46 ++++++++++++++++++++++++++++++++++-
 1 file changed, 45 insertions(+), 1 deletion(-)

diff --git a/dlls/gdiplus/tests/graphics.c b/dlls/gdiplus/tests/graphics.c
index dd25dd54fb2..fc9700b1058 100644
--- a/dlls/gdiplus/tests/graphics.c
+++ b/dlls/gdiplus/tests/graphics.c
@@ -6849,6 +6849,7 @@ static void test_GdipDrawImagePointsRectOnMemoryDC(void)
     RECT rect = {100, 100, 180, 180};
     UINT width = rect.right - rect.left;
     UINT height = rect.bottom - rect.top;
+    ColorPalette palette;
     GpStatus status = 0;
     union
     {
@@ -6896,7 +6897,6 @@ static void test_GdipDrawImagePointsRectOnMemoryDC(void)
     expect(Ok, status);

GdipDisposeImage(src_img.image);
-    GdipDeleteGraphics(graphics);
     GdipFree(src_img_data);

pixel = GetBitmapPixelBuffer(hdc, bmp, width, height);
@@ -6914,6 +6914,50 @@ static void test_GdipDrawImagePointsRectOnMemoryDC(void)
        "Expected GdipDrawImageRectRectI take effect!\n" );
     GdipFree(pixel);

+    /* Draw a PixelFormat8bppIndexed bitmap with a palette that has alpha */
+    src_img_data = GdipAlloc(src_img_width * src_img_height);
+    memset(src_img_data, 0, src_img_width * src_img_height);
+    status = GdipCreateBitmapFromScan0(src_img_width, src_img_height, src_img_width,
+                                       PixelFormat8bppIndexed, src_img_data, &src_img.bitmap);
+    expect(Ok, status);
+
+    palette.Flags = PaletteFlagsHasAlpha;
+    palette.Count = 1;
+    palette.Entries[0] = 0x00ffffff;
+    status = GdipSetImagePalette(src_img.image, &palette);
+    expect(Ok, status);
+
+    status = GdipDrawImageRectRectI(graphics, src_img.image, rect.left + width / 2,
+                                    rect.top + height / 2, width / 2, height / 2, 0, 0,
+                                    src_img_width, src_img_height, UnitPixel, NULL, NULL, NULL);
+    expect(Ok, status);
+
+    pixel = GetBitmapPixelBuffer(hdc, bmp, width, height);
+    color[0] = get_bitmap_pixel(width / 2, height / 2);
+    todo_wine
+    ok(is_blue_color(color[0]), "Got unexpected color %#lx.\n", color[0]);
+    GdipFree(pixel);
+
+    /* Draw a PixelFormat8bppIndexed bitmap with a palette that has alpha without PaletteFlagsHasAlpha */
+    palette.Flags = PaletteFlagsGrayScale;
+    status = GdipSetImagePalette(src_img.image, &palette);
+    expect(Ok, status);
+
+    status = GdipDrawImageRectRectI(graphics, src_img.image, rect.left + width / 2,
+                                    rect.top + height / 2, width / 2, height / 2, 0, 0,
+                                    src_img_width, src_img_height, UnitPixel, NULL, NULL, NULL);
+    expect(Ok, status);
+
+    pixel = GetBitmapPixelBuffer(hdc, bmp, width, height);
+    color[0] = get_bitmap_pixel(width / 2, height / 2);
+    todo_wine
+    ok(is_blue_color(color[0]), "Got unexpected color %#lx.\n", color[0]);
+    GdipFree(pixel);
+
+    GdipDisposeImage(src_img.image);
+    GdipFree(src_img_data);
+
+    GdipDeleteGraphics(graphics);
     SelectObject(hdc, old);
     DeleteObject(bmp);
     DeleteDC(hdc);

[PATCH v4 2/2] gdiplus: Fix drawing indexed bitmaps with a palette that has alpha.

[Zhiyi Zhang]

From: Zhiyi Zhang

---
 dlls/gdiplus/graphics.c       | 4 ++--
 dlls/gdiplus/tests/graphics.c | 2 --
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/dlls/gdiplus/graphics.c b/dlls/gdiplus/graphics.c
index 49a9d453b3d..700914e6f6e 100644
--- a/dlls/gdiplus/graphics.c
+++ b/dlls/gdiplus/graphics.c
@@ -3451,7 +3451,7 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image
             if (bitmap->format == PixelFormat16bppRGB555 ||
                 bitmap->format == PixelFormat24bppRGB)
                 dst_format = bitmap->format;
-            else if (bitmap->format & (PixelFormatAlpha|PixelFormatPAlpha))
+            else if (bitmap->image.flags & ImageFlagsHasAlpha)
                 dst_format = PixelFormat32bppPARGB;
             else
                 dst_format = PixelFormat32bppRGB;
@@ -3494,7 +3494,7 @@ GpStatus WINGDIPAPI GdipDrawImagePointsRect(GpGraphics *graphics, GpImage *image

gdi_transform_acquire(graphics);

-            if (bitmap->format & (PixelFormatAlpha|PixelFormatPAlpha))
+            if (bitmap->image.flags & ImageFlagsHasAlpha)
             {
                 gdi_alpha_blend(graphics, pti[0].x, pti[0].y, pti[1].x - pti[0].x, pti[2].y - pti[0].y,
                                 src_hdc, srcx, srcy, srcwidth, srcheight);
diff --git a/dlls/gdiplus/tests/graphics.c b/dlls/gdiplus/tests/graphics.c
index fc9700b1058..96ef52ce935 100644
--- a/dlls/gdiplus/tests/graphics.c
+++ b/dlls/gdiplus/tests/graphics.c
@@ -6934,7 +6934,6 @@ static void test_GdipDrawImagePointsRectOnMemoryDC(void)

pixel = GetBitmapPixelBuffer(hdc, bmp, width, height);
     color[0] = get_bitmap_pixel(width / 2, height / 2);
-    todo_wine
     ok(is_blue_color(color[0]), "Got unexpected color %#lx.\n", color[0]);
     GdipFree(pixel);

@@ -6950,7 +6949,6 @@ static void test_GdipDrawImagePointsRectOnMemoryDC(void)

pixel = GetBitmapPixelBuffer(hdc, bmp, width, height);
     color[0] = get_bitmap_pixel(width / 2, height / 2);
-    todo_wine
     ok(is_blue_color(color[0]), "Got unexpected color %#lx.\n", color[0]);
     GdipFree(pixel);

[Zhiyi Zhang (＠zhiyi)]

On Tue Jul  1 03:25:34 2025 +0000, Zhiyi Zhang wrote:
> changed this line in [version 3 of the diff](/wine/wine/-/merge_requests/8461/diffs?diff_id=189892&start_sha=9baa15765a3635f938025660c71e1035409d3cc8#5be9ed8b7c2f88d687bb28583f357cc92af4f881_6919_6919)

Removing this line causes test failures because GdipAlloc() on Windows doesn't zero memory. Please see https://gitlab.winehq.org/wine/wine/-/jobs/170083 for the result with v3 that doesn't have this line.

[Zhiyi Zhang (＠zhiyi)]

On Tue Jul  1 04:37:01 2025 +0000, Zhiyi Zhang wrote:
> Removing this line causes test failures because GdipAlloc() on Windows
> doesn't zero memory. Please see
> https://gitlab.winehq.org/wine/wine/-/jobs/170083 for the result with v3
> that doesn't have this line.

We should probably change GdipAlloc() to use malloc() for better performance. We had cases in MediaFoundation where zeroing memory for a large buffer causes stutters. I will send a patch.

[Zhiyi Zhang (＠zhiyi)]

On Tue Jul  1 04:40:57 2025 +0000, Zhiyi Zhang wrote:
> We should probably change GdipAlloc() to use malloc() for better
> performance. We had cases in MediaFoundation where zeroing memory for a
> large buffer causes stutters. I will send a patch.

I sent https://gitlab.winehq.org/wine/wine/-/merge_requests/8471 to avoid zeroing out allocated memory from GdipAlloc().

[PATCH v4 0/2] MR8461: gdiplus: Fix drawing indexed bitmaps with a palette that has alpha. - approved

[Esme Povirk (＠madewokherd)]

This merge request was approved by Esme Povirk.