[PATCH 4/4] comctl32/imagelist: Support adding 32bpp images to a non-32bpp image list.

[Ziqing Hui]

From: Ziqing Hui

---
 dlls/comctl32/imagelist.c       | 25 +++++++++++++++++++++++--
 dlls/comctl32/tests/imagelist.c |  2 --
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/dlls/comctl32/imagelist.c b/dlls/comctl32/imagelist.c
index db5beb14042..edf0d40e476 100644
--- a/dlls/comctl32/imagelist.c
+++ b/dlls/comctl32/imagelist.c
@@ -270,6 +270,7 @@ static void premultiply_alpha_channel(DWORD *bits, int pixel_count)
 static void add_dib_bits( HIMAGELIST himl, int pos, int count, int width, int height,
                           BITMAPINFO *info, BITMAPINFO *mask_info, DWORD *bits, BYTE *mask_bits )
 {
+    BOOL image_list_is_32bpp = (image_list_color_flag(himl) == ILC_COLOR32);
     int i, j, n;
     POINT pt;
     int stride = info->bmiHeader.biWidth;
@@ -293,13 +294,32 @@ static void add_dib_bits( HIMAGELIST himl, int pos, int count, int width, int he
 #if __WINE_COMCTL32_VERSION == 6
             for (i = 0; i < height; i++)
                 premultiply_alpha_channel(&bits[i * stride + n * width], width);
+
+            if (!image_list_is_32bpp)
+            {
+                himl->item_flags[pos + n] = 0;
+
+                /* Image list is not 32bpp, no alpha channel in image list bitmap.
+                 * We need to do alpha blend here by ourselves. */
+                for (i = 0; i < height; i++)
+                {
+                    for (j = n * width; j < (n + 1) * width; j++)
+                    {
+                        DWORD *pixel = &bits[i * stride + j], alpha = *pixel >> 24;
+                        DWORD r = (*pixel & 0x00ff0000) >> 16;
+                        DWORD g = (*pixel & 0x0000ff00) >> 8;
+                        DWORD b = *pixel & 0x000000ff;
+                        *pixel = ((r + 0xff - alpha) << 16) | ((g + 0xff - alpha) << 8) | (b + 0xff - alpha);
+                    }
+                }
+            }
 #endif /* __WINE_COMCTL32_VERSION == 6 */

if (mask_info && himl->hbmMask)  /* generate the mask from the alpha channel */
             {
                 for (i = 0; i < height; i++)
                     for (j = n * width; j < (n + 1) * width; j++)
-                        if ((bits[i * stride + j] >> 24) > 25) /* more than 10% alpha */
+                        if (!image_list_is_32bpp || (bits[i * stride + j] >> 24) > 25) /* more than 10% alpha */
                             mask_bits[i * mask_stride + j / 8] &= ~(0x80 >> (j % 8));
                         else
                             mask_bits[i * mask_stride + j / 8] |= 0x80 >> (j % 8);
@@ -333,8 +353,9 @@ static BOOL add_with_alpha( HIMAGELIST himl, HDC hdc, int pos, int count,

if (!GetObjectW( hbmImage, sizeof(bm), &bm )) return FALSE;

-    /* if either the imagelist or the source bitmap don't have an alpha channel, bail out now */
+#if __WINE_COMCTL32_VERSION == 5
     if (image_list_color_flag(himl) != ILC_COLOR32) return FALSE;
+#endif /* __WINE_COMCTL32_VERSION == 5 */
     if (bm.bmBitsPixel != 32) return FALSE;

SelectObject( hdc, hbmImage );
diff --git a/dlls/comctl32/tests/imagelist.c b/dlls/comctl32/tests/imagelist.c
index 7cd23a9da2f..98f061ba712 100644
--- a/dlls/comctl32/tests/imagelist.c
+++ b/dlls/comctl32/tests/imagelist.c
@@ -2693,13 +2693,11 @@ static void test_alpha(BOOL v6)
         }

image_list_get_image_bits_by_bitmap(himl, i / 2, bits);
-        todo_wine_if(v6 && i != 0 && i != 2 && i != 4 && i != 6 && i != 18)
         ok(colour_match(bits[0], expected[0]) && colour_match(bits[1], expected[1]),
                 "Got bits [%08X, %08X], expected [%08X, %08X].\n",
                 bits[0], bits[1], expected[0], expected[1]);

image_list_get_image_bits_by_draw(himl, i / 2, bits);
-        todo_wine_if(v6 && i != 0 && i != 2 && i != 4 && i != 6 && i != 18)
         ok(colour_match(bits[0], expected[0]) && colour_match(bits[1], expected[1]),
                 "Got bits [%08X, %08X], expected [%08X, %08X].\n",
                 bits[0], bits[1], expected[0], expected[1]);