Module: wine
Branch: master
Commit: 7f97af2e2e40e39371dd1c847fdeec4d2b012d71
URL: http://source.winehq.org/git/wine.git/?a=commit;h=7f97af2e2e40e39371dd1c847…
Author: Stefan Dösinger <stefan(a)codeweavers.com>
Date: Thu Dec 13 12:12:23 2007 +0100
winex11: Ignore the alpha if all pixels are 0.
---
dlls/winex11.drv/mouse.c | 34 +++++++++++++++++++++++++++++++++-
1 files changed, 33 insertions(+), 1 deletions(-)
diff --git a/dlls/winex11.drv/mouse.c b/dlls/winex11.drv/mouse.c
index b175c6b..97e097b 100644
--- a/dlls/winex11.drv/mouse.c
+++ b/dlls/winex11.drv/mouse.c
@@ -409,6 +409,7 @@ static XcursorImage *create_cursor_image( CURSORICONINFO *ptr )
int and_width_bytes, xor_width_bytes;
XcursorPixel *pixel_ptr;
XcursorImage *image;
+ BOOL alpha_zero = TRUE;
ymax = (ptr->nHeight > 32) ? 32 : ptr->nHeight;
xmax = (ptr->nWidth > 32) ? 32 : ptr->nWidth;
@@ -425,6 +426,37 @@ static XcursorImage *create_cursor_image( CURSORICONINFO *ptr )
image = pXcursorImageCreate( xmax, ymax );
pixel_ptr = image->pixels;
+ /* Generally 32 bit bitmaps have an alpha channel which is used in favor
+ * of the AND mask. However, if all pixels have alpha = 0x00, the bitmap
+ * is treated like one without alpha and the masks are used. As soon as
+ * one pixel has alpha != 0x00, and the mask ignored as described in the
+ * docs.
+ *
+ * This is most likely for applications which create the bitmaps with
+ * CreateDIBitmap, which creates a device dependent bitmap, so the format
+ * that arrives when loading depends on the screen's bpp. Apps that were
+ * written at 8 / 16 bpp times do not know about the 32 bit alpha, so
+ * they would get a completely transparent cursor on 32 bit displays.
+ *
+ * Non-32 bit bitmaps always use the AND mask
+ */
+ if(ptr->bBitsPerPixel == 32)
+ {
+ for (y = 0; alpha_zero && y < ymax; ++y)
+ {
+ xor_ptr = xor_bits + (y * xor_width_bytes);
+ for (x = 0; x < xmax; ++x)
+ {
+ if (xor_ptr[3] != 0x00)
+ {
+ alpha_zero = FALSE;
+ break;
+ }
+ xor_ptr+=4;
+ }
+ }
+ }
+
/* On windows, to calculate the color for a pixel, first an AND is done
* with the background and the "and" bitmap, then an XOR with the "xor"
* bitmap. This means that when the data in the "and" bitmap is 0, the
@@ -484,7 +516,7 @@ static XcursorImage *create_cursor_image( CURSORICONINFO *ptr )
return 0;
}
- if (ptr->bBitsPerPixel != 32)
+ if (alpha_zero)
{
/* Alpha channel */
if (~*and_ptr & (1 << (7 - (x & 7)))) *pixel_ptr |= 0xff << 24;