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Cleanup 

(cherry picked from commit 79de08db06)
This commit is contained in:
Camilla Löwy 2021-11-30 20:34:47 +01:00
parent 18d7c241f8
commit 84c881c1a8
1 changed files with 10 additions and 11 deletions
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21
src/x11_window.c
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@ -2133,20 +2133,19 @@ void _glfwPlatformSetWindowIcon(_GLFWwindow* window,
for (j = 0; j < images[i].width * images[i].height; j++)
{
*target++ = (((unsigned long)images[i].pixels[j * 4 + 0]) << 16) |
(((unsigned long)images[i].pixels[j * 4 + 1]) << 8) |
(((unsigned long)images[i].pixels[j * 4 + 2]) << 0) |
(((unsigned long)images[i].pixels[j * 4 + 3]) << 24);
*target++ = (((unsigned long) images[i].pixels[j * 4 + 0]) << 16) |
(((unsigned long) images[i].pixels[j * 4 + 1]) << 8) |
(((unsigned long) images[i].pixels[j * 4 + 2]) << 0) |
(((unsigned long) images[i].pixels[j * 4 + 3]) << 24);
}
}
// Important: Despite XChangeProperty docs indicating that `icon` (unsigned char*) would be
// in the format of the icon image, e.g. 32-bit below, the function actually casts the ptr
// (unsigned char*) internally to (long*) and then if long is defined as 64-bits, as on IL64
// platforms, extracts only 32 bits from the long leaving the other 32 unused. That is, on a
// 64-bit platform XChangeProperty expects 64-bit integers representing 32-bit pixels.
//
// See https://github.com/glfw/glfw/pull/1986#issuecomment-962445299
// NOTE: XChangeProperty expects 32-bit values like the image data above to be
// placed in the 32 least significant bits of individual longs. This is
// true even if long is 64-bit and a WM protocol calls for "packed" data.
// This is because of a historical mistake that then became part of the Xlib
// ABI. Xlib will pack these values into a regular array of 32-bit values
// before sending it over the wire.
XChangeProperty(_glfw.x11.display, window->x11.handle,
_glfw.x11.NET_WM_ICON,
XA_CARDINAL, 32,