use unsigned long / correct incompatability with underlying libxcb expectations

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2021-11-15 16:59:33 -07:00
parent bb2b007af6
commit 3d8a194eef

View File

@ -2100,13 +2100,13 @@ void _glfwSetWindowIconX11(_GLFWwindow* window, int count, const GLFWimage* imag
{ {
if (count) if (count)
{ {
int elements = 0; int longCount = 0;
for (int i = 0; i < count; i++) for (int i = 0; i < count; i++)
elements += 2 + images[i].width * images[i].height; longCount += 2 + images[i].width * images[i].height;
uint32_t* icon = _glfw_calloc(elements, sizeof(uint32_t)); unsigned long* icon = _glfw_calloc(longCount, sizeof(unsigned long));
uint32_t* target = icon; unsigned long* target = icon;
for (int i = 0; i < count; i++) for (int i = 0; i < count; i++)
{ {
@ -2115,19 +2115,26 @@ void _glfwSetWindowIconX11(_GLFWwindow* window, int count, const GLFWimage* imag
for (int j = 0; j < images[i].width * images[i].height; j++) for (int j = 0; j < images[i].width * images[i].height; j++)
{ {
*target++ = (((uint32_t)images[i].pixels[j * 4 + 0]) << 16) | *target++ = (((unsigned long)images[i].pixels[j * 4 + 0]) << 16) |
(((uint32_t)images[i].pixels[j * 4 + 1]) << 8) | (((unsigned long)images[i].pixels[j * 4 + 1]) << 8) |
(((uint32_t)images[i].pixels[j * 4 + 2]) << 0) | (((unsigned long)images[i].pixels[j * 4 + 2]) << 0) |
(((uint32_t)images[i].pixels[j * 4 + 3]) << 24); (((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
XChangeProperty(_glfw.x11.display, window->x11.handle, XChangeProperty(_glfw.x11.display, window->x11.handle,
_glfw.x11.NET_WM_ICON, _glfw.x11.NET_WM_ICON,
XA_CARDINAL, 32, XA_CARDINAL, 32,
PropModeReplace, PropModeReplace,
(unsigned char*) icon, (unsigned char*) icon,
elements); longCount);
_glfw_free(icon); _glfw_free(icon);
} }