Different cursor formats in IOFrameBufferShared
- by Thomi
Hi,
I'm reading the moust cursor pixmap data from the StdFBShmem_t structure, as defined in the IOFrameBufferShared API.
Everything works fine, 90% of the time. However, I have noticed that some applications on the mac set a cursor in a different format. According to the documentation for the data structures, the cursor pixmap format should always be in the same format as the frame buffer. My frame buffer is 32BPP. I expect the pixmap data to be in the format 0xAARRGGBB, which is it. However, in some cases, I'm reading data that looks like a mask. Specifically, the pixel will either be 0x00FFFFFF or `0x00000000. This looks to me to be a mask for separate pixel data stored somewhere else.
As far as I can tell, the only application that uses this cursor pixel format is Qt Creator, but I need to work with all applications, so I'd like to sort this out.
The code I'm using to read the cursor pixmap data is:
NSAutoreleasePool *autoReleasePool = [[NSAutoreleasePool alloc] init];
NSPoint mouseLocation = [NSEvent mouseLocation];
NSArray *allScreens = [NSScreen screens];
NSEnumerator *screensEnum = [allScreens objectEnumerator];
NSScreen *screen;
NSDictionary *screenDesc = nil;
while ((screen = [screensEnum nextObject]))
{
NSRect screenFrame = [screen frame];
screenDesc = [screen deviceDescription];
if (NSMouseInRect(mouseLocation, screenFrame, NO))
break;
}
if (screen)
{
kern_return_t err;
CGDirectDisplayID displayID = (CGDirectDisplayID) [[screenDesc objectForKey:@"NSScreenNumber"] pointerValue];
task_port_t taskPort = mach_task_self();
io_service_t displayServicePort = CGDisplayIOServicePort(displayID);
io_connect_t displayConnection =0;
err = IOFramebufferOpen(displayServicePort,
taskPort,
kIOFBSharedConnectType,
&displayConnection);
if (KERN_SUCCESS == err)
{
union
{
vm_address_t vm_ptr;
StdFBShmem_t *fbshmem;
} cursorInfo;
vm_size_t size;
err = IOConnectMapMemory(displayConnection,
kIOFBCursorMemory,
taskPort,
&cursorInfo.vm_ptr,
&size,
kIOMapAnywhere | kIOMapDefaultCache | kIOMapReadOnly);
if (KERN_SUCCESS == err)
{
// for some reason, cursor data is not always in the same format as the frame buffer. For this reason, we need
// some way to detect which structure we should be reading.
QByteArray pixData((const char*)cursorInfo.fbshmem->cursor.rgb24.image[currentFrame], m_mouseInfo.currentSize.width() * m_mouseInfo.currentSize.height() * 4);
IOConnectUnmapMemory(displayConnection,
kIOFBCursorMemory,
taskPort,
cursorInfo.vm_ptr);
} // IOConnectMapMemory
else
qDebug() << "IOConnectMapMemory Failed:" << err;
IOServiceClose(displayConnection);
} // IOServiceOpen
else
qDebug() << "IOFramebufferOpen Failed:" << err;
}// if screen
[autoReleasePool release];
My question is:
How can I detect if the cursor is a different format from the framebuffer?
Where can I read the actual pixel data? the bm18Cursor structure contains a mask section, but it's not in the right place for me to be reading it using the code above.
Cheers,
