Thread-topic: Using Cocoa cursors in a Carbon world
User-agent: Microsoft-Entourage/11.3.6.070618
Thanks to my co-worker, John Kerr, we got the NSCursor-From-Carbon-Cursor
code to create a color cursor that looks correct when drawing.
However, I still see the flicker.
I am posting the resulting code for the benefits of other Carbon->Cocoa
conversion efforts. I hope others find it useful (I apologize for my company
mandated email client's text wrapping):
//--------------------------------------------------------------------------
static NSImageRep* CreateImageRepWith16BitsOfData(const Bits16 data, const
Bits16 mask)
{
NSBitmapImageRep *result = nil;
if (data && mask) {
unsigned char *bmData = nil;
result = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL
pixelsWide:16
pixelsHigh:16
bitsPerSample:8
samplesPerPixel:4
hasAlpha:YES
isPlanar:NO
colorSpaceName:NSDeviceRGBColorSpace
bytesPerRow:64
bitsPerPixel:32];
bmData = [result bitmapData];
unsigned char monoComponent;
uint16_t row, rowMask;
int x, y;
for (y = 0; y < 16; y++) {
row = CFSwapInt16BigToHost(data[y]);
rowMask = CFSwapInt16BigToHost(mask[y]);
for (x = 0; x < 16; x++) {
monoComponent = (row & (1 << (15 - x))) ? 0x00 : 0xFF;
if (monoComponent == 0x00) {
// If the monoComponent is 0, then it must be drawn, the
alpha must be 1.
bmData[3] = 0xFF;
}
else {
bmData[3] = (rowMask & (1 << (15 - x))) ? 0xFF : 0x00;
// alpha
if (bmData[3] == 0x00) { // if the mask is 0, then the
monoComponent must be drawn (or == 0).
monoComponent = 0;
}
}
bmData[0] = bmData[1] = bmData[2] = monoComponent; // RGB
bmData += 4;
}
}
return [result autorelease];
}
return nil;
}
//--------------------------------------------------------------------------
static NSImage* CreateNSImageFromCarbonCursor( CursHandle legacyCursorH )
{
NSImage* cursorImage = [[NSImage alloc] initWithSize: NSMakeSize(16.0f,
16.0f) ];
[cursorImage addRepresentation:
CreateImageRepWith16BitsOfData((*legacyCursorH)->data,
(*legacyCursorH)->mask)];
return cursorImage;
}
//--------------------------------------------------------------------------
NSCursor* CreateNSCursorFromCarbonCursor( short legacyCursorResID )
{
CursHandle legacyCursorH = MacGetCursor(legacyCursorResID);
NSCursor* cursor = nil;
if (legacyCursorH) {
NSAutoreleasePool* localPool = nil;
localPool = [[NSAutoreleasePool alloc] init];
NSImage* nsImage = CreateNSImageFromCarbonCursor( legacyCursorH );
if (nsImage) {
float hotSpotX = (*legacyCursorH)->hotSpot.h;
float hotSpotY = (*legacyCursorH)->hotSpot.v;
cursor = [[NSCursor alloc] initWithImage:nsImage
hotSpot:NSMakePoint( hotSpotX, hotSpotY )];
[nsImage release];
}
[localPool release];
}
return cursor;
}
On 8/28/07 9:39 PM, "John Stiles" <email@hidden> wrote:
> Could the real issue be switching between black-and-white cursors,
> and color cursors?
> It is possible that on some video hardware, one is supported on the
> card, and the other is not, so the system would need to do handstands
> to switch between the two.
> You could try modifying the attached code to create a color image
> instead of a black-and-white one.
>
>
> On Aug 28, 2007, at 6:36 PM, Lyndsey Ferguson wrote:
>
>>
>> Hello Everyone,
>>
>> I've been meaning to write this email-list a nice letter stating
>> how much I
>> appreciate everyone's help and being a part of the community (even
>> if I wait
>> to contribute until I see no one knows an answer) - however, now is
>> not that
>> moment :)
>>
>> I've been struggling with a problem that I would appreciate your
>> suggestions
>> on. I believe I have exhausted my options, but I thought I would
>> check with
>> my peers to see if they have any other ideas.
>>
>> Our application is switching over to a system where we are using
>> NSCursor
>> for the majority (not all - time constraints) of our cursors. It
>> works quite
>> nicely. I didn't write the code, but it was written by a Software
>> Engineer
>> who did a good job.
>>
>> Unfortunately, he's gone and we are experiencing some issues. It
>> seems that
>> on the PowerPC (Tiger and Leopard), when the application switches
>> the cursor
>> from a Carbon cursor (via MacGetCursor and MacSetCursor) to a Cocoa
>> cursor
>> (via NSImage to NSCursor and NSCursor's -set function) one can see
>> a flicker
>> of the Carbon cursor in the vicinity of the mouse position (not
>> where the
>> hotspot is).
>>
>> I thought that perhaps the issue was switching between the two
>> types. So as
>> a test, I changed the code to not switch to a Carbon cursor ever,
>> but switch
>> to another Cocoa based cursor. Flicker was gone. Yay, I thought.
>>
>> So my next step was to find a way to create a Cocoa based cursor
>> from the
>> Carbon CursHandle. I found some code on the internet which appears to
>> fulfill that intention (I've attached it for your info - it doesn't
>> seem to
>> completely work, but it displays a similar image to what is
>> expected). So
>> now, I should be switching from Cocoa cursor to Cocoa cursor.
>>
>> Yet I still see a flicker.
>>
>> So I thought that perhaps the call MacGetCursor, which was made in
>> the code
>> to generate the Carbon based Cocoa cursor was causing a problem. So I
>> changed the code so that it caches the Cocoa cursors and only calls
>> MacGetCursor for the first time the Carbon-based Cocoa cursor is
>> created.
>> Flicker still happens.
>>
>> I've tried tracking down and logging any other call to MacSetCursor
>> so that
>> I could see if there was any legacy cursor setting while switching
>> between
>> Carbon/Carbon-based-Cocoa cursor and new Cocoa cursor. No calls to
>> MacSetCursor are made.
>>
>> So, now I'm out of ideas. Anyone familiar with pixel copying code
>> able to
>> comment on the code I've attached with regards to correctness?
>> Anyone else
>> had to deal with this problem? Ideas? I'm ready to try any suggestion.
>>
>> Thank you in advance,
>> Lyndsey Ferguson
>> --
>> Mr. Lyndsey D. Ferguson
>> Software Engineer
>> Nemetschek N.A., Inc.
>> http://www.nemetschek.net
>>
>>
>> <CreateCocoaCursorFromCarbon.cpp>
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>
--
Mr. Lyndsey D. Ferguson
Software Engineer
Nemetschek N.A., Inc.
http://www.nemetschek.net
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