> On Jun 25, 2015, at 6:10 PM, Raglan T. Tiger <r...@crusaderrabbit.net> wrote:
>
> I have a list of generic bitmaps that are to be transformed to NSImages. The
> list can be long, I haven limits on it.
>
> Here is the code I use to populate an NSMenu that gets set into an
> NSPopUpButton.
>
> I need to speed this process up ... any suggestions?
>
> NSMenu *comboMenu = [[[NSMenu alloc] init] autorelease];
> POSITION pos = listOfBBitmaps.GetHeadPosition();
> while ( pos )
> {
> BBitmap *image = &listOfBBitmaps.GetNext ( pos );
>
> CGColorSpaceRef colorSpace;
> colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
> CGContextRef context;
> context = CGBitmapContextCreate (image->m_array, image->m_pixelsx,
> image->m_pixelsy, 8, image->m_pixelsx * 4, colorSpace,
> kCGImageAlphaNoneSkipFirst|kCGBitmapByteOrder32Host);
>
> CGImageRef cgImage = CGBitmapContextCreateImage (context);
>
> CGContextRelease(context);
> CGColorSpaceRelease(colorSpace);
>
> size_t width = CGImageGetWidth( cgImage );
> size_t height = CGImageGetHeight( cgImage );
> NSRect imageRect = NSMakeRect(0, 0, width, height);
> NSImage *nsImage = [[[NSImage alloc] initWithSize:imageRect.size]
> autorelease];
>
> if ( [nsImage respondsToSelector:@selector(lockFocusFlipped:)] )
> {
> [nsImage lockFocusFlipped:YES];
> }
> else
> {
> [nsImage setFlipped:YES];
> [nsImage lockFocus];
> }
> CGContextRef imageContext = (CGContextRef)[[NSGraphicsContext
> currentContext] graphicsPort];
> CGContextDrawImage(imageContext, *(CGRect*)&imageRect, cgImage);
>
> [nsImage unlockFocus];
>
> NSMenuItem *menuItem = [[[NSMenuItem alloc] init] autorelease];
> [menuItem setImage: nsImage];
>
> [menuItem setTitle:[NSString stringWithFormat:@"untitled"]];
>
> [comboMenu addItem:menuItem];
>
> m_imageCount++;
>
> }
First suggestion is to cache the results so you don't have to convert every
time.
Second is to start the process in the background as soon as you think you'll
need the images rather than doing it synchronously.
Third is to avoid using drawing to create the NSImage. There are two separate
approaches:
1) Create the image by creating an NSBitmapImageRep from the bitmap
data and then creating an NSImage and adding that rep to it. You would call
-initWithBitmapDataPlanes:pixelsWide:pixelsHigh:bitsPerSample:samplesPerPixel:hasAlpha:isPlanar:colorSpaceName:bitmapFormat:bytesPerRow:bitsPerPixel:
to create the NSBitmapImageRep. You would use -initWithSize: to create the
NSImage. You would add the image rep to the image using -addRepresentation:.
2) Create a CGImage using CGImageCreate(). Create an NSImage using
-initWithCGImage:size:.
I doubt there's significant performance difference between the two methods, so
choose whichever seems most natural.
Regards,
Ken
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