[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Difficulty masking an image with another image

Subject: Difficulty masking an image with another image
From: Peter Bates <email@hidden>
Date: Thu, 11 May 2006 17:28:50 -0700
Delivered-to: email@hidden
Delivered-to: email@hidden

HI folks,

I'm just getting my feet wet with Quartz 2D and built a small app to try out some functions. The following code doesn't behave as I expected. Specifically the asterisked line below leaves maskedImage as nil. Either MyImage or aGrayScaleImage will display correctly. Any help appreciated.

Thanks,
Pete

void drawMaskedImage(CGContextRef context, CGRect contextRect) { CGImageRef image, mask, maskedImage; CGDataProviderRef imageProvider, maskProvider; CFStringRef imagePath, maskPath; CFURLRef imageUrl, maskUrl; NSString *k9TeethImage = [[NSBundle mainBundle] pathForImageResource:@"MyImage.png"]; char *imageFileName=[k9TeethImage UTF8String]; NSString *maskImage = [[NSBundle mainBundle] pathForImageResource:@"aGrayScaleImage.png"]; char *maskFileName=[maskImage UTF8String];

imagePath = CFStringCreateWithCString (NULL, imageFileName, kCFStringEncodingUTF8); imageUrl = CFURLCreateWithFileSystemPath (NULL, imagePath, kCFURLPOSIXPathStyle, NULL); maskPath = CFStringCreateWithCString (NULL, maskFileName, kCFStringEncodingUTF8); maskUrl = CFURLCreateWithFileSystemPath (NULL, maskPath, kCFURLPOSIXPathStyle, NULL); imageProvider = CGDataProviderCreateWithURL (imageUrl); maskProvider = CGDataProviderCreateWithURL (maskUrl); image = CGImageCreateWithPNGDataProvider (imageProvider, NULL, true, kCGRenderingIntentDefault); mask = CGImageCreateWithPNGDataProvider (maskProvider, NULL, true, kCGRenderingIntentDefault);

	CFRelease(imagePath);
	CFRelease(maskPath);
	CFRelease (imageUrl);
	CFRelease (maskUrl);
	CGDataProviderRelease (imageProvider);
	CGDataProviderRelease (maskProvider);
	
	CGRect aRect=CGRectMake (0, 0, 900, 1200);
	CGSize theSize=CGSizeMake (900,1200);

CGLayerRef imageLayerRef=CGLayerCreateWithContext (context, theSize, NULL); CGContextRef layerContext=CGLayerGetContext (imageLayerRef); // Create the masked image maskedImage=CGImageCreateWithMask(image, mask); // **************************************** // Draw it to the layer CGContextDrawImage(layerContext,aRect,maskedImage); // Then draw the layer to the window graphics context CGContextDrawLayerInRect(context, contextRect, imageLayerRef); }

- (void)drawRect:(NSRect)rect { float a,b,c,d; a=rect.origin.x; b=rect.origin.y; c=rect.size.width; d=rect.size.height; CGRect theRect=CGRectMake(a,b,c,d); CGContextRef theContext=[[NSGraphicsContext currentContext] graphicsPort]; drawMaskedImage(theContext,theRect); }

_______________________________________________
Do not post admin requests to the list. They will be ignored.
Quartz-dev mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/quartz-dev/email@hidden

This email sent to email@hidden

Follow-Ups:
- Re: Difficulty masking an image with another image
  - From: Scott Thompson <email@hidden>
- Re: Difficulty masking an image with another image
  - From: "Corey O'Connor" <email@hidden>

Prev by Date: Re: Speed up drawing using CGContextFlush
Next by Date: Re: Difficulty masking an image with another image
Previous by thread: Re: Speed up drawing using CGContextFlush
Next by thread: Re: Difficulty masking an image with another image
Index(es):
- Date
- Thread

Home