Search Results

Search found 7 results on 1 pages for 'cgimagecreatewithmask'.

Page 1/1 | 1 

• CGImageCreateWithMask with an image as a mask

  - by Peyman

  Hi I am trying to use an image (painted as Core Graphics) to create a mask. What I am doing is this 1. creating a Core Graphics path CGContextSaveGState(context); CGContextBeginPath(context); CGContextMoveToPoint(context,circleCenter.x,circleCenter.y); //CGContextSetAllowsAntialiasing(myBitmapContext, YES); CGContextAddArc(context,circleCenter.x, circleCenter.y,circleRadius,startingAngle, endingAngle, 0); // 0 is counterclockwise CGContextClosePath(context); CGContextSetRGBStrokeColor(context,1.0,0.0,0.0,1.0); CGContextSetRGBFillColor(context,1.0,0.0,0.0,0.2); CGContextDrawPath(context, kCGPathFillStroke); 2. then I'm saving the context that has the path just painted CGImageRef pacmanImage = CGBitmapContextCreateImage (context); 3. restoring the context CGContextRestoreGState(context); CGContextSaveGState(context); 4. creating a 1 bit mask (which will provide the black-white mask) bitsPerComponent = 1; bitsPerPixel = bitsPerComponent * 1 ; bytesPerRow = (CGImageGetWidth(imgToMaskRef) * bitsPerPixel); mask = CGImageCreate(CGImageGetWidth(imgToMaskRef), CGImageGetHeight(imgToMaskRef), bitsPerComponent, bitsPerPixel, bytesPerRow, greyColorSpace, kCGImageAlphaNone, CGImageGetDataProvider(pacmanImage), NULL, //decode YES, //shouldInterpolate kCGRenderingIntentDefault); 5. masking the imgToMaskRef (which is a CGImageRef imgToMaskRef =imgToMask.CGImage;) with the mask just created imageMaskedWithImage = CGImageCreateWithMask(imgToMaskRef, mask); CGContextDrawImage(context,imgRectBox, imageMaskedWithImage); CGImageRef maskedImageFinal = CGBitmapContextCreateImage (context); returning the maskedImageFinal to the caller of this method (as wheelChoiceMadeState, which is a CGImageRef) who then updates the CALayer contents property with the image theLayer.contents = (id) wheelChoiceMadeState; the problem I am seeing is that the mask does not work properly and looks very strange indeed. I get strange patterns across the path painted by the Core Graphics. My hunch is there is something with CGImageGetDataProvider() but I am not sure. Any help would be appreciated thank you

  Read the article

• How to get rid of previous reflection when reflecting a UIImageView (with changing pictures)?

  - by epale

  Hi everyone, I have managed to use the reflection sample app from apple to create a reflection from a UIImageView. But the problem is that when I change the picture inside the UIImageView, the reflection from the previous displayed picture remains on the screen. The new reflection on the next picture then overlaps the previous reflection. How do I ensure that the previous reflection is removed when I change to the next picture? Thank you so much. I hope my question is not too basic. Here is the codes which i used so far: //reflection self.view.autoresizesSubviews = YES; self.view.userInteractionEnabled = YES; // create the reflection view CGRect reflectionRect = currentView.frame; // the reflection is a fraction of the size of the view being reflected reflectionRect.size.height = reflectionRect.size.height * kDefaultReflectionFraction; // and is offset to be at the bottom of the view being reflected reflectionRect = CGRectOffset(reflectionRect, 0, currentView.frame.size.height); reflectionView = [[UIImageView alloc] initWithFrame:reflectionRect]; // determine the size of the reflection to create NSUInteger reflectionHeight = currentView.bounds.size.height * kDefaultReflectionFraction; // create the reflection image, assign it to the UIImageView and add the image view to the containerView reflectionView.image = [self reflectedImage:currentView withHeight:reflectionHeight]; reflectionView.alpha = kDefaultReflectionOpacity; [self.view addSubview:reflectionView]; //reflection */ Then the codes below are used to form the reflection: CGImageRef CreateGradientImage(int pixelsWide, int pixelsHigh) { CGImageRef theCGImage = NULL; // gradient is always black-white and the mask must be in the gray colorspace CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); // create the bitmap context CGContextRef gradientBitmapContext = CGBitmapContextCreate(nil, pixelsWide, pixelsHigh, 8, 0, colorSpace, kCGImageAlphaNone); // define the start and end grayscale values (with the alpha, even though // our bitmap context doesn't support alpha the gradient requires it) CGFloat colors[] = {0.0, 1.0, 1.0, 1.0}; // create the CGGradient and then release the gray color space CGGradientRef grayScaleGradient = CGGradientCreateWithColorComponents(colorSpace, colors, NULL, 2); CGColorSpaceRelease(colorSpace); // create the start and end points for the gradient vector (straight down) CGPoint gradientStartPoint = CGPointZero; CGPoint gradientEndPoint = CGPointMake(0, pixelsHigh); // draw the gradient into the gray bitmap context CGContextDrawLinearGradient(gradientBitmapContext, grayScaleGradient, gradientStartPoint, gradientEndPoint, kCGGradientDrawsAfterEndLocation); CGGradientRelease(grayScaleGradient); // convert the context into a CGImageRef and release the context theCGImage = CGBitmapContextCreateImage(gradientBitmapContext); CGContextRelease(gradientBitmapContext); // return the imageref containing the gradient return theCGImage; } CGContextRef MyCreateBitmapContext(int pixelsWide, int pixelsHigh) { CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // create the bitmap context CGContextRef bitmapContext = CGBitmapContextCreate (nil, pixelsWide, pixelsHigh, 8, 0, colorSpace, // this will give us an optimal BGRA format for the device: (kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst)); CGColorSpaceRelease(colorSpace); return bitmapContext; } (UIImage *)reflectedImage:(UIImageView *)fromImage withHeight:(NSUInteger)height { if (!height) return nil; // create a bitmap graphics context the size of the image CGContextRef mainViewContentContext = MyCreateBitmapContext(fromImage.bounds.size.width, height); // offset the context - // This is necessary because, by default, the layer created by a view for caching its content is flipped. // But when you actually access the layer content and have it rendered it is inverted. Since we're only creating // a context the size of our reflection view (a fraction of the size of the main view) we have to translate the // context the delta in size, and render it. // CGFloat translateVertical= fromImage.bounds.size.height - height; CGContextTranslateCTM(mainViewContentContext, 0, -translateVertical); // render the layer into the bitmap context CALayer *layer = fromImage.layer; [layer renderInContext:mainViewContentContext]; // create CGImageRef of the main view bitmap content, and then release that bitmap context CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext); CGContextRelease(mainViewContentContext); // create a 2 bit CGImage containing a gradient that will be used for masking the // main view content to create the 'fade' of the reflection. The CGImageCreateWithMask // function will stretch the bitmap image as required, so we can create a 1 pixel wide gradient CGImageRef gradientMaskImage = CreateGradientImage(1, height); // create an image by masking the bitmap of the mainView content with the gradient view // then release the pre-masked content bitmap and the gradient bitmap CGImageRef reflectionImage = CGImageCreateWithMask(mainViewContentBitmapContext, gradientMaskImage); CGImageRelease(mainViewContentBitmapContext); CGImageRelease(gradientMaskImage); // convert the finished reflection image to a UIImage UIImage *theImage = [UIImage imageWithCGImage:reflectionImage]; // image is retained by the property setting above, so we can release the original CGImageRelease(reflectionImage); return theImage; } */

  Read the article

• Masking to Transparent returns empty image

  - by Tibi

  Hi there, I'm trying to put white color in my images to transparent with the following code. Problem is that "CGImageRef maskedTransparent" is blank. I don't understand because the code I'm using is nearly a copy paste from the doc ... Any idea ? (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage { CGImageRef maskRef = maskImage.CGImage; CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef), CGImageGetHeight(maskRef), CGImageGetBitsPerComponent(maskRef), CGImageGetBitsPerPixel(maskRef), CGImageGetBytesPerRow(maskRef), CGImageGetDataProvider(maskRef), NULL, false); CGImageRef masked = CGImageCreateWithMask([image CGImage], mask); //Array defining min & max RGB values to be transformed to transparent colors. float maskingMinMax[6] = {255, 255, 255, 255, 255, 255}; //masking image to remove range in maskinLinMax CGImageRef maskedTransparent = CGImageCreateWithMaskingColors(masked, maskingMinMax); return [UIImage imageWithCGImage:maskedTransparent]; }

  Read the article

• Crashing when masking an image

  - by shameer

  I am trying to mask an image with a 'mask image". its work fine at first time. but when i try one more time with in the application with same mask image . Application crashed. but when trying with another mask image it works fine. Why this happens? pls help? Console shows ": CGImageMaskCreate: invalid mask bits/component: 4294967295." (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage { CGImageRef maskRef = maskImage.CGImage; CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef), CGImageGetHeight(maskRef), CGImageGetBitsPerComponent(maskRef), CGImageGetBitsPerPixel(maskRef), CGImageGetBytesPerRow(maskRef), CGImageGetDataProvider(maskRef), NULL, false); CGImageRef masked = CGImageCreateWithMask([image CGImage], mask); UIImage *img2=[UIImage imageWithCGImage:masked]; CGImageRelease(maskRef); CGImageRelease(mask); CGImageRelease(masked); return img2; } fun1() { view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]]; } fun2() { view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]]; view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image3.png"]]; } fun3() { view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]]; view.image=[self maskImage:image1 withMask:[UIImage imageNamed:@"image2.png"]]; } When calling fun1 and fun2 apllication works fine. Application crashing when calling fun3.

  Read the article

• iPhone development: pointer being freed was not allocated

  - by w4nderlust

  Hello, i got this message from the debugger: Pixture(1257,0xa0610500) malloc: *** error for object 0x21a8000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug so i did a bit of tracing and got: (gdb) shell malloc_history 1257 0x21a8000 ALLOC 0x2196a00-0x21a89ff [size=73728]: thread_a0610500 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) | CA::Transaction::commit() | CA::Context::commit_transaction(CA::Transaction*) | CALayerDisplayIfNeeded | -[CALayer _display] | CABackingStoreUpdate | backing_callback(CGContext*, void*) | -[CALayer drawInContext:] | -[UIView(CALayerDelegate) drawLayer:inContext:] | -[AvatarView drawRect:] | -[AvatarView overlayPNG:] | +[UIImageUtility createMaskOf:] | UIGraphicsGetImageFromCurrentImageContext | CGBitmapContextCreateImage | create_bitmap_data_provider | malloc | malloc_zone_malloc and i really can't understand what i am doing wrong. here's the code of the [UIImageUtility createMaskOf:] function: + (UIImage *)createMaskOf:(UIImage *)source { CGRect rect = CGRectMake(0, 0, source.size.width, source.size.height); UIGraphicsBeginImageContext(CGSizeMake(source.size.width, source.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 0, source.size.height); CGContextScaleCTM(context, 1.0, -1.0); UIImage *original = [self createGrayCopy:source]; CGContextRef context2 = CGBitmapContextCreate(NULL, source.size.width, source.size.height, 8, 4 * source.size.width, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipLast); CGContextDrawImage(context2, CGRectMake(0, 0, source.size.width, source.size.height), original.CGImage); CGImageRef unmasked = CGBitmapContextCreateImage(context2); const float myMaskingColorsFrameColor[6] = { 1,256,1,256,1,256 }; CGImageRef mask = CGImageCreateWithMaskingColors(unmasked, myMaskingColorsFrameColor); CGContextSetRGBFillColor (context, 256,256,256, 1); CGContextFillRect(context, rect); CGContextDrawImage(context, rect, mask); UIImage *whiteMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return whiteMasked; } the other custom function called before that is the following: - (UIImage *)overlayPNG:(SinglePart *)sp { NSLog([sp description]); // Rect and context setup CGRect rect = CGRectMake(0, 0, sp.image.size.width, sp.image.size.height); NSLog(@"%f x %f", sp.image.size.width, sp.image.size.height); // Create an image of a color filled rectangle UIImage *baseColor = nil; if (sp.hasOwnColor) { baseColor = [UIImageUtility imageWithRect:rect ofColor:sp.color]; } else { SinglePart *facePart = [editingAvatar.face.partList objectAtIndex:0]; baseColor = [UIImageUtility imageWithRect:rect ofColor:facePart.color]; } // Crete the mask of the layer UIImage *mask = [UIImageUtility createMaskOf:sp.image]; mask = [UIImageUtility createGrayCopy:mask]; // Create a new context for merging the overlay and a mask of the layer UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context2 = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context2, 0, sp.image.size.height); CGContextScaleCTM(context2, 1.0, -1.0); // Create masked overlay color layer CGImageRef MaskedImage = CGImageCreateWithMask (baseColor.CGImage, mask.CGImage); // Draw the base color layer CGContextDrawImage(context2, rect, MaskedImage); // Get the result of the masking UIImage* overlayMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context, 0, sp.image.size.height); CGContextScaleCTM(context, 1.0, -1.0); // Get the result of the blending of the masked overlay and the base image CGContextDrawImage(context, rect, overlayMasked.CGImage); // Set the blend mode for the next drawn image CGContextSetBlendMode(context, kCGBlendModeOverlay); // Component image drawn CGContextDrawImage(context, rect, sp.image.CGImage); UIImage* blendedImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRelease(MaskedImage); return blendedImage; }

  Read the article

• UIImage rounded corners

  - by catlan

  I try to get rounded corners on a UIImage, what I read so far, the easiest way is to use a mask images. For this I used code from TheElements iPhone Example and some image resize code I found. My problem is that resizedImage is always nil and I don't find the error... - (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize { CGSize imageSize = [self size]; float width = imageSize.width; float height = imageSize.height; // scaleFactor will be the fraction that we'll // use to adjust the size. For example, if we shrink // an image by half, scaleFactor will be 0.5. the // scaledWidth and scaledHeight will be the original, // multiplied by the scaleFactor. // // IMPORTANT: the "targetHeight" is the size of the space // we're drawing into. The "scaledHeight" is the height that // the image actually is drawn at, once we take into // account the ideal of maintaining proportions float scaleFactor = 0.0; float scaledWidth = targetSize.width; float scaledHeight = targetSize.height; CGPoint thumbnailPoint = CGPointMake(0,0); // since not all images are square, we want to scale // proportionately. To do this, we find the longest // edge and use that as a guide. if ( CGSizeEqualToSize(imageSize, targetSize) == NO ) { // use the longeset edge as a guide. if the // image is wider than tall, we'll figure out // the scale factor by dividing it by the // intended width. Otherwise, we'll use the // height. float widthFactor = targetSize.width / width; float heightFactor = targetSize.height / height; if ( widthFactor < heightFactor ) scaleFactor = widthFactor; else scaleFactor = heightFactor; // ex: 500 * 0.5 = 250 (newWidth) scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the thumbnail in the frame. if // wider than tall, we need to adjust the // vertical drawing point (y axis) if ( widthFactor < heightFactor ) thumbnailPoint.y = (targetSize.height - scaledHeight) * 0.5; else if ( widthFactor > heightFactor ) thumbnailPoint.x = (targetSize.width - scaledWidth) * 0.5; } CGContextRef mainViewContentContext; CGColorSpaceRef colorSpace; colorSpace = CGColorSpaceCreateDeviceRGB(); // create a bitmap graphics context the size of the image mainViewContentContext = CGBitmapContextCreate (NULL, targetSize.width, targetSize.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast); // free the rgb colorspace CGColorSpaceRelease(colorSpace); if (mainViewContentContext==NULL) return NULL; //CGContextSetFillColorWithColor(mainViewContentContext, [[UIColor whiteColor] CGColor]); //CGContextFillRect(mainViewContentContext, CGRectMake(0, 0, targetSize.width, targetSize.height)); CGContextDrawImage(mainViewContentContext, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), self.CGImage); // Create CGImageRef of the main view bitmap content, and then // release that bitmap context CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext); CGContextRelease(mainViewContentContext); CGImageRef maskImage = [[UIImage imageNamed:@"Mask.png"] CGImage]; CGImageRef resizedImage = CGImageCreateWithMask(mainViewContentBitmapContext, maskImage); CGImageRelease(mainViewContentBitmapContext); // convert the finished resized image to a UIImage UIImage *theImage = [UIImage imageWithCGImage:resizedImage]; // image is retained by the property setting above, so we can // release the original CGImageRelease(resizedImage); // return the image return theImage; }

  Read the article

• UIImage rounded corners

  - by catlan

  I try to get rounded corners on a UIImage, what I read so far, the easiest way is to use a mask images. For this I used code from TheElements iPhone Example and some image resize code I found. My problem is that resizedImage is always nil and I don't find the error... - (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize { CGSize imageSize = [self size]; float width = imageSize.width; float height = imageSize.height; // scaleFactor will be the fraction that we'll // use to adjust the size. For example, if we shrink // an image by half, scaleFactor will be 0.5. the // scaledWidth and scaledHeight will be the original, // multiplied by the scaleFactor. // // IMPORTANT: the "targetHeight" is the size of the space // we're drawing into. The "scaledHeight" is the height that // the image actually is drawn at, once we take into // account the ideal of maintaining proportions float scaleFactor = 0.0; float scaledWidth = targetSize.width; float scaledHeight = targetSize.height; CGPoint thumbnailPoint = CGPointMake(0,0); // since not all images are square, we want to scale // proportionately. To do this, we find the longest // edge and use that as a guide. if ( CGSizeEqualToSize(imageSize, targetSize) == NO ) { // use the longeset edge as a guide. if the // image is wider than tall, we'll figure out // the scale factor by dividing it by the // intended width. Otherwise, we'll use the // height. float widthFactor = targetSize.width / width; float heightFactor = targetSize.height / height; if ( widthFactor < heightFactor ) scaleFactor = widthFactor; else scaleFactor = heightFactor; // ex: 500 * 0.5 = 250 (newWidth) scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the thumbnail in the frame. if // wider than tall, we need to adjust the // vertical drawing point (y axis) if ( widthFactor < heightFactor ) thumbnailPoint.y = (targetSize.height - scaledHeight) * 0.5; else if ( widthFactor > heightFactor ) thumbnailPoint.x = (targetSize.width - scaledWidth) * 0.5; } CGContextRef mainViewContentContext; CGColorSpaceRef colorSpace; colorSpace = CGColorSpaceCreateDeviceRGB(); // create a bitmap graphics context the size of the image mainViewContentContext = CGBitmapContextCreate (NULL, targetSize.width, targetSize.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast); // free the rgb colorspace CGColorSpaceRelease(colorSpace); if (mainViewContentContext==NULL) return NULL; //CGContextSetFillColorWithColor(mainViewContentContext, [[UIColor whiteColor] CGColor]); //CGContextFillRect(mainViewContentContext, CGRectMake(0, 0, targetSize.width, targetSize.height)); CGContextDrawImage(mainViewContentContext, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), self.CGImage); // Create CGImageRef of the main view bitmap content, and then // release that bitmap context CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext); CGContextRelease(mainViewContentContext); CGImageRef maskImage = [[UIImage imageNamed:@"Mask.png"] CGImage]; CGImageRef resizedImage = CGImageCreateWithMask(mainViewContentBitmapContext, maskImage); CGImageRelease(mainViewContentBitmapContext); // convert the finished resized image to a UIImage UIImage *theImage = [UIImage imageWithCGImage:resizedImage]; // image is retained by the property setting above, so we can // release the original CGImageRelease(resizedImage); // return the image return theImage; }

  Read the article

1