GPUImagePicture类静态图像处理操作，它可以是需要处理的静态图像，也可以是一张作为纹理使用的图片，调用向它发送PRocessImage消息，进行图像滤镜处理。
方法
- (id)initWithURL:(NSURL *)url
说明：使用指定url的图片来初始化GPUImagePicture
- (id)initWithImage:(UIImage *)newImageSource
说明：使用指定的UIImage对象来初始化GPUImagePicture
- (id)initWithCGImage:(CGImageRef)newImageSource
说明：使用指定的CGImageRef对象来初始化GPUImagePicture
- (id)initWithImage:(UIImage *)newImageSource smoothlyScaleOutput:(BOOL)smoothlyScaleOutput
说明：使用指定的UIImage对象来初始化GPUImagePicture，是否按比例调整输入图像的尺寸
- (void)processImage
说明：进行图像处理实际操作。
- (BOOL)processImageWithCompletionHandler:(void (^)(void))completion
说明：进行图像处理实际的操作，completion为当处理结束执行的操作。
完整代码
#import <UIKit/UIKit.h>#import"GPUImageOutput.h"@interface GPUImagePicture : GPUImageOutput
{
CGSize pixelSizeOfImage;
BOOL hasprocessedImage;
dispatch_semaphore_t imageUpdateSemaphore;
}//Initialization and teardown- (id)initWithURL:(NSURL *)url;- (id)initWithImage:(UIImage *)newImageSource;-(id)initWithCGImage:(CGImageRef)newImageSource;- (id)initWithImage:(UIImage *)newImageSource smoothlyScaleOutput:(BOOL)smoothlyScaleOutput;-(id)initWithCGImage:(CGImageRef)newImageSource smoothlyScaleOutput:(BOOL)smoothlyScaleOutput;//Image rendering- (void)processImage;-(CGSize)outputImageSize;/**
* Process image with all targets and filters asynchronously
* The completion handler is called after processing finished in the
* GPU's dispatch queue - and only if this method did not return NO.
*
* @returns NO if resource is blocked and processing is discarded, YES otherwise*/- (BOOL)processImageWithCompletionHandler:(void(^)(void))completion;- (void)processImageUpToFilter:(GPUImageOutput<GPUImageInput> *)finalFilterInChain withCompletionHandler:(void(^)(UIImage *processedImage))block;
@end
#import"GPUImagePicture.h"@implementation GPUImagePicture#pragmamark -#pragmamark Initialization and teardown
- (id)initWithURL:(NSURL *)url;
{
NSData*imageData =[[NSData alloc] initWithContentsOfURL:url];if(!(self =[self initWithData:imageData]))
{returnnil;
}returnself;
}- (id)initWithData:(NSData *)imageData;
{
UIImage*inputImage =[[UIImage alloc] initWithData:imageData];if(!(self =[self initWithImage:inputImage]))
{returnnil;
}returnself;
}- (id)initWithImage:(UIImage *)newImageSource;
{if(!(self =[self initWithImage:newImageSource smoothlyScaleOutput:NO]))
{returnnil;
}returnself;
}-(id)initWithCGImage:(CGImageRef)newImageSource;
{if(!(self =[self initWithCGImage:newImageSource smoothlyScaleOutput:NO]))
{returnnil;
}returnself;
}- (id)initWithImage:(UIImage *)newImageSource smoothlyScaleOutput:(BOOL)smoothlyScaleOutput;
{return[self initWithCGImage:[newImageSource CGImage] smoothlyScaleOutput:smoothlyScaleOutput];
}-(id)initWithCGImage:(CGImageRef)newImageSource smoothlyScaleOutput:(BOOL)smoothlyScaleOutput;
{if(!(self =[super init]))
{returnnil;
}
hasProcessedImage=NO;
self.shouldSmoothlyScaleOutput=smoothlyScaleOutput;
imageUpdateSemaphore= dispatch_semaphore_create(0);
dispatch_semaphore_signal(imageUpdateSemaphore);//TODO: Dispatch this whole thing asynchronously to move image loading off main threadCGFloat widthOfImage =CGImageGetWidth(newImageSource);
CGFloat heightOfImage=CGImageGetHeight(newImageSource);//If passed an empty image reference, CGContextDrawImage will fail in future versions of the SDK.NSAssert( widthOfImage >0&& heightOfImage >0,@"Passed image must not be empty - it should be at least 1px tall and wide");
pixelSizeOfImage=CGSizeMake(widthOfImage, heightOfImage);
CGSize pixelSizeToUseForTexture=pixelSizeOfImage;
BOOL shouldRedrawUsingCoreGraphics=NO;//For now, deal with images larger than the maximum texture size by resizing to be within that limitCGSize scaledImageSizeToFitOnGPU =[GPUImageContext sizeThatFitsWithinATextureForSize:pixelSizeOfImage];if(!CGSizeEqualToSize(scaledImageSizeToFitOnGPU, pixelSizeOfImage))
{
pixelSizeOfImage=scaledImageSizeToFitOnGPU;
pixelSizeToUseForTexture=pixelSizeOfImage;
shouldRedrawUsingCoreGraphics=YES;
}if(self.shouldSmoothlyScaleOutput)
{//In order to use mipmaps, you need to provide power-of-two textures, so convert to the next largest power of two and stretch to fillCGFloat powerClosestToWidth =ceil(log2(pixelSizeOfImage.width));
CGFloat powerClosestToHeight=ceil(log2(pixelSizeOfImage.height));
pixelSizeToUseForTexture= CGSizeMake(pow(2.0, powerClosestToWidth), pow(2.0, powerClosestToHeight));
shouldRedrawUsingCoreGraphics=YES;
}
GLubyte*imageData =NULL;
CFDataRef dataFromImageDataProvider=NULL;
GLenum format=GL_BGRA;if(!shouldRedrawUsingCoreGraphics) {/*Check that the memory layout is compatible with GL, as we cannot use glPixelStore to
* tell GL about the memory layout with GLES.*/if(CGImageGetBytesPerRow(newImageSource) != CGImageGetWidth(newImageSource) *4||CGImageGetBitsPerPixel(newImageSource)!=32||CGImageGetBitsPerComponent(newImageSource)!=8)
{
shouldRedrawUsingCoreGraphics=YES;
}else{/*Check that the bitmap pixel format is compatible with GL*/CGBitmapInfo bitmapInfo=CGImageGetBitmapInfo(newImageSource);if((bitmapInfo & kCGBitmapFloatComponents) !=0) {/*We don't support float components for use directly in GL*/shouldRedrawUsingCoreGraphics=YES;
}else{
CGBitmapInfo byteOrderInfo= bitmapInfo &kCGBitmapByteOrderMask;if(byteOrderInfo ==kCGBitmapByteOrder32Little) {/*Little endian, for alpha-first we can use this bitmap directly in GL*/CGImageAlphaInfo alphaInfo= bitmapInfo &kCGBitmapAlphaInfoMask;if(alphaInfo != kCGImageAlphaPremultipliedFirst && alphaInfo != kCGImageAlphaFirst &&alphaInfo!=kCGImageAlphaNoneSkipFirst) {
shouldRedrawUsingCoreGraphics=YES;
}
}elseif(byteOrderInfo == kCGBitmapByteOrderDefault || byteOrderInfo ==kCGBitmapByteOrder32Big) {/*Big endian, for alpha-last we can use this bitmap directly in GL*/CGImageAlphaInfo alphaInfo= bitmapInfo &kCGBitmapAlphaInfoMask;if(alphaInfo != kCGImageAlphaPremultipliedLast && alphaInfo != kCGImageAlphaLast &&alphaInfo!=kCGImageAlphaNoneSkipLast) {
shouldRedrawUsingCoreGraphics=YES;
}else{/*Canaccessdirectly using GL_RGBA pixel format*/format=GL_RGBA;
}
}
}
}
}//CFAbsoluteTime elapsedTime, startTime = CFAbsoluteTimeGetCurrent();if(shouldRedrawUsingCoreGraphics)
{//For resized or incompatible image: redrawimageData = (GLubyte *)calloc(1, (int)pixelSizeToUseForTexture.width * (int)pixelSizeToUseForTexture.height *4);
CGColorSpaceRef genericRGBColorspace=CGColorSpaceCreateDeviceRGB();
CGContextRef imageContext= CGBitmapContextCreate(imageData, (size_t)pixelSizeToUseForTexture.width, (size_t)pixelSizeToUseForTexture.height,8, (size_t)pixelSizeToUseForTexture.width *4, genericRGBColorspace, kCGBitmapByteOrder32Little |kCGImageAlphaPremultipliedFirst);//CGContextSetBlendMode(imageContext, kCGBlendModeCopy);//From Technical Q&A QA1708:http://developer.apple.com/library/ios/#qa/qa1708/_index.htmlCGContextDrawImage(imageContext, CGRectMake(0.0,0.0, pixelSizeToUseForTexture.width, pixelSizeToUseForTexture.height), newImageSource);
CGContextRelease(imageContext);
CGColorSpaceRelease(genericRGBColorspace);
}else{//Access the raw image bytes directlydataFromImageDataProvider =CGDataProviderCopyData(CGImageGetDataProvider(newImageSource));
imageData= (GLubyte *)CFDataGetBytePtr(dataFromImageDataProvider);
}//elapsedTime = (CFAbsoluteTimeGetCurrent() - startTime) * 1000.0;//NSLog(@"Core Graphics drawing time: %f", elapsedTime);//CGFloat currentRedTotal = 0.0f, currentGreenTotal = 0.0f, currentBlueTotal = 0.0f, currentAlphaTotal = 0.0f;//NSUInteger totalNumberOfPixels = round(pixelSizeToUseForTexture.width * pixelSizeToUseForTexture.height);////for (NSUInteger currentPixel = 0; currentPixel < totalNumberOfPixels; currentPixel++)//{//currentBlueTotal += (CGFloat)imageData[(currentPixel * 4)] / 255.0f;//currentGreenTotal += (CGFloat)imageData[(currentPixel * 4) + 1] / 255.0f;//currentRedTotal += (CGFloat)imageData[(currentPixel * 4 + 2)] / 255.0f;//currentAlphaTotal += (CGFloat)imageData[(currentPixel * 4) + 3] / 255.0f;//}////NSLog(@"Debug, average input image red: %f, green: %f, blue: %f, alpha: %f", currentRedTotal / (CGFloat)totalNumberOfPixels, currentGreenTotal / (CGFloat)totalNumberOfPixels, currentBlueTotal / (CGFloat)totalNumberOfPixels, currentAlphaTotal / (CGFloat)totalNumberOfPixels);runSynchronouslyOnVideoProcessingQueue(^{
[GPUImageContext useImageProcessingContext];
outputFramebuffer=[[GPUImageContext sharedFramebufferCache] fetchFramebufferForSize:pixelSizeToUseForTexture onlyTexture:YES];
[outputFramebuffer disableReferenceCounting];
glBindTexture(GL_TEXTURE_2D, [outputFramebuffer texture]);if(self.shouldSmoothlyScaleOutput)
{
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
}//no need to use self.outputTextureOptions here since pictures need this texture formats and typeglTexImage2D(GL_TEXTURE_2D,0, GL_RGBA, (int)pixelSizeToUseForTexture.width, (int)pixelSizeToUseForTexture.height,0, format, GL_UNSIGNED_BYTE, imageData);if(self.shouldSmoothlyScaleOutput)
{
glGenerateMipmap(GL_TEXTURE_2D);
}
glBindTexture(GL_TEXTURE_2D,0);
});if(shouldRedrawUsingCoreGraphics)
{free(imageData);
}else{if(dataFromImageDataProvider)
{
CFRelease(dataFromImageDataProvider);
}
}returnself;
}//ARC forbids explicit message send of 'release'; since iOS 6 even for dispatch_release() calls: stripping it out in that case is required.- (void)dealloc;
{
[outputFramebuffer enableReferenceCounting];
[outputFramebuffer unlock];#if!OS_OBJECT_USE_OBJCif(imageUpdateSemaphore !=NULL)
{
dispatch_release(imageUpdateSemaphore);
}#endif}#pragmamark -#pragmamark Image rendering
- (void)removeAllTargets;
{
[super removeAllTargets];
hasProcessedImage=NO;
}- (void)processImage;
{
[self processImageWithCompletionHandler:nil];
}- (BOOL)processImageWithCompletionHandler:(void(^)(void))completion;
{
hasProcessedImage=YES;//dispatch_semaphore_wait(imageUpdateSemaphore, DISPATCH_TIME_FOREVER);if(dispatch_semaphore_wait(imageUpdateSemaphore, DISPATCH_TIME_NOW) !=0)
{returnNO;
}
runAsynchronouslyOnVideoProcessingQueue(^{for(id<GPUImageInput> currentTargetintargets)
{
NSInteger indexOfObject=[targets indexOfObject:currentTarget];
NSInteger textureIndexOfTarget=[[targetTextureIndices objectAtIndex:indexOfObject] integerValue];
[currentTarget setCurrentlyReceivingMonoChromeInput:NO];
[currentTarget setInputSize:pixelSizeOfImage atIndex:textureIndexOfTarget];
[currentTarget setInputFramebuffer:outputFramebuffer atIndex:textureIndexOfTarget];
[currentTarget newFrameReadyAtTime:kCMTimeIndefinite atIndex:textureIndexOfTarget];
}
dispatch_semaphore_signal(imageUpdateSemaphore);if(completion !=nil) {
completion();
}
});returnYES;
}- (void)processImageUpToFilter:(GPUImageOutput<GPUImageInput> *)finalFilterInChain withCompletionHandler:(void(^)(UIImage *processedImage))block;
{
[finalFilterInChain useNextFrameForImageCapture];
[self processImageWithCompletionHandler:^{
UIImage*imageFromFilter =[finalFilterInChain imageFromCurrentFramebuffer];
block(imageFromFilter);
}];
}-(CGSize)outputImageSize;
{returnpixelSizeOfImage;
}- (void)addTarget:(id<GPUImageInput>)newTarget atTextureLocation:(NSInteger)textureLocation;
{
[super addTarget:newTarget atTextureLocation:textureLocation];if(hasProcessedImage)
{
[newTarget setInputSize:pixelSizeOfImage atIndex:textureLocation];
[newTarget newFrameReadyAtTime:kCMTimeIndefinite atIndex:textureLocation];
}
}
@end