iOS常用图像格式转换
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0.9292016.12.26 16:30:08字数 116阅读 6,104
在iOS多媒体开发时，需要经常转换图像格式以便调试。下面列了一些常用工具方法，在UIImage, CVPixelBufferRef,Texture之间完成格式转换。
1. 其他格式转为UIImage
1.1 CVImageBufferRef (RGB)转为UIImage
-(UIImage*)imageFromRGBImageBuffer:(CVImageBufferRef)imageBuffer{CVPixelBufferLockBaseAddress(imageBuffer,0);void*baseAddress=CVPixelBufferGetBaseAddress(imageBuffer);size_t bytesPerRow=CVPixelBufferGetBytesPerRow(imageBuffer);size_t width=CVPixelBufferGetWidth(imageBuffer);size_t height=CVPixelBufferGetHeight(imageBuffer);CGColorSpaceRef colorSpace=CGColorSpaceCreateDeviceRGB();CGContextRef context=CGBitmapContextCreate(baseAddress,width,height,8,bytesPerRow,colorSpace,kCGBitmapByteOrder32Little|kCGImageAlphaPremultipliedFirst);CGImageRef quartzImage=CGBitmapContextCreateImage(context);CVPixelBufferUnlockBaseAddress(imageBuffer,0);CGContextRelease(context);CGColorSpaceRelease(colorSpace);UIImage*image=[UIImage imageWithCGImage:quartzImage];CGImageRelease(quartzImage);return(image);}
1.2 CVImageBufferRef (YUV)转为UIImage
-(UIImage*)imageFromYUVImageBuffer:(CVImageBufferRef)imageBuffer{CVPixelBufferLockBaseAddress(imageBuffer,0);size_t bytesPerRow=CVPixelBufferGetBytesPerRowOfPlane(imageBuffer,0);size_t width=CVPixelBufferGetWidthOfPlane(imageBuffer,0);size_t height=CVPixelBufferGetHeightOfPlane(imageBuffer,0);void*lumaAddress=CVPixelBufferGetBaseAddress(imageBuffer);CGColorSpaceRef rgbSpace=CGColorSpaceCreateDeviceGray();CGContextRef context=CGBitmapContextCreate(lumaAddress,width,height,8,bytesPerRow,rgbSpace,kCGBitmapByteOrderDefault);CGImageRef imageRef=CGBitmapContextCreateImage(context);CGContextRelease(context);CVPixelBufferUnlockBaseAddress(imageBuffer,0);UIImage*image=[UIImage imageWithCGImage:imageRef];CGImageRelease(imageRef);returnimage;}
1.3 纹理 (Texture)转为UIImage
-(UIImage*)imageFromTextureWithwidth:(int)width height:(int)height{// glActiveTexture(GL_TEXTURE1); 先绑定某个纹理intsize=width*height*4;GLubyte*buffer=malloc(size);glReadPixels(0,0,width,height,GL_RGBA,GL_UNSIGNED_BYTE,buffer);CGDataProviderRef provider=CGDataProviderCreateWithData(NULL,buffer,size,NULL);intbitsPerComponent=8;intbitsPerPixel=32;intbytesPerRow=4*width;CGColorSpaceRef colorSpaceRef=CGColorSpaceCreateDeviceRGB();CGBitmapInfo bitmapInfo=kCGBitmapByteOrderDefault;CGColorRenderingIntent renderingIntent=kCGRenderingIntentDefault;CGImageRef imageRef=CGImageCreate(width,height,bitsPerComponent,bitsPerPixel,bytesPerRow,colorSpaceRef,bitmapInfo,provider,NULL,NO,renderingIntent);UIImage*image=[UIImage imageWithCGImage:imageRef];free(buffer);returnimage;}
1.4 data (RGB)转为UIImage
-(UIImage*)imageFromRGBData:(void*)data width:(int)width height:(int)height{CGColorSpaceRef rgbSpace=CGColorSpaceCreateDeviceRGB();CGContextRef context=CGBitmapContextCreate(data,width,height,8,width*4,rgbSpace,kCGImageAlphaPremultipliedFirst|kCGBitmapByteOrder32Little);CGImageRef imageRef=CGBitmapContextCreateImage(context);CGContextRelease(context);UIImage*image=[UIImage imageWithCGImage:imageRef];CGImageRelease(imageRef);returnimage;}
1.5 data (Y)转为UIImage
-(UIImage*)imageFromYData:(void*)data width:(int)width height:(int)height{CGColorSpaceRef rgbSpace=CGColorSpaceCreateDeviceGray();CGContextRef context=CGBitmapContextCreate(data,width,height,8,width,rgbSpace,kCGBitmapByteOrderDefault);CGImageRef imageRef=CGBitmapContextCreateImage(context);CGContextRelease(context);UIImage*image=[UIImage imageWithCGImage:imageRef];CGImageRelease(imageRef);returnimage;}
2. UIImage转为其他格式
2.1 UIImage转为CVPixelBufferRef(RGB)
-(CVPixelBufferRef)imageToRGBPixelBuffer:(UIImage*)image{CGSize frameSize=CGSizeMake(CGImageGetWidth(image.CGImage),CGImageGetHeight(image.CGImage));NSDictionary*options=[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES],kCVPixelBufferCGImageCompatibilityKey,[NSNumber numberWithBool:YES],kCVPixelBufferCGBitmapContextCompatibilityKey,nil];CVPixelBufferRef pxbuffer=NULL;CVReturn status=CVPixelBufferCreate(kCFAllocatorDefault,frameSize.width,frameSize.height,kCVPixelFormatType_32BGRA,(__bridge CFDictionaryRef)options,&pxbuffer);NSParameterAssert(status==kCVReturnSuccess&&pxbuffer!=NULL);CVPixelBufferLockBaseAddress(pxbuffer,0);void*pxdata=CVPixelBufferGetBaseAddress(pxbuffer);CGColorSpaceRef rgbColorSpace=CGColorSpaceCreateDeviceRGB();CGContextRef context=CGBitmapContextCreate(pxdata,frameSize.width,frameSize.height,8,CVPixelBufferGetBytesPerRow(pxbuffer),rgbColorSpace,(CGBitmapInfo)kCGBitmapByteOrder32Little|kCGImageAlphaPremultipliedFirst);CGContextDrawImage(context,CGRectMake(0,0,CGImageGetWidth(image.CGImage),CGImageGetHeight(image.CGImage)),image.CGImage);CGColorSpaceRelease(rgbColorSpace);CGContextRelease(context);CVPixelBufferUnlockBaseAddress(pxbuffer,0);returnpxbuffer;}
2.2 UIImage转为CVPixelBufferRef(YUV)
-(CVPixelBufferRef)imageToYUVPixelBuffer:(UIImage*)image{CGSize frameSize=CGSizeMake(CGImageGetWidth(image.CGImage),CGImageGetHeight(image.CGImage));NSDictionary*options=[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES],kCVPixelBufferCGImageCompatibilityKey,[NSNumber numberWithBool:YES],kCVPixelBufferCGBitmapContextCompatibilityKey,nil];CVPixelBufferRef pxbuffer=NULL;CVPixelBufferCreate(kCFAllocatorDefault,frameSize.width,frameSize.height,kCVPixelFormatType_420YpCbCr8BiPlanarFullRange,(__bridge CFDictionaryRef)options,&pxbuffer);CVPixelBufferLockBaseAddress(pxbuffer,0);void*pxdata=CVPixelBufferGetBaseAddressOfPlane(pxbuffer,0);CGColorSpaceRef colorSpace=CGColorSpaceCreateDeviceGray();CGContextRef context=CGBitmapContextCreate(pxdata,frameSize.width,frameSize.height,8,CVPixelBufferGetBytesPerRowOfPlane(pxbuffer,0),colorSpace,kCGImageAlphaNone);CGContextDrawImage(context,CGRectMake(0,0,CGImageGetWidth(image.CGImage),CGImageGetHeight(image.CGImage)),image.CGImage);CGColorSpaceRelease(colorSpace);CGContextRelease(context);CVPixelBufferUnlockBaseAddress(pxbuffer,0);returnpxbuffer;}