iphone - UIImage 到 BitmapContext

Question

我想将一个简单的 UIImage 转换为 BitmapContext，但找不到任何将 UIImage 转换为 BitmapContext 的教程。请告诉我该怎么做？

谢谢!

Answer 1

可能这段代码对你有帮助

CGSize newSize = CGSizeMake(320, 400);
UIGraphicsBeginImageContext( newSize );

[imageView.image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];



UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

NSData * data = UIImagePNGRepresentation(newImage);
[data writeToFile:@"foo.png" atomically:YES];


 UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);///save image in phone

OR For Bitmap.

CGContextRelease(context);
context = CGBitmapContextCreate (NULL,                                                     
                                image.size.width,
                                image.size.height,
                                8,    // bits per component
                                bitmapBytesPerRow,
                                colorSpace,
                                kCGImageAlphaLast
                                );
CGColorSpaceRelease( colorSpace );                                                                      

CGContextDrawImage(context, CGRectMake(0, 0, image.size.width, image.size.height), image.CGImage);
pixelData = CGBitmapContextGetData(context);