Error With CBitmapContextCreate, CGContextDrawImage, CGBitmapContextCreateImage
- by wsidell
Error: CGBitmapContextCreate: invalid data bytes/row: should be at least 400 for 8 integer bits/component, 3 components, kCGImageAlphaNoneSkipFirst.
Error: CGContextDrawImage: invalid context
Error: CGBitmapContextCreateImage: invalid context
Currently, I have in application that runs perfectly in OS 4.0, but I have been trying to get it to work properly in 3.1.3 and I keep getting the errors mentioned above.
I am fairly new to iPhone development and am not exactly sure what the problem would be. I am using image resize code that I found in another post on stackoverflow.
Here is the code:
- (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize{
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
if (CGSizeEqualToSize(imageSize, targetSize) == NO) {
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor) {
scaleFactor = widthFactor; // scale to fit height
}
else {
scaleFactor = heightFactor; // scale to fit width
}
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor > heightFactor) {
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}
else if (widthFactor < heightFactor) {
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
CGImageRef imageRef = [sourceImage CGImage];
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
if (bitmapInfo == kCGImageAlphaNone) {
bitmapInfo = kCGImageAlphaNoneSkipLast;
}
CGContextRef bitmap;
if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) {
bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
} else {
bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
}
// In the right or left cases, we need to switch scaledWidth and scaledHeight,
// and also the thumbnail point
if (sourceImage.imageOrientation == UIImageOrientationLeft) {
thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x);
CGFloat oldScaledWidth = scaledWidth;
scaledWidth = scaledHeight;
scaledHeight = oldScaledWidth;
CGContextRotateCTM (bitmap, radians(90));
CGContextTranslateCTM (bitmap, 0, -targetHeight);
} else if (sourceImage.imageOrientation == UIImageOrientationRight) {
thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x);
CGFloat oldScaledWidth = scaledWidth;
scaledWidth = scaledHeight;
scaledHeight = oldScaledWidth;
CGContextRotateCTM (bitmap, radians(-90));
CGContextTranslateCTM (bitmap, -targetWidth, 0);
} else if (sourceImage.imageOrientation == UIImageOrientationUp) {
// NOTHING
} else if (sourceImage.imageOrientation == UIImageOrientationDown) {
CGContextTranslateCTM (bitmap, targetWidth, targetHeight);
CGContextRotateCTM (bitmap, radians(-180.));
}
CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage* newImage = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return newImage;
Any help would be appreciated. If you need more info, I will gladly post it.
