我对核心图形有点新,我保留了一个错误,当合并它们时第二张图片没有出现:
- (UIImage*)imageByCombiningImage:(UIImage*)gfirstImage withImage:(UIImage*)gsecondImage atPositionX:(int)xPosition withPositionY:(int)yPosition{
UIImage *firstImage = nil;
UIImage *secondImage = nil;
firstImage = gfirstImage;
secondImage = gsecondImage;
// int ratio = secondImage.size.height/secondImage.size.width;
// int newWidth = firstImage.size.width/3;
// int newHeight = (firstImage.size.height/3)*ratio;
CGSize scaledSize = CGSizeMake(firstImage.size.width, firstImage.size.height);
CGSize badgeScaledSize = scaledSize;
if(firstImage.size.width > 500){
scaledSize = CGSizeMake(firstImage.size.width/4, firstImage.size.height/3);
}
if(firstImage.size.width < firstImage.size.height){
badgeScaledSize = CGSizeMake((firstImage.size.width/4)*prevPinchScale, (firstImage.size.height/4)*prevPinchScale);
}
if(firstImage.size.width > firstImage.size.height){
badgeScaledSize = CGSizeMake((firstImage.size.width/4)*prevPinchScale, (firstImage.size.height/4)*prevPinchScale);
}
secondImage = [secondImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit bounds:badgeScaledSize interpolationQuality:0.5];
CGSize newImageSize = CGSizeMake(firstImage.size.width, firstImage.size.height);
UIGraphicsBeginImageContext(newImageSize);
NSLog(@"first image size width: %f, size height: %f", firstImage.size.width, firstImage.size.height);
NSLog(@"first image size width: %f, size height: %f", newImageSize.width, newImageSize.height);
[firstImage drawAtPoint:CGPointMake(0,
0)];
[secondImage drawAtPoint:CGPointMake(xPosition,
yPosition)];
UIImage *image = nil;
image = UIGraphicsGetImageFromCurrentImageContext();
NSLog(@"got image of width: %f and height: %f", image.size.width, image.size.height);
UIGraphicsEndImageContext();
return image;
}
错误如下:
<Error>: CGContextConcatCTM: invalid context 0x0
<Error>: CGContextSetInterpolationQuality: invalid context 0x0
<Error>: CGContextDrawImage: invalid context 0x0
<Error>: CGBitmapContextCreateImage: invalid context 0x0
答案 0 :(得分:2)
这些错误实际上并没有从您的代码中抛出,而是在UIImage + Resize.m中我假设您正在使用。如果删除行
,则代码运行正常secondImage = [secondImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit bounds:badgeScaledSize interpolationQuality:0.5];
如果您查看该方法,您会发现它调用另一种方法,使得四次调用都会出错。
- (UIImage *)resizedImage:(CGSize)newSize
transform:(CGAffineTransform)transform
drawTransposed:(BOOL)transpose
interpolationQuality:(CGInterpolationQuality)quality {
CGRect newRect = CGRectIntegral(CGRectMake(0, 0, newSize.width, newSize.height));
CGRect transposedRect = CGRectMake(0, 0, newRect.size.height, newRect.size.width);
CGImageRef imageRef = self.CGImage;
// Build a context that's the same dimensions as the new size
CGContextRef bitmap = CGBitmapContextCreate(NULL,
newRect.size.width,
newRect.size.height,
CGImageGetBitsPerComponent(imageRef),
0,
CGImageGetColorSpace(imageRef),
CGImageGetBitmapInfo(imageRef));
// Rotate and/or flip the image if required by its orientation
CGContextConcatCTM(bitmap, transform);
// Set the quality level to use when rescaling
CGContextSetInterpolationQuality(bitmap, quality);
// Draw into the context; this scales the image
CGContextDrawImage(bitmap, transpose ? transposedRect : newRect, imageRef);
// Get the resized image from the context and a UIImage
CGImageRef newImageRef = CGBitmapContextCreateImage(bitmap);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef];
// Clean up
CGContextRelease(bitmap);
CGImageRelease(newImageRef);
return newImage;
}
似乎值位图无效。我会检查以确保在CGBitmapContextCreate调用上,您传递实际值而不是创建大小为0x0的上下文。