56
我尝试在UIImage上获得圆角，到目前为止我读到的最简单的方法是使用蒙版图像。为此，我使用了TheElements iPhone示例中的代码和我找到的一些图像大小调整代码。我的问题是resizedImage始终是零，我没有找到错误...UIImage圆角
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize
{
CGSize imageSize = [self size];
float width = imageSize.width;
float height = imageSize.height;
// scaleFactor will be the fraction that we'll
// use to adjust the size. For example, if we shrink
// an image by half, scaleFactor will be 0.5. the
// scaledWidth and scaledHeight will be the original,
// multiplied by the scaleFactor.
//
// IMPORTANT: the "targetHeight" is the size of the space
// we're drawing into. The "scaledHeight" is the height that
// the image actually is drawn at, once we take into
// account the ideal of maintaining proportions
float scaleFactor = 0.0;
float scaledWidth = targetSize.width;
float scaledHeight = targetSize.height;
CGPoint thumbnailPoint = CGPointMake(0,0);
// since not all images are square, we want to scale
// proportionately. To do this, we find the longest
// edge and use that as a guide.
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
// use the longeset edge as a guide. if the
// image is wider than tall, we'll figure out
// the scale factor by dividing it by the
// intended width. Otherwise, we'll use the
// height.
float widthFactor = targetSize.width/width;
float heightFactor = targetSize.height/height;
if (widthFactor < heightFactor)
scaleFactor = widthFactor;
else
scaleFactor = heightFactor;
// ex: 500 * 0.5 = 250 (newWidth)
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the thumbnail in the frame. if
// wider than tall, we need to adjust the
// vertical drawing point (y axis)
if (widthFactor < heightFactor)
thumbnailPoint.y = (targetSize.height - scaledHeight) * 0.5;
else if (widthFactor > heightFactor)
thumbnailPoint.x = (targetSize.width - scaledWidth) * 0.5;
}
CGContextRef mainViewContentContext;
CGColorSpaceRef colorSpace;
colorSpace = CGColorSpaceCreateDeviceRGB();
// create a bitmap graphics context the size of the image
mainViewContentContext = CGBitmapContextCreate (NULL, targetSize.width, targetSize.height, 8, 0, colorSpace, kCGImageAlphaPremultipliedLast);
// free the rgb colorspace
CGColorSpaceRelease(colorSpace);
if (mainViewContentContext==NULL)
return NULL;
//CGContextSetFillColorWithColor(mainViewContentContext, [[UIColor whiteColor] CGColor]);
//CGContextFillRect(mainViewContentContext, CGRectMake(0, 0, targetSize.width, targetSize.height));
CGContextDrawImage(mainViewContentContext, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), self.CGImage);
// Create CGImageRef of the main view bitmap content, and then
// release that bitmap context
CGImageRef mainViewContentBitmapContext = CGBitmapContextCreateImage(mainViewContentContext);
CGContextRelease(mainViewContentContext);
CGImageRef maskImage = [[UIImage imageNamed:@"Mask.png"] CGImage];
CGImageRef resizedImage = CGImageCreateWithMask(mainViewContentBitmapContext, maskImage);
CGImageRelease(mainViewContentBitmapContext);
// convert the finished resized image to a UIImage
UIImage *theImage = [UIImage imageWithCGImage:resizedImage];
// image is retained by the property setting above, so we can
// release the original
CGImageRelease(resizedImage);
// return the image
return theImage;
}
不错的一个为我工作 – Soniya 2013-08-23 09:23:52