Reputation: 1278
UIButton, how to set size and position of background image ?
e.g how to change size and position the image to be on top of the UIButton
EDIT: issue fixed by using setImageEdgeInsets:
e.g:
[button setTitleEdgeInsets:UIEdgeInsetsMake(0, -image.size.width, 0, 0)];
[button setImageEdgeInsets:UIEdgeInsetsMake(0, button.titleLabel.bounds.size.width, 0, 0)];
Upvotes: 0
Views: 3728
Reputation: 12671
AFAIK there is no property like that, but in my opinion you will have to scale the image according to the size of the UIButton
.
for example you can use this code
UIImage *resultImage = [self imageByScalingAndCroppingForSize:CGSizeMake(button.frame.size.height,button.frame.size.width) : sourchImage];
method for scaling
- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize:(UIImage *)srcimage
{
UIImage *sourceImage = srcimage;
UIImage *newImage = nil;
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;
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
NSLog(@"could not scale image");
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}
Upvotes: 1
Reputation: 1622
If you really want to scale an image, do it, but you should resize it before using it. Resizing it at run time will just lose CPU cycles.
This is the category I'm using to scale an image :
UIImage+Extra.h
@interface UIImage (Extras)
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize;
@end;
UIImage+Extra.m
@implementation UIImage (Extras)
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize {
UIImage *sourceImage = self;
UIImage *newImage = nil;
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)) {
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor < heightFactor)
scaleFactor = widthFactor;
else
scaleFactor = heightFactor;
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;
}
}
// this is actually the interesting part:
UIGraphicsBeginImageContext(targetSize);
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if(newImage == nil) NSLog(@"could not scale image");
return newImage ;
}
@end
You can use it to the size you want. Like :
[self.itemImageButton setImage:[stretchImage imageByScalingProportionallyToSize:CGSizeMake(20,20)]];
Upvotes: 1