I have a UIImageView and the objective is to scale it down proportionally by giving it either a height or width.
UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://farm4.static.flickr.com/3092/2915896504_a88b69c9de.jpg"]]];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
//Add image view
[self.view addSubview:imageView];
//set contentMode to scale aspect to fit
imageView.contentMode = UIViewContentModeScaleAspectFit;
//change width of frame
CGRect frame = imageView.frame;
frame.size.width = 100;
imageView.frame = frame;
The image did get resized but the position is not at the top left. What is the best approach to scaling image/imageView and how do I correct the position?
This question is related to
objective-c
cocoa-touch
The answer is
Here is how you can scale it easily.
This works in 2.x with the Simulator and the iPhone.
UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];
one can resize an UIImage this way
image = [UIImage imageWithCGImage:[image CGImage] scale:2.0 orientation:UIImageOrientationUp];
I think you can do something like
image.center = [[imageView window] center];
imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = YES;
I think you can do something like
image.center = [[imageView window] center];
UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://farm4.static.flickr.com/3092/2915896504_a88b69c9de.jpg"]]];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
//set contentMode to scale aspect to fit
imageView.contentMode = UIViewContentModeScaleAspectFit;
//change width of frame
//CGRect frame = imageView.frame;
//frame.size.width = 100;
//imageView.frame = frame;
//original lines that deal with frame commented out, yo.
imageView.frame = CGRectMake(10, 20, 60, 60);
...
//Add image view
[myView addSubview:imageView];
The original code posted at the top worked well for me in iOS 4.2.
I found that creating a CGRect and specifying all the top, left, width, and height values was the easiest way to adjust the position in my case, which was using a UIImageView inside a table cell. (Still need to add code to release objects)
This works fine for me Swift 2.x:
imageView.contentMode = .ScaleAspectFill
imageView.clipsToBounds = true;
Here is how you can scale it easily.
This works in 2.x with the Simulator and the iPhone.
UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];
Usually I use this method for my apps (Swift 2.x compatible):
// Resize UIImage
func resizeImage(image:UIImage, scaleX:CGFloat,scaleY:CGFloat) ->UIImage {
let size = CGSizeApplyAffineTransform(image.size, CGAffineTransformMakeScale(scaleX, scaleY))
let hasAlpha = true
let scale: CGFloat = 0.0 // Automatically use scale factor of main screen
UIGraphicsBeginImageContextWithOptions(size, !hasAlpha, scale)
image.drawInRect(CGRect(origin: CGPointZero, size: size))
let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return scaledImage
}
Fixed easily, once I found the documentation!
imageView.contentMode = .scaleAspectFit
I used following code.where imageCoverView is UIView holds UIImageView
if (image.size.height<self.imageCoverView.bounds.size.height && image.size.width<self.imageCoverView.bounds.size.width)
{
[self.profileImageView sizeToFit];
self.profileImageView.contentMode =UIViewContentModeCenter
}
else
{
self.profileImageView.contentMode =UIViewContentModeScaleAspectFit;
}
imageView.contentMode = UIViewContentModeScaleAspectFill;
imageView.clipsToBounds = YES;
I think you can do something like
image.center = [[imageView window] center];
one can resize an UIImage this way
image = [UIImage imageWithCGImage:[image CGImage] scale:2.0 orientation:UIImageOrientationUp];
I've seen a bit of conversation about scale types so I decided to put together an article regarding some of the most popular content mode scaling types.
The associated image is here:
You could try making the imageView size match the image. The following code is not tested.
CGSize kMaxImageViewSize = {.width = 100, .height = 100};
CGSize imageSize = image.size;
CGFloat aspectRatio = imageSize.width / imageSize.height;
CGRect frame = imageView.frame;
if (kMaxImageViewSize.width / aspectRatio <= kMaxImageViewSize.height)
{
frame.size.width = kMaxImageViewSize.width;
frame.size.height = frame.size.width / aspectRatio;
}
else
{
frame.size.height = kMaxImageViewSize.height;
frame.size.width = frame.size.height * aspectRatio;
}
imageView.frame = frame;
Set your UIimageview by scale.........
For Swift :
self.imageViews.contentMode = UIViewContentMode.ScaleToFill
I just tried this, and UIImage does not support _imageScaledToSize.
I ended up adding a method to UIImage using a category - a suggestion I found on the Apple Dev forums.
In a project-wide .h -
@interface UIImage (Extras)
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize;
@end;
Implementation:
@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) == NO) {
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;
Here is how you can scale it easily.
This works in 2.x with the Simulator and the iPhone.
UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];
You could try making the imageView size match the image. The following code is not tested.
CGSize kMaxImageViewSize = {.width = 100, .height = 100};
CGSize imageSize = image.size;
CGFloat aspectRatio = imageSize.width / imageSize.height;
CGRect frame = imageView.frame;
if (kMaxImageViewSize.width / aspectRatio <= kMaxImageViewSize.height)
{
frame.size.width = kMaxImageViewSize.width;
frame.size.height = frame.size.width / aspectRatio;
}
else
{
frame.size.height = kMaxImageViewSize.height;
frame.size.width = frame.size.height * aspectRatio;
}
imageView.frame = frame;
If the solutions proposed here aren't working for you, and your image asset is actually a PDF, note that XCode actually treats PDFs differently than image files. In particular, it doesn't seem able to scale to fill properly with a PDF: it ends up tiled instead. This drove me crazy until I figured out that the issue was the PDF format. Convert to JPG and you should be good to go.
Set your ImageView by selecting Mode to Aspect Fill and check the Clip Subviews box.
I think you can do something like
image.center = [[imageView window] center];
You could try making the imageView size match the image. The following code is not tested.
CGSize kMaxImageViewSize = {.width = 100, .height = 100};
CGSize imageSize = image.size;
CGFloat aspectRatio = imageSize.width / imageSize.height;
CGRect frame = imageView.frame;
if (kMaxImageViewSize.width / aspectRatio <= kMaxImageViewSize.height)
{
frame.size.width = kMaxImageViewSize.width;
frame.size.height = frame.size.width / aspectRatio;
}
else
{
frame.size.height = kMaxImageViewSize.height;
frame.size.width = frame.size.height * aspectRatio;
}
imageView.frame = frame;
This works fine for me Swift 2.x:
imageView.contentMode = .ScaleAspectFill
imageView.clipsToBounds = true;
If the solutions proposed here aren't working for you, and your image asset is actually a PDF, note that XCode actually treats PDFs differently than image files. In particular, it doesn't seem able to scale to fill properly with a PDF: it ends up tiled instead. This drove me crazy until I figured out that the issue was the PDF format. Convert to JPG and you should be good to go.
UIImageView+Scale.h:
#import <Foundation/Foundation.h>
@interface UIImageView (Scale)
-(void) scaleAspectFit:(CGFloat) scaleFactor;
@end
UIImageView+Scale.m:
#import "UIImageView+Scale.h"
@implementation UIImageView (Scale)
-(void) scaleAspectFit:(CGFloat) scaleFactor{
self.contentScaleFactor = scaleFactor;
self.transform = CGAffineTransformMakeScale(scaleFactor, scaleFactor);
CGRect newRect = self.frame;
newRect.origin.x = 0;
newRect.origin.y = 0;
self.frame = newRect;
}
@end
Set your UIimageview by scale.........
UIImageView+Scale.h:
#import <Foundation/Foundation.h>
@interface UIImageView (Scale)
-(void) scaleAspectFit:(CGFloat) scaleFactor;
@end
UIImageView+Scale.m:
#import "UIImageView+Scale.h"
@implementation UIImageView (Scale)
-(void) scaleAspectFit:(CGFloat) scaleFactor{
self.contentScaleFactor = scaleFactor;
self.transform = CGAffineTransformMakeScale(scaleFactor, scaleFactor);
CGRect newRect = self.frame;
newRect.origin.x = 0;
newRect.origin.y = 0;
self.frame = newRect;
}
@end
UIImage *image = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:@"http://farm4.static.flickr.com/3092/2915896504_a88b69c9de.jpg"]]];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
//set contentMode to scale aspect to fit
imageView.contentMode = UIViewContentModeScaleAspectFit;
//change width of frame
//CGRect frame = imageView.frame;
//frame.size.width = 100;
//imageView.frame = frame;
//original lines that deal with frame commented out, yo.
imageView.frame = CGRectMake(10, 20, 60, 60);
...
//Add image view
[myView addSubview:imageView];
The original code posted at the top worked well for me in iOS 4.2.
I found that creating a CGRect and specifying all the top, left, width, and height values was the easiest way to adjust the position in my case, which was using a UIImageView inside a table cell. (Still need to add code to release objects)
I've seen a bit of conversation about scale types so I decided to put together an article regarding some of the most popular content mode scaling types.
The associated image is here:
Fixed easily, once I found the documentation!
imageView.contentMode = .scaleAspectFit
I used following code.where imageCoverView is UIView holds UIImageView
if (image.size.height<self.imageCoverView.bounds.size.height && image.size.width<self.imageCoverView.bounds.size.width)
{
[self.profileImageView sizeToFit];
self.profileImageView.contentMode =UIViewContentModeCenter
}
else
{
self.profileImageView.contentMode =UIViewContentModeScaleAspectFit;
}
Set your ImageView by selecting Mode to Aspect Fill and check the Clip Subviews box.
Here is how you can scale it easily.
This works in 2.x with the Simulator and the iPhone.
UIImage *thumbnail = [originalImage _imageScaledToSize:CGSizeMake(40.0, 40.0) interpolationQuality:1];
For Swift :
self.imageViews.contentMode = UIViewContentMode.ScaleToFill
I just tried this, and UIImage does not support _imageScaledToSize.
I ended up adding a method to UIImage using a category - a suggestion I found on the Apple Dev forums.
In a project-wide .h -
@interface UIImage (Extras)
- (UIImage *)imageByScalingProportionallyToSize:(CGSize)targetSize;
@end;
Implementation:
@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) == NO) {
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;
Source: Stackoverflow.com