image position not correct after scaling - iphone

Question

I am using UIViewContentModeScaleToFill to scale image.After scaling,Image is not showing on correct position.Help me.
Below is my code:
UIImage *image=[UIImage imageNamed:#"image2.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
imageView.frame=CGRectMake(0, 0, 200, 200);
imageView.contentMode = UIViewContentModeScaleAspectFit;
//change width of frame
CGRect frame = imageView.frame;
imageView.frame = frame;
[self.view addSubview:imageView];
After scaling:
refer to image 1
Before scaling:
refer to image 2
I want scaling image starting from origin point (0,0).

Answer 1

Hi try the below code i hope it help you to get idea....
UIImage *image=[UIImage imageNamed:#"image2.png"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
// imageView.contentMode = UIViewContentModeScaleToFill;
imageView.contentMode = UIViewContentModeScaleAspectFit;
imageView.frame = self.view.bounds;
[self.view addSubview:imageView];
Update after below comment:
I want to crop the image without changing its aspect ration.the width
is 200px.and height will change according to width. – shivam
you want to crop means you try the below category code:
UIImage+MyImage.h
#import <UIKit/UIKit.h>
#interface UIImage (MyImage)
+ (UIImage*)imageFromView:(UIView*)view;
+ (UIImage*)imageFromView:(UIView*)view scaledToSize:(CGSize)newSize;
+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize;
+ (void)beginImageContextWithSize:(CGSize)size;
+ (UIImage *)croppedImage:(UIImage *)myImage :(CGRect)bounds;
+ (UIImage *) imageFromColor:(UIColor *)color;
#end
UIImage+MyImage.m
#import "UIImage+MyImage.h"
#implementation UIImage (MyImage)
+ (void)beginImageContextWithSize:(CGSize)size
{
if ([[UIScreen mainScreen] respondsToSelector:#selector(scale)]) {
if ([[UIScreen mainScreen] scale] == 2.0) {
UIGraphicsBeginImageContextWithOptions(size, YES, 2.0);
} else {
UIGraphicsBeginImageContext(size);
}
} else {
UIGraphicsBeginImageContext(size);
}
}
+ (void)endImageContext
{
UIGraphicsEndImageContext();
}
+ (UIImage*)imageFromView:(UIView*)view
{
[self beginImageContextWithSize:[view bounds].size];
BOOL hidden = [view isHidden];
[view setHidden:NO];
[[view layer] renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
[self endImageContext];
[view setHidden:hidden];
return image;
}
+ (UIImage*)imageFromView:(UIView*)view scaledToSize:(CGSize)newSize
{
UIImage *image = [self imageFromView:view];
if ([view bounds].size.width != newSize.width ||
[view bounds].size.height != newSize.height) {
image = [self imageWithImage:image scaledToSize:newSize];
}
return image;
}
+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
[self beginImageContextWithSize:newSize];
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
[self endImageContext];
return newImage;
}
+ (UIImage *)croppedImage:(UIImage *)myImage :(CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect(myImage.CGImage, bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
CGSize asd = croppedImage.size;
return croppedImage;
}
+ (UIImage *) imageFromColor:(UIColor *)color {
CGRect rect = CGRectMake(0, 0, 1, 1);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
// [[UIColor colorWithRed:222./255 green:227./255 blue: 229./255 alpha:1] CGColor]) ;
CGContextFillRect(context, rect);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}
#end
the call will be :
imageView.image=[UIImage croppedImage:imageView.Image :CGRectMake(0,0,200,200) ];

Answer 2

First of all, you've got UIViewContentModeScaleAspectFit in your code, not UIViewContentModeScaleToFill as you've said. Post an original image, please.
Second, the 'change width of frame' part is useless, imageView.size.width is already set to 200. Scaling modes don't change view's frame at all, they change the way it shows its content.
I don't know what's the 'correct position' you are talking about, but try to make imageView fullscreen like this:
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
imageView.contentMode = UIViewContentModeScaleToFill;
imageView.frame = self.view.frame;

Answer 3

you can use this code for fix unwanted rotate image
Swift 5 Extension:
extension UIImage {
/// Fix image orientaton to protrait up
func fixedOrientation() -> UIImage? {
guard imageOrientation != UIImage.Orientation.up else {
// This is default orientation, don't need to do anything
return self.copy() as? UIImage
}
guard let cgImage = self.cgImage else {
// CGImage is not available
return nil
}
guard let colorSpace = cgImage.colorSpace, let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: cgImage.bitsPerComponent, bytesPerRow: 0, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
return nil // Not able to create CGContext
}
var transform: CGAffineTransform = CGAffineTransform.identity
switch imageOrientation {
case .down, .downMirrored:
transform = transform.translatedBy(x: size.width, y: size.height)
transform = transform.rotated(by: CGFloat.pi)
case .left, .leftMirrored:
transform = transform.translatedBy(x: size.width, y: 0)
transform = transform.rotated(by: CGFloat.pi / 2.0)
case .right, .rightMirrored:
transform = transform.translatedBy(x: 0, y: size.height)
transform = transform.rotated(by: CGFloat.pi / -2.0)
case .up, .upMirrored:
break
#unknown default:
fatalError("Missing...")
break
}
// Flip image one more time if needed to, this is to prevent flipped image
switch imageOrientation {
case .upMirrored, .downMirrored:
transform = transform.translatedBy(x: size.width, y: 0)
transform = transform.scaledBy(x: -1, y: 1)
case .leftMirrored, .rightMirrored:
transform = transform.translatedBy(x: size.height, y: 0)
transform = transform.scaledBy(x: -1, y: 1)
case .up, .down, .left, .right:
break
#unknown default:
fatalError("Missing...")
break
}
ctx.concatenate(transform)
switch imageOrientation {
case .left, .leftMirrored, .right, .rightMirrored:
ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
default:
ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
break
}
guard let newCGImage = ctx.makeImage() else { return nil }
return UIImage.init(cgImage: newCGImage, scale: 1, orientation: .up)
}
}
Objective C Code :
-(UIImage *)scaleAndRotateImage:(UIImage *)image{
// No-op if the orientation is already correct
if (image.imageOrientation == UIImageOrientationUp) return image;
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
CGAffineTransform transform = CGAffineTransformIdentity;
switch (image.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, image.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, image.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationUp:
case UIImageOrientationUpMirrored:
break;
}
switch (image.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, image.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, image.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationUp:
case UIImageOrientationDown:
case UIImageOrientationLeft:
case UIImageOrientationRight:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, image.size.width, image.size.height,
CGImageGetBitsPerComponent(image.CGImage), 0,
CGImageGetColorSpace(image.CGImage),
CGImageGetBitmapInfo(image.CGImage));
CGContextConcatCTM(ctx, transform);
switch (image.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
// Grr...
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.height,image.size.width), image.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,image.size.width,image.size.height), image.CGImage);
break;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage *img = [UIImage imageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
return img;
}
Use of code
UIImage *img=[info objectForKey:UIImagePickerControllerOriginalImage];
img=[self scaleAndRotateImage:img];
NSData *image = UIImageJPEGRepresentation(img, 0.1);