I encountered a problem when I pinch, pan or rotate a UIImageview in drawInRect, the transform is not being preserved.
How can I preserve the transform in drawInRect?
I tried this but no go :(
- (UIImage*) combineImage:(UIImageView *)selectedImage withOverlay:(UIImageView *)overlayImage
{
/* Identify the region that needs to be cropped */
CGRect viewForImgFrame = self.viewForImg.frame;
NSLog(#"view %#", NSStringFromCGRect(viewForImgFrame));
NSLog(#"selectedImage Img value %#",selectedImage);
NSLog(#"overlayImage Img value %#",overlayImage);
CGSize newImageSize =self.viewForImg.frame.size;
NSLog(#"CGSize %#",NSStringFromCGSize(newImageSize));
UIGraphicsBeginImageContextWithOptions(newImageSize, NO, 0.0); //retina res
//[self.viewForImg.layer renderInContext:UIGraphicsGetCurrentContext()];
[selectedImage.image drawInRect:CGRectMake(0, 0, selectedImage.frame.size.width, selectedImage.frame.size.height)];
CGContextConcatCTM(UIGraphicsGetCurrentContext(), overlayImage.transform);
[overlayImage.image drawInRect:CGRectMake(overlayImage.frame.origin.x, overlayImage.frame.origin.y, overlayImage.frame.size.width, overlayImage.frame.size.height)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
NSData *imgData = UIImageJPEGRepresentation(image, 0.9); //UIImagePNGRepresentation ( image ); // get JPEG representation
UIImage * imagePNG = [UIImage imageWithData:imgData]; // wrap UIImage around PNG representation
UIGraphicsEndImageContext();
return imagePNG;
}
Any comments are greatly appreciated.
you need to try
CGRectApplyAffineTransform(<#CGRect rect#>, <#CGAffineTransform t#>)
your code should be like
CGContextConcatCTM(UIGraphicsGetCurrentContext(), overlayImage.transform);
CGRect rect = CGRectMake(overlayImage.frame.origin.x, overlayImage.frame.origin.y, overlayImage.frame.size.width, overlayImage.frame.size.height);
CGRect transformedRect = CGRectApplyAffineTransform(rect, overlayImage.transform);
[overlayImage.image drawInRect:transformedRect];
It turned out that the AutoresizingMask changed rect size
[slider setAutoresizingMask:UIViewAutoresizingNone];
Related
I am using Xcode 7.3 and ojective-c one of my application when I am converting the camera image into base64 then image will be rotation 90 degree left I try so many method to fix this issue but did not working any one.
Below are the code:
NSString *data64URLString = [NSString stringWithFormat:#"data:image/png;base64,%#", [UIImageJPEGRepresentation(image, 0) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength]];
I try all the orientation by this ways but it's not working:
CGImageRef cgRef = image.CGImage;
image = [[UIImage alloc] initWithCGImage:cgRef scale:1.0 orientation:UIImageOrientationDownMirrored];
UIImage *originalImage = image;
Try this code:
- (UIImage *)imageRotatedByDegrees:(UIImage*)oldImage deg:(CGFloat)degrees
{
//Calculate the size of the rotated view's containing box for our drawing space
UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,oldImage.size.width, oldImage.size.height)];
CGAffineTransform t = CGAffineTransformMakeRotation(degrees * M_PI / 180);
rotatedViewBox.transform = t;
CGSize rotatedSize = rotatedViewBox.frame.size;
//Create the bitmap context
UIGraphicsBeginImageContext(rotatedSize);
CGContextRef bitmap = UIGraphicsGetCurrentContext();
//Move the origin to the middle of the image so we will rotate and scale around the center.
CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);
//Rotate the image context
CGContextRotateCTM(bitmap, (degrees * M_PI / 180));
//Now, draw the rotated/scaled image into the context
CGContextScaleCTM(bitmap, 1.0, -1.0);
CGContextDrawImage(bitmap, CGRectMake(-oldImage.size.width / 2, -oldImage.size.height / 2, oldImage.size.width, oldImage.size.height), [oldImage CGImage]);
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
As per this thread, PNG format has a known issue with rotation, I would suggest you to try UIImageJPEGRepresentation with data:image/jpg; instead of data:image/png;. This way it will probably set the rotation flag.
Hope it helps!
You can save to your app and get image from memory to view with code:
- (UIImage *)finishSavePhotoWithImagePickerController:(NSDictionary *()info {
UIImage *editedImage = (UIImage *) [info objectForKey:UIImagePickerControllerEditedImage];
UIImage *originalImage = (UIImage *) [info objectForKey:UIImagePickerControllerOriginalImage];
if (editedImage) {
imageToSave = editedImage;
} else {
imageToSave = originalImage;
}
NSData *imageData = UIImageJPEGRepresentation(imageToSave, 1.0);
[imageData writeToFile:#"yourFilePath" options:NSDataWritingFileProtectionNone error:nil];
UIImage *showImage = [[UIImage alloc] initWithContentsOfFile:#"yourFilePath"];
return showImage;
}
Been trying to fix this problem all day to no avail.
Pretty much, I'm taking a screenshot of the view, then trying to crop out the first 50px and a footer. Problem is that when I do this, the result is a little blowed up, and quality is lost. Here's what I wrote, which I think conforms to retina.
-(UIImage *)takeSnapShotAndReturn{
//Take screenshot of whole view
if([[UIScreen mainScreen] respondsToSelector:#selector(scale)]){
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,NO,[UIScreen mainScreen].scale);
}
else{
UIGraphicsBeginImageContext(self.view.window.bounds.size);
}
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
combinedImage = [self cropOutArea:image withRectangle:CGRectMake(0, 50, 320, 467)];
UIImageWriteToSavedPhotosAlbum(combinedImage, nil, nil, nil);
UIGraphicsEndImageContext();
return image;
}
-(UIImage *)cropOutArea:(UIImage*)image withRectangle:(CGRect)rectangle{
if(image.scale > 1){
rectangle = CGRectMake(rectangle.origin.x * image.scale,
rectangle.origin.y * image.scale,
rectangle.size.width * image.scale,
rectangle.size.height * image.scale);
}
CGImageRef imageRef = CGImageCreateWithImageInRect(image.CGImage, rectangle);
UIImage *result = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation];
CGImageRelease(imageRef);
return result;
}
I find cropping extremely confusing!
I'm not sure EXACTLY what you're trying to do, but this may be it .....
-(UIImage *)simplishTopCropAndTo640:(UIImage *)fromImage
// moderately optimised!
{
float shortDimension = fminf(fromImage.size.width, fromImage.size.height);
// 1.use CGImageCreateWithImageInRect to take only the top square...
// 2. use drawInRect (or CGContextDrawImage, same) to scale...
CGRect topSquareOfOriginalRect =
CGRectMake(0,0, shortDimension,shortDimension);
// NOT fromImage.size.width,fromImage.size.width);
CGImageRef topSquareIR = CGImageCreateWithImageInRect(
fromImage.CGImage, topSquareOfOriginalRect);
CGSize size = CGSizeMake( 640,640 );
CGRect sized = CGRectMake(0.0f, 0.0f, size.width, size.height);
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
CGContextRef cc = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(cc, kCGInterpolationLow);
CGContextTranslateCTM(cc, 0, size.height);
CGContextScaleCTM(cc, 1.0, -1.0);
CGContextDrawImage(cc, sized, topSquareIR );
// arguably, those three lines more simply...
//[[UIImage imageWithCGImage:topSquareIR] drawInRect:sized];
CGImageRelease(topSquareIR);
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
result =
[UIImage imageWithCGImage:result.CGImage
scale:result.scale
orientation: fromImage.imageOrientation];
//consider...something like...
//[UIImage imageWithCGImage:cgimg
// scale:3 orientation:fromImage.imageOrientation];
return result;
}
Consider also this valuable category .....
-(UIImage *)ordinaryCrop:(CGRect)toRect
{
// crops any image, to any rect. you can't beat that
CGImageRef imageRef = CGImageCreateWithImageInRect([self CGImage], toRect);
UIImage *cropped = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return cropped;
}
Finally don't forget this if you're using the camera "the most useful code in the universe!" iOS UIImagePickerController result image orientation after upload
Hope it helps somehow
Try setting this BOOL property before releasing result in cropOutArea.
result.layer.masksToBounds = YES
So I have a UIImage which I want to crop. I looked and found imageByCroppingToRect method for CIImage. So, I converted the data to CIImage instead of UIImage, crop it using the specified method and then convert the resulting CIImage to UIImage and then display it in a UIImageView.
My code is
NSData *data = [[NSData alloc]initWithData:[def objectForKey:#"imageData"]];
//UIImage *normalImage = [[UIImage alloc]initWithData:data];
CIImage *originalImage = [CIImage imageWithData:data];
[originalImage imageByCroppingToRect:CGRectMake(10, 72, 300, 300)];
self.imageView.image = [UIImage imageWithCIImage:originalImage];
The problem is the image gets rotated by 90 degrees and I am not sure if it is being cropped. This image is captured using the device's camera. I use AVFoundation to access the camera. My session preset is AVCaptureSessionPresetPhoto. I think this is why I get the zooming.
CGRect rect = CGRectMake(10, 72, 300, 300);
CGImageRef imref = CGImageCreateWithImageInRect([yourOriginalImage CGImage], rect);
UIImage *newSubImage = [UIImage imageWithCGImage:imref];
try this. may help u.
EDIT:
Firstly fix your image orientation:
refs : https://github.com/j3r3miah/mapmatic-ios/blob/master/Mapmatic/UIImage+FixOrientation.m
then use above code to crop the Image to Specified Rect.
Not really an answer to your question, but an answer to your problem
https://github.com/mbcharbonneau/UIImage-Categories
especially this file : https://github.com/mbcharbonneau/UIImage-Categories/blob/master/UIImage%2BResize.m
- (UIImage *)croppedImage:(CGRect)bounds {
CGFloat scale = MAX(self.scale, 1.0f);
CGRect scaledBounds = CGRectMake(bounds.origin.x * scale, bounds.origin.y * scale, bounds.size.width * scale, bounds.size.height * scale);
CGImageRef imageRef = CGImageCreateWithImageInRect([self CGImage], scaledBounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:self.scale orientation:UIImageOrientationUp];
CGImageRelease(imageRef);
return croppedImage;
}
you will find there all you need to crop your image
I'm trying to crop a image into a square shape, and then scale it to a size 200x200. Here's the code I use, but it's not really working for me. The image I get is sometimes in a different orientation, or isn't cropped from the center, or is wider than it should be.
float scale = _avatar.image.scale;
UIImageOrientation orientation = _avatar.image.imageOrientation;
if(_avatar.image.size.width < _avatar.image.size.height){ // avatar is a UIImageView
float startingY = (_avatar.image.size.height-_avatar.image.size.width)/2; // image is taller, determine the origin of the width-sized square, which will be the new image
CGImageRef imageRef = CGImageCreateWithImageInRect([_avatar.image CGImage], CGRectMake(0, startingY, _avatar.image.size.width, _avatar.image.size.width));
_avatar.image = [UIImage imageWithCGImage:imageRef scale:scale orientation:orientation];
CGImageRelease(imageRef);
} else {
float startingX = (_avatar.image.size.width-_avatar.image.size.height)/2; // image is wider, determine the origin of the height-sized square, which will be the new image
CGImageRef imageRef = CGImageCreateWithImageInRect([_avatar.image CGImage], CGRectMake(startingX, 0, _avatar.image.size.height, _avatar.image.size.height));
_avatar.image = [UIImage imageWithCGImage:imageRef scale:scale orientation:orientation];
CGImageRelease(imageRef);
}
UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), YES, 0.0);
[_avatar.image drawInRect:CGRectMake(0, 0, 200, 200)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
How it must be done to achieve the correct result?
I would suggest you to use this category for UIImage posted on github. They are also really simple classes and you can also use them to learn what is under the hood.
The UIImage has done all the coordinate and orientation tricks for you. So you should not use the width and height from an UIImage object to caculate the square's coordinate. You can take advantages of the UIKit to crop an image.
CGFloat startingX = 0;
CGFloat startingY = 0;
CGFloat squareWidth;
if(_avatar.image.size.width < _avatar.image.size.height){ // avatar is a UIImageView
startingY = (_avatar.image.size.height-_avatar.image.size.width)/2; // image is taller, determine the origin of the width-sized square, which will be the new image
squareWidth = _avatar.image.size.width;
} else {
startingX = (_avatar.image.size.width-_avatar.image.size.height)/2; // image is wider, determine the origin of the height-sized square, which will be the new image
squareWidth = _avatar.image.size.height;
}
UIGraphicsBeginImageContextWithOptions(CGSizeMake(squareWidth, squareWidth), YES, 0.0);
[_avatar.image drawAtPoint:CGPointMake(-startingX, -startingY)]; // Make an offset to draw part of the image
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), YES, 0.0);
[croppedImage drawInRect:CGRectMake(0, 0, 200, 200)];
UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I am using the following code to convert the contents of a UIView to a PNG image:
UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
This works fine. If the UIView is 500 pixels high, and I'd like to generate two images (one of the top half and one of the bottom half), how would I go about doing this?
Any help would be greatly appreciated.
There are a few ways you could do this. One way is to draw it into one big image, then make two sub-images:
static UIImage *halfOfImage(UIImage *fullImage, CGFloat yOffset) {
// Pass yOffset == 0 for the top half.
// Pass yOffset == 0.5 for the bottom half.
CGImageRef cgImage = fullImage.CGImage;
size_t width = CGImageGetWidth(cgImage);
size_t height = CGImageGetHeight(cgImage);
CGRect rect = CGRectMake(0, height * yOffset, width, height * 0.5f);
CGImageRef cgSubImage = CGImageCreateWithImageInRect(cgImage, rect);
UIImage *subImage = [UIImage imageWithCGImage:cgSubImage scale:fullImage.scale
orientation:fullImage.imageOrientation];
CGImageRelease(cgSubImage);
return subImage;
}
...
UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImage *topHalfImage = halfOfImage(viewImage, 0);
UIImage *bottomHalfImage = halfOfImage(viewImage, 0.5f);