CGImageCreateWithImageInRect incorrect area? - ios

I am using this github image cropper: https://github.com/iosdeveloper/ImageCropper
In this image cropper, in the init method they have these lines:
CGRect rect;
rect.size.width = image.size.width;
rect.size.height = image.size.height;
[imageView setFrame:rect];
Beforehand, I resize the image to the screens resolution not points. So if I leave the code above the way it is, my UIImage will not fill the UIImageView for some odd reason, and I have tried to adjust the contentModes also.
But if I adjust it to this (the size of the UIPopover that the image cropper is in):
[imageView setFrame:CGRectMake(0, 0, 320, 480)];
The UIImage will fill the UIPopover.
The real issue is here:
If I zoom into a certain part of the image and execute the code below, it will take screenshot of the top left part of the UIImage no where near to where I have cropped the image to. Although it does abide by the scrollView's zoomScale.
Here is the screenshot code:
- (void)finishCropping {
float zoomScale = 1.0 / [scrollView zoomScale];
CGRect rect;
rect.origin.x = [scrollView contentOffset].x * zoomScale;
rect.origin.y = [scrollView contentOffset].y * zoomScale;
rect.size.width = [scrollView bounds].size.width * zoomScale;
rect.size.height = [scrollView bounds].size.height * zoomScale;
CGImageRef cr = CGImageCreateWithImageInRect([[imageView image] CGImage], rect);
UIImage *cropped = [UIImage imageWithCGImage:cr];
CGImageRelease(cr);
[delegate imageCropper:self didFinishCroppingWithImage:cropped];
}
Does anyone know why this is happening?
Thanks!

I think you have at first to use [UIImage imageWithCGImage:cr scale:self.scale orientation:self.imageOrientation] instead [UIImage imageWithCGImage:cr] to create UIImage, this will take off many problems with orientation and double check the width and height are in the right direction in rect.

Related

Convert UIScrollViewPoint to UIImage + ZOOM + ROTATE

I need to crop UIImage which is loaded in UIScrollview with some rect of Another UIView which is also in UIScrollView
Following is View Hierarchy
--> View
--> UIScrollView
--> viewBase (UIView)
--> UIImageView -> (Zoomed & rotated )
--> UIView (Target View)(Movable User can move anywhere in scrollview to crop rect)
My Image is Rotated & Zoomed I need to get exact part of image in TargetView
I am drawing UIImage with rotation on context following is code
CGFloat angleCroppedImageRetreacted = atan2f(self.imgVPhoto.transform.b, self.imgVPhoto.transform.a);
angleCroppedImageRetreacted = angleCroppedImageRetreacted * (180 / M_PI);
UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, self.imgVPhoto.image.size.width, self.imgVPhoto.image.size.height)];
rotatedViewBox.transform = CGAffineTransformMakeRotation(-angleCroppedImageRetreacted);
CGSize rotatedSize = rotatedViewBox.frame.size;
UIGraphicsBeginImageContext(rotatedSize);
CGContextRef bitmap = UIGraphicsGetCurrentContext();
CGContextTranslateCTM(bitmap, rotatedSize.width / 2.0f, rotatedSize.height / 2.0f);
CGContextRotateCTM(bitmap, -angleCroppedImageRetreacted);
CGContextScaleCTM(bitmap, 1.0f, -1.0f);
CGContextDrawImage(bitmap, CGRectMake(-self.imgVPhoto.image.size.width / 2.0f,
-self.imgVPhoto.image.size.height / 2.0f,
self.imgVPhoto.image.size.width,
self.imgVPhoto.image.size.height),
self.imgVPhoto.image.CGImage);
UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
And it works fine . I am getting Rotated UIImage same as i can see in Simulator
For converting Point of Target View to UIImage I use following code which is NOT WORKING
CGPoint imageViewPoint = [self.viewBase convertPoint:self.targetImageview.center toView:self.imgVPhoto];
float percentX = imageViewPoint.x / self.imgVPhoto.frame.size.width;
float percentY = imageViewPoint.y / self.imgVPhoto.frame.size.height;
CGPoint imagePoint = CGPointMake(resultImage.size.width * percentX, resultImage.size.height * percentY);
rect.origin = imagePoint;
//rect.origin.x *= (self.imgVPhoto.image.size.width / self.imgVPhoto.frame.size.width);
//rect.origin.y *= (self.imgVPhoto.image.size.height / self.imgVPhoto.frame.size.height);
imageRef = CGImageCreateWithImageInRect([resultImage CGImage], rect);
img = [UIImage imageWithCGImage:imageRef scale:viewImage.scale orientation:viewImage.imageOrientation];
I think issue is we can't use Rect after Transform Apply
Please Help me to crop UIImage which is zoomed and rotated from rect on same Hierarchy
If you need more info pls ask
I am answering my own question .
Thanks to Matic for giving a idea
I changed a logic
I have achieved same functionality what i looking for
CGPoint locationInImageView = [self.viewBase convertPoint:self.targetImageview.center toView:self.view]; // received from touch
locationInImageView = [self.view convertPoint:locationInImageView toView:self.imgVPhoto];
// I GOT LOCATION IN UIIMAGEVIEW OF TOUCH POINT
UIGraphicsBeginImageContextWithOptions(self.view.frame.size, NO, 0);
[self.imgVPhoto.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img1 = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// I GOT UIIMAGE FROM CURRENT CONTEXT
CGFloat width = self.targetImageview.frame.size.width * self.zoomScale ;
CGFloat height = self.targetImageview.frame.size.height * self.zoomScale ;
//2 IS SCALE FACTOR
CGFloat xPos = (locationInImageView.x * 2) - width / 2;
CGFloat yPos = (locationInImageView.y * 2) - height / 2;
CGRect rect1 = CGRectMake(xPos, yPos, width, height);
CGImageRef imageRef = CGImageCreateWithImageInRect([img1 CGImage], rect1);
// YAHHH YOU HAVE EXACT IMAGE
UIImage *img = [UIImage imageWithCGImage:imageRef scale:img1.scale orientation:img1.imageOrientation];

Crop zoomed image in UIScrollView issue

After going through this link, issue with my code is that output image is unable to set proper x and y values as cropped image seems to have 0 and 0 in the resultant image irrespective to where I zoom (or where the scroll offset is calculated). Here's what I tried.
- (IBAction)crop:(id)sender
{
float zoomScale = 1.0f / [self.scroll zoomScale];
CGRect rect;
NSLog(#"contentOffset is :%f,%f",[self.scroll contentOffset].x,[self.scroll contentOffset].y);
rect.origin.x = self.scroll.contentOffset.x * zoomScale;
rect.origin.y = self.scroll.contentOffset.y * zoomScale;
rect.size.width = self.scroll.bounds.size.width * zoomScale;
rect.size.height = self.scroll.bounds.size.height * zoomScale;
UIGraphicsBeginImageContextWithOptions( CGSizeMake(rect.size.width, rect.size.height),
NO,
0.);
NSLog(#"rect offset is :%f,%f",rect.origin.x,rect.origin.y);
CGPoint point = CGPointMake(-rect.origin.x, -rect.origin.y); **//even though above NSLog have some values, but output image is unable to set proper x and y values as cropped image seems to have 0 and 0 in the resultant image.**
[[self.imagV image] drawAtPoint:point
blendMode:kCGBlendModeCopy
alpha:1];
self.croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
DTImageViewController *imageViewController = [[DTImageViewController alloc] initWithNibName:#"DTImageViewController" bundle:nil];
imageViewController.image = self.croppedImage;
[self.navigationController pushViewController:imageViewController animated:YES];
}
Similar code as already posted but just taking whole UIScrollView bounds without passing a CGRect
-(void)takeScreenShotOfScrollView
{
UIGraphicsBeginImageContextWithOptions(scrollView.bounds.size, YES, [UIScreen mainScreen].scale);
CGPoint offset = scrollView.contentOffset;
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -offset.x, -offset.y);
[scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
img = [SDImageHelper imageWithImage:img_image scaledToSize:CGSizeMake(769, 495)];
}
BONUS:
The cropping method
+(UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
//UIGraphicsBeginImageContext(newSize);
// In next line, pass 0.0 to use the current device's pixel scaling factor (and thus account for Retina resolution).
// Pass 1.0 to force exact pixel size.
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
I'm using the following code for this and it does exactly what expected:
- (UIImage *) croppedImageOfView:(UIView *) view withFrame:(CGRect) rect
{
UIGraphicsBeginImageContextWithOptions(rect.size,NO,0.0);
CGContextTranslateCTM(UIGraphicsGetCurrentContext(), -rect.origin.x, -rect.origin.y);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *visibleScrollViewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return visibleScrollViewImage;
}
- (void) crop
{
CGRect neededRect = CGRectMake(50,50,100,100);
UIImage *image = [self croppedImageOfView:_scrollView withFrame:neededRect];
}
Works well even if content is zoomed, the only thing that must be calculated wisely is needed area CGRect.

Draw rotated and scaled UILabel text inside UIImage

I have one UIScrollView with a UIImageView inside from where I obtain a cropped UIImage (considering scale, offset, bounds,...). On the other hand, I have a UILabel which I can rotate, pinch and pan anywhere over the UIScrollView. The problem comes when I try to generate the final image with the label text inside (with it's original/equivalent position, rotation,...) on the cropped UIImage (bigger than screen size).
I've tried everything. This is my last attempt trying to position the text, but it's always misplaced.
// Compute rect to draw the text inside
CGSize imageSize = inImage.size;
NSDictionary *attr = #{NSForegroundColorAttributeName: fontColor, NSFontAttributeName: textFont};
CGSize textSize = [text sizeWithAttributes:attr];
CGRect textRect = CGRectMake(labelCenterPoint.x, labelCenterPoint.y, textSize.width, textSize.height);
// Create the image
UIGraphicsBeginImageContext(imageSize);
[inImage drawInRect:CGRectMake(0, 0, imageSize.width, imageSize.height)];
// Rotate text from center
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextTranslateCTM( context, 0.5f * textSize.width, 0.5f * textSize.height ) ;
CGContextRotateCTM(context, rotation);
[text drawInRect:CGRectIntegral(textRect) withAttributes:attr];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
I think the problem is the textRect origin. Do I have to make the UILabel a subView of the UIScrollView too and make the textRect origin relative to the UIScrollView parameters? or am I missing something?. Is there a better way?.
Thanks in advance!.
Edit:
I have finally found an acceptable solution (although is not too much precise). I think the problem was about the two existing coordinate systems, so I tried a different approach:
// Calculate the relative position of the UILabel with respect
// to the ScrollView that contains the image
float xPosition = label.frame.origin.x - scrollView.frame.origin.x;
float yPosition = label.frame.origin.y - scrollView.frame.origin.y;
// Calculate the proportion to apply to the position
// (the image is bigger than screen)
float xProportion = image.frame.size.width / scrollView.frame.size.width;
float yProportion = image.frame.size.height / scrollView.frame.size.height;
UIImageView *testView = [[UIImageView alloc] initWithImage:image];
UILabel *tempLabel = [[UILabel alloc] initWithFrame:
CGRectMake((xPosition*xProportion),
(yPosition*yProportion),
label.frame.size.width*xProportion,
label.frame.size.height*yProportion)];
tempLabel.text = label.text;
tempLabel.font = [UIFont fontWithName:label.font.fontName
size:label.font.pointSize*3];
tempLabel.textColor = label.textColor;
tempLabel.textAlignment = NSTextAlignmentCenter;
tempLabel.transform = CGAffineTransformMakeRotation(rotation);
tempLabel.adjustsFontSizeToFitWidth = YES;
tempLabel.minimumScaleFactor = 0.05;
[testView addSubview:tempLabel];
UIGraphicsBeginImageContext(testView.image.size);
[testView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *imageWithText = UIGraphicsGetImageFromCurrentImageContext();
I hope this may help someone. All suggestions are welcome of course.

Objective-C iOS Crop Image Using Zoom?

I am trying to use this code to allow users to zoom and crop their images in my app:
https://github.com/iosdeveloper/ImageCropper/tree/master/Classes/ImageCropper
code snippet
float zoomScale = 1.0 / [scrollView zoomScale];
CGRect rect;
rect.origin.x = [scrollView contentOffset].x * zoomScale;
rect.origin.y = [scrollView contentOffset].y * zoomScale;
rect.size.width = [scrollView bounds].size.width * zoomScale;
rect.size.height = [scrollView bounds].size.height * zoomScale;
CGImageRef cr = CGImageCreateWithImageInRect([[imageView image] CGImage], rect);
UIImage *cropped = [UIImage imageWithCGImage:cr];
CGImageRelease(cr);
[delegate imageCropper:self didFinishCroppingWithImage:cropped];
But it does not take into account images being rotated (I guess it's some sort of metadata on the iPhone images). I do not want to have users draw a rectangle to crop as I much prefer this interface.
Can someone tell me how to make it not rotate my images?
I am building in iOS 5 & 6 if that helps.
[EDIT] Also, this is done nicely in the Game Center application for uploading your profile picture. Anyone know where I can find the code for that?
I found an answer here that helped me do what I wanted
iOS: Cropping a still image grabbed from a UIImagePickerController camera with overlay
Code Snippet for those interested
float zoomScale = 1.0 / [scrollView zoomScale];
CGRect rect;
NSLog(#"contentOffset is :%f,%f",[scrollView contentOffset].x,[scrollView contentOffset].y);
rect.origin.x = fabsf([scrollView contentOffset].x * zoomScale);
rect.origin.y = fabsf([scrollView contentOffset].y * zoomScale);
rect.size.width = fabsf([scrollView bounds].size.width * zoomScale);
rect.size.height = fabsf([scrollView bounds].size.height * zoomScale);
UIGraphicsBeginImageContextWithOptions( CGSizeMake( rect.size.width,
rect.size.height),
NO,
0.);
[[imageView image] drawAtPoint:CGPointMake( -rect.origin.x, -rect.origin.y)
blendMode:kCGBlendModeCopy
alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Image cropping issue in iOS

I am creating an iPhone app which has image cropping feature. In this, I am getting the photos from the UIImagePickerController and passing it for cropping. There it has a scrollview and the selected image will be added as a subview to the scrollview. And I am using a UIButton for selecting the area for cropping. User can move the button over the imageview and place it anywhere, and when click on CROP button, the area similar to the frame size of the button should be cropped from the imageview.
I used the following code, but it is not returning the actual image.
CGRect clippedRect = CGRectMake(self.scrollView.frame.origin.x+90, self.scrollView.frame.origin.y, self.scrollView.frame.size.width-180, self.scrollView.frame.size.height-220);
CGImageRef imageRef = CGImageCreateWithImageInRect([self.myPhoto CGImage], clippedRect);
UIImage *newImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
self.imageView.image = newImage;
also used
- (UIImage *)cropImage:(UIImage *)oldImage {
CGSize imageSize = self.cropFrame.frame.size;
UIGraphicsBeginImageContextWithOptions( CGSizeMake( imageSize.width, imageSize.height), NO, 0.);
[oldImage drawAtPoint:CGPointMake( xPosition, yPosition)
blendMode:kCGBlendModeCopy
alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
but the result image is not the exact image as per the button frame. I am getting the image from another area.
Updated code
- (void)loadPhoto{
CGFloat w = self.myPhoto.size.width;
CGFloat h = self.myPhoto.size.height;
CGRect imageViewFrame = CGRectMake(0.0f, 0.0f, roundf(w / 2.0f), roundf(h / 2.0f));
self.scrollView.contentSize = imageViewFrame.size;
UIImageView *iv = [[UIImageView alloc] initWithFrame:imageViewFrame];
iv.contentMode = UIViewContentModeScaleAspectFit;
iv.image = self.myPhoto;
[self.view addSubview:iv];
self.imageView = iv;
[iv release];
}
CGRect crop;//= CGRectMake(10, 10, 360, 360);
crop.origin.x = self.cropFrame.frame.origin.x;
crop.origin.y = self.cropFrame.frame.origin.y;
crop.size.width = roundf(self.cropFrame.frame.size.width * 2.0f); //self.cropFrame.frame.size.width * 2;
crop.size.height = roundf(self.cropFrame.frame.size.height * 2.0f); //self.cropFrame.frame.size.height * 2;
NSLog(#"Rect: %#", NSStringFromCGRect(crop));
self.imageView.image = [self croppedImage:crop];
- (UIImage *)croppedImage:(CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect([self.imageView.image CGImage], bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:self.myPhoto.imageOrientation];
CGImageRelease(imageRef);
return croppedImage;
}
Please help to find a solution.
The iOS has a default feature for cropping images.Try this code.
picker.allowsEditing = YES;
and also check this controller for cropping..this is exactly the one you are looking for I think https://github.com/barrettj/BJImageCropper .Hope this helps you..
Since you are using a scrollView that allows the image to be scrolled, you need to adjust your crop rect to the scrollView's position:
float zoomScale = self.scrollView.zoomScale;
int cropX = (self.scrollView.contentOffset.x-imageView.frame.origin.x)/zoomScale;
int cropY = (self.scrollView.contentOffset.y-imageView.frame.origin.y)/zoomScale;
You could use this crop tool that I made. It essentially gives you an interface to allow the user to select the crop area. I think it is in line with that you are looking for.
https://github.com/nicholjs/BFCropInterface
Believing you have solve this problem. Me too had this when tried cropping functionality
Set image.size as the imageView.size & scrollView.contentSize. Below code will give the rect to crop
cropRect.origin = scrollView.contentOffset;
cropRect.size = scrollView.bounds.size;
cropRect.origin.x /= scrollView.zoomScale;
cropRect.origin.y /= scrollView.zoomScale;
cropRect.size.width /= scrollView.zoomScale;
cropRect.size.height /= scrollView.zoomScale;
If planning to show the full image first on visible rect. Setting the imageView.size & scrollView.contentSize to visible view size will give crop image of some other area. Instead try finding the zoom scale by
CGFloat dxWidth = viewCrop.frame.size.width / imageView.image.size.width;
CGFloat dxHeight = viewCrop.frame.size.height / imageView.image.size.height;
CGFloat zoomScale = fmaxf(dWidth, dHeight)
and apply (if by adding subView then after addSubView)
scrollView.minimumZoomScale = zoomScale; // to disable further zoom-out
[scrollView setZoomScale: zoomScale];

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