better crop image quality, this should fix issue #11and #7 for Custom…

… Crop
gekitz · Mar 4, 2013 · 2a91f31 · 2a91f31
1 parent 50df2c3
commit 2a91f31
Show file tree

Hide file tree

Showing 2 changed files with 58 additions and 12 deletions.
diff --git a/GKClasses/GKImageCropView.m b/GKClasses/GKImageCropView.m
@@ -12,6 +12,13 @@
 
 #import <QuartzCore/QuartzCore.h>
 
+#define rad(angle) ((angle) / 180.0 * M_PI)
+
+static CGRect GKScaleRect(CGRect rect, CGFloat scale)
+{
+	return CGRectMake(rect.origin.x * scale, rect.origin.y * scale, rect.size.width * scale, rect.size.height * scale);
+}
+
 @interface ScrollView : UIScrollView
 @end
 
@@ -48,6 +55,8 @@ @interface GKImageCropView ()<UIScrollViewDelegate>
 @property (nonatomic, strong) GKImageCropOverlayView *cropOverlayView;
 @property (nonatomic, assign) CGFloat xOffset;
 @property (nonatomic, assign) CGFloat yOffset;
+
+- (CGAffineTransform)_orientationTransformedRectOfImage:(UIImage *)image;
 @end
 
 @implementation GKImageCropView
@@ -96,18 +105,55 @@ - (UIImage *)croppedImage{
         CGFloat xPositionInScrollView = resizeableView.contentView.frame.origin.x + self.scrollView.contentOffset.x - self.xOffset;
         CGFloat yPositionInScrollView = resizeableView.contentView.frame.origin.y + self.scrollView.contentOffset.y - self.yOffset;
         CGContextTranslateCTM(ctx, -(xPositionInScrollView), -(yPositionInScrollView));
+
+		[self.scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
+		UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
+		UIGraphicsEndImageContext();
+		return viewImage;
     }
     else {
 
-		CGFloat scale = self.scrollView.maximumZoomScale / self.scrollView.zoomScale;
-        UIGraphicsBeginImageContextWithOptions(self.scrollView.frame.size, self.scrollView.opaque, scale);
-        CGContextRef ctx = UIGraphicsGetCurrentContext();
-        CGContextTranslateCTM(ctx, -self.scrollView.contentOffset.x, -self.scrollView.contentOffset.y);
+		//scaled width/height in regards of real width to crop width
+		CGFloat scaleWidth = self.imageToCrop.size.width / self.cropSize.width;
+		CGFloat scaleHeight = self.imageToCrop.size.height / self.cropSize.height;
+		CGFloat scale = MAX(scaleWidth, scaleHeight);
+
+		//extract visible rect from scrollview and scale it 
+		CGRect visibleRect = [scrollView convertRect:scrollView.bounds toView:imageView];
+		visibleRect = GKScaleRect(visibleRect, scale);
+
+		//transform visible rect to image orientation
+		CGAffineTransform rectTransform = [self _orientationTransformedRectOfImage:self.imageToCrop];
+		visibleRect = CGRectApplyAffineTransform(visibleRect, rectTransform);
+
+		//finally crop image
+		CGImageRef imageRef = CGImageCreateWithImageInRect([self.imageToCrop CGImage], visibleRect);
+		UIImage *result = [UIImage imageWithCGImage:imageRef scale:self.imageToCrop.scale orientation:self.imageToCrop.imageOrientation];
+		CGImageRelease(imageRef);
+
+		return result;
     }
-    [self.scrollView.layer renderInContext:UIGraphicsGetCurrentContext()];
-    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
-    UIGraphicsEndImageContext();
-    return viewImage;
+}
+
+- (CGAffineTransform)_orientationTransformedRectOfImage:(UIImage *)img
+{
+	CGAffineTransform rectTransform;
+	switch (img.imageOrientation)
+	{
+		case UIImageOrientationLeft:
+			rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(90)), 0, -img.size.height);
+			break;
+		case UIImageOrientationRight:
+			rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-90)), -img.size.width, 0);
+			break;
+		case UIImageOrientationDown:
+			rectTransform = CGAffineTransformTranslate(CGAffineTransformMakeRotation(rad(-180)), -img.size.width, -img.size.height);
+			break;
+		default:
+			rectTransform = CGAffineTransformIdentity;
+	};
+
+	return CGAffineTransformScale(rectTransform, img.scale, img.scale);
 }
 
 #pragma mark -
@@ -126,12 +172,12 @@ - (id)initWithFrame:(CGRect)frame
         self.scrollView.delegate = self;
         self.scrollView.clipsToBounds = NO;
         self.scrollView.decelerationRate = 0.0; 
-        self.scrollView.backgroundColor = [UIColor clearColor];
+        self.scrollView.backgroundColor = [UIColor greenColor];
         [self addSubview:self.scrollView];
 
         self.imageView = [[UIImageView alloc] initWithFrame:self.scrollView.frame];
         self.imageView.contentMode = UIViewContentModeScaleAspectFit;
-        self.imageView.backgroundColor = [UIColor blackColor];
+        self.imageView.backgroundColor = [UIColor greenColor];
         [self.scrollView addSubview:self.imageView];
 
 

diff --git a/GKImagePicker/ViewController.m b/GKImagePicker/ViewController.m
@@ -31,7 +31,7 @@ @implementation ViewController
 - (void)showPicker:(UIButton *)btn{
 
     self.imagePicker = [[GKImagePicker alloc] init];
-    self.imagePicker.cropSize = CGSizeMake(320, 320);
+    self.imagePicker.cropSize = CGSizeMake(280, 280);
     self.imagePicker.delegate = self;
 
     if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
@@ -95,7 +95,7 @@ - (void)viewDidLoad
     [self.view addSubview:self.customCropButton];
 
     self.normalCropButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
-    [self.normalCropButton setTitle:@"Normal Crop" forState:UIControlStateNormal];
+    [self.normalCropButton setTitle:@"Apple's Build In Crop" forState:UIControlStateNormal];
     [self.normalCropButton addTarget:self action:@selector(showNormalPicker:) forControlEvents:UIControlEventTouchUpInside];
     [self.view addSubview:self.normalCropButton];