将图像剪裁成覆盖图的形状 – iOS

我使用pickerController的视图和uinavigationcontrollerdelegate添加覆盖，如下所示。

-(void)navigationController:(UINavigationController *)navigationController didShowViewController: (UIViewController *)viewController animated:(BOOL)animated{ if ([navigationController.viewControllers count] == 3) { CGFloat screenHeight = [[UIScreen mainScreen] bounds].size.height; UIView *plCropOverlay = [[[viewController.view.subviews objectAtIndex:1]subviews] objectAtIndex:0]; plCropOverlay.hidden = YES; int position = 0; if (screenHeight == 568) { position = 124; } else { position = 80; } CAShapeLayer *circleLayer = [CAShapeLayer layer]; UIBezierPath *path2 = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(0.0f, position, 320.0f, 320.0f)]; [path2 setUsesEvenOddFillRule:YES]; [circleLayer setPath:[path2 CGPath]]; [circleLayer setFillColor:[[UIColor clearColor] CGColor]]; UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 320, screenHeight-72) cornerRadius:0]; [path appendPath:path2]; [path setUsesEvenOddFillRule:YES]; CAShapeLayer *fillLayer = [CAShapeLayer layer]; fillLayer.path = path.CGPath; fillLayer.fillRule = kCAFillRuleEvenOdd; fillLayer.fillColor = [UIColor blackColor].CGColor; fillLayer.opacity = 0.8; [viewController.view.layer addSublayer:fillLayer]; } } 

当添加上面定义的覆盖，我倾向于得到这个观点：

我可以使用已定义的CGRect将图像精确地裁剪为正方形。

  CGImageRef imageRef = CGImageCreateWithImageInRect([imageToCrop CGImage], rect); UIImage *cropped = [UIImage imageWithCGImage:imageRef]; CGImageRelease(imageRef); 

如果有一个圆形覆盖和imagePickers编辑属性是YES的接近这个问题？ 我可以放大和缩小图片。 我怎样才能在这里使用BezierPath？

Answer 1

你的问题addClip简短的回答，但你提到你是一个初学者，所以这里是从A到Z的所有步骤！

首先，尝试这个类别，看看是否有帮助。 （如果你不熟悉，有类别有谷歌或只是在这里问一个评论。）

 -(UIImage *)doMask { UIImage *maskImage = [UIImage imageNamed:@"yourMask.png"]; CGImageRef maskRef = maskImage.CGImage; CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef), CGImageGetHeight(maskRef), CGImageGetBitsPerComponent(maskRef), CGImageGetBitsPerPixel(maskRef), CGImageGetBytesPerRow(maskRef), CGImageGetDataProvider(maskRef), NULL, false); CGImageRef maskedImageRef = CGImageCreateWithMask([self CGImage], mask); UIImage *maskedImage = [UIImage imageWithCGImage:maskedImageRef]; CGImageRelease(mask); CGImageRelease(maskedImageRef); return maskedImage; } 

只是创build（我的意思是在Photoshop中）一个PNG面具，并熟悉该过程。

我鼓励你先掌握这个过程

这里是关键的类别，将有助于…

 -(UIImage *)becomeSquare { CGSize imageSize = self.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; UIImage *result = self; if (width != height) { CGFloat newDimension = MIN(width, height); CGFloat widthOffset = (width - newDimension) / 2; CGFloat heightOffset = (height - newDimension) / 2; UIGraphicsBeginImageContextWithOptions( CGSizeMake(newDimension, newDimension), NO, 0. ); [result drawAtPoint:CGPointMake(-widthOffset, -heightOffset) blendMode:kCGBlendModeCopy alpha:1. ]; result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } return result; } 

还有一对…

 -(UIImage *)doScale { UIImage *result = self; CGSize size = CGSizeMake(320,320); UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f); [result drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)]; result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return result; } -(UIImage *)scaled640AnyShape { if ( self.size.height < 5.0 ) return nil; if ( self.size.width < 5.0 ) return nil; UIImage *result = self; float widthShouldBe = 640.0; float heightShouldBe = widthShouldBe * ( self.size.height / self.size.width ); CGSize size = CGSizeMake( widthShouldBe ,heightShouldBe ); UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f); [result drawInRect:CGRectMake(0.0f, 0.0f, size.width, size.height)]; result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return result; } 

（显然可以根据需要更改硬编码的输出大小。）

请注意，您的最终结果将通过适当顺序的组合来实现，例如：

 yourImage = [yourImage doSquare]; yourImage = [yourImage doMask]; 

一旦你有这个工作…

然后 ….

为什么你问，有很多示例代码关于..例如， https ://stackoverflow.com/a/13870097/294884

正如你所看到的，你从根本上…

 UIGraphicsBeginImageContextWithOptions(...); UIBezierPath * path = [UIBezierPath bezierPathWithRoundedRect:imageRect cornerRadius:10.f]; [path addClip]; [yourImage drawInRect:imageRect]; ... then ... UIGraphicsGetImageFromCurrentImageContext(); .. see the extensive code above for how to save it and so on. 

您只需使用上面的缩放示例即可进行缩放。

另外请注意，当您更改“区域裁剪”时… https://stackoverflow.com/a/17884863/294884

这是一个关键技术的例子…

 -(UIImage *)squareAndSmall { // genius credits: https://stackoverflow.com/a/17884863/294884 CGSize finalsize = CGSizeMake(640,640); CGFloat scale = MAX( finalsize.width/self.size.width, finalsize.height/self.size.height); CGFloat width = self.size.width * scale; CGFloat height = self.size.height * scale; // for example, the central area.... CGRect imageRect = CGRectMake( (finalsize.width - width)/2.0f, (finalsize.height - height)/2.0f, width, height); // or, the top area... CGRect imageRect = CGRectMake( 0, 0, width, height); UIGraphicsBeginImageContextWithOptions(finalsize, NO, 0); [self drawInRect:imageRect]; UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage; } 

希望这一切都有帮助！

Answer 2

发现这个博客文章非常有趣，整齐，简单，由尼米特帕雷克。

以下代码复制/粘贴到您的“viewcontroller.h”文件中：

 #import <UIKit/UIKit.h> @interface UIImagePickerDemoViewController : UIViewController< UIImagePickerControllerDelegate, UINavigationControllerDelegate> @property(nonatomic,retain) UIImagePickerController *imgPicker; @property(nonatomic,retain) IBOutlet UIImageView *image_view; //- (UIImage*)imageByCropping:(UIImage *)imageToCrop toRect:(CGRect)rect; - (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage; @end 

以下代码复制/粘贴到“viewcontroller.m”文件中：

 // Following method is use for the mask the image. - (UIImage*) maskImage:(UIImage *)image withMask:(UIImage *)maskImage { CGImageRef maskRef = maskImage.CGImage; CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef), CGImageGetHeight(maskRef), CGImageGetBitsPerComponent(maskRef), CGImageGetBitsPerPixel(maskRef), CGImageGetBytesPerRow(maskRef), CGImageGetDataProvider(maskRef), NULL, false); CGImageRef masked = CGImageCreateWithMask([image CGImage], mask); return [UIImage imageWithCGImage:masked]; } // Following method is use for Cropping the image for a perticular size. - (UIImage*)imageByCropping:(UIImage *)imageToCrop toRect:(CGRect)rect { UIGraphicsBeginImageContext(rect.size); CGContextRef currentContext = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(currentContext, 0.0, rect.size.height); CGContextScaleCTM(currentContext, 1.0, -1.0); CGRect clippedRect = CGRectMake(0, 0, rect.size.width, rect.size.height); CGContextClipToRect( currentContext, clippedRect); CGRect drawRect = CGRectMake(rect.origin.x * -1,rect.origin.y * -1,imageToCrop.size.width,imageToCrop.size.height); CGContextDrawImage(currentContext, drawRect, imageToCrop.CGImage); CGContextScaleCTM(currentContext, 1.0, -1.0); UIImage *cropped = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return cropped; } // Calling the method of maskimage. //=============================Camera Enable(display)============================================ -(IBAction)next:(id)sender{ if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { self.imgPicker.sourceType = UIImagePickerControllerSourceTypeCamera; } [self presentModalViewController:self.imgPicker animated:YES]; } -(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{ [picker dismissModalViewControllerAnimated:YES]; } - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { [picker dismissModalViewControllerAnimated:YES]; UIImage *img = [info objectForKey:@"UIImagePickerControllerOriginalImage"]; self.image_view.image=[self maskImage:img withMask:[UIImage imageNamed:@"frame.png"]]; } //=============================================================================================== // Calling the method of cropping the image. //=============================Camera Enable(display)============================================ -(IBAction)next:(id)sender{ if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { self.imgPicker.sourceType = UIImagePickerControllerSourceTypeCamera; } [self presentModalViewController:self.imgPicker animated:YES]; } -(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{ [picker dismissModalViewControllerAnimated:YES]; } - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { [picker dismissModalViewControllerAnimated:YES]; UIImage *img = [info objectForKey:@"UIImagePickerControllerOriginalImage"]; self.image_view.image = [self imageByCropping:img toRect:CGRectMake(0, 0, 420, 40)]; } //=============================================================================================== 

输出：

在这里抓住源代码。

Answer 3

我有完全相同的configuration文件图像select器控制器。 这是我的委托代码。 我不认为你需要一切，但你可以在这里find一些有用的信息

 -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { NSString *mediaType = info[UIImagePickerControllerMediaType]; if([mediaType isEqualToString:(NSString *) kUTTypeImage]) { UIImage *image = info[UIImagePickerControllerOriginalImage]; UIImage *editedImage = (UIImage *) [info objectForKey:UIImagePickerControllerEditedImage]; CGRect croppingRect = [info[UIImagePickerControllerCropRect] CGRectValue]; if (editedImage) { image = editedImage; } else { CGFloat smaller = 1; if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) { smaller = 0.9; } CGFloat width = MIN(image.size.width * smaller, image.size.height * (smaller * 0.95)); croppingRect = CGRectMake(0 + (image.size.width - width) / 2, 0 + (image.size.height - width) / 2, width, width); } UIImage *finalImage = nil; if (editedImage) { finalImage = [UIImage image:editedImage byScalingAndCroppingForSize:kCroppedImageSize]; } else { finalImage = [UIImage image:image byScalingAndCroppingForSize:kCroppedImageSize]; } if ([self.imagePickerDelegate respondsToSelector:@selector(profileImagePicker:didSelectImage:)]) { [self.imagePickerDelegate profileImagePicker:self didSelectImage:finalImage]; } else { NSAssert(nil, @"Delegate should confirm ProfileImagePickerControllerDelegate protocol"); } } else if ([mediaType isEqualToString:(NSString *) kUTTypeVideo]) { NSAssert(nil, @"Movie is not supported"); } }