[英]How to crop center part of large image in iOS?
當從中心裁剪圖像時,裁剪圖像將采用源圖像的縱橫比,但根據我的要求,縱橫比將隨着新的裁剪尺寸而變化。
我想獲得具有新縱橫比的圖像的確切中心部分。例如,大圖像的大小為 (320*480) 然后我想裁剪圖像的中心部分 (100,100) 並且縱橫比也將是 100*100 ,不需要外部的白色或黑色部分,圖像質量會很高。
裁剪功能:
- (UIImage *)cropImage:(UIImage*)image andFrame:(CGRect)rect {
//Note : rec is nothing but the image frame which u want to crop exactly.
rect = CGRectMake(rect.origin.x*image.scale,
rect.origin.y*image.scale,
rect.size.width*image.scale,
rect.size.height*image.scale);
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], rect);
UIImage *result = [UIImage imageWithCGImage:imageRef
scale:image.scale
orientation:image.imageOrientation];
CGImageRelease(imageRef);
return result;
}
請幫我。
這可能會運行
- (UIImage *)imageByCroppingImage:(UIImage *)image toSize:(CGSize)size
{
// not equivalent to image.size (which depends on the imageOrientation)!
double refWidth = CGImageGetWidth(image.CGImage);
double refHeight = CGImageGetHeight(image.CGImage);
double x = (refWidth - size.width) / 2.0;
double y = (refHeight - size.height) / 2.0;
CGRect cropRect = CGRectMake(x, y, size.height, size.width);
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], cropRect);
UIImage *cropped = [UIImage imageWithCGImage:imageRef scale:0.0 orientation:self.imageOrientation];
CGImageRelease(imageRef);
return cropped;
}
float imgHeight = 100.0f; //Any according to requirement
float imgWidth = 100.0f; //Any according to requirement
CGRect cropRect = CGRectMake((largeImage.size.width/2)-(imgWidth/2),largeImage.size.height/2)-(imgHeight/2),imgWidth,imgHeight);
CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage CGImage], cropRect);
// or use the UIImage wherever you like
UIImage *croppedImg = [UIImage imageWithCGImage:imageRef]];
CGImageRelease(imageRef);
var imageView = UIImageView()
// height and width values corresponds to rectangle height and width
imageView = UIImageView(frame: CGRectMake(0, 0, width, height ))
imageView.image = UIImage(named: "Your Image Name")
// by setting content mode to .ScaleAspectFill image centrally fill in imageView. image might appear beyond image frame.
imageView.contentMode = .ScaleAspectFill
// by setting .clipsToBouds to true, image set to image frame.
imageView.clipsToBounds = true
view.addSubview(imageView)
// 運行這段代碼
-(UIImage *)croppedImage
{
UIImage *myImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[self.bezierPath closePath];
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0.0, 0.0, 0.0, 0.0);
_b_image = self.bg_imageview.image;
CGSize imageSize = _b_image.size;
CGRect imageRect = CGRectMake(0, 0, imageSize.width, imageSize.height);
UIGraphicsBeginImageContextWithOptions(imageSize, NO, [[UIScreen mainScreen] scale]);
[self.bezierPath addClip];
[_b_image drawInRect:imageRect];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
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