剪辑的UIImage到UIBezierPath(未掩蔽)
我试图剪辑基于给定UIBezierPath
一个UIImage
,但所得到的图像保留原始形状和尺寸。我希望形状和大小类似于路径,即新图像的可见内容。剪辑的UIImage到UIBezierPath(未掩蔽)
看看下面的例子中:
以下是我使用来掩盖给出的路径图像代码:
func imageByApplyingClippingBezierPath(_ path: UIBezierPath) -> UIImage {
UIGraphicsBeginImageContextWithOptions(CGSize(
width: size.width,
height: size.height
), false, 0.0)
let context = UIGraphicsGetCurrentContext()!
context.saveGState()
path.addClip()
draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
let newImage = UIGraphicsGetImageFromCurrentImageContext()!
context.restoreGState()
UIGraphicsEndImageContext()
return newImage
}
一个解决办法是农作物在掩盖它之后的图像,但理想情况下,我希望这样做尽可能简单而有效。
任何溶液/提示,将不胜感激。
感谢Rob我能够实施cropping(to:)
方法CGImage
的解决方案。
这是一个两个步骤的过程,其中第一I使用给定的路径遮蔽图像,然后裁剪使用路径的边界的结果。
以下是用于实现剪裁UIBezierPath
UIImage
扩展我的最终工作的源代码:
extension UIImage {
func imageByApplyingClippingBezierPath(_ path: UIBezierPath) -> UIImage {
// Mask image using path
let maskedImage = imageByApplyingMaskingBezierPath(path)
// Crop image to frame of path
let croppedImage = UIImage(cgImage: maskedImage.cgImage!.cropping(to: path.bounds)!)
return croppedImage
}
func imageByApplyingMaskingBezierPath(_ path: UIBezierPath) -> UIImage {
// Define graphic context (canvas) to paint on
UIGraphicsBeginImageContext(size)
let context = UIGraphicsGetCurrentContext()!
context.saveGState()
// Set the clipping mask
path.addClip()
draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
let maskedImage = UIGraphicsGetImageFromCurrentImageContext()!
// Restore previous drawing context
context.restoreGState()
UIGraphicsEndImageContext()
return maskedImage
}
}
伟大的工作! man〜 – Jerome
下面的目标c版本仅显示解决方案的裁剪部分,我们可能有任何机会可以获得所有解决方案的完整客观c版本? @Aleksander我真的很感激它。 –
我使用按照客观C,对于任何图像裁剪非transperant矩形。检查它是否有帮助
@implementation UIImage (cropTransperant)
- (UIImage *) CropimageByTrimmingTransparentPixels {
int rows = self.size.height;
int cols = self.size.width;
int bytesPerRow = cols*sizeof(uint8_t);
if (rows < 2 || cols < 2) {
return self;
}
uint8_t *bitmapData = calloc(rows*cols, sizeof(uint8_t));
CGContextRef contextRef = CGBitmapContextCreate(bitmapData, cols, rows, 8, bytesPerRow, NULL, kCGImageAlphaOnly);
CGImageRef cgImage = self.CGImage;
CGRect rect = CGRectMake(0, 0, cols, rows);
CGContextDrawImage(contextRef, rect, cgImage);
//get all non-transparent pixels in every row and every column
uint16_t *rowSum = calloc(rows, sizeof(uint16_t));
uint16_t *colSum = calloc(cols, sizeof(uint16_t));
//loop through all pixels
for (int row = 0; row < rows; row++) {
for (int col = 0; col < cols; col++)
{
if (bitmapData[row*bytesPerRow + col]) { //when you get non transperant pixel
rowSum[row]++;
colSum[col]++;
}
}
}
UIEdgeInsets crop = UIEdgeInsetsMake(0, 0, 0, 0); //croprect, initialize with 0,0,0,
for (int i = 0; i<rows; i++) { //get top
if (rowSum[i] > 0) {
crop.top = i; break;
}
}
for (int i = rows; i >= 0; i--) { //get bottom
if (rowSum[i] > 0) {
crop.bottom = MAX(0, rows-i-1); break;
}
}
for (int i = 0; i<cols; i++) { //get left
if (colSum[i] > 0) {
crop.left = i; break;
}
}
for (int i = cols; i >= 0; i--) { //get right
if (colSum[i] > 0) {
crop.right = MAX(0, cols-i-1); break;
}
}
free(bitmapData);
free(colSum);
free(rowSum);
if (crop.top == 0 && crop.bottom == 0 && crop.left == 0 && crop.right == 0) {
return self;
}
else {
rect.origin.x += crop.left;
rect.origin.y += crop.top;
rect.size.width -= crop.left + crop.right;
rect.size.height -= crop.top + crop.bottom;
//crop image to calcualted rect
CGImageRef newImage = CGImageCreateWithImageInRect(cgImage, rect);
return [UIImage imageWithCGImage:newImage];
}
}
@end
我没有机会测试您的代码,但从逻辑上来说它似乎有意义。不过,理想情况下,我正在寻找更简单,更高效的解决方案。我不知道为什么它被拒绝投票,任何人都在意解释? – Aleksander
不,请继续前进并裁剪它。这很简单,只需要调用一次'CGImageCreateWithImageInRect'。 – Rob
感谢您对@Rob的评论,你会介意分享一个关于如何实现这个的快速代码片段吗? – Aleksander
不需要编码样本Rob,我想通了。感谢指针! – Aleksander