最近公司项目要做图片处理这里总结一下:
1.普通上下文
CGContextRef ref = UIGraphicsGetCurrentContext();
CGContextSaveGState(ref);
XXXXX
XXXXX
CGContextRestoreGState(ref);
2.遮罩处理
利用图层
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = self.bounds;
maskLayer.fillMode = kCAFillRuleEvenOdd;
// UIBezierPath *maskLayerPath = [UIBezierPath bezierPath];
// [maskLayerPath appendPath:[UIBezierPath bezierPathWithOvalInRect:CGRectMake(5, 5, 100, 100)]];
// maskLayer.path = maskLayerPath.CGPath;
maskLayer.contents = (__bridge id _Nullable)(maskImage.CGImage);
[self.layer setMask:maskLayer];
3.剪切遮罩处理(针对图片)
1.CGContextClipToMask(ref, self.bounds, imgRef);
按图片剪裁context,alpha=0干掉,alpha=1留下;
参数 CGContextRef Rect CGImageRef
2.CGImageCreateWithMask([image CGImage], mask);
两张图片,mask处理,mask图片alpha=1,纯白表示透明, 纯黑表示要留下, 其他颜色,相应混合处理
CGImageCreateWithMaskingColors([image CGImage], CGFloat _UnNull maskColor);
一张图片,按colorspace的要求进行处理
- (UIImage*)maskImage:(UIImage *)image withMask:(UIImage *)maskImage {
// UIImage *blackImg = [self imageBlackToTransparent:maskImage];
// CGImageRef maskRef = blackImg.CGImage;
CGImageRef maskRef = maskImage.CGImage;
maskRef = [PuzzleView maskableImageRefConvertFrom:maskRef];
// const CGFloat maskcolor[6] = {0,0,0,0,0,0};
// CGImageRef maskRef = CGImageCreateWithMaskingColors(maskImage.CGImage, maskcolor);
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];
// UIImage *blackImg = [self imageBlackToTransparent:maskImage];
// CGImageRef maskRef = blackImg.CGImage;
// CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
// CGImageGetHeight(maskRef),
//
// CGImageGetBitsPerComponent(maskRef),
//
// CGImageGetBitsPerPixel(maskRef),
//
// CGImageGetBytesPerRow(maskRef),
// CGImageGetDataProvider(maskRef), NULL, false);
// CGImageRef sourceImage = [image CGImage];
// CGImageRef imageWithAlpha = sourceImage;
// [self imageDump:maskImage];
// if (CGImageGetAlphaInfo(sourceImage) == kCGImageAlphaNone) {
// imageWithAlpha = [self CopyImageAndAddAlphaChannel:sourceImage];
// }
// CGImageRef masked = CGImageCreateWithMask(imageWithAlpha, mask);
// CGImageRelease(mask);
// if (sourceImage != imageWithAlpha) {
// CGImageRelease(imageWithAlpha);
// }
// UIImage* retImage = [UIImage imageWithCGImage:masked];
// CGImageRelease(masked);
// return retImage;
}
4.关于截屏失真
- (IBAction)saveBtnTap:(UIButton *)sender {
// 这个方法将scale 变为屏幕 scale,默认1.0. 改为屏幕scale后变为屏幕分辨率
UIGraphicsBeginImageContextWithOptions(self.mainView.bounds.size, NO, [UIScreen mainScreen].scale);
[self.mainView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(image,nil, nil, nil);
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"" message:@"保存成功" delegate:self cancelButtonTitle:@"取消" otherButtonTitles:nil, nil];
[alertView show];
}