如何检查一个UIView或一个UIImage的像素颜色？ [英] How to check pixel color of a UIView or a UIImage?

问题描述

我想检查是否整个的UIView充满了一种颜色。我设法用code以下块得到的UIView的截图：

I am trying to check if an entire UIView is filled with one color. I managed to get a screenshot of the UIView using the following block of code:

UIImage *image = [self imageFromView];
NSFileManager *fileManager = [NSFileManager defaultManager];
NSData *myImageData = UIImagePNGRepresentation(image);
[fileManager createFileAtPath:@"/Users/{username}/Desktop/myimage.png" contents:myImageData attributes:nil];
[imageData writeToFile:@"/testImage.jpg" atomically:YES];

有关imageFromView的方法实现如下：

The method implementation for imageFromView is the following:

- (UIImage*)imageFromView{  
UIImage *bitmapImage;
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
bitmapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return bitmapImage; 
}

所以，从我个人理解，我现在的UIView的位图图像。我如何访问的UIImage的每个像素和检查，以确认它实际上是一种颜色（即的UIColor blackColor）？

So from what I understand, I now have a bitmap image of the UIView. How do I access each pixel of the UIImage and check to verify it is in fact one color (i.e. UIColor blackColor)?

推荐答案

如果你回到<一个href=\"http://stackoverflow.com/questions/10113737/ios-looping-over-the-pixels-of-an-image/10114115#10114115%20that%20answer\">that回答，下面的（未经测试）段应该让你开始：

If you go back to that answer, the following (untested) snippet should get you started:

- (BOOL) checkForUniqueColor: (UIImage *) image {
    CGImageInspection * inspector = 
        [CGImageInspection imageInspectionWithCGImage: [image CGImage]] ;

    for (CGFloat x = 0 ; x < image.size.width ; x += 1.0f) {
        for (CGFloat y = 0 ; y < image.size.height ; y += 1.0f) {
            CGFloat red ;
            CGFloat green ;
            CGFloat blue ;
            CGFloat alpha ;

            [inspector colorAt: (CGPoint) {x, y}
                           red: &red
                         green: &green
                          blue: &blue
                         alpha: &alpha
            ] ;

            if (red == ... && green == ... && blue == ... && alpha == ...) {

            }
        }
    }
}

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