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PODetect black pixel in image iOS
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copied!<p>As of now I am searching every pixel 1 by 1 checking the color and seeing if it's black... if it isn't I move on to the next pixel. This is taking forever as I can only check approx. 100 pixels per second (speeding up my NSTimer freezes the app because it can't check fast enough.) So is there anyway I can just have Xcode return all the pixels that are black and ignore everything else so I only have to check those pixels and not every pixel. I am trying to detect a black pixel furthest to the left on my image. </p> <p>Here is my current code.</p> <pre><code>- (void)viewDidLoad { timer = [NSTimer scheduledTimerWithTimeInterval: 0.01 target: self selector:@selector(onTick:) userInfo: nil repeats:YES]; y1 = 0; x1 = 0; initialImage = 0; height1 = 0; width1 = 0; } -(void)onTick:(NSTimer *)timer { if (initialImage != 1) { /* IMAGE INITIALLY GETS SET HERE... "image2.image = [blah blah blah];" took this out for non disclosure reasons */ initialImage = 1; } //image2 is the image I'm checking the pixels of. width1 = (int)image2.size.width; height1 = (int)image2.size.height; CFDataRef imageData = CGDataProviderCopyData(CGImageGetDataProvider(image2.CGImage)); const UInt32 *pixels = (const UInt32*)CFDataGetBytePtr(imageData); if ( (pixels[(x1+(y1*width1))]) == 0x000000) { //0x000000 is black right? NSLog(@"black!"); NSLog(@"x = %i", x1); NSLog(@"y = %i", y1); }else { NSLog(@"val: %lu", (pixels[(x1+(y1*width1))])); NSLog(@"x = %i", x1); NSLog(@"y = %i", y1); x1 ++; if (x1 >= width1) { y1 ++; x1 = 0; } } if (y1 > height1) { /* MY UPDATE IMAGE CODE GOES HERE (IMAGE CHANGES EVERY TIME ALL PIXELS HAVE BEEN CHECKED */ y1 = 0; x1 = 0; } </code></pre> <p>Also what if a pixel is really close to black but not perfectly black... Can I add a margin of error in there somewhere so it will still detect pixels that are like 95% black? Thanks!</p>

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