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Get pixel color from UIImage in Swift
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| func getColorForPixel(image:CGImageRef, point:CGPoint) -> UIColor { | |
| let imageWidth = CGImageGetWidth(image) | |
| let imageHeight = CGImageGetHeight(image) | |
| let imageRect = CGRect(x: 0, y: 0, width: imageWidth, height: imageHeight) | |
| let bitmapBytesForRow = Int(imageWidth * 4) | |
| let bitmapByteCount = bitmapBytesForRow * Int(imageHeight) | |
| let colorSpace = CGColorSpaceCreateDeviceRGB() | |
| let bitmapMemory = malloc(bitmapByteCount) | |
| let bitmapInformation = CGImageAlphaInfo.PremultipliedFirst.rawValue | |
| let colorContext = CGBitmapContextCreate(bitmapMemory, imageWidth, imageHeight, 8, bitmapBytesForRow, colorSpace, bitmapInformation) | |
| CGContextClearRect(colorContext, imageRect) | |
| CGContextDrawImage(colorContext, imageRect, image) | |
| let data = CGBitmapContextGetData(colorContext) | |
| let dataType = UnsafePointer<UInt8>(data) | |
| let offset = 4 * (Int(imageWidth) * Int(point.y)) + Int(point.x) | |
| let redComponent = CGFloat(dataType[offset + 1])/255.0 | |
| let greenComponent = CGFloat(dataType[offset + 2])/255.0 | |
| let blueComponent = CGFloat(dataType[offset + 3])/255.0 | |
| return UIColor(red: redComponent, green: greenComponent, blue: blueComponent, alpha: 1.0) | |
| } |
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you forgot to call
free(bitmapMemory)