[英]How to change the result to print the RGB pixel value in Objective C
I have this code and I want it to return the RGB colour value of each pixel, not the brightness. 我有这段代码,我希望它返回每个像素的RGB颜色值,而不是亮度。 At the moment it prints the brightness of every pixel onto the command line and I want that to change this to print the RGB value of each pixel instead.
目前,它将每个像素的亮度打印到命令行上,我希望更改它以打印每个像素的RGB值。 Im fairly new to Objective-C so some help and explanation would be greatly appreciated :).
我对Objective-C还是很陌生,所以将非常感谢您的帮助和解释:)。
An example of what I have so far. 到目前为止,我所拥有的一个例子。 This image shows the brightness of each pixel
此图像显示每个像素的亮度
// 1. Get pixels of image
CGImageRef inputCGImage = [image CGImage];
NSUInteger width = CGImageGetWidth(inputCGImage);
NSUInteger height = CGImageGetHeight(inputCGImage);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
UInt32 * pixels;
pixels = (UInt32 *) calloc(height * width, sizeof(UInt32));
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(pixels, width, height,
bitsPerComponent, bytesPerRow, colorSpace,
kCGImageAlphaPremultipliedLast|kCGBitmapByteOrder32Big);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), inputCGImage);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);
#define Mask8(x) ( (x) & 0xFF )
#define R(x) ( Mask8(x) )
#define G(x) ( Mask8(x >> 8 ) )
#define B(x) ( Mask8(x >> 16) )
// 2. Iterate and log!
NSLog(@"Brightness of image:");
UInt32 * currentPixel = pixels;
for (NSUInteger j = 0; j < height; j++) {
for (NSUInteger i = 0; i < width; i++) {
UInt32 color = *currentPixel;
printf("%3.0f ", (R(color)+G(color)+B(color))/3.0);
currentPixel++;
}
printf("\n");
}
free(pixels);
Just change this line: 只需更改此行:
printf("%3.0f ", (R(color)+G(color)+B(color))/3.0);
to 至
printf("(r=%3.0f, g=%3.0f, b=%3.0f) ", R(color), G(color), B(color));
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