獲取圖像中的所有顏色

Question

我用CIColorPosterize CIFilter繪製了一張帶有圖案的圖像。該圖像包含幾個顏色。 在這一點上，我想提取一個UIColor的數組與該圖像的n顏色。 有這樣的功能嗎？否則，這可能是一個有效的方法來實現這一點？

謝謝專家！

Answer 1

你可以試試這個..

CGImageRef imageRef = [yourImage CGImage]; 
NSUInteger width = CGImageGetWidth(imageRef); 
NSUInteger height = CGImageGetHeight(imageRef); 
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char)); 

// Now your rawData contains the image data in the RGBA8888 pixel format. 
int byteIndex = (bytesPerRow * yy) + xx * bytesPerPixel; 
for (int i = 0 ; i < count ; byteIndex += 4,++i) 
{ 
    CGFloat red = (rawData[byteIndex]  * 1.0)/255.0; 
    CGFloat green = (rawData[byteIndex + 1] * 1.0)/255.0; 
    CGFloat blue = (rawData[byteIndex + 2] * 1.0)/255.0; 
    CGFloat alpha = (rawData[byteIndex + 3] * 1.0)/255.0;  
    UIColor *acolor = [UIColor colorWithRed:red green:green blue:blue alpha:alpha]; 
    [result addObject:acolor]; 
} 

free(rawData); 
NSLog(@"Extracted colors count %d",result.count);