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嘿,夥計們,我目前正在嘗試遍歷UIImage的所有像素,但我實現它的方式需要很多時間。所以我認爲這是我實施它的錯誤方式。 這是我的方法,我如何得到一個像素的RGBA值:如何遍歷UIImage的所有像素?
+(NSArray*)getRGBAsFromImage:(UIImage*)image atX:(int)xx andY:(int)yy count:(int)count
{
// Initializing the result array
NSMutableArray *result = [NSMutableArray arrayWithCapacity:count];
// First get the image into your data buffer
CGImageRef imageRef = [image CGImage]; // creating an Instance of
NSUInteger width = CGImageGetWidth(imageRef); // Get width of our Image
NSUInteger height = CGImageGetHeight(imageRef); // Get height of our Image
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // creating our colour Space
// Getting that raw Data out of an image
unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char));
NSUInteger bytesPerPixel = 4; // Bytes per pixel defined
NSUInteger bytesPerRow = bytesPerPixel * width; // Bytes per row
NSUInteger bitsPerComponent = 8; // Bytes per component
CGContextRef context = CGBitmapContextCreate(rawData, width, height,
bitsPerComponent, bytesPerRow, colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace); // releasing the color space
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
// Now your rawData contains the image data in the RGBA8888 pixel format.
int byteIndex = (bytesPerRow * yy) + xx * bytesPerPixel;
for (int ii = 0 ; ii < count ; ++ii)
{
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;
byteIndex += 4;
UIColor *acolor = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
[result addObject:acolor];
}
free(rawData);
return result;
}
這是我的代碼通過所有的像素是如何解析:
有沒有讓所有的更快的方法uiimage實例的RGBA值?