根据图片获取图片的主色调

- (UIColor)mostColor:(UIImage)image{
if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1
int bitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;
else
int bitmapInfo = kCGImageAlphaPremultipliedLast;
endif
//第一步 先把图片缩小 加快计算速度. 但越小结果误差可能越大
CGSize thumbSize=CGSizeMake(image.size.width/20, image.size.height/20);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL,
thumbSize.width,
thumbSize.height,
8,//bits per component
thumbSize.width4,
colorSpace,
bitmapInfo);
CGRect drawRect = CGRectMake(0, 0, thumbSize.width, thumbSize.height);
CGContextDrawImage(context, drawRect, image.CGImage);
CGColorSpaceRelease(colorSpace);
//第二步 取每个点的像素值
unsigned char data = CGBitmapContextGetData (context);
if (data == NULL) return nil;
NSCountedSet cls=[NSCountedSet setWithCapacity:thumbSize.widththumbSize.height];
for (int x=0; x<thumbSize.width; x++) {
for (int y=0; y<thumbSize.height; y++) {
int offset = 4(xy);
int red = data[offset];
int green = data[offset+1];
int blue = data[offset+2];
int alpha = data[offset+3];
if (alpha>0) {//去除透明
if (red==255&&green==255&&blue==255) {//去除白色
}else{
NSArray *clr=@[@(red),@(green),@(blue),@(alpha)];
[cls addObject:clr];
}
}
}
}
CGContextRelease(context);
//第三步 找到出现次数最多的那个颜色
NSEnumerator *enumerator = [cls objectEnumerator];
NSArray *curColor = nil;
NSArray *MaxColor=nil;
NSUInteger MaxCount=0;
while ( (curColor = [enumerator nextObject]) != nil )
{
NSUInteger tmpCount = [cls countForObject:curColor];
if ( tmpCount < MaxCount ) continue;
MaxCount=tmpCount;
MaxColor=curColor;
}
return [UIColor colorWithRed:([MaxColor[0] intValue]/255.0f) green:([MaxColor[1] intValue]/255.0f) blue:([MaxColor[2] intValue]/255.0f) alpha:([MaxColor[3] intValue]/255.0f)];
}