[代码分享]UIImage：获取图片主色调

-(UIColor*)mostColor{


#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(50, 50);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate( NULL ,
                                                 thumbSize.width,
                                                 thumbSize.height,
                                                 8, //bits per component
                                                 thumbSize.width*4,
                                                 colorSpace,
                                                 bitmapInfo);

    CGRect drawRect = CGRectMake(0, 0, thumbSize.width, thumbSize.height);
    CGContextDrawImage(context, drawRect, self .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.width*thumbSize.height];

    for ( int x=0; x

        for ( int y=0; y

            int offset = 4*(x*y);

            int red = data[offset];
            int green = data[offset+1];
            int blue = data[offset+2];
            int alpha =  data[offset+3];

            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)];
}