[代码分享]UIImage：获取图片主色调

-(UIColor*)mostColor{

     

     

#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1

    intbitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;

#else

    intbitmapInfo = 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

    unsignedchar* data = CGBitmapContextGetData (context);

     

    if(data == NULL)returnnil;

     

    NSCountedSet*cls=[NSCountedSetsetWithCapacity:thumbSize.width*thumbSize.height];

 

    for(intx=0; x<thumbSize.width; x++) {

        for(inty=0; y<thumbSize.height; y++) {

             

            intoffset = 4*(x*y);

             

            intred = data[offset];

            intgreen = data[offset+1];

            intblue = data[offset+2];

            intalpha =  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;

    NSUIntegerMaxCount=0;

     

    while ( (curColor = [enumerator nextObject]) != nil)

    {

        NSUIntegertmpCount = [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)];

}