-(UIColor*)mostColor

{

#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_6_1

intbitmapInfo = kCGBitmapByteOrderDefault | kCGImageAlphaPremultipliedLast;

#else

intbitmapInfo = kCGImageAlphaPremultipliedLast;

#endif

//第一步 先把圖片縮小 加快計算速度. 但越小結果誤差可能越大

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 取每個點的像素值

unsignedchar* data = CGBitmapContextGetData (context);

if(data ==NULL)returnnil;

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

for(intx=0; x

for(inty=0; 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 找到出現次數最多的那個顏色

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)];

}