用另一种颜色替换图像内的特定颜色 [英] Replace a particular color inside an image with another color

问题描述

我有一个房间图像。

现在，用户将点击图像中任何特定颜色的蓝色。

Now, user will click on any particular color suppose blue color in image.

并且用户也会选择替换的颜色，如黑色。

And also user will select replaced color like "black" color.

因此，图像中的所有蓝色颜色将被替换为黑色 颜色。

So, all "blue" color inside the image will be replaced by "black" color.

任何人都知道如何在iPhone中实现这一目标？

Any one have idea for how to achieve this in iPhone?

帮助表示赞赏。

推荐答案

1. 您必须遍历图像中的每个像素并获取其rgb
   值


2. 检查其rgb值是否与fromColor rgb值匹配，如果是，则
   将像素值更改为toColor rgb值。如果不是，只需将
   保留为像素和转到下一个.. ..

从记忆中写出一个函数......可能的错误......自己纠正

Wrote a function from memory..errors possible..correct yourself

-(UIImage*)changeColor:(UIImage*)myImage fromColor:(UIColor*)fromColor toColor:(UIColor*)toColor{
    CGImageRef originalImage    = [myImage CGImage];
    CGColorSpaceRef colorSpace  = CGColorSpaceCreateDeviceRGB();
    CGContextRef bitmapContext  = 
CGBitmapContextCreate(NULL,CGImageGetWidth(originalImage),CGImageGetHeight(originalImage),
 8,CGImageGetWidth(originalImage)*4,colorSpace,kCGImageAlphaPremultipliedLast);
    CGColorSpaceRelease(colorSpace);
    CGContextDrawImage(bitmapContext, CGRectMake(0, 0, 
CGBitmapContextGetWidth(bitmapContext),CGBitmapContextGetHeight(bitmapContext)), 
originalImage);
    UInt8 *data          = CGBitmapContextGetData(bitmapContext);
    int numComponents    = 4;
    int bytesInContext   = CGBitmapContextGetHeight(bitmapContext) *      
    CGBitmapContextGetBytesPerRow(bitmapContext);
    double redIn, greenIn, blueIn,alphaIn;
    CGFloat fromRed,fromGreen,fromBlue,fromAlpha;
    CGFloat toRed,toGreen,toBlue,toAlpha; 

    //Get RGB values of fromColor
    int fromCountComponents = CGColorGetNumberOfComponents([fromColor CGColor]);
    if (fromCountComponents == 4) {
     const CGFloat *_components = CGColorGetComponents([fromColor CGColor]);
     fromRed = _components[0];
     fromGreen = _components[1];
     fromBlue = _components[2];
     fromAlpha = _components[3];
    }


    //Get RGB values for toColor
    int toCountComponents = CGColorGetNumberOfComponents([toColor CGColor]);
    if (toCountComponents == 4) {
      const CGFloat *_components = CGColorGetComponents([toColor CGColor]);
      toRed   = _components[0];
      toGreen = _components[1];
      toBlue  = _components[2];
      toAlpha = _components[3];
    }


    //Now iterate through each pixel in the image..
    for (int i = 0; i < bytesInContext; i += numComponents) {
        //rgba value of current pixel..
        redIn    =   (double)data[i]/255.0;
        greenIn  =   (double)data[i+1]/255.0;
        blueIn   =   (double)data[i+2]/255.0;
        alphaIn  =   (double)data[i+3]/255.0;

        //now you got current pixel rgb values...check it curresponds with your fromColor
        if( redIn == fromRed && greenIn == fromGreen && blueIn == fromBlue ){
            //image color matches fromColor, then change current pixel color to toColor
            data[i]    =   toRed;
            data[i+1]  =   toGreen;
            data[i+2]  =   toBlue;
            data[i+3]  = toAlpha;       
        }
    }
    CGImageRef outImage =   CGBitmapContextCreateImage(bitmapContext);
    myImage             =   [UIImage imageWithCGImage:outImage];
    CGImageRelease(outImage);
    return myImage;
}

我希望你不是每次都调用这个函数...这是一个位处理器很重......如果我是你的处理器，我会对你不满意.. :)

I hope you are not calling this function every time...It is a bit processor heavy..And if I was your processor, I wouldn't be happy with you..:)

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