java - 我正在尝试对处理中的图像进行马赛克效果，但图像保持不变？

Question

我对处理很陌生。

我正在尝试创建一个对普通图像应用马赛克效果的程序。我想要实现的是让图像创建过滤器大小的 block (例如 30 像素)并将其替换为该 block 的 r、g、b 和颜色的平均值

这是我到目前为止所做的:

class ME {

  PImage image;

  ME(String imagename) {
    this.image = loadImage(imagename);
  }


  void display(int length, int height ) {
    image.resize(length, height);
    image(this.image, 0, 0);
  }


  void effect(int filterationSize) {
  print("smth");
    image.loadPixels(); 
    float r, g, b;

    for (int v = 0; v < (width*height ); v += filterationSize*width) 
    {
      for (int h = 0; h < width; h+=filterationSize)
      {
        r = g = b = 0;

        for (int bH = 0; bH<filterationSize; bH++)
        {
           for (int bV = 0; bV<filterationSize; bV++)
        {

        int p = v+h+bH+bV*width;

        if ( p < width*width)
          {


            r += (red(this.image.pixels[p]) / (filterationSize*filterationSize));
            g += (green(this.image.pixels[p]) / (filterationSize*filterationSize));
            b += (blue(this.image.pixels[p]) / (filterationSize*filterationSize));
          }


        }


        }



         for (int blockH = 0; blockH<filterationSize; blockH++)
      {
        for (int blockV = 0; blockV<filterationSize; blockV++)
        {
          int p = v+h+blockH+blockV*width;

          if ( p < width*width)
          {

            this.image.pixels[p] = color(r, g, b);
          }
        }
      }
      }
    }

    this.image.updatePixels();

  }
}

这是我的主课:

ME img ;

void setup(){
  size(500 ,500);
  img = new ME("image.png");
  img.display(width , height);

}



void draw(){

   img.effect(30);

}

但最终图像与开始时的图像相同。

Answer 1

在对图像应用效果后，您错过了显示图像的机会:

void draw(){
    img.effect(30);
    img.display(width , height);
}

但您可能想在图像加载后应用一次效果:

    ME img;

void setup(){
   size(500 ,500);
   img = new ME("image.png");
   img.display(width , height);
   img.effect(30);
}

void draw(){
    img.effect(30);
    img.display(width, height);
}

您还可以改进effect 算法。

计算瓦片数量，但注意行或列中的最后一个瓦片可能会被剪掉:

int tiles_x = width / filterationSize;
if ( width % filterationSize > 0 ) 
    tiles_x += 1;

int tiles_y = height / filterationSize;
if ( height % filterationSize > 0 ) 
    tiles_y += 1;

计算开始结束坐标和循环内方 block 的“大小”:

int start_x = tile_x*filterationSize;
int start_y = tile_y*filterationSize;
int end_x   = min(start_x+filterationSize, width); 
int end_y   = min(start_y+filterationSize, height);
int size    = (end_x-start_x) * (end_y-start_y); 

现在很容易计算一个图 block 的像素平均值。完整的算法可能如下所示:

void effect(int filterationSize) {
    image.loadPixels(); 

    int tiles_x = width / filterationSize;
    if ( width % filterationSize > 0 ) 
        tiles_x += 1;
    int tiles_y = height / filterationSize;
    if ( height % filterationSize > 0 ) 
        tiles_y += 1;

    print( tiles_x, tiles_y );
    for ( int tile_y = 0; tile_y < tiles_x; tile_y ++ ) {
        for ( int tile_x = 0; tile_x < tiles_y; tile_x ++ ) {

            int start_x = tile_x*filterationSize;
            int start_y = tile_y*filterationSize;
            int end_x   = min(start_x+filterationSize, width); 
            int end_y   = min(start_y+filterationSize, height);
            int size    = (end_x-start_x) * (end_y-start_y);

            float r = 0, g = 0, b = 0;
            for (int by = start_y; by < end_y; by++ ) {
                for (int bx = start_x; bx < end_x; bx++ ) {
                    int p = by * width + bx;
                    r += red(this.image.pixels[p])   / size;
                    g += green(this.image.pixels[p]) / size;
                    b += blue(this.image.pixels[p])  / size;
                }
            }

            for (int by = start_y; by < end_y; by++ ) {
                for (int bx = start_x; bx < end_x; bx++ ) {
                    int p = by * width + bx;
                    this.image.pixels[p] = color(r, g, b);
                }
            }
        }
    }
    this.image.updatePixels();
}

查看应用于 256*256 图像和 32 block 长度的效果: