Question

我正在制作一个草图，其中包含以下内容：

调整大图片的大小以使其适合800 x 600屏幕。

显示图片

按下键时应用某些效果

在屏幕上显示图像并打印一条Done消息

一切正常，期望它不能正确显示图像。

这是黑白效果：

void blackAndWhite() {
  loadPixels();
  for (int i = 0;i < img.pixels.length;i++) {
    int pixel = img.pixels[i];

    // println("Working on pixel " + i + " out of " + img.pixels.length); 

    int red = (int) red(pixel);
    int green = (int) green(pixel);
    int blue = (int) blue(pixel);

    /*
     * Luminosity Method.
     */
    //      red = (int) (red * 0.21);
    //      green = (int) (green * 0.71);
    //      blue = (int) (blue * 0.07);

    /*
     * Average Method
     */
    //  float avg = (int) (red + green + blue / 3);
    //  red = green = blue = (int) avg;

    /*
     * Lightness Method
     */
    int mostProminent = max(red, green, blue);
    int leastProminent = min(red, green, blue);
    int avg = (int) ((mostProminent + leastProminent) / 2);
    red = green = blue = avg;

    pixel = color(red, green, blue);
    img.pixels[i] = pixel;
  }
  println("Done");
  updatePixels();
  image(img, WIDTH/2, HEIGHT/2, calculatedWidth, calculatedHeight);
}

但是，只显示彩色图像:(
我知道算法有效，因为我在其他图像上尝试过（不使用此草图） 出了什么问题？

Answer 1

以下代码可以正常使用：

PImage img;

void setup () {
  img = loadImage ("img.png");
  size(img.width, img.height);
}

void draw () {
  image(img, 0, 0);
}

void keyReleased () {
  blackAndWhite();
}

void blackAndWhite() {

  img.loadPixels();
  for (int i = 0;i < img.pixels.length;i++) {
    int pixel = img.pixels[i];

    // println("Working on pixel " + i + " out of " + img.pixels.length); 

    int red = (int) red(pixel);
    int green = (int) green(pixel);
    int blue = (int) blue(pixel);

    /*
     * Luminosity Method.
     */
    //      red = (int) (red * 0.21);
    //      green = (int) (green * 0.71);
    //      blue = (int) (blue * 0.07);

    /*
     * Average Method
     */
    //  float avg = (int) (red + green + blue / 3);
    //  red = green = blue = (int) avg;

    /*
     * Lightness Method
     */
    int mostProminent = max(red, green, blue);
    int leastProminent = min(red, green, blue);
    int avg = (int) ((mostProminent + leastProminent) / 2);
    red = green = blue = avg;

    pixel = color(red, green, blue);
    img.pixels[i] = pixel;
  }
  println("Done");
  img.updatePixels();
}

我的猜测是你忘了写 img .loadPixels（）而不是loadPixels（），或者草图的 draw（）方法出错了。< / p>

处理草图不会在屏幕上显示修改后的图像

1 个答案: