尝试两种不同的方法来转换图片 - JavaFX

Question

所以我还在学习 Java。现在正在学习JavaFX。

我有一张树的照片。我想尝试两种不同的方法。我使用的第一种方法是使用一元运算符将图像颜色变为灰色。

现在我想尝试第二种方法，使用我制作的ColourTransformer 接口，以获得一个 10 像素宽的灰色框来替换图像边框上的像素。

这就是我所做的。对于第二种方法，我不太确定如何指定像素。有什么建议吗？

这就是我所做的

public class ColourFilter extends Application {

   //Using Unary Operator to transform image to grayscale - Method 1
   public static Image transform(Image in, UnaryOperator<Color> f) {
      int width = (int) in.getWidth();
      int height = (int) in.getHeight();
      WritableImage out = new WritableImage(
              width, height);
      for (int x = 0; x < width; x++)
         for (int y = 0; y < height; y++)
            out.getPixelWriter().setColor(x, y,
                    f.apply(in.getPixelReader().getColor(x, y)));
      return out;
   }
   public static <T> UnaryOperator<T> compose(UnaryOperator<T> op1, UnaryOperator<T> op2) {
      return t -> op2.apply(op1.apply(t));
   }

   //Using ColourTransformer interface to get 10 pixel wide gray frame replacing the pixels on the border of an image - Method 2
   public static Image transform(Image in, ColourTransformer f) {
      int width = (int) in.getWidth();
      int height = (int) in.getHeight();
      WritableImage out = new WritableImage(
              width, height);
      for (int x = 0; x < width; x++)
         for (int y = 0; y < height; y++)
            out.getPixelWriter().setColor(x, y, f.apply(x, y, in.getPixelReader().getColor(x, y)));
      return out;
   }
   @FunctionalInterface
   interface ColourTransformer {
      Color apply(int x, int y, Color colorAtXY);
   }

   public void start(Stage stage) {
      Image image = new Image("amazing-trees.jpg");
      Image image2 = transform(image, Color::brighter);
      Image image3 = transform(image2, Color::grayscale);
      // alternative to two previous image transforms -- composition
      //Image image3 = transform(image, compose(Color::brighter, Color::grayscale));
      stage.setScene(new Scene(new VBox(
              new ImageView(image),
              // new ImageView(image2),
              new ImageView(image3))));
      stage.show();
   }
}

Answer 1

正如编译错误消息所说，您正在尝试调用

f.apply(Color);

其中f 是ColourTransformer：但是您在ColorTransformer 中使用三个参数定义了apply 方法：apply(int, int, Color)。

你需要更换

f.apply(in.getPixelReader().getColor(x, y))

与

f.apply(x, y, in.getPixelReader().getColor(x, y))

即

public static Image transform(Image in, ColourTransformer f) {
    int width = (int) in.getWidth();
    int height = (int) in.getHeight();
    WritableImage out = new WritableImage(
          width, height);
    for (int x = 0; x < width; x++)
        for (int y = 0; y < height; y++)
            out.getPixelWriter().setColor(x, y, f.apply(x, y, in.getPixelReader().getColor(x, y)));
    return out;

}

您可以通过以下方式获得 10 像素的灰色边框：

Image image = new Image("amazing-trees.jpg");
int width = (int) image.getWidth();
int height = (int) image.getHeight();
Image framedImage = transform(image, (x, y, color) -> {
    if (x < 10 || y < 10 || width - x < 10 || height - y < 10) {
        return Color.GRAY ;
    } else return color ;
});