Question

我需要创建一个我的类SimpleRGB的新实例，它是为了将图片的像素更改为一种颜色而创建的。我知道我没有正确创建实例，但无法弄清楚如何做到这一点。

/**
 * Get the NEW image containing only the red color. The red values of this
 * new image should be exactly the same as red value of this image. The
 * green and blue values of this new image should be 0s.
 *
 * @return the NEW image (SimpleRGB) containing only the red color of this
 * image.
 */
public SimpleRGB getRedImage() {
   SimpleRGB redImage = new SimpleRGB(aRed);
   return redImage;
}

这是完整的课程

public class SimpleRGB {

private int aWidth;
private int aHeight;
private int[][] aRed;
private int[][] aBlue;
private int[][] aGreen;


public SimpleRGB(int aWidth, int aHeight) {
    aRed = new int[aWidth][aHeight];
    aBlue = new int[aWidth][aHeight];
    aGreen = new int[aWidth][aHeight];
}

/**
 * Gets the width of this image.
 *
 * @return the width of this image.
 */
public int getWidth() {
    return aWidth;
}

/**
 * Gets the height of this image.
 *
 * @return the height of this image.
 */
public int getHeight() {
    return aHeight;
}

/**
 * Sets the red value at coordinate (x,y) to aRed.
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @param aRed the red value (0 - 255)
 */
public void setRed(int x, int y, int aRed) {
    this.aRed[x][y] = aRed;
}

/**
 * Sets the green value at coordinate (x,y) to aGreen.
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @param aGreen the green value (0 - 255)
 */
public void setGreen(int x, int y, int aGreen) {
    this.aGreen[x][y] = aGreen;
}

/**
 * Sets the blue value at coordinate (x,y) to aBlue.
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @param aBlue the blue value (0 - 255)
 */
public void setBlue(int x, int y, int aBlue) {
    this.aBlue[x][y] = aBlue;
}

/**
 * Gets the red value at coordinate (x,y).
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @return the value of red at coordinate (x,y).
 */
public int getRed(int x, int y) {
    return aRed[x][y];
}

/**
 * Gets the green value at coordinate (x,y).
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @return the value of green at coordinate (x,y).
 */
public int getGreen(int x, int y) {
    return aGreen[x][y];
}

/**
 * Gets the blue value at coordinate (x,y).
 *
 * @param x the x coordinate of this image.
 * @param y the y coordinate of this image.
 * @return the value of blue at coordinate (x,y).
 */
public int getBlue(int x, int y) {
    return aBlue[x][y];

}

/**
 * Get the NEW image containing only the red color. The red values of this
 * new image should be exactly the same as red value of this image. The
 * green and blue values of this new image should be 0s.
 *
 * @return the NEW image (SimpleRGB) containing only the red color of this
 * image.
 */
public SimpleRGB getRedImage() {
   SimpleRGB redImage = new SimpleRGB(aWidth,aHeight);
   return redImage;

}

/**
 * Get the NEW image containing only the green color. The green values of
 * this new image should be exactly the same as green value of this image.
 * The red and blue values of this new image should be 0s.
 *
 * @return the NEW image (SimpleRGB) containing only the green color of this
 * image.
 */
public SimpleRGB getGreenImage() {
    SimpleRGB greenImage = new SimpleRGB(aWidth,aHeight);
    return greenImage;

}

/**
 * Get the NEW image containing only the blue color. The blue values of this
 * new image should be exactly the same as blue value of this image. The red
 * and green values of this new image should be 0s.
 *
 * @return the NEW image (SimpleRGB) containing only the blue color of this
 * image.
 */
public SimpleRGB getBlueImage() {
    SimpleRGB blueImage = new SimpleRGB(aWidth,aHeight);
    return blueImage;

}

/**
 * Get the NEW image representing the greyscale of this image. The grey
 * colors are colors that the red, green and blue value are exactly the
 * same. To convert an RGB image into a greyscale image, use the following
 * formula to calculate the new value. (0.21 * red) + (0.72 * green) + (0.07
 * * blue) For example, suppose the (R,G,B) value of this image at
 * coordinate (10,20) are (10,100,200), since (0.21 * 10) + (0.72 * 100) +
 * (0.07 * 200) = 88 the (R,G,B) value of the new greyscale image at (10,20)
 * should be (88,88,88).
 *
 * @return the NEW image representing the greyscale of this image.
 */
public SimpleRGB getGreyImage() {
    SimpleRGB greyImage = new SimpleRGB(aWidth,aHeight);
    return greyImage;

}

}

Answer 1

我愿意：

public SimpleRGB getRedImage() {
    SimpleRGB result = new SimpleRGB(aWidth,aHeight);
    for (int x = 0; x < aWidth; x++) {
        for (int y = 0; y < aHeight; y++) {
            result.setRed(x, y, this.getRed(x, y));
        }
    }
    return result;
}

这将创建一个新的SimpleRGB图像，其所有颜色值都设置为0（默认情况下，int数组中的所有值都初始化为0）。然后它设置这个新的SimpleRGB的红色值，以匹配当前RGB中每个点的当前RGB红色值。

Answer 2

public SimpleRGB getRedImage() {
    SimpleRGB redImage = new SimpleRGB(aWidth, aHeight);
    for (int x = 0; x < aWidth; ++x) {
        System.arraycopy(aRed[x], 0, redImage.aRed[x], 0, aHeight);
    }
    return redImage;
}

这会立即直接使用私有字段，而低级方法System.arraycopy可以快速复制。

想要创建我的班级的新实例

2 个答案: