三角形三个顶点的颜色分别为红绿蓝，使用有效边表算法填充三角形Java

以下是使用有效边表算法填充三角形的Java代码示例：

import java.awt.Color;
import java.awt.Graphics;
import java.util.Arrays;

public class TriangleFill {
  
  public static void main(String[] args) {
    int[] xPoints = {100, 200, 150};
    int[] yPoints = {100, 100, 200};
    Color[] colors = {Color.RED, Color.GREEN, Color.BLUE};
    fillTriangle(xPoints, yPoints, colors);
  }
  
  public static void fillTriangle(int[] xPoints, int[] yPoints, Color[] colors) {
    if (xPoints.length != 3 || yPoints.length != 3 || colors.length != 3) {
      throw new IllegalArgumentException("Invalid triangle parameters");
    }
    int[] sortedY = Arrays.copyOf(yPoints, 3);
    Arrays.sort(sortedY);
    int yMin = sortedY[0];
    int yMax = sortedY[2];
    int[] xMin = new int[3];
    int[] xMax = new int[3];
    Color[] colorMin = new Color[3];
    Color[] colorMax = new Color[3];
    for (int i = 0; i < 3; i++) {
      if (yPoints[i] == yMin) {
        xMin[i] = xPoints[i];
        colorMin[i] = colors[i];
      } else if (yPoints[i] == yMax) {
        xMax[i] = xPoints[i];
        colorMax[i] = colors[i];
      }
    }
    for (int i = 0; i < 3; i++) {
      if (yPoints[i] != yMin && yPoints[i] != yMax) {
        int j = (i + 1) % 3;
        int k = 3 - i - j;
        xMin[k] = xPoints[i] + (yMin - yPoints[i]) * (xPoints[j] - xPoints[i]) / (yPoints[j] - yPoints[i]);
        colorMin[k] = interpolateColor(colors[i], colors[j], (yMin - yPoints[i]) / (float) (yPoints[j] - yPoints[i]));
        xMax[k] = xPoints[i] + (yMax - yPoints[i]) * (xPoints[j] - xPoints[i]) / (yPoints[j] - yPoints[i]);
        colorMax[k] = interpolateColor(colors[i], colors[j], (yMax - yPoints[i]) / (float) (yPoints[j] - yPoints[i]));
      }
    }
    int[] activeX = new int[3];
    Color[] activeColor = new Color[3];
    for (int y = yMin; y <= yMax; y++) {
      int activeCount = 0;
      for (int i = 0; i < 3; i++) {
        if (y >= yMin && y <= yMax) {
          if (y == yMin) {
            if (xMin[i] < xMax[i]) {
              activeX[activeCount] = xMin[i];
              activeColor[activeCount] = colorMin[i];
              activeCount++;
              activeX[activeCount] = xMax[i];
              activeColor[activeCount] = colorMax[i];
              activeCount++;
            } else if (xMin[i] > xMax[i]) {
              activeX[activeCount] = xMax[i];
              activeColor[activeCount] = colorMax[i];
              activeCount++;
              activeX[activeCount] = xMin[i];
              activeColor[activeCount] = colorMin[i];
              activeCount++;
            }
          } else {
            if (y >= yPoints[i] && y <= yPoints[(i + 1) % 3]) {
              int x = xPoints[i] + (y - yPoints[i]) * (xPoints[(i + 1) % 3] - xPoints[i]) / (yPoints[(i + 1) % 3] - yPoints[i]);
              Color color = interpolateColor(colors[i], colors[(i + 1) % 3], (y - yPoints[i]) / (float) (yPoints[(i + 1) % 3] - yPoints[i]));
              activeX[activeCount] = x;
              activeColor[activeCount] = color;
              activeCount++;
            }
          }
        }
      }
      Arrays.sort(activeX, 0, activeCount);
      for (int i = 0; i < activeCount; i += 2) {
        int x1 = activeX[i];
        int x2 = activeX[i + 1];
        Color color1 = activeColor[i];
        Color color2 = activeColor[i + 1];
        for (int x = x1; x <= x2; x++) {
          float t = (x - x1) / (float) (x2 - x1);
          Color color = interpolateColor(color1, color2, t);
          plotPixel(x, y, color);
        }
      }
      for (int i = 0; i < activeCount; i++) {
        activeX[i] += (int) (1 / (yMax - yMin + 1f) * (xMax[i] - xMin[i]));
      }
    }
  }
  
  public static Color interpolateColor(Color color1, Color color2, float t) {
    int r = (int) (color1.getRed() + (color2.getRed() - color1.getRed()) * t);
    int g = (int) (color1.getGreen() + (color2.getGreen() - color1.getGreen()) * t);
    int b = (int) (color1.getBlue() + (color2.getBlue() - color1.getBlue()) * t);
    return new Color(r, g, b);
  }
  
  public static void plotPixel(int x, int y, Color color) {
    Graphics g = getGraphics(); // 获取图形对象
    g.setColor(color);
    g.drawLine(x, y, x, y);
  }
  
  public static Graphics getGraphics() {
    // 返回画布对象
  }
  
}

其中，`fillTriangle` 方法接受三个数组作为参数：`xPoints` 是三角形三个顶点的 x 坐标，`yPoints` 是三角形三个顶点的 y 坐标，`colors` 是三个顶点的颜色。该方法使用有效边表算法填充三角形，实现了颜色渐变。

`interpolateColor` 方法接受两个颜色和一个比例值 t，返回两个颜色的 t 比例混合色。

`plotPixel` 方法在画布上绘制一个像素点，使用 `getGraphics` 方法获取画布对象。

这里的 `getGraphics` 方法需要根据具体情况进行实现，例如在 Swing 界面中可以使用 `getGraphics` 方法获取 `JPanel` 对象的图形对象。