java - 用Java画线

Question

好的，所以我在编写这个程序时遇到了问题。我已经完成了第一部分，但我不知道如何完成它。我尝试了不同的解决方案和一切，但我仍然不知道。这是我到目前为止所拥有的。我需要做的是让它从四个角落开始。

public void paintComponent( Graphics g )
{
    super.paintComponent( g );
    int width = getWidth();
    int height = getHeight();
    int number, x, y, dx, dy;
    x = 0;
    y = height;
    number = 15;
    dx = width / number;
    dy = height / number;
    for ( int i = 1; i < number; i++ )
    {
        x += dx;
        y -= dy;
        g.drawLine( 0, 0, x, y );
    }
}

Answer 1

我推测您想从每个角到对角线绘制 15 条线的扇形。我建议编写一个例程将风扇从一个点绘制到任意线段，然后使用它：

drawFan(Graphics g,
        int number,     // number of fan lines
        int x0, int y0, // coordinates of the point
        int sx, int sy, // coordinates of the line segment start
        int ex, int ey) // coordinates of the line segment end
{
    int x = sx,
        y = sy,
        dx = (ex - sx) / number,
        dy = (ey - sy) / number;
    for (int i = 1; i < number; ++i) {
        x += dx;
        y += dy;
        g.drawLine(x0, y0, x, y);
    }
}

然后，您可以使用每个角和对角线的适当值来调用它。

public void paintComponent( Graphics g )
{
    super.paintComponent( g );
    int width = getWidth();
    int height = getHeight();
    drawFan(g, 15, 0, 0, 0, height, width, 0);          // top left corner
    drawFan(g, 15, 0, height, 0, 0, width, height);     // bottom left corner
    drawFan(g, 15, width, height, 0, height, width, 0); // bottom right corner
    drawFan(g, 15, width, 0, 0, 0, width, height);      // top right corner
}

Answer 2

这是解决方案，我的建议是了解坐标系在 Java 中的工作原理，然后就很容易了。

public void paintComponent( Graphics g ){
    super.paintComponent(g);
    int widthX = getWidth();
    int heightY = getHeight();

    int num, i, j;
    num = 15;
    i = 0;
    j = 15;

    while( i != 16 && j != -1 ){

        g.drawLine( 0, 0, widthX*i/num, heightY*j/num );
        g.drawLine(  widthX*i/num, heightY*j/num, widthX, heightY );
        g.drawLine(  widthX*i/num, heightY*i/num,  widthX, 0);
        g.drawLine(  widthX*j/num, heightY*j/num,  0, heightY);

        i++;
        j--;

    }//end while 
}//end method paintComponent