Question

我有一个问题，我似乎无法修复我的Java代码。

我创建了一个显示地图的程序，当你点击地图时，你会在地图上点缀一个边/节点。当我相互连接两个节点时，会显示一条线连接点。

到目前为止，我还是这么好，但是......当x1,y1坐标的值小于x2,y2时，它很好......

我发现这是setBounds一直在欺骗我......但我不知道如何解决我的问题，我似乎无法在任何地方找到任何类似的问题... 有没有人遇到过这种问题，如果有的话，你是怎么解决这个问题的？

import java.awt.*;
import javax.swing.*;

public class DrawMyLine extends JComponent{
    private int fx, fy, tx, ty;
    private int h,w;
    private int m;
    private double k;
    private Destinations from;
    private Destinations to;

public DrawMyLine(Destinations from, Destinations to){
    this.from=from;
    this.to=to;
    setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));

    fx = from.getX();
    fy = from.getY();
    tx = to.getX();
    ty = to.getY();


    //w = Math.abs(tx - fx);
    //h = Math.abs(ty - fy);
    w = tx - fx;
    h = ty - fy;

    int x,y;

    if(ty>fy){ //This is my, not so great solution so far...
        x = fx;
        y = fy;
    }
    else{
        x = tx;
        y = ty;
    }

    setBounds(x+5,y+5, w, h); //How do I reverse the boundary?
    setPreferredSize(new Dimension(w, h));
    setMinimumSize(new Dimension(w, h));
    setMaximumSize(new Dimension(w, h));
    }

//@Override
protected void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(Color.BLACK);
        g.drawLine(0,0,w,h);
}

//Method to reduce the clickable area to 5 pixels from the line
public boolean contains(int x, int y){

    k = ((ty-fy)/(tx-fx));
    if(k >= 0){
        m = 0;
    }
    else{
        m = ty - fy;
    }
    return Math.abs(y - k * x - m) < 5;
}//contains 

public Destinations getFrom(){
    return from;
}
public Destinations getTo(){
    return to;
}

}

在主要（连接两个节点时）：

DrawMyLine dml = new DrawMyLine(from,to);
panel.add(dml);
panel.repaint();
dml.addMouseListener(lineListener);

任何人都可以帮助我吗？请！

Answer 1

不要反转边界，反转渲染。

想一想......

enter image description here

在上面的图片中，唯一改变的是起点和终点。矩形的大小没有改变。

所有界限必须与正值一起使用。在Swing中，没有矩形具有负大小的东西。

现在我的示例使用java.awt.Point呈现，但基本概念仍然是......

// Find the smallest point between the two
int x = Math.min(p1.x, p2.x);
int y = Math.min(p1.y, p2.y);
// Size is based on the maximum value of the two points differences...
int width = Math.max(p1.x - p2.x, p2.x - p1.x);
int height = Math.max(p1.y - p2.y, p2.y - p1.y);

现在可以显示效果区域的大小。绘制线条只是在两点之间画一条线（而不是你使用的0, 0, width, height）

Answer 2

好的，我认为我理解逻辑，但是当我测试我的程序时，它似乎就像线条越界了。

import java.awt.*;
import javax.swing.*;

public class DrawMyLine extends JComponent{
    private int fx, fy, tx, ty;
    private int h,w;
    private int m;
    private double k;
    private Destinations from;
    private Destinations to;

    public DrawMyLine(Destinations from, Destinations to){
    this.from=from;
    this.to=to;
    setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));

    fx = from.getX();
    fy = from.getY();
    tx = to.getX();
    ty = to.getY();


    // Find the smallest point between the two
    x1 = Math.min(fx, tx);
    y1 = Math.min(fy, fy);
    // Size is based on the maximum value of the two points differences...
    int w = Math.max(fx - tx, tx - fx);
    int h = Math.max(fy - ty, ty - fy);

    setBounds(x1,y1, w, h);
    setPreferredSize(new Dimension(w, h));
    setMinimumSize(new Dimension(w, h));
    setMaximumSize(new Dimension(w, h));
}

//Method to reduce the clickable area to 5 pixels from the line
public boolean contains(int x, int y){

    k = ((ty-fy)/(tx-fx));
    if(k >= 0){
        m = 0;
    }
    else{
        m = ty - fy;
    }
    return Math.abs(y - k * x - m) < 5;
}//contains 

//@Override
protected void paintComponent(Graphics g){
    super.paintComponent(g);
    g.setColor(Color.BLACK);

    if(fx<tx || fy<ty){ // Something like this?
    g.drawLine(fx,fy,tx,ty);
    }
    else{
    g.drawLine(tx,ty,fx,fy);
    }
}

public Destinations getFrom(){
return from;
}
public Destinations getTo(){
return to;
}

}

有些线条显示的只是一小块......见图片......

http://imgur.com/Ue9VtEL

为什么会这样？

drawLine组件与setBounds

2 个答案: