Java开发网 - 在SWT下怎么重绘2D图形

Topic: 在SWT下怎么重绘2D图形

1.在SWT下怎么重绘2D图形	Copy to clipboard
Posted by: huwd Posted on: 2004-12-02 22:58 我的例子很简单，用SWT创建一个GUI，有一个按钮，只要按一下，就在SHELL上画一条线段，这些我都做好了但窗口一最小化，线段就消失了，我知道以前在SWING里面，重写paint方法就可以了，但这里SWT下，应该怎么弄，请说的详细点吧，谢谢了，急用！！！

2.Re:在SWT下怎么重绘2D图形 [Re: huwd]

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Posted by: lxh_ming
Posted on: 2004-12-03 00:22

给你一段重新继承Label 的代码，就在
    addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        if ( MyLabel.this.isSelected )
          drawFocusComponent Envelope

;
      }
    });
这一段里实现
package com.gui.application.Component.control;

import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;

import com.gui.application.Component.base.IStyle;

public class MyLabel extends Label {

  private static final int startX = 5;
  private static final int startY = 5;
  private static final int endX = 24;
  private static final int endY = 24;

  private boolean isSelected;

  private static MyLabel selected;

  private void drawFocusComponent(PaintEvent e) {
    final GC gc = e.gc;
    gc.drawFocus(startX, startY, endX, endY);
  }

  public MyLabel(final Composite comp, int arg1) {
    super(comp, arg1);
    addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        if ( MyLabel.this.isSelected )
          drawFocusComponent Envelope

;
      }
    });
    addMouseListener(new MouseAdapter() {
      public void mouseDown(MouseEvent e) {
if ( selected == MyLabel.this )
return;
        MyLabel.this.isSelected = true;
        if ( null != selected ) {
          selected.isSelected = false;
selected.redraw();
}
        selected = MyLabel.this;
MyLabel.this.redraw();
if ( comp instanceof IStyle ) {
if ( null != MyLabel.this.getData() )
( ( IStyle )comp ).paintObjectChanged( ( Class )MyLabel.this.getData() );
}
      }
    });
  }

  public void dispose() {
    super.dispose();
  }

  protected void checkSubclass() {
  }
}

3.Re:在SWT下怎么重绘2D图形 [Re: huwd]

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Posted by: huwd
Posted on: 2004-12-03 09:03

还是搞不太懂，而且我这里没有IStyle类
我的代码如下，最好能直接在我代码上改
我是在ECLIPSE里面用VISUAL EDITOR做的，大部分代码都自动生成
只有画线那段是自己写的

import org.eclipse.swt.graphics.*;

import java.awt.geom.Line2D;
import java.awt.geom.Line2D.Double;

import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.SWT;

public class myswt {

  private org.eclipse.swt.widgets.Shell sShell = null;
  private Button button = null;

  protected Double line;

  protected GC gc;

  public static void main(String[] args) {
org.eclipse.swt.widgets.Display display = org.eclipse.swt.widgets.Display
        .getDefault();
    myswt thisClass = new myswt();
    thisClass.createSShell();
    thisClass.sShell.open();

    while (!thisClass.sShell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }

  /**
   * This method initializes sShell
   */
  private void createSShell() {
    sShell = new org.eclipse.swt.widgets.Shell();
    button = new Button(sShell, SWT.NONE);
    sShell.setSize(new org.eclipse.swt.graphics.Point(511, 326));
    sShell.setText("Shell");
    button.setBounds(new org.eclipse.swt.graphics.Rectangle(32, 25, 72,28));
    button.setText("OK");
    button
        .addSelectionListener(new org.eclipse.swt.events.SelectionAdapter() {
          public void widgetSelected(
              org.eclipse.swt.events.SelectionEvent e) {
            System.out.println("widgetSelected()"); // TODO
                                // Auto-generated
                                // Event stub
                                // widgetSelected()
/************画线**********/
            gc = new GC(sShell);
            gc.drawLine(100, 100, 200, 200);
            /************画线**********/
          }
        });
  }

}
初渉SWT，请多多包含！

4.Re:在SWT下怎么重绘2D图形 [Re: huwd]

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Posted by: lxh_ming
Posted on: 2004-12-03 09:43

你的编程思路有点不对，至少你应该在你的类里面保存划线的起点和终点
我改了一下你的代码：
<code>
import org.eclipse.swt.events.PaintEvent;
import java.awt.geom.Line2D.Double;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;

public class myswt {

  private org.eclipse.swt.widgets.Shell sShell = null;

  private Button button = null;

  protected Double line;

  protected GC gc;

  private boolean canDraw;

  public static void main(String[] args) {
    org.eclipse.swt.widgets.Display display = org.eclipse.swt.widgets.Display
        .getDefault();
    myswt thisClass = new myswt();
    thisClass.createSShell();
    thisClass.sShell.open();

    while (!thisClass.sShell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    display.dispose();
  }

  /**
   * This method initializes sShell
   */
  private void createSShell() {
    sShell = new org.eclipse.swt.widgets.Shell();
    button = new Button(sShell, SWT.NONE);
    sShell.setSize(new org.eclipse.swt.graphics.Point(511, 326));
    sShell.setText("Shell");
    button
        .setBounds(new org.eclipse.swt.graphics.Rectangle(32, 25, 72,
            28));
    button.setText("OK");
    button
        .addSelectionListener(new org.eclipse.swt.events.SelectionAdapter() {
          public void widgetSelected(
              org.eclipse.swt.events.SelectionEvent e) {
            canDraw = !canDraw;
            sShell.redraw();

          }
        });
    sShell.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent arg0) {
        if (canDraw) {
          GC gc = new GC(sShell);
          gc.drawLine(100, 100, 200, 200);
          gc.dispose();
        }
      }

    });

  }
}
<code>

5.Re:在SWT下怎么重绘2D图形 [Re: huwd]	Copy to clipboard
Posted by: huwd Posted on: 2004-12-03 18:31 非常感谢，我这个问题在多个论坛都发过，这里回答的最快最好再次感谢

6.Re:在SWT下怎么重绘2D图形 [Re: huwd]	Copy to clipboard
Posted by: huwd Posted on: 2004-12-03 18:37 另外，GC里面似乎没有draw(Shape s)的方法这样就不能把事先保存下来的图元类，如Line2D.double,Ellipse2D.Double一下子画上去了，是这样吗？

7.Re:在SWT下怎么重绘2D图形 [Re: huwd]	Copy to clipboard
Posted by: lxh_ming Posted on: 2004-12-04 00:59 都是通过Draw2D的功能来实现的，画Shape也没有什么难度，自己定义好类就可以了