【原创】在Swing中实现二维图元处理 - 继往开来吐故纳新

本文系原创文章,转载请注明出处(jungleosng.yculblog.com)

在Swing中绘制二维图,并有拖曳,缩放,链接,输出功能,主要有几大技术要点
1.绘画时的闪烁问题,解决方法是先将所有图元画到一张后台图上,在将后台图一次性画到面板上,请见public void paint(Graphics g)的处理.
2.鼠标响应:解决方法是添加面板的鼠标点击,鼠标拖曳处理,以鼠标的位置来确定图元的处理,请见函数public void mousePressed(MouseEvent e),public void mouseDragged(MouseEvent e)和public void mouseClicked(MouseEvent e).
3.单个图元处理:每个图元继承Actor2D类,它需要记住当前图元的起始位置和缩放比例.
4.多个图元处理:当大图元移动时,直线/折线图元需要根据大图元确定自己的位置,这时需要访问图元列表,以便知道那条直线在自身上.
5.输出图片:这个相对简单,看函数public boolean saveImage(String imagePath)的处理就可以了.
先写道这里,细节以后再整理,大家有兴趣先看看代码吧.

public class PaintBoard extends JPanel implements MouseListener,
MouseMotionListener, KeyListener {

// 背景图
private Image bgImage;
private Graphics bg;

// 画板上的二维图元列表
private ArrayList drawList=new ArrayList();

// 画板几何尺寸
private int myWidth;
private int myHeight;
......
// 绘画图元时的偏移尺寸
private int xOffset, yOffset;

// 构造函数
public PaintBoard(MakeSqlToolbar toolbar) {
    super();
    this.toolbar = toolbar;
    this.addMouseListener(this);
    this.addMouseMotionListener(this);
    this.addKeyListener(this);
}

// 调整画面大小时的处理
private void resizePaintBoard() {
    if (myWidth != this.getSize().width
        || myHeight != this.getSize().height) {
      bgImage = null;
      myWidth = this.getSize().width;
      myHeight = this.getSize().height;
    }
}

// 重新调整背景
private void reArrangeBg() {
    if (bgImage == null) {
      bgImage = this.createImage(myWidth, myHeight);
      bg = bgImage.getGraphics();
    }
}

  // 绘图的关键函数
public void paint(Graphics g) {
    resizePaintBoard();
    reArrangeBg();

    // 设置背景
    bg.setColor(Color.white);
    bg.fillRect(0, 0, myWidth, myHeight);

   // 在背景图绘画图元
   if (drawList != null) {
      for (Iterator it = drawList.iterator(); it.hasNext();) {
        Actable actor = (Actable) it.next();
        actor.paint(bg);
      }
    }

// 将背景图画在面板上
g.drawImage(bgImage, 0, 0, this);
}

private boolean mousePressActorTest(Actor2D actor, int x, int y) {
    if (actor.isInRect(x, y)) {
      actor.setStatus(Actor2D.Status_Active);
      xOffset = x - actor.getLeft();
      yOffset = y - actor.getTop();

      if(!(actor instanceof ActorTable)){
        return true;
      }
      ActorTable actorTable=(ActorTable)actor;

      for (Iterator it = drawList.iterator(); it.hasNext();) {
        Actor2D actorTmp = (Actor2D) it.next();

        if (actorTmp instanceof ActorLine) {
          ActorLine actorLine = (ActorLine) actorTmp;
          ActorPoint currPoint;

          currPoint=actorLine.getStartPt();
          currPoint.setInner(actorTable.isInColumns(currPoint.getLeft(),currPoint.getTop()));

          currPoint=actorLine.getEndPt();
          currPoint.setInner(actorTable.isInColumns(currPoint.getLeft(),currPoint.getTop()));
        }
      }

      return true;
    }

    return false;
}

public void mousePressed(MouseEvent e) {
for (Iterator it = drawList.iterator(); it.hasNext();) {
Actor2D actor = (Actor2D) it.next();

      if (actor instanceof ActorLine) {
        ActorLine actorLine = (ActorLine) actor;
        actorLine.setStatus(Actor2D.Status_Sleep);
      } else {
        actor.setStatus(Actor2D.Status_Sleep);
      }
    }

for (Iterator it = drawList.iterator(); it.hasNext();) {
Actor2D actor = (Actor2D) it.next();

      if (actor instanceof ActorLine) {
        ActorLine actorLine = (ActorLine) actor;
        if (mousePressActorTest(actorLine.getStartPt(), e.getX(), e
            .getY()))
          break;
        if (mousePressActorTest(actorLine.getEndPt(), e.getX(), e
            .getY()))
          break;
      } else {
        if (mousePressActorTest(actor, e.getX(), e.getY()))
          break;
      }
    }

repaint();
}

private boolean mouseClickActorTest(Actor2D actor, int x, int y) {
    if (actor.isInRect(x, y)) {
      actor.setStatus(Actor2D.Status_Active);
      return true;
    } else {
      return false;
    }
}

public void mouseClicked(MouseEvent e) {
this.requestFocusInWindow();

for (Iterator it = drawList.iterator(); it.hasNext();) {
Actor2D actor = (Actor2D) it.next();

      if (actor instanceof ActorLine) {
        ActorLine actorLine = (ActorLine) actor;
        if (mouseClickActorTest(actorLine.getStartPt(), e.getX(), e
            .getY()))
          break;
        if (mouseClickActorTest(actorLine.getEndPt(), e.getX(), e
            .getY()))
          break;
      } else {
        if (mouseClickActorTest(actor, e.getX(), e.getY()))
          break;
      }
    }

repaint();
}

private void mouseDragActorTest(Actor2D actor, int x, int y) {
    if (!actor.isActive()) return;

    Actor2D actorTest=new Actor2D(actor.getLeft(),actor.getTop(),actor.getWidth(),actor.getHeight());
    actorTest.setLeft(x - xOffset);
    actorTest.setTop(y - yOffset);
    makeActorInBound(actorTest);

    int xChanged=actor.getLeft()-actorTest.getLeft();
    int yChanged=actor.getTop()-actorTest.getTop();

    if(actor instanceof ActorTable){
      ActorTable actorTable = (ActorTable) actor;

      for (Iterator it = drawList.iterator(); it.hasNext();) {
        Actor2D actorTmp = (Actor2D) it.next();

        if(actorTmp instanceof ActorLine){
          ActorLine actorLine=(ActorLine)actorTmp;
          ActorPoint currPoint;

          currPoint=actorLine.getStartPt();
          if(actorTable.isInColumns(currPoint.getLeft(),currPoint.getTop()) && currPoint.isInner()){
            currPoint.setLeft(currPoint.getLeft()-xChanged);
            currPoint.setTop(currPoint.getTop()-yChanged);
          }

          currPoint=actorLine.getEndPt();
          if(actorTable.isInColumns(currPoint.getLeft(),currPoint.getTop()) && currPoint.isInner()){
            currPoint.setLeft(currPoint.getLeft()-xChanged);
            currPoint.setTop(currPoint.getTop()-yChanged);
          }
        }
      }
    }

    actor.setLeft(actor.getLeft()-xChanged);
    actor.setTop(actor.getTop()-yChanged);
}

public void mouseDragged(MouseEvent e) {
for (Iterator it = drawList.iterator(); it.hasNext();) {
Actor2D actor = (Actor2D) it.next();

      if (actor instanceof ActorLine) {
        ActorLine actorLine = (ActorLine) actor;
        mouseDragActorTest(actorLine.getStartPt(), e.getX(), e.getY());
        mouseDragActorTest(actorLine.getEndPt(), e.getX(), e.getY());
      } else {
        mouseDragActorTest(actor, e.getX(), e.getY());
      }
    }

repaint();
}

private void keyPressedActorTest(Actor2D actor, int x, int y) {
    if (actor.isActive()) {
      actor.setLeft(actor.getLeft() + x);
      actor.setTop(actor.getTop() + y);
      makeActorInBound(actor);
    }
}

public void keyPressed(KeyEvent e) {
int keyCode = e.getKeyCode();

int xMicroOffset = 1, yMicroOffset = 1;

    if (keyCode == KeyEvent.VK_RIGHT) {
      yMicroOffset = 0;
    } else if (keyCode == KeyEvent.VK_LEFT) {
      xMicroOffset = -xMicroOffset;
      yMicroOffset = 0;
    } else if (keyCode == KeyEvent.VK_UP) {
      yMicroOffset = -yMicroOffset;
      xMicroOffset = 0;
    } else if (keyCode == KeyEvent.VK_DOWN) {
      xMicroOffset = 0;
    }

for (Iterator it = drawList.iterator(); it.hasNext();) {
Actor2D actor = (Actor2D) it.next();

      if (actor instanceof ActorLine) {
        ActorLine actorLine = (ActorLine) actor;
        keyPressedActorTest(actorLine.getStartPt(), xMicroOffset,
            yMicroOffset);
        keyPressedActorTest(actorLine.getEndPt(), xMicroOffset,
            yMicroOffset);
      } else {
        keyPressedActorTest(actor, xMicroOffset, yMicroOffset);
      }
    }

    if (keyCode == KeyEvent.VK_DELETE) {
      for (int i = 0; i < drawList.size(); i++) {
        Actor2D actor = (Actor2D) drawList.get(i);

if (actor instanceof ActorLine) {
ActorLine actorLine = (ActorLine) actor;

          if (actorLine.getStartPt().isActive()) {
            if (ComDlgUtils
                .popupConfirmCancelDialog("Do you wanna remove the Line:"
                    + actor.getName() + "?") == true) {
              drawList.remove(i);
            }
          }

          if (actorLine.getEndPt().isActive()) {
            if (ComDlgUtils
                .popupConfirmCancelDialog("Do you wanna remove the Line:"
                    + actor.getName() + "?") == true) {
              drawList.remove(i);
            }
          }
        } else {
          if (actor.isActive()) {
            if (ComDlgUtils
                .popupConfirmCancelDialog("Do you wanna remove the table:"
                    + actor.getName() + "?") == true) {
              drawList.remove(i);
            }
          }
        }
      }
    }

repaint();
}

private void makeActorInBound(Actor2D Actor) {
    if (Actor.getLeft() < 0) {
      Actor.setLeft(0);
    }

    if (Actor.getTop() < 0) {
      Actor.setTop(0);
    }

    if (Actor.getRight() > myWidth) {
      Actor.setLeft(myWidth - Actor.getWidth());
    }

    if (Actor.getBottom() > myHeight) {
      Actor.setTop(myHeight - Actor.getHeight());
    }
}

public void mouseMoved(MouseEvent e) {
toolbar.setMousePos(e.getX(), e.getY());
}

public boolean saveImage(String imagePath) {
    try {
      FileOutputStream out = new FileOutputStream(imagePath);
      JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
      BufferedImage tag = new BufferedImage(myWidth, myHeight,
          BufferedImage.TYPE_INT_RGB);
      tag.getGraphics().drawImage(bgImage, 0, 0, myWidth, myHeight, null);
      encoder.encode(tag);
      out.close();
      return true;
    } catch (Exception e) {
      ComDlgUtils.popupErrorDialog(e.getMessage());
      return false;
    }
}

public ArrayList getDrawList() {
    return drawList;
}

public void setDrawList(ArrayList drawList) {
this.drawList = drawList;
}

public void keyTyped(KeyEvent e) {
}

public void keyReleased(KeyEvent e) {

}

public void mouseEntered(MouseEvent e) {
}

public void mouseExited(MouseEvent e) {
}

public void mouseReleased(MouseEvent e) {

}
}