扩展JLabel实现图像的裁剪

      这个组件的功能：

      1. 对图片进行裁剪

      2. 为每副图像维持一个裁剪操作栈

      3. 裁剪的撤销，重做

      4. 裁剪时可以遮掩图像，以突出显示裁剪矩形边框

      5. 设置遮掩的颜色，裁剪边框的颜色

      原理：JLabel持有一个剪裁矩形框，和一个遮掩矩形框。并为JLabel添加MouseListener监听器实现开始裁剪和结束裁剪，MouseMotion事件监听器实现设置裁剪矩形边框的大小。

直接上代码：

 

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package killer.swing.component; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.geom.Point2D; import java.awt.geom.Rectangle2D; import java.awt.image.BufferedImage; import java.util.HashMap; import java.util.Vector; import javax.swing.Icon; import javax.swing.ImageIcon; import javax.swing.JLabel; import javax.swing.JOptionPane; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseMotionListener; /** * 进行图片裁剪 * @author chosen0ne */ public class ImageCutComponent extends JLabel { private Rectangle2D rect = new Rectangle2D.Double();//剪裁区域 private BufferedImage image;//当前显示的图像 private Point2D source=new Point2D.Double();//被选择区域的顶点 private ImageStack current=new ImageStack();//当前组件显示的图像对应的操作栈 private HashMap<String,ImageStack> imageStacks=new HashMap<String, ImageStack>();//每个图像对应的裁剪操作栈 private Rectangle2D rectCover=new Rectangle2D.Double();//剪裁时，用于遮挡图像的矩形，这样可以区分剪裁框 private boolean doCover=false;//指示是否进行遮掩 private MouseHandler mouseHandler=new MouseHandler(this); private MouseMotionListener motionListener=new MouseMotionHandler(this); private Color colorCover=new Color(0.7f, 0.7f, 0.7f, 0.3f);//遮掩的颜色 private Color colorBorder=Color.yellow;//裁剪矩形的边框的颜色 public ImageCutComponent(){ this.addMouseListener(this.mouseHandler); this.addMouseMotionListener(motionListener); this.setHorizontalAlignment(javax.swing.SwingConstants.LEFT);//设置水平左对齐 this.setVerticalAlignment(javax.swing.SwingConstants.TOP);//设置垂直上对齐 } /** * 删除裁剪功能 */ public void removeCutAbility(){ this.removeMouseListener(mouseHandler); this.removeMouseMotionListener(motionListener); } /** * 添加裁剪功能 */ public void addCutAbility(){ this.addMouseListener(mouseHandler); this.addMouseMotionListener(motionListener); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; if(doCover){//如果进行裁剪，将图像遮掩 g2.setColor(colorCover); g2.fill(rectCover); } g2.setColor(Color.YELLOW); g2.draw(rect); } /** * 设置是否进行颜色覆盖 * @param f */ public void setDoCover(boolean cover){ this.doCover=cover; } /** * 返回是否进行颜色覆盖 * @return */ public boolean getDoCover(){ return this.doCover; } /** * 返回显示的图像 * @return */ public Image getImage(){ return this.image; } /** * 设置显示的图像 * @param image */ public void setImage(BufferedImage image){ this.image=image; } /** * 删除所有在裁剪过程中，生成的图像 */ public void removeAllImages(){ this.imageStacks.clear(); } /** * 设置剪裁区域 * @param r */ public void setSelectRegion(Rectangle2D r) { this.rect.setFrame(r); } /** * 清除剪裁区域 */ public void clearSelectRegion() { this.rect.setFrame(0, 0, 0, 0); } /** * 得到剪裁区域 * @return */ public Rectangle2D getSelectRegion(){ return this.rect; } /** * 对JLabel的方法进行覆盖，调用此方法时同时设置显示的图像指向该图片 * 并设置覆盖矩形的大小 * @param icon */ @Override public void setIcon(Icon icon) { super.setIcon(icon); ImageIcon imageIcon = (ImageIcon) icon; if (imageIcon != null) { this.image = this.convertImageToBuffer(imageIcon.getImage()); rectCover=new Rectangle2D.Double(0,0,image.getWidth(null),image.getHeight(null)); } } /** * 取得裁剪矩形的左上角顶点 * @return */ public Point2D getSource() { return this.source; } /** * 设置裁剪矩形的左上角的顶点 * @param p */ public void setSource(Point2D p) { this.source = p; } /** * 进行裁剪 */ public void doCut() { int result=JOptionPane.showConfirmDialog(this, "进行裁剪", "提示", JOptionPane.YES_NO_OPTION, JOptionPane.INFORMATION_MESSAGE); if(result==JOptionPane.NO_OPTION){ this.clearSelectRegion(); this.repaint(); return; } Image bImage=this.doResize(image, rect); current.add(bImage); this.setIcon(new ImageIcon(bImage)); this.clearSelectRegion(); this.repaint(); } /** * 返回点p在图像上对应的点，不能超过图像的长、宽 * @param p * @return */ public Point2D getPoint(Point2D p){ if(image==null) return new Point2D.Double(); int imageWidth = image.getWidth(this); int x=(int) (p.getX() > imageWidth ? imageWidth : p.getX()); int imageHeight=image.getHeight(this); int y=(int) (p.getY() > imageHeight ? imageHeight : p.getY()); return new Point2D.Double(x, y); } /** * 判断某点是否在图像内 * @param p * @return */ public boolean inImage(Point2D p){ if(image==null) return false; int imageWidth = image.getWidth(this); int imageHeight=image.getHeight(this); if(p.getX()<imageWidth&&p.getY()<imageHeight) return true; return false; } /** * 操作栈中是否有前一个图像 * @return */ public boolean hasPrevious(){ return current.hasPrevious(); } /** * 操作栈中是否有后一个图像 * @return */ public boolean hasNext(){ return current.hasNext(); } /** * 设置遮掩颜色 * @param color */ public void setColorCover(Color color){ this.colorCover=color; } /** * 返回遮掩颜色 * @return */ public Color getColorCover(){ return this.colorCover; } /** * 设置裁剪矩形的边框颜色 * @param color */ public void setColorBorder(Color color){ this.colorBorder=color; } /** * 返回裁剪矩形边框的颜色 * @return */ public Color getColorBorder(){ return this.colorBorder; } /** * 返回操作栈中前一个图像 */ public Image previous(){ Image img=current.previous(); this.setIcon(new ImageIcon(img)); return img; } /** * 返回操作栈中后一个图像 */ public Image next(){ Image img=current.next(); this.setIcon(new ImageIcon(img)); return img; } /** * 为每个文件添加原始图像 * @param image */ public void addOrdinary(Image image){ this.current.add(image); } /** * 设置当前操作栈current指向文件fileName对应的操作栈 * @param fileName */ public void setCurrent(String fileName){ if(!imageStacks.containsKey(fileName)) imageStacks.put(fileName, new ImageStack()); current=imageStacks.get(fileName); } /** * 返回图像file在操作栈对应的当前图像 * @param file * @return */ public Image getCurrentImage(String file){ return imageStacks.get(file).getCurrent(); } private BufferedImage convertImageToBuffer(Image pic){ BufferedImage bufferedImage = new BufferedImage(pic.getWidth(null), pic.getHeight(null), BufferedImage.TYPE_INT_RGB); Graphics g = bufferedImage.createGraphics(); g.drawImage(pic, 0, 0, null); g.dispose(); return bufferedImage; } /** * 对图像进行裁剪 * @param image * @param rect 裁剪的区域 * @return */ public Image doResize(BufferedImage image,Rectangle2D rect){ return image.getSubimage((int)rect.getX(), (int)rect.getY(), (int)rect.getWidth(), (int)rect.getHeight()); } /** * 图像操作栈 * @author chosen0ne */ private class ImageStack { private Vector<Image> vec=new Vector<Image>(); private int index=-1; public boolean hasNext(){ return index<vec.size()-1; } public boolean hasPrevious(){ return index>0; } public Image next(){ return vec.get(++index); } public Image previous(){ return vec.get(--index); } public void add(Image i){ vec.add(i); index++; } public Image getCurrent(){ return vec.get(index); } } /** * * @author chosen0ne */ public class MouseHandler extends MouseAdapter { private ImageCutComponent component; public MouseHandler(ImageCutComponent l) { this.component = l; } /** * 当鼠标按下，设置裁剪的起点和并设置进行遮掩 * @param e */ @Override public void mousePressed(MouseEvent e) { this.component.setSource(component.getPoint(e.getPoint())); this.component.setDoCover(true); } /** * 当释放鼠标，进行图像的裁剪并设置不进行遮掩 * @param e */ @Override public void mouseReleased(MouseEvent e){ if(component.inImage(e.getPoint())&&component.getSelectRegion().getWidth()!=0 &&component.getSelectRegion().getHeight()!=0){ this.component.doCut(); this.component.setDoCover(false); } } } /** * * @author chosen0ne */ class MouseMotionHandler implements MouseMotionListener { private ImageCutComponent component; public MouseMotionHandler(ImageCutComponent l) { this.component = l; } /** * 拖拽时，设置裁剪矩形的大小 * @param e */ @Override public void mouseDragged(MouseEvent e) { Rectangle2D rect = getRectangle(component.getSource(), component.getPoint(e.getPoint())); this.component.setSelectRegion(rect); this.component.repaint(); } public void mouseMoved(MouseEvent e) { } private Rectangle2D getRectangle(Point2D p1, Point2D p2) { int x = (int) Math.min(p1.getX(), p2.getX()); int y = (int) Math.min(p1.getY(), p2.getY()); double h = Math.abs(p1.getY() - p2.getY()); double w = Math.abs(p1.getX() - p2.getX()); return new Rectangle2D.Double(x, y, w, h); } } }  

 

效果图：

            

 

此组件必须保证图像的左上角定点位于父组件的左上角，可以将这个组件包含于JScrollPanel中，效果很好