获取Jpanel上绘制的Path2D形状的（起始）X和Y坐标
所以，我有一个程序，我可以使用Path2D对象向JPanel添加形状，然后我可以单击并拖动它们。 我想要做的是能够在药物之后找到形状的最终X和Y坐标。 坐标需要是左上角坐标 。 有任何想法吗？
// add a circle to center of the screen public void addCircle(int width, int height) { Path2D circ = new Path2D.Double(); circ.append(new Ellipse2D.Double(getWidth() / 2 - width / 2, getHeight() / 2 - height / 2, width, height), true); shapes.add(circ); repaint(); } .................. //paint all shapes @Override protected void paintComponent(Graphics g) { super.paintComponent(g); this.setOpaque(true); this.setBackground(Color.WHITE); Graphics2D g2 = (Graphics2D) g; g2.setStroke(new BasicStroke(2)); for (Path2D shape : shapes) { g2.draw(shape); } } .................. // if the mouse click is in the circle, set pressed=true @Override public void mousePressed(MouseEvent e) { if (e.getButton() != MouseEvent.BUTTON1) { return; } for (int i = 0; i < shapes.size(); i++) { if (shapes.get(i) != null && shapes.get(i).contains(e.getPoint())) { currentIndex = i; pressed = true; this.point = e.getPoint(); } } } //if pressed=true, move circle with mouse @Override public void mouseDragged(MouseEvent e) { if (pressed && !lineSelected) { int deltaX = e.getX() - point.x; int deltaY = e.getY() - point.y; shapes.get(currentIndex).transform( AffineTransform.getTranslateInstance(deltaX, deltaY)); point = e.getPoint(); //I need to find the new coordinates here!!!!!!!!!!! repaint(); } } 完整代码
class Canvas extends JPanel { private static final long serialVersionUID = 1L; private List shapes = new ArrayList(); private int currentIndex; private Point lineStartingPoint = new Point(); private Point lineEndingPoint = new Point(); private boolean drawing; private boolean lineSelected; private Path2D.Double linePath; private Shapes myShapes = new Shapes(); private List circles = new ArrayList(); public Canvas() { MyMouseAdapter myMouseAdapter = new MyMouseAdapter(); addMouseListener(myMouseAdapter); addMouseMotionListener(myMouseAdapter); } public void setList(ArrayList shapes) { } public List getList() { return null; } public void addSquare(int width, int height) { Path2D rect2 = new Path2D.Double(); rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2 - height / 2, width, height), true); shapes.add(rect2); repaint(); } public void addLine() { lineSelected = true; repaint(); } public void addCircle(int width, int height) { myShapes.addCircle(getWidth() / 2 - width / 2, getHeight() / 2 - height / 2, width, height); Path2D circ = new Path2D.Double(); circ.append(new Ellipse2D.Double(getWidth() / 2 - width / 2, getHeight() / 2 - height / 2, width, height), true); circles.add(circ); shapes.add(circ); repaint(); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); this.setOpaque(true); this.setBackground(Color.WHITE); Graphics2D g2 = (Graphics2D) g; if (lineSelected) { g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setStroke(new BasicStroke(2)); g2.drawLine(lineStartingPoint.x, lineStartingPoint.y, lineEndingPoint.x, lineEndingPoint.y); } g2.setStroke(new BasicStroke(2)); for (Path2D shape : shapes) { g2.draw(shape); } } class MyMouseAdapter extends MouseAdapter { private boolean pressed = false; private Point point; @Override public void mousePressed(MouseEvent e) { if (e.getButton() != MouseEvent.BUTTON1) { return; } for (int i = 0; i < shapes.size(); i++) { if (shapes.get(i) != null && shapes.get(i).contains(e.getPoint())) { currentIndex = i; pressed = true; this.point = e.getPoint(); } if (circles.get(i) != null && circles.get(i).contains(e.getPoint())) { currentIndex = i; pressed = true; this.point = e.getPoint(); } } if (lineSelected) { drawing = true; lineStartingPoint = e.getPoint(); lineEndingPoint = lineStartingPoint; } } @Override public void mouseDragged(MouseEvent e) { if (pressed && !lineSelected) { int deltaX = e.getX() - point.x; int deltaY = e.getY() - point.y; shapes.get(currentIndex).transform( AffineTransform.getTranslateInstance(deltaX, deltaY)); point = e.getPoint(); myShapes.updateCircleLocation(currentIndex, point.x, point.y); System.out.println(point.x + " " + point.y); repaint(); } if (drawing) { lineEndingPoint = e.getPoint(); repaint(); } } @Override public void mouseReleased(MouseEvent e) { if (drawing && lineSelected) { drawing = false; lineSelected = false; lineEndingPoint = e.getPoint(); linePath = new Path2D.Double(); linePath.moveTo(lineStartingPoint.getX(), lineStartingPoint.getY()); linePath.lineTo(lineEndingPoint.getX(), lineEndingPoint.getY()); shapes.add(linePath); repaint(); } pressed = false; } } }
编辑
偏移计算：
int deltaX = e.getX() - point.x; int deltaY = e.getY() - point.y; shapes.get(currentIndex).transform( AffineTransform.getTranslateInstance(deltaX, deltaY)); point = e.getPoint(); int newXPos = e.getX() - deltaX; // final X pos int newXPos = e.getX() - deltaX; // final Y pos
在你可以做任何事情之前，你需要知道从形状的角落点击鼠标的偏移量，这将允许你拖动对象，使它不会突然“跳”到你当前的鼠标位置……
@Override public void mousePressed(MouseEvent e) { //... for (Shape shape : myShapes) { //... this.point = e.getPoint(); int deltaX = point.x - shape.getBounds().x; int deltaY = point.y - shape.getBounds().y; offset = new Point(deltaX, deltaY); //... } } }
然后，您将计算当前鼠标位置和偏移之间的变化增量。 因为您正在应用翻译，您还需要减去形状的当前位置，因为翻译基于形状的当前位置，我们只想应用更改量
@Override public void mouseDragged(MouseEvent e) { if (pressed) { int index = myShapes.indexOf(clickedShape); myShapes.remove(index); int deltaX = e.getPoint().x - offset.x; int deltaY = e.getPoint().y - offset.y; clickedShape = new Path2D.Double(clickedShape, AffineTransform.getTranslateInstance( deltaX - clickedShape.getBounds().x, deltaY - clickedShape.getBounds().y)); myShapes.add(index, clickedShape); point = e.getPoint(); repaint(); } }
现在，说了这么多，不要这样做……
protected void paintComponent(Graphics g) { //... this.setOpaque(true); this.setBackground(Color.WHITE);
从paint方法中更改组件的状态可以设置无限循环的重绘请求，这可以阻塞您的系统。 此外，您所做的更改将不会应用于当前图形上下文，因为这些属性通常由paint方法应用…
还有一份工作副本……
import java.awt.BasicStroke; import java.awt.Color; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Point; import java.awt.Rectangle; import java.awt.RenderingHints; import java.awt.Shape; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.geom.AffineTransform; import java.awt.geom.Ellipse2D; import java.awt.geom.Path2D; import java.util.ArrayList; import java.util.List; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; class Canvas extends JPanel { private static final long serialVersionUID = 1L; private boolean drawing; private List myShapes = new ArrayList (); public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(new Canvas()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public Canvas() { MyMouseAdapter myMouseAdapter = new MyMouseAdapter(); addMouseListener(myMouseAdapter); addMouseMotionListener(myMouseAdapter); addSquare(100, 100); } @Override public Dimension getPreferredSize() { return new Dimension(400, 400); } public void setList(ArrayList shapes) { } public List getList() { return null; } public void addSquare(int width, int height) { Path2D rect2 = new Path2D.Double(); rect2.append(new Rectangle(getWidth() / 2 - width / 2, getHeight() / 2 - height / 2, width, height), true); myShapes.add(rect2); repaint(); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; g2.setStroke(new BasicStroke(2)); for (Shape shape : myShapes) { g2.draw(shape); } } class MyMouseAdapter extends MouseAdapter { private boolean pressed = false; private Point point; private Point offset; private Shape clickedShape; @Override public void mousePressed(MouseEvent e) { if (e.getButton() != MouseEvent.BUTTON1) { return; } for (Shape shape : myShapes) { if (shape != null && shape.contains(e.getPoint())) { System.out.println("Clicked"); pressed = true; clickedShape = shape; this.point = e.getPoint(); int deltaX = point.x - shape.getBounds().x; int deltaY = point.y - shape.getBounds().y; offset = new Point(deltaX, deltaY); System.out.println(point + "x" + offset); repaint(); break; } } } @Override public void mouseDragged(MouseEvent e) { if (pressed) { int index = myShapes.indexOf(clickedShape); myShapes.remove(index); int deltaX = e.getPoint().x - offset.x; int deltaY = e.getPoint().y - offset.y; clickedShape = new Path2D.Double(clickedShape, AffineTransform.getTranslateInstance( deltaX - clickedShape.getBounds().x, deltaY - clickedShape.getBounds().y)); myShapes.add(index, clickedShape); point = e.getPoint(); repaint(); } } @Override public void mouseReleased(MouseEvent e) { offset = null; pressed = false; } } }