我正在开发一个在 JScrollPane 中显示 map (继承自 JComponent)的 Java 程序。当 MouseWheelListener 触发时， map 会缩放并且 JScrollPane 的视口(viewport)会调整为以鼠标位置为中心。
一切正常，除了调用 setSize(Dimension d) 会强制 map 在调整 View 之前立即重新绘制，从而导致“卡顿”。但是，在 setSize 完成执行之前我无法调整 View ，否则视口(viewport)“居中”的计算将变得困惑(由于 getHeight() 和 getWidth () 调用，) 因此视口(viewport)调整在使用 invokeLater 调用的可运行对象内进行。
我想找到一种方法，可以直接从以前的 map 大小和视口(viewport)位置移动到新 View ，而不会看到场景重绘两次。
setIgnoreRepaint(boolean) 对我不起作用。还有其他方法吗？
编辑:这是我从您的示例代码中得出的结果，它复制了我的问题，尽管没有那么明显，因为绘图中进行的计算要少得多。如果快速滚动图像，您会发现在将六边形调整为新大小和将视口(viewport)调整为新位置之间存在短暂的停顿。
您可以看到六边形被重新绘制了两次。 (调用 setSize() 方法一次，调用 setViewPosition() 方法一次。)
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class ZoomWithSelectionInViewport implements MouseWheelListener{
private int zoom = 80;
JComponent b;
int hexSize = 3;
public ZoomWithSelectionInViewport() throws Exception{
b = new JComponent() {
private static final long serialVersionUID = 1L;
@Override
public Dimension getMinimumSize() {
return new Dimension(700, 700);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = ((Graphics2D) g);
int vertOffsetX, vertOffsetY, horizOffsetX, horizOffsetY;
vertOffsetX = (int)((double)hexSize* Math.sqrt(3.0f));
vertOffsetY = (int)((double)-hexSize-1* Math.sqrt(3.0f)/2.0f);
horizOffsetX = (int) ((double)hexSize* Math.sqrt(3.0f));
horizOffsetY = (int) ((double)hexSize+1* Math.sqrt(3.0f)/2.0f);
for(int x = 0; x < 50; x++)
{
for(int y = 0; y < 50; y++)
{
int[] xcoords = new int[6]; int[] ycoords = new int[6];
for(int i = 0; i < 6; i++)
{
xcoords[i] = (int)((hexSize+x * horizOffsetX + y * vertOffsetX) + (double)hexSize * Math.cos(i * 2 * Math.PI / 6));
ycoords[i] = (int)(((getSize().height /2 )+ x * horizOffsetY + y * vertOffsetY) + (double)hexSize * Math.sin(i * 2 * Math.PI / 6));
}
g2d.setStroke(new BasicStroke(hexSize/2.5f));
g2d.setColor(Color.GRAY);
g2d.drawPolygon(xcoords, ycoords, 6);
}
}
}
};
JScrollPane view = new JScrollPane(b);
b.addMouseWheelListener(this);
JFrame f = new JFrame();
f.setLocation(10, 10);
f.setDefaultCloseOperation(3);
f.add(view);
f.setSize(500,500);
f.setVisible(true);
view.setWheelScrollingEnabled(false);
}
public void mouseWheelMoved(MouseWheelEvent e) {
zoom = 100*-Integer.signum(e.getWheelRotation());
if(hexSize - Integer.signum(e.getWheelRotation()) > 0)
hexSize-= Integer.signum(e.getWheelRotation());
Dimension targetSize = new Dimension(b.getWidth()+zoom,b.getHeight()+zoom);
b.setPreferredSize(targetSize);
b.setSize(targetSize);
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JViewport tempView = (JViewport)b.getParent();
tempView.setViewPosition(new Point(b.getWidth()/2,b.getHeight()/2));
}
});
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
ZoomWithSelectionInViewport example = new ZoomWithSelectionInViewport();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
最佳答案
我的好奇心，不知道发生了什么，你能用这个吗 SSCCE在那里添加您的问题并使用代码编辑您的问题
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class ZoomWithSelectionInViewport {
private Point startPoint = new Point(0, 0);
private Point rectLocale = new Point();
private Dimension rectSize = new Dimension();
private int zoom = 80;
private BufferedImage capture = null;
private BufferedImage raw;
public ZoomWithSelectionInViewport() throws Exception {
raw = new Robot().createScreenCapture(new Rectangle(
Toolkit.getDefaultToolkit().getScreenSize()));
MouseBehavior behavior = new MouseBehavior();
JPanel b = new JPanel() {
private static final long serialVersionUID = 1L;
@Override
public Dimension getMinimumSize() {
return new Dimension(500, 500);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = ((Graphics2D) g);
g2d.drawImage(raw, 0, 0, null);
if (capture != null) {
int width2 = (int) (rectSize.width + rectSize.width * (zoom / 500d));
int height2 = (int) (rectSize.height + rectSize.height * (zoom / 500d));
int x2 = rectLocale.x - ((width2 - rectSize.width) / 2);
int y2 = rectLocale.y - ((height2 - rectSize.height) / 2);
Image scaledInstance = capture.getScaledInstance(
width2, height2, Image.SCALE_AREA_AVERAGING);
g2d.drawImage(scaledInstance, x2, y2, null);
g2d.drawRect(x2, y2, width2, height2);
} else {
g2d.draw(new Rectangle(rectLocale, rectSize));
}
}
};
b.addMouseMotionListener(behavior);
b.addMouseListener(behavior);
b.addMouseWheelListener(behavior);
JFrame f = new JFrame();
f.setLocation(10, 10);
f.setDefaultCloseOperation(3);
f.add(b);
f.pack();
f.setVisible(true);
}
private class MouseBehavior extends MouseAdapter {
@Override
public void mousePressed(MouseEvent e) {
startPoint = e.getPoint();
rectLocale = new Point();
rectSize = new Dimension();
capture = null;
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
@Override
public void mouseDragged(MouseEvent e) {
Point currentPoint = e.getPoint();
rectSize.width = Math.abs(currentPoint.x - startPoint.x);
rectSize.height = Math.abs(currentPoint.y - startPoint.y);
if (e.isShiftDown()) {
rectSize.width = rectSize.height = Math.min(rectSize.width, rectSize.height);
int dx = startPoint.x - rectSize.width;
int dy = startPoint.y - rectSize.height;
rectLocale.x = startPoint.x < currentPoint.x ? startPoint.x : Math.max(dx, dy);
rectLocale.y = startPoint.y < currentPoint.y ? startPoint.y : Math.min(dx, dy);
} else {
rectLocale.x = Math.min(currentPoint.x, startPoint.x);
rectLocale.y = Math.min(currentPoint.y, startPoint.y);
}
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
@Override
public void mouseReleased(MouseEvent e) {
if (rectSize.width <= 0 || rectSize.height <= 0) {
capture = null;
} else {
capture = raw.getSubimage(Math.max(0, rectLocale.x),
Math.max(0, rectLocale.y), rectSize.width, rectSize.height);
}
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
zoom = Math.min(2000, Math.max(0, zoom + e.getUnitsToScroll() * 10));
if (e.getSource() instanceof JComponent) {
((JComponent) e.getSource()).repaint();
}
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
ZoomWithSelectionInViewport example = new ZoomWithSelectionInViewport();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
另一种可能是
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
public class ZoomDemo {
private PaintSurface canvas = new PaintSurface();
private JFrame frame = new JFrame();
private AffineTransform aT = new AffineTransform();
private Point2D p1 = null;
private Point2D p2 = null;
public ZoomDemo() {
frame.setSize(500, 500);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
ScaleListener scaleListener = new ScaleListener();
canvas.addMouseWheelListener(scaleListener);
canvas.addMouseListener(scaleListener);
frame.add(canvas);
frame.setVisible(true);
}
public class ScaleListener extends MouseAdapter {
private double scale = 1;
@Override
public void mouseClicked(MouseEvent e) {
p1 = e.getPoint();
try {
p2 = aT.inverseTransform(p1, new Point2D.Double());
/*
* p1 is the point relative to canvas where the user physically
* held the mouse.
*
* Since you may want to deal with a virtual mouse location
* relative to an untransformed canvas, you inverse transform p1
* to p2.
*
* For example: when the user held the mouse over, let's say,
* the displayed left upper corner of the red rectangle.
*
* p2 now will point to the upper left corner of the red
* rectangle in an untransformed canvas.
*/
applyScale();
} catch (NoninvertibleTransformException e1) {
e1.printStackTrace();
}
canvas.repaint();
}
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
if (p1 != null && p2 != null) {
scale -= (0.05 * e.getWheelRotation());
if (scale > 5) {
scale = 5;
}
if (scale < 1) {
scale = 1;
aT.setToIdentity();
} else {
applyScale();
}
canvas.repaint();
}
}
private void applyScale() {
aT.setToIdentity();
// *** variation one (your implementation)
aT.translate(p1.getX(), p1.getY());
aT.scale(scale, scale);
aT.translate(-p2.getX(), -p2.getY());
// *** variation two
// aT.translate(p1.getX(), p1.getY());
// aT.scale(scale, scale);
// aT.translate(-p1.getX(), -p1.getY());
// *** variation three
// aT.translate(p2.getX(), p2.getY());
// aT.scale(scale, scale);
// aT.translate(-p2.getX(), -p2.getY());
}
}
public class PaintSurface extends JComponent {
private static final long serialVersionUID = 1L;
{
this.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
}
/*
* Override paintComponent, not paint!!!
*/
@Override
protected void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g.create();
try {
g2.setColor(Color.black);
g2.fillRect(0, 0, getWidth(), getHeight());
// g2.setTransform(aT); <<<<<<<<< !!!!!!!
/*
* A transform (translation for example) may already have been
* applied to the Graphics object by a parent. This is removed
* by setTransform.
*/
g2.transform(aT); // <<<<<<<<<< !!!!!!!
g2.setColor(Color.red);
g2.drawRect(50, 50, 100, 100);
g2.setColor(Color.blue);
g2.drawRect(200, 200, 150, 50);
if (p2 != null) {
g2.setColor(Color.green);
g2.fill(new Rectangle2D.Double(p2.getX() - 4, p2.getY() - 4, 8, 8));
}
} finally {
g2.dispose();
}
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ZoomDemo zoomDemo = new ZoomDemo();
}
});
}
}
同样的问题，
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JViewport;
//http://stackoverflow.com/questions/6819243/jscrollpane-jumping-when-scrollbars-start-being-used
public class LockViewPortToPoint extends JFrame {
private static final long serialVersionUID = 1L;
public static void main(String[] arg) {
LockViewPortToPoint lockViewPortToPoint = new LockViewPortToPoint();
}
public LockViewPortToPoint() {
initComponents();
setVisible(true);
}
private void initComponents() {
setLayout(new BorderLayout());
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(600, 600);
setPreferredSize(new Dimension(600, 600));
add(new TopPanel());
}
private class TopPanel extends JPanel {
private static final long serialVersionUID = 1L;
private JScrollPane scrollPane;
TopPanel() {
setPreferredSize(new Dimension(500, 500));
scrollPane = new JScrollPane(new InteriorPanel());
scrollPane.setPreferredSize(new Dimension(500, 500));
scrollPane.getVerticalScrollBar().setPreferredSize(new Dimension(10, 490));
scrollPane.getHorizontalScrollBar().setPreferredSize(new Dimension(490, 10));
scrollPane.setWheelScrollingEnabled(false);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
add(scrollPane);
}
}
private class InteriorPanel extends JPanel {
private static final long serialVersionUID = 1L;
private double scale = 10.0;
private final double scaleModifier = 0.1;
private final int width = 10;
private Point loc = new Point(0, 0);
private final int SIZE = 10;
private Point orig = new Point(250, 250);
InteriorPanel() {
super(true);
setPreferredSize(new Dimension((int) (scale * width * SIZE), (int) (scale * width * SIZE)));
this.addMouseWheelListener(new MapMouseWheelListener());
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2D.scale(scale, scale);
for (int row = 0; row <= SIZE; row++) {
for (int col = 0; col < SIZE; col++) {
if ((col + row) % 2 == 0) {
g2D.setColor(Color.white);
} else {
g2D.setColor(Color.black);
}
g2D.fillRect(col * width, row * width, width, width);
}
}
}
private void incrementScale(int notches) {
double modifier = 0;
final double prevScale = scale;
if (notches != 0) {
modifier = 1.0 + -notches / Math.abs(notches) * scaleModifier;
}
scale *= Math.pow(modifier, Math.abs(notches));
/*if (scale * width < 1) {
scale = 1.0/width;
} else if (scale * width * 3 > parentHeight || scale * width * 3 > parentWidth) {
if (parentHeight > parentWidth) {
scale = parentWidth / 3.0 / width;
} else {
scale = parentHeight / 3.0 / width;
}
} else if (scale * width * SIZE < parentWidth) {
scale = parentWidth / (double)SIZE / width;
} else if (scale * width * SIZE < parentHeight) {
scale = parentHeight / (double)SIZE / width;
}*/
setPreferredSize(new Dimension((int) (scale * width * SIZE), (int) (scale * width * SIZE)));
orig = new Point(((int) (scale * width * SIZE)) / 2, ((int) (scale * width * SIZE) / 2));
final JViewport viewport = ((JViewport) (getParent().getParent().getComponent(0)));
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
viewport.setViewPosition(new Point(
orig.x - (int) Math.round(loc.x * (1 - scale / prevScale)),
orig.y - (int) Math.round(loc.y * (1 - scale / prevScale))));
}
});
/*viewport.scrollRectToVisible(new Rectangle(new Point(
orig.x - (int) Math.round(loc.x * (1 - scale / prevScale)),
orig.y - (int) Math.round(loc.y * (1 - scale / prevScale))))); */
System.out.println(orig + "\n " + loc + "\n " + (1 - scale / prevScale));
revalidate();
repaint();
}
private class MapMouseWheelListener implements MouseWheelListener {
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
loc = e.getPoint();
incrementScale(e.getWheelRotation());
}
}
}
}
另一个例子
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
//http://stackoverflow.com/questions/115103/how-do-you-implement-position-sensitive-zooming-inside-a-jscrollpane
public class FPanel extends javax.swing.JPanel {
private static final long serialVersionUID = 1L;
private Dimension preferredSize = new Dimension(400, 400);
private Rectangle2D[] rects = new Rectangle2D[50];
public static void main(String[] args) {
JFrame jf = new JFrame("test");
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setSize(400, 400);
jf.add(new JScrollPane(new FPanel()));
jf.setVisible(true);
}
public FPanel() {
// generate rectangles with pseudo-random coords
for (int i = 0; i < rects.length; i++) {
rects[i] = new Rectangle2D.Double(
Math.random() * .8, Math.random() * .8,
Math.random() * .2, Math.random() * .2);
}
// mouse listener to detect scrollwheel events
addMouseWheelListener(new MouseWheelListener() {
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
updatePreferredSize(e.getWheelRotation(), e.getPoint());
}
});
}
private void updatePreferredSize(int wheelRotation, Point stablePoint) {
double scaleFactor = findScaleFactor(wheelRotation);
scaleBy(scaleFactor);
Point offset = findOffset(stablePoint, scaleFactor);
offsetBy(offset);
getParent().doLayout();
revalidate();
repaint();
}
private double findScaleFactor(int wheelRotation) {
double d = wheelRotation * 1.08;
return (d > 0) ? 1 / d : -d;
}
private void scaleBy(double scaleFactor) {
int w = (int) (getWidth() * scaleFactor);
int h = (int) (getHeight() * scaleFactor);
preferredSize.setSize(w, h);
}
private Point findOffset(Point stablePoint, double scaleFactor) {
int x = (int) (stablePoint.x * scaleFactor) - stablePoint.x;
int y = (int) (stablePoint.y * scaleFactor) - stablePoint.y;
return new Point(x, y);
}
private void offsetBy(Point offset) {
Point location = getLocation();
setLocation(location.x - offset.x, location.y - offset.y);
}
@Override
public Dimension getPreferredSize() {
return preferredSize;
}
private Rectangle2D r = new Rectangle2D.Float();
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.red);
int w = getWidth();
int h = getHeight();
for (Rectangle2D rect : rects) {
r.setRect(rect.getX() * w, rect.getY() * h,
rect.getWidth() * w, rect.getHeight() * h);
((Graphics2D) g).draw(r);
}
}
}
关于Java:在不重新绘制的情况下调整组件大小？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8873525/