Java，如何绘制不断变化的图形 [英] Java, how to draw constantly changing graphics
问题描述
以前没有这样做过，所以显然我很讨厌.这里围绕当前鼠标位置的 64 像素在表单上绘制得更大一些.问题是，它有点"变慢，我不知道从哪里开始修复.
Have not done this before, so obviously I suck at it. Here 64 pixels around current mouse position get drawn little bigger on a form. Problem is, that it's 'kind of' to slow, and I have no idea where to start fixing.
除此之外，我创建了一个线程，当它完成时不断调用更新图形和像文本一样的一点 fps，以真正显示绘制事物的速度.
Besides that, I made a thread, that constantly calls update graphics when it's finished and a little fps like text, to show really how fast things are drawn.
图像示例:(图像来自 Eclipse 中的字母a")
Image example: (Image is from letter 'a' in Eclipse)
代码示例:
@SuppressWarnings("serial")
public static class AwtZoom extends Frame {
private BufferedImage image;
private long timeRef = new Date().getTime();
Robot robot = null;
public AwtZoom() {
super("Image zoom");
setLocation(new Point(640, 0));
setSize(400, 400);
setVisible(true);
final Ticker t = new Ticker();
this.image = (BufferedImage) (this.createImage(320, 330));
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
t.done();
dispose();
}
});
try {
robot = new Robot();
} catch (AWTException e) {
e.printStackTrace();
}
t.start();
}
private class Ticker extends Thread {
public boolean update = true;
public void done() {
update = false;
}
public void run() {
try {
while (update == true) {
update(getGraphics());
// try {
// Thread.sleep(200);
// } catch (InterruptedException e) {
// e.printStackTrace();
// return;
// }
}
} catch (Exception e) {
update=false;
}
}
}
public void update(Graphics g) {
paint(g);
}
boolean isdone = true;
public void paint(Graphics g) {
if (isdone) {
isdone=false;
int step = 40;
Point p = MouseInfo.getPointerInfo().getLocation();
Graphics2D gc = this.image.createGraphics();
try {
for (int x = 0; x < 8; x++) {
for (int y = 0; y < 8; y++) {
gc.setColor(robot.getPixelColor(p.x - 4 + x, p.y
- 4 + y));
gc.fillOval(x * step, y * step, step - 3, step - 3);
gc.setColor(Color.GRAY);
gc.drawOval(x * step, y * step, step - 3, step - 3);
}
}
} catch (Exception e) {
e.printStackTrace();
}
gc.dispose();
isdone = true;
iter++;
}
g.drawImage(image, 40, 45, this);
g.setColor(Color.black);
StringBuilder sb = new StringBuilder();
sb.append(iter)
.append(" frames in ")
.append((double) (new Date().getTime() - this.timeRef) / 1000)
.append("s.");
g.drawString(sb.toString(), 50, 375);
}
int iter = 0;
}
所做的更改:
* 添加了gc.dispose();"
* 添加了isdone"，因此无法更快地调用重绘，然后应该调用.
* 添加了 此链接 到 thrashgod 源代码重写
* 将 此链接添加到 thrashgod 源代码重写 2
Changes made:
* added "gc.dispose();"
* added "isdone", so redraw could not be called faster, then it should.
* added this link to thrashgod source rewrite
* added this link to thrashgod source rewrite 2
推荐答案
这是我的主要重写，有以下值得注意的变化:
Here's my major rewrite with the following noteworthy changes:
- 我已经将检测像素颜色的任务与绘图任务分开了
- 我已将 robots.getPixelColor(...) 替换为 robots.createScreenCapture(...) 以一次获取所有 64 个像素，而不是一次获取一个像素
- 我已经引入了智能剪裁 - 只有需要重绘的才会被重绘.
- 我已经修复了线程，因此模型和视图的所有更新都发生在事件调度线程上
自动收报机不断运行.当它检测到像素颜色的变化时(由于鼠标移动到不同的区域或鼠标下的像素发生变化)，它会准确地检测到发生了什么变化，更新模型，然后请求视图重新绘制.这种方法会立即更新到人眼中.289 次屏幕更新累计耗时 1 秒.
The ticker runs constantly. When it detects a change in pixel colour (either due to the mouse moving to a different region or the pixels under the mouse changing) it detects exactly what changed, updates the model, then requests the view to repaint. This approach updates instantly to the human eye. 289 screen updates took cumulatively 1 second.
对于一个安静的周六晚上来说，这是一个令人愉快的挑战.
It was an enjoyable challenge for a quiet Saturday evening.
import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
public class ZoomPanel extends JPanel {
private static final int STEP = 40;
private int iter = 0;
private long cumulativeTimeTaken = 0;
public static void main(String[] args) {
final JFrame frame = new JFrame("Image zoom");
final ZoomPanel zoomPanel = new ZoomPanel();
frame.getContentPane().add(zoomPanel);
final Ticker t = new Ticker(zoomPanel);
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
t.done();
frame.dispose();
}
});
t.start();
frame.setLocation(new Point(640, 0));
frame.pack();
frame.setVisible(true);
}
private final Color[][] model = new Color[8][8];
public ZoomPanel() {
setSize(new Dimension(400, 400));
setMinimumSize(new Dimension(400, 400));
setPreferredSize(new Dimension(400, 400));
setOpaque(true);
}
private void setColorAt(int x, int y, Color pixelColor) {
model[x][y] = pixelColor;
repaint(40 + x * STEP, 45 + y * STEP, 40 + (x * STEP) - 3, 45 + (y * STEP) - 3);
}
private Color getColorAt(int x, int y) {
return model[x][y];
}
public void paintComponent(Graphics g) {
long start = System.currentTimeMillis();
if (!SwingUtilities.isEventDispatchThread()) {
throw new RuntimeException("Repaint attempt is not on event dispatch thread");
}
final Graphics2D g2 = (Graphics2D) g;
g2.setColor(getBackground());
try {
for (int x = 0; x < 8; x++) {
for (int y = 0; y < 8; y++) {
g2.setColor(model[x][y]);
Ellipse2D e = new Ellipse2D.Double(40 + x * STEP, 45 + y * STEP, STEP - 3, STEP - 3);
g2.fill(e);
g2.setColor(Color.GRAY);
g2.draw(e);
}
}
} catch (Exception e) {
e.printStackTrace();
}
iter++;
g2.setColor(Color.black);
long stop = System.currentTimeMillis();
cumulativeTimeTaken += stop - start;
StringBuilder sb = new StringBuilder();
sb.append(iter)
.append(" frames in ")
.append((double) (cumulativeTimeTaken) / 1000)
.append("s.");
System.out.println(sb);
}
private static class Ticker extends Thread {
private final Robot robot;
public boolean update = true;
private final ZoomPanel view;
public Ticker(ZoomPanel zoomPanel) {
view = zoomPanel;
try {
robot = new Robot();
} catch (AWTException e) {
throw new RuntimeException(e);
}
}
public void done() {
update = false;
}
public void run() {
int runCount = 0;
while (update) {
runCount++;
if (runCount % 100 == 0) {
System.out.println("Ran ticker " + runCount + " times");
}
final Point p = MouseInfo.getPointerInfo().getLocation();
Rectangle rect = new Rectangle(p.x - 4, p.y - 4, 8, 8);
final BufferedImage capture = robot.createScreenCapture(rect);
for (int x = 0; x < 8; x++) {
for (int y = 0; y < 8; y++) {
final Color pixelColor = new Color(capture.getRGB(x, y));
if (!pixelColor.equals(view.getColorAt(x, y))) {
final int finalX = x;
final int finalY = y;
SwingUtilities.invokeLater(new Runnable() {
public void run() {
view.setColorAt(finalX, finalY, pixelColor);
}
});
}
}
}
}
}
}
}
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