图形上下文在第一次绘制时未对齐
Mad*_*mer 15 java swing affinetransform
我一直在为另一个问题找到答案,并遇到了一个我以前从未见过的奇怪问题......
基本上,程序使用a AffineTransform来提供Graphics元素的翻译,缩放和旋转,简单的东西,之前完成了一千次
问题是,当屏幕第一次出现时,输出不是它应该的位置,但是一旦我触摸其中一个控件(调整其中一个幻灯片),它就会跳到正确的位置.
根据屏幕截图,Graphics内容似乎被其他控件的数量错位.
如果我从GUI中删除控件,它将出现在正确的位置(位于中心).如果我调整窗口的大小,它并没有解决这个问题,它只有当滑块之一触发修复repaint的DrawPane...
我已经在输出中添加了诊断信息,并且所有值都相同 - 也就是说,它们在程序首次启动时以及将所有滑块值调整为初始值时打印相同的值.
如果我从中删除setRotation和setScale调用AffineTransform,它不会修复它.如果我删除了setTranslation,则在面板更新之前,方块最初不会被绘制(它在屏幕外绘制)
如果我使用Graphics2D g2d = (Graphics)g;而不是g.create()相同的结果(是的,我在paintComponent退出方法之前重置转换;))
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.geom.AffineTransform;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class Parker {
public static void main(String[] args) {
new Parker();
}
public Parker() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new ControlPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ControlPane extends JPanel {
private JSlider slider; //declare slider
private DrawPane myPanel;
public ControlPane() {
setLayout(new BorderLayout());
myPanel = new DrawPane();
myPanel.setBackground(Color.cyan); //change background color
slider = new JSlider(SwingConstants.VERTICAL, 0, 400, 100);// restrains the slider from scaling square to 0-300 pixels
slider.setMajorTickSpacing(20); //will set tick marks every 10 pixels
slider.setPaintTicks(true); //this actually paints the ticks on the screen
slider.addChangeListener(
new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
myPanel.setScale(slider.getValue()); //Wherever you set the slider, it will pass that value and that will paint on the screen
}
}
);
JSlider rotate = new JSlider(SwingConstants.VERTICAL, 0, 720, 0);
rotate.setMajorTickSpacing(20); //will set tick marks every 10 pixels
rotate.setPaintTicks(true); //this actually paints the ticks on the screen
rotate.addChangeListener(
new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
JSlider slider = (JSlider) e.getSource();
myPanel.setAngle(slider.getValue());
}
}
);
add(slider, BorderLayout.WEST);
add(rotate, BorderLayout.EAST);
add(myPanel);
slider.setValue(0);
slider.setValue(100);
rotate.setValue(0);
}
}
public class DrawPane extends JPanel {
private double scale = 1;
private double angle = 0;
private final int rectWidth = 20;
private final int rectHeight = 20;
@Override
protected void paintComponent(Graphics g)//paints obj on the screen
{
super.paintComponent(g); //prepares graphic object for drawing
int originX = getWidth() / 2;
int originY = getHeight() / 2;
int xOffset = -(rectWidth / 2);
int yOffset = -(rectHeight / 2);
g.setColor(Color.BLACK);
Graphics2D g2d = (Graphics2D) g.create();
AffineTransform at = new AffineTransform();
at.translate(originX, originY);
g2d.setTransform(at);
g2d.scale(scale, scale);
g2d.rotate(Math.toRadians(angle), 0, 0);
g2d.fillRect(xOffset, yOffset, rectWidth, rectHeight);
g2d.dispose();
g.setColor(Color.RED);
g.drawRect(originX + xOffset, originY + yOffset, rectWidth, rectWidth);
}
public void setAngle(double angle) {
this.angle = angle;
repaint();
}
public void setScale(int scale) {
// Scaling is normalized so that 1 = 100%
this.scale = (scale / 100d);
repaint();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
}
基本上,似乎Graphics上下文由于某种原因在第一次绘制时没有被正确翻译,我不知道为什么......
ps-在Windows 7下对Java 6和Java 7进行测试
pps-我也尝试在屏幕可见之前将初始比例和旋转设置为其他值,结果相同
系统属性
awt.toolkit=sun.awt.windows.WToolkit
file.encoding=UTF-8
file.encoding.pkg=sun.io
file.separator=\
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
java.awt.printerjob=sun.awt.windows.WPrinterJob
java.class.path=C:\DevWork\personal\java\projects\wip\SystemProperties\build\classes
java.class.version=51.0
java.endorsed.dirs=C:\Program Files\Java\jdk1.7.0_51\jre\lib\endorsed
java.ext.dirs=C:\Program Files\Java\jdk1.7.0_51\jre\lib\ext;C:\Windows\Sun\Java\lib\ext
java.home=C:\Program Files\Java\jdk1.7.0_51\jre
java.io.tmpdir=C:\Users\shane\AppData\Local\Temp\
java.runtime.name=Java(TM) SE Runtime Environment
java.runtime.version=1.7.0_51-b13
java.specification.name=Java Platform API Specification
java.specification.vendor=Oracle Corporation
java.specification.version=1.7
java.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
java.vendor.url.bug=http://bugreport.sun.com/bugreport/
java.version=1.7.0_51
java.vm.info=mixed mode
java.vm.name=Java HotSpot(TM) 64-Bit Server VM
java.vm.specification.name=Java Virtual Machine Specification
java.vm.specification.vendor=Oracle Corporation
java.vm.specification.version=1.7
java.vm.vendor=Oracle Corporation
java.vm.version=24.51-b03
os.arch=amd64
os.name=Windows 7
os.version=6.1
path.separator=;
sun.arch.data.model=64
sun.cpu.endian=little
sun.cpu.isalist=amd64
sun.desktop=windows
sun.io.unicode.encoding=UnicodeLittle
sun.java.command=systemproperties.SystemProperties
sun.java.launcher=SUN_STANDARD
sun.jnu.encoding=Cp1252
sun.management.compiler=HotSpot 64-Bit Tiered Compilers
sun.os.patch.level=Service Pack 1
user.country=AU
user.dir=C:\DevWork\personal\java\projects\wip\SystemProperties
user.home=C:\Users\shane
user.language=en
user.name=shane
user.script=
user.timezone=
user.variant=
更新
如果我用...
g2d.translate(originX, originY);
g2d.scale(scale, scale);
g2d.rotate(Math.toRadians(angle), 0, 0);
而不是AffineTransform,它工作正常.我注意到我使用的方式并不重要AffineTransform(仅翻译,仅旋转,仅缩放)我似乎得到相同的结果
更新了示例图像
显示调整框架的示例...
nb矩形的最后位置偏移是MouseListener下面提到的结果
但是,如果我添加MosueListener到DrawPane(类或者照片直接内或经由外部myPanel实例),并调用repaint上mouseClicked,它正确地重新对准:P
更新
如果我翻译a Shape,使用以下内容
AffineTransform at = new AffineTransform();
at.translate(originX, originY);
at.scale(scale, scale);
at.rotate(Math.toRadians(angle), 0, 0);
g2d.setTransform(at);
Rectangle2D rect = new Rectangle2D.Double(xOffset, yOffset, rectWidth, rectHeight);
Shape shape = at.createTransformedShape(rect);
System.out.println(rect.getBounds());
System.out.println(shape.getBounds());
结果输出符合预期,但(图形)输出仍然是错误的......
在AffineTransform与传递到图形上下文关联paintComponent()并不总是恒等变换.由于不清楚的原因,m12条目38.0最初具有值,并且在调整封闭框架的大小之后.通俗易懂,可以修改由提供的副本g.create().
Graphics2D g2d = (Graphics2D) g.create();
AffineTransform at = g2d.getTransform();
at.translate(originX, originY);
g2d.setTransform(at);
g2d.scale(scale, scale);
g2d.rotate(Math.toRadians(angle), 0, 0);
g2d.fillRect(xOffset, yOffset, rectWidth, rectHeight);
g2d.dispose();
附录:正如@MadProgrammer观察到的那样,"如果我从GUI中删除控件,它就会出现......在中心." 实际上,观察到的水平偏移恰好是sliderin 的优选宽度BorderLayout.WEST.我怀疑在调整大小后调整原点以Component#paintAll()更容易地满足合同:"图形上下文的原点,它的(0, 0)坐标点,是该组件的左上角."
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