我有以下类来旋转图像，当我给它旋转的程度，但它不能正常工作。问题在于，例如，如果我旋转90度，则旋转后，rotateCrossing（）内的变量“currentRotationAngle”逐渐设置为90。发生这种情况是因为我总是通过偏移量（10）增加该变量。
下次我要旋转180度，因为变量已经是90，它只旋转另一个90（90 + 90 = 180）而不是整个180度。我试图通过在“stop（）”方法中将“currentRotationAngle”设置为0来修复它，只要旋转结束，它就会让旋转返回到它的起始位置。
这就是我想要的，当我给它度数时，我希望它从最后一个旋转位置开始精确旋转到那个度数。请以下是课程。
public class CrossingPanel extends JPanel{
private static final long serialVersionUID = 1L;
// private data members
private Image crossingImage;
private int currentRotationAngle;
private int imageWidth;
private int imageHeight;
private AffineTransform affineTransform;
private boolean clockwise;
private static int ROTATE_ANGLE_OFFSET = 10;
private boolean finishRotation = false;
private int degreesToTurn;
private static int LENGTH = 75;
private static int RAIL_LENGTH = 130;
private int ARROWLENGTH = 4;
private static int TICKSIZE = 10;
private GeneralPath path;
private int xCoordinate;
private int yCoordinate;
private javax.swing.Timer timer;
private void initialize(){
//this.crossingImage = getImage("images/railCrossing.JPG");
this.crossingImage = Toolkit.getDefaultToolkit().getImage("images/crossingsHorizontal.JPG");
// MediaTracker mt = new MediaTracker(this);
// mt.addImage(this.crossingImage, 1);
this.path = new GeneralPath();
this.imageWidth = this.getCrossingImage().getWidth(this);
this.imageHeight = this.getCrossingImage().getHeight(this);
this.affineTransform = new AffineTransform();
this.setCurrentRotationAngle(0);
this.setDegreesToTurn(0);
timer = new javax.swing.Timer(20, new MoveListener());
// timer.start();
}
public CrossingPanel(int x, int y/*, BufferedImage img*/) {
this.setxCoordinate(x);
this.setyCoordinate(y);
this.setPreferredSize(new Dimension(50, 50));
this.setBackground(Color.red);
TitledBorder border = BorderFactory.createTitledBorder("image");
//this.setBorder(border);
this.setLayout(new FlowLayout());
this.initialize();
}
public GeneralPath getPath() {
return path;
}
public void setPath(GeneralPath path) {
this.path = path;
}
private void constructInterfaceComponents(){
}
private Shape createVerticalRail(){
//System.out.print("dddd: " + this.LENGTH + "\n");
this.getPath().moveTo(0, LENGTH);
this.getPath().lineTo(RAIL_LENGTH,75);
float cm = 72 / 2.54f;
float lengthCentimeter = RAIL_LENGTH;
for (float i = 260.0f, j = 340; i >= 0; i -= 15.0f, j += 20) {
float tick = i * cm;
// path.moveTo(340, i);
// path.lineTo(360, i);
}
this.getPath().closePath();
return this.getPath();
}
public void paintComponent(Graphics grp){
Rectangle rect = this.getBounds();
Graphics2D g2d = (Graphics2D)grp;
//set the background color to black
g2d.setColor(Color.BLACK);
// g2d.draw(this.createVerticalRail());
//set the translation to the mid of the component
this.getAffineTransform().setToTranslation(this.getxCoordinate(), this.getyCoordinate());
//rotate with the rotation point as the mid of the image
this.getAffineTransform().rotate(Math.toRadians(this.getCurrentRotationAngle()), this.getCrossingImage().getWidth(this) /2,
this.getCrossingImage().getHeight(this)/2);
//draw the image using the AffineTransform
g2d.drawImage(this.getCrossingImage(), this.getAffineTransform(), this);
}
public void rotateCrossing(int degrees){
// this condition is there to avoid division of zero
// and also there is no need to rotate 0 degrees
if(degrees == 0){
this.stop();
return;
}
currentRotationAngle += ROTATE_ANGLE_OFFSET;
if (currentRotationAngle % degrees == 0) {
timer.stop();
this.finishRotation = true;
}
repaint();
}
public int getDegreesToTurn() {
return degreesToTurn;
}
public void setDegreesToTurn(int degreesToTurn) {
this.degreesToTurn = degreesToTurn;
}
private class MoveListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
rotateCrossing(degreesToTurn);
}
}
void start(int degreesToTurn) {
if (timer != null) {
timer.start();
}
this.setDegreesToTurn(degreesToTurn);
}
void stop() {
timer.stop();
this.setCurrentRotationAngle(0);
}
public Image getCrossingImage() {
return crossingImage;
}
public void setCrossingImage(Image crossingImage) {
this.crossingImage = crossingImage;
}
public int getCurrentRotationAngle() {
return currentRotationAngle;
}
public void setCurrentRotationAngle(int currentRotationAngle) {
this.currentRotationAngle = currentRotationAngle;
}
public int getImageWidth() {
return imageWidth;
}
public void setImageWidth(int imageWidth) {
this.imageWidth = imageWidth;
}
public int getImageHeight() {
return imageHeight;
}
public void setImageHeight(int imageHeight) {
this.imageHeight = imageHeight;
}
public AffineTransform getAffineTransform() {
return affineTransform;
}
public void setAffineTransform(AffineTransform affineTransform) {
this.affineTransform = affineTransform;
}
public boolean isClockwise() {
return clockwise;
}
public void setClockwise(boolean clockwise) {
this.clockwise = clockwise;
}
public int getxCoordinate() {
return xCoordinate;
}
public void setxCoordinate(int xCoordinate) {
this.xCoordinate = xCoordinate;
}
public int getyCoordinate() {
return yCoordinate;
}
public void setyCoordinate(int yCoordinate) {
this.yCoordinate = yCoordinate;
}
public javax.swing.Timer getTimer() {
return timer;
}
public void setTimer(javax.swing.Timer timer) {
this.timer = timer;
}
public boolean isFinishRotation() {
return finishRotation;
}
public void setFinishRotation(boolean finishRotation) {
this.finishRotation = finishRotation;
}
}
我希望有人帮我修复它。
谢谢大家。
答案 0 :(得分：0)
这个方法对于度参数的目的是多么奇怪？ 我想你用相同的度数值多次调用这个方法。在这种情况下，您应该使用度数的绝对值（270不是180）。
public void rotateCrossing(int degrees){
// this condition is there to avoid division of zero
if(degrees == 0){
this.stop();
return;
}
currentRotationAngle += ROTATE_ANGLE_OFFSET;
if (currentRotationAngle % degrees == 0) { // this line isn't correct I think
timer.stop();
this.finishRotation = true;
}
repaint();
}
我建议使用以下代码：
private class MoveListener implements ActionListener {
private int cyclesToGo;
public MoveListener(){
cyclesToGo = CrossingPanel.this.degreesToTurn / ROTATE_ANGLE_OFFSET; // how many time to call repaint
}
public void actionPerformed(ActionEvent e) {
if (cyclesToGo-- > 0) rotateCrossing();
else {
CrossingPanel.this.stop(); // call outer class methods
CrossingPanel.this.finishRotation = true; // call outer class methods
}
}
}
// this method increments currentRotationAngle and calles repaint
public void rotateCrossing(){
currentRotationAngle += ROTATE_ANGLE_OFFSET;
repaint();
}