我正在尝试围绕其中心旋转自定义形状，但无法获得预期的结果。
我想要的是
*形状应围绕其中心旋转而不移动自身。*
我的解决方案目前正在做的是 围绕其中心旋转整个形状，每次旋转都会改变其位置。
我有多个形状，所以我创建了一个类来封装一个形状及其在下面的类中的变换
public abstract class Shoe implements Shape, ShoeShape {
// variable declaration
/**
*
*/
public Shoe() {
position = new Point();
lastPosition = new Point();
}
public void draw(Graphics2D g2, AffineTransform transform, boolean firstTime) {
AffineTransform af = firstTime ? getInitTransform()
: getCompositeTransform();
if (af != null) {
Shape s = af.createTransformedShape(this);
if (getFillColor() != null) {
g2.setColor(getFillColor());
g2.fill(s);
} else {
g2.draw(s);
}
}
}
}
public AffineTransform getCompositeTransform() {
AffineTransform af = new AffineTransform();
af.setToIdentity();
af.translate(position.getX(), position.getY());
Point2D centerP = calculateShapeCenter();
af.rotate(orientation, centerP.getX(), centerP.getY());
return af;
}
public void onMouseDrag(MouseEvent me, Rectangle2D canvasBoundary,
int selectionOperation) {
// shape operation can be either resize , rotate , translate ,
switch (selectionOperation) {
case MmgShoeViewer.SHAPE_OPERATION_MOVE:
// MOVEMENT
break;
case MmgShoeViewer.SHAPE_OPERATION_ROTATE:
Point2D origin = calculateShapeCenter();
Point2D.Double starting = new Point2D.Double(me.getX(), me.getY());
currentAngle = RotationHelper.getAngle(origin, starting);
rotationAngle = currentAngle - startingAngle;
rotate(rotationAngle);
break;
case MmgShoeViewer.SHAPE_OPERATION_RESIZE:
break;
default:
System.out.println(" invalid select operation");
}
}
public void onMousePress(MouseEvent me, Rectangle2D canvasBoundary,
int selectionOperation) {
// shape operation can be either resize , rotate , translate ,
switch (selectionOperation) {
case MmgShoeViewer.SHAPE_OPERATION_MOVE:
break;
case MmgShoeViewer.SHAPE_OPERATION_ROTATE:
Point2D origin = calculateShapeCenter();
Point2D.Double starting = new Point2D.Double(me.getX(), me.getY());
startingAngle = RotationHelper.getAngle(origin, starting);
setShapeOperation(selectionOperation);
break;
case MmgShoeViewer.SHAPE_OPERATION_RESIZE:
break;
default:
System.out.println(" invalid select operation");
}
}
public void onMouseRelease(MouseEvent me, Rectangle2D canvasBoundary,
int selectionOperation) {
// shape operation can be either resize , rotate , translate ,
switch (selectionOperation) {
case MmgShoeViewer.SHAPE_OPERATION_MOVE:
break;
case MmgShoeViewer.SHAPE_OPERATION_ROTATE:
// FIXME rotation angle computation
setShapeOperation(-1);
break;
case MmgShoeViewer.SHAPE_OPERATION_RESIZE:
break;
default:
System.out.println(" invalid select operation");
}
}
public void rotate(double angle) {
orientation = (float) angle;
}
public void translate(double deltaX, double deltaY) {
position.setLocation(deltaX, deltaY);
lastPosition.setLocation(deltaX, deltaY);
}
// another getter and setter
我正在使用以下方法计算旋转角度
public static double getAngle(Point2D origin, Point2D other) {
double dy = other.getY() - origin.getY();
double dx = other.getX() - origin.getX();
double angle;
if (dx == 0) {// special case
angle = dy >= 0 ? Math.PI / 2 : -Math.PI / 2;
} else {
angle = Math.atan(dy / dx);
if (dx < 0) // hemisphere correction
angle += Math.PI;
}
// all between 0 and 2PI
if (angle < 0) // between -PI/2 and 0
angle += 2 * Math.PI;
return angle;
}
在画布鼠标侦听器的鼠标按下事件中
selectedShape.onMousePress(me, canvasBoundary, shoeViewer
.getShapeOperation());
我只是调用选定形状的 onMousePress 方法
在画布鼠标侦听器的鼠标拖动方法中，我只是调用所选形状的 onMouseDrag 方法，它会更新旋转角度，正如您从第一类中看到的那样
selectedShape.onMouseDrag(me, canvasBoundary, shoeViewer
.getShapeOperation());
你可以看到单个形状的绘制方法，根据当前变换绘制形状，我从paintComponent调用
Iterator<Shoe> shoeIter = shoeShapeMap.values().iterator();
while (shoeIter.hasNext()) {
Shoe shoe = shoeIter.next();
shoe.draw(g2, firstTime);
}
其中 shoeShapeMap 包含当前在画布上的所有自定义形状。
我在计算角度或确定锚点时做错了吗？我当前的解决方案通过检查所有条件 [90 度等] 将形状旋转 360 度，如您在上述方法中所见。
我希望形状应该围绕其中心旋转而不调整其位置？用这个词很难解释，所以请给我建议任何更好的方法来在这里展示我想要完成的事情？
我想我已经提到了与这个问题有关的所有事情。如果您有任何疑问，请随时问我。
我在这里找到了 2 个相关帖子，但我无法从他们那里找到太多信息。