您需要添加2行代码来制作箭头(或使用相同的点创建一个填充箭头的多边形)。
请注意,箭头的方向可以根据“主”连接的线端点之间的差异确定。构成箭头的每条线的一端需要与主线的末端坐标相同。另一端可以通过将沿着主线方向的部分和垂直于主线的部分组合计算得出。
public class Arrow extends Group {
private final Line line;
public Arrow() {
this(new Line(), new Line(), new Line());
}
private static final double arrowLength = 20;
private static final double arrowWidth = 7;
private Arrow(Line line, Line arrow1, Line arrow2) {
super(line, arrow1, arrow2);
this.line = line;
InvalidationListener updater = o -> {
double ex = getEndX();
double ey = getEndY();
double sx = getStartX();
double sy = getStartY();
arrow1.setEndX(ex);
arrow1.setEndY(ey);
arrow2.setEndX(ex);
arrow2.setEndY(ey);
if (ex == sx && ey == sy) {
arrow1.setStartX(ex);
arrow1.setStartY(ey);
arrow2.setStartX(ex);
arrow2.setStartY(ey);
} else {
double factor = arrowLength / Math.hypot(sx-ex, sy-ey);
double factorO = arrowWidth / Math.hypot(sx-ex, sy-ey);
double dx = (sx - ex) * factor;
double dy = (sy - ey) * factor;
double ox = (sx - ex) * factorO;
double oy = (sy - ey) * factorO;
arrow1.setStartX(ex + dx - oy);
arrow1.setStartY(ey + dy + ox);
arrow2.setStartX(ex + dx + oy);
arrow2.setStartY(ey + dy - ox);
}
};
startXProperty().addListener(updater);
startYProperty().addListener(updater);
endXProperty().addListener(updater);
endYProperty().addListener(updater);
updater.invalidated(null);
}
public final void setStartX(double value) {
line.setStartX(value);
}
public final double getStartX() {
return line.getStartX();
}
public final DoubleProperty startXProperty() {
return line.startXProperty();
}
public final void setStartY(double value) {
line.setStartY(value);
}
public final double getStartY() {
return line.getStartY();
}
public final DoubleProperty startYProperty() {
return line.startYProperty();
}
public final void setEndX(double value) {
line.setEndX(value);
}
public final double getEndX() {
return line.getEndX();
}
public final DoubleProperty endXProperty() {
return line.endXProperty();
}
public final void setEndY(double value) {
line.setEndY(value);
}
public final double getEndY() {
return line.getEndY();
}
public final DoubleProperty endYProperty() {
return line.endYProperty();
}
}
使用
@Override
public void start(Stage primaryStage) {
Pane root = new Pane();
Arrow arrow = new Arrow();
root.getChildren().add(arrow);
root.setOnMouseClicked(evt -> {
switch (evt.getButton()) {
case PRIMARY:
arrow.setEndX(evt.getX());
arrow.setEndY(evt.getY());
break;
case SECONDARY:
arrow.setStartX(evt.getX());
arrow.setStartY(evt.getY());
break;
}
});
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}