Homework SourseCreate a java project that Draw a circle with three random
Create a java project that:
- Draw a circle with three random initial points on the circle.
- Link the points to form a triangle.
- Print the angles values in the triangle.
- Use the mouse to drag a point along the perimeter of the circle. As you drag it, the triangle and angles are redisplayed dynamically.
Here is the formula to compute angles:
A = acos((a * a - b * b - c * c) / (-2 * b * c))
B = acos((b * b - a * a - c * c) / (-2 * a * c))
C = acos((c * c - b * b - a * a) / (-2 * a * b))
Solution
@Suppresswarnings(\"WeakerAccess\")
public class DragPoints extends Application {
@Override
public void start(Stage primaryStage) {
final PointPane pane = new PointPane(640, 480);
pane.setStyle(\"-fx-background-color: wheat;\");
Label label = new Label(\"Click and drag the points.\");
BorderPane borderPane = new BorderPane(pane);
BorderPane.setAlignment(label, Pos.CENTER);
label.setPadding(new Insets(5));
borderPane.setBottom(label);
Scene scene = new Scene(borderPane);
primaryStage.setTitle(\"Exercise15_21\");
primaryStage.setScene(scene);
primaryStage.show();
}
private class PointPane extends Pane {
final Circle circle = new Circle();
final Vertex[] v = new Vertex[3];
final int strokeWidth = 2;
final Color circleStroke = Color.GRAY, legStroke = Color.BLACK;
@SuppressWarnings(\"SameParameterValue\")
PointPane(double w, double h) {
this.setPrefSize(w, h);
this.setWidth(w);
this.setHeight(h);
circle.setStroke(circleStroke);
circle.setFill(Color.TRANSPARENT);
circle.setStrokeWidth(strokeWidth);
circle.radiusProperty().bind(this.heightProperty().multiply(0.4));
circle.centerXProperty().bind(this.widthProperty().divide(2));
circle.centerYProperty().bind(this.heightProperty().divide(2));
this.getChildren().add(circle);
for (int i = 0; i < v.length; i++) {
v[i] = new Vertex(circle, 2 * Math.PI / v.length * (i + Math.random()));
v[i].radiusProperty().bind(circle.radiusProperty().divide(10));
v[i].setPosition();
v[i].setStroke(new Color(i == 0 ? 1 : 0, i == 1 ? 1 : 0, i == 2 ? 1 : 0, 1));
v[i].setFill(Color.TRANSPARENT);
v[i].setStrokeWidth(strokeWidth);
this.getChildren().add(v[i]);
v[i].setOnMouseDragged(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
int i;
for (i = 0; i < v.length; i++)
if (v[i] == event.getSource())
break;
v[i].setAngle(event.getX(), event.getY());
moveUpdate((Vertex) event.getSource());
}
});
}
for (int i = 0; i < v.length; i++) {
int j = i + 1 < v.length ? i + 1 : 0;
int k = j + 1 < v.length ? j + 1 : 0;
v[i].bindLeg(v[j], v[k]);
v[i].leg.setStroke(legStroke);
v[i].leg.setStrokeWidth(strokeWidth);
this.getChildren().add(v[i].leg);
this.getChildren().add(v[i].text);
}
for(DoubleProperty p: new DoubleProperty[]
{circle.radiusProperty(), circle.centerXProperty(), circle.centerYProperty()})
p.addListener(new ResizeListener());
moveUpdate(v[0]);
}
void moveUpdate(Vertex vert) {
vert.setPosition();
double[] legLength = new double[3];
for (int i = 0; i < v.length; i++)
legLength[i] = v[i].getLegLength();
for (int i = 0; i < v.length; i++) {
int j = i + 1 < v.length ? i + 1 : 0;
int k = j + 1 < v.length ? j + 1 : 0;
double a = legLength[i], b = legLength[j], c = legLength[k];
double d = Math.toDegrees(Math.acos((a * a - b * b - c * c) / (-2 * b * c)));
v[i].setText(d);
}
}
private class ResizeListener implements ChangeListener<Number> {
@Override
public void changed(ObservableValue<? extends Number> observableValue, Number oldWidth, Number newWidth) {
for (Vertex aV : v) {
aV.setPosition();
}
}
}
}
private class Vertex extends Circle {
final Circle circle;
final Line leg;
final Text text;
double centerAngle;
Vertex(Circle circle, double centerAngle) {
this.circle = circle;
this.setAngle(centerAngle);
this.leg = new Line();
this.text = new Text();
this.text.setFont(Font.font(20));
this.text.setStroke(Color.BLACK);
this.text.setTextAlignment(TextAlignment.CENTER);
this.text.xProperty().bind(this.centerXProperty().add(25));
this.text.yProperty().bind(this.centerYProperty().subtract(10));
}
double getCenterAngle() {return this.centerAngle;}
void setPosition() {
this.setCenterX(circle.getCenterX() + circle.getRadius() * Math.cos(this.getCenterAngle()));
this.setCenterY(circle.getCenterY() + circle.getRadius() * Math.sin(this.getCenterAngle()));
}
void setAngle(double centerAngle) {
this.centerAngle = centerAngle;
}
void setAngle(double x, double y) {
this.setAngle(Math.atan2(y - circle.getCenterY(), x - circle.getCenterX()));
}
void bindLeg(Vertex v1, Vertex v2) {
leg.startXProperty().bind(v1.centerXProperty());
leg.startYProperty().bind(v1.centerYProperty());
leg.endXProperty().bind(v2.centerXProperty());
leg.endYProperty().bind(v2.centerYProperty());
}
double getLegLength() {
return Math.sqrt(Math.pow(leg.getStartX()-leg.getEndX(),2) + Math.pow(leg.getStartY()-leg.getEndY(),2));
}
void setText(double angle) {
this.text.setText(String.format(\"%.0f\\u00B0\", angle));
}
}
}
| @Suppresswarnings(\"WeakerAccess\") public class DragPoints extends Application { |
| @Override |
| public void start(Stage primaryStage) { |
| final PointPane pane = new PointPane(640, 480); |
| pane.setStyle(\"-fx-background-color: wheat;\"); |
| Label label = new Label(\"Click and drag the points.\"); |
| BorderPane borderPane = new BorderPane(pane); |
| BorderPane.setAlignment(label, Pos.CENTER); |
| label.setPadding(new Insets(5)); |
| borderPane.setBottom(label); |
| Scene scene = new Scene(borderPane); |
| primaryStage.setTitle(\"Exercise15_21\"); |
| primaryStage.setScene(scene); |
| primaryStage.show(); |
| } |
| private class PointPane extends Pane { |
| final Circle circle = new Circle(); |
| final Vertex[] v = new Vertex[3]; |
| final int strokeWidth = 2; |
| final Color circleStroke = Color.GRAY, legStroke = Color.BLACK; |
| @SuppressWarnings(\"SameParameterValue\") |
| PointPane(double w, double h) { |
| this.setPrefSize(w, h); |
| this.setWidth(w); |
| this.setHeight(h); |
| circle.setStroke(circleStroke); |
| circle.setFill(Color.TRANSPARENT); |
| circle.setStrokeWidth(strokeWidth); |
| circle.radiusProperty().bind(this.heightProperty().multiply(0.4)); |
| circle.centerXProperty().bind(this.widthProperty().divide(2)); |
| circle.centerYProperty().bind(this.heightProperty().divide(2)); |
| this.getChildren().add(circle); |
| for (int i = 0; i < v.length; i++) { |
| v[i] = new Vertex(circle, 2 * Math.PI / v.length * (i + Math.random())); |
| v[i].radiusProperty().bind(circle.radiusProperty().divide(10)); |
| v[i].setPosition(); |
| v[i].setStroke(new Color(i == 0 ? 1 : 0, i == 1 ? 1 : 0, i == 2 ? 1 : 0, 1)); |
| v[i].setFill(Color.TRANSPARENT); |
| v[i].setStrokeWidth(strokeWidth); |
| this.getChildren().add(v[i]); |
| v[i].setOnMouseDragged(new EventHandler<MouseEvent>() { |
| @Override |
| public void handle(MouseEvent event) { |
| int i; |
| for (i = 0; i < v.length; i++) |
| if (v[i] == event.getSource()) |
| break; |
| v[i].setAngle(event.getX(), event.getY()); |
| moveUpdate((Vertex) event.getSource()); |
| } |
| }); |
| } |
| for (int i = 0; i < v.length; i++) { |
| int j = i + 1 < v.length ? i + 1 : 0; |
| int k = j + 1 < v.length ? j + 1 : 0; |
| v[i].bindLeg(v[j], v[k]); |
| v[i].leg.setStroke(legStroke); |
| v[i].leg.setStrokeWidth(strokeWidth); |
| this.getChildren().add(v[i].leg); |
|
|
| this.getChildren().add(v[i].text); |
| } |
| for(DoubleProperty p: new DoubleProperty[] |
| {circle.radiusProperty(), circle.centerXProperty(), circle.centerYProperty()}) |
| p.addListener(new ResizeListener()); |
| moveUpdate(v[0]); |
| } |
| void moveUpdate(Vertex vert) { |
| vert.setPosition(); |
| double[] legLength = new double[3]; |
| for (int i = 0; i < v.length; i++) |
| legLength[i] = v[i].getLegLength(); |
| for (int i = 0; i < v.length; i++) { |
| int j = i + 1 < v.length ? i + 1 : 0; |
| int k = j + 1 < v.length ? j + 1 : 0; |
| double a = legLength[i], b = legLength[j], c = legLength[k]; |
| double d = Math.toDegrees(Math.acos((a * a - b * b - c * c) / (-2 * b * c))); |
| v[i].setText(d); |
| } |
| } |
| private class ResizeListener implements ChangeListener<Number> { |
| @Override |
| public void changed(ObservableValue<? extends Number> observableValue, Number oldWidth, Number newWidth) { |
| for (Vertex aV : v) { |
| aV.setPosition(); |
| } |
| } |
| } |
| } |
| private class Vertex extends Circle { |
| final Circle circle; |
| final Line leg; |
| final Text text; |
| double centerAngle; |
| Vertex(Circle circle, double centerAngle) { |
| this.circle = circle; |
| this.setAngle(centerAngle); |
| this.leg = new Line(); |
| this.text = new Text(); |
| this.text.setFont(Font.font(20)); |
| this.text.setStroke(Color.BLACK); |
| this.text.setTextAlignment(TextAlignment.CENTER); |
| this.text.xProperty().bind(this.centerXProperty().add(25)); |
| this.text.yProperty().bind(this.centerYProperty().subtract(10)); |
| } |
| double getCenterAngle() {return this.centerAngle;} |
| void setPosition() { |
| this.setCenterX(circle.getCenterX() + circle.getRadius() * Math.cos(this.getCenterAngle())); |
| this.setCenterY(circle.getCenterY() + circle.getRadius() * Math.sin(this.getCenterAngle())); |
| } |
| void setAngle(double centerAngle) { |
| this.centerAngle = centerAngle; |
| } |
| void setAngle(double x, double y) { |
| this.setAngle(Math.atan2(y - circle.getCenterY(), x - circle.getCenterX())); |
| } |
| void bindLeg(Vertex v1, Vertex v2) { |
| leg.startXProperty().bind(v1.centerXProperty()); |
| leg.startYProperty().bind(v1.centerYProperty()); |
| leg.endXProperty().bind(v2.centerXProperty()); |
| leg.endYProperty().bind(v2.centerYProperty()); |
| } |
| double getLegLength() { |
| return Math.sqrt(Math.pow(leg.getStartX()-leg.getEndX(),2) + Math.pow(leg.getStartY()-leg.getEndY(),2)); |
| } |
| void setText(double angle) { |
| this.text.setText(String.format(\"%.0f\\u00B0\", angle)); |
| } |
| } |
| } |
