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bytecodeman/GenerateATree.java Secret

Created Nov 18, 2019
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Generate a Tree Recursion GUI
package chapter18;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
public class GenerateATree extends Application {
@Override // Override the start method in the Application class
public void start(Stage primaryStage) {
TreePane pane = new TreePane();
TextField tfOrder = new TextField();
tfOrder.setOnAction(e -> pane.setDepth(Integer.parseInt(tfOrder.getText())));
tfOrder.setPrefColumnCount(4);
tfOrder.setAlignment(Pos.BOTTOM_RIGHT);
// Pane to hold label, text field, and a button
HBox hBox = new HBox(10);
hBox.getChildren().addAll(new Label("Enter an order: "), tfOrder);
hBox.setAlignment(Pos.CENTER);
BorderPane borderPane = new BorderPane();
borderPane.setCenter(pane);
borderPane.setBottom(hBox);
// Create a scene and place it in the stage
Scene scene = new Scene(borderPane, 200, 210);
primaryStage.setTitle("Exercise18_39");
primaryStage.setScene(scene);
primaryStage.show();
scene.widthProperty().addListener(ov -> pane.paint());
scene.heightProperty().addListener(ov -> pane.paint());
}
/** Pane for displaying triangles */
static class TreePane extends Pane {
private int depth = 0;
private double angleFactor = Math.PI / 5;
private double sizeFactor = 0.58;
private double startX = 0;
private double startY = 0;
public TreePane() {
this.setOnMouseDragged(e -> {
startX = e.getX();
startY = e.getY() + 40;
paint();
});
}
public void setDepth(int depth) {
this.depth = depth;
paint();
}
public void paint() {
getChildren().clear();
startX = getWidth() / 2;
startY = getHeight();
paintBranch(depth, startX, startY - 10, getHeight() / 3, Math.PI / 2);
}
public void paintBranch(int depth, double x1, double y1, double length, double angle) {
if (depth >= 0)
{
double x2 = x1 + Math.cos(angle) * length;
double y2 = y1 - Math.sin(angle) * length;
// Draw the line
getChildren().add(new Line(x1, y1, x2, y2));
// Draw the left branch
paintBranch(depth - 1, x2, y2, length * sizeFactor, angle + angleFactor);
// Draw the right branch
paintBranch(depth - 1, x2, y2, length * sizeFactor, angle - angleFactor);
}
}
}
public static void main(String[] args) {
launch(args);
}
}
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