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Paint with RxJava and JavaFx
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import javafx.application.Application; | |
import javafx.event.EventHandler; | |
import javafx.geometry.Point2D; | |
import javafx.scene.Group; | |
import javafx.scene.Scene; | |
import javafx.scene.canvas.Canvas; | |
import javafx.scene.canvas.GraphicsContext; | |
import javafx.scene.input.MouseEvent; | |
import javafx.stage.Stage; | |
import static javafx.scene.input.MouseEvent.*; | |
import rx.Observable; | |
import rx.Subscriber; | |
import rx.functions.Func1; | |
import rx.subscriptions.Subscriptions; | |
public class Paint extends Application { | |
@Override | |
public void start(Stage stage) throws Exception { | |
Integer screenWidth = 800; | |
Integer screenHeight = 600; | |
Canvas canvas = new Canvas(screenHeight, screenWidth); | |
GraphicsContext gc = canvas.getGraphicsContext2D(); | |
Group root = new Group(); | |
root.getChildren().add(canvas); | |
Observable<Boolean> leftButtonUp = leftButtonUp(canvas); | |
Observable<Boolean> leftButtonDown = leftButtonDown(canvas); | |
leftButtonUp.subscribe(up -> System.out.println("up: "+up)); | |
leftButtonDown.subscribe(down -> System.out.println("down: "+down)); | |
Observable<MouseEvent> mouseMoves = mouseMoves(canvas); | |
Observable<MouseEvent> mouseDrags = mouseDrags(canvas); | |
Observable<MouseEvent> mouse = Observable.merge(mouseMoves, mouseDrags); | |
Observable<Point2D[]> mouseDiffs = | |
mouse | |
.buffer(2, 1) | |
.map(buffer -> new Point2D[]{ | |
new Point2D(buffer.get(0).getX(), buffer.get(0).getY()), | |
new Point2D(buffer.get(1).getX(), buffer.get(1).getY()) | |
}); | |
Observable<Point2D[]> paint = | |
mouseDiffs | |
.window(leftButtonDown, (Boolean b) -> leftButtonUp) | |
.flatMap(x -> x); | |
paint.subscribe(diff -> { | |
gc.strokeLine(diff[0].getX(), diff[0].getY(),diff[1].getX(), diff[1].getY()); | |
}); | |
stage.setTitle("Rx Paint"); | |
stage.setScene(new Scene(root)); | |
stage.show(); | |
} | |
Observable<Boolean> leftButtonDown(Canvas canvas) { | |
return Observable.create((Subscriber<? super Boolean> subscriber) -> { | |
EventHandler<MouseEvent> handler = mouseEvent -> subscriber.onNext(true); | |
canvas.addEventHandler(MOUSE_PRESSED, handler); | |
subscriber.add(Subscriptions.create(() -> canvas.removeEventHandler(MOUSE_PRESSED, handler))); | |
}); | |
} | |
Observable<Boolean> leftButtonUp(Canvas canvas) { | |
return Observable.create((Subscriber<? super Boolean> subscriber) -> { | |
EventHandler<MouseEvent> handler = mouseEvent -> subscriber.onNext(false); | |
canvas.addEventHandler(MOUSE_RELEASED, handler); | |
subscriber.add(Subscriptions.create(() -> canvas.removeEventHandler(MOUSE_RELEASED, handler))); | |
}); | |
} | |
Observable<MouseEvent> mouseMoves(Canvas canvas) { | |
return Observable.create((Subscriber<? super MouseEvent> subscriber) -> { | |
EventHandler<MouseEvent> handler = subscriber::onNext; | |
canvas.addEventHandler(MOUSE_MOVED, handler); | |
subscriber.add(Subscriptions.create(() -> canvas.removeEventHandler(MOUSE_MOVED, handler))); | |
}); | |
} | |
Observable<MouseEvent> mouseDrags(Canvas canvas) { | |
return Observable.create((Subscriber<? super MouseEvent> subscriber) -> { | |
EventHandler<MouseEvent> handler = subscriber::onNext; | |
canvas.addEventHandler(MOUSE_DRAGGED, handler); | |
subscriber.add(Subscriptions.create(() -> canvas.removeEventHandler(MOUSE_DRAGGED, handler))); | |
}); | |
} | |
} |
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