Make Rectangle transparent

Question

I need to make a drawn rectangle mouse transparent, in order to see the desktop. The following code draws my rectangle. What should I add to get that ? Thanks for help

public void start(Stage primaryStage) {
    Group group = new Group();

    Rectangle rect = new Rectangle(20,20,200,200);

    rect.setArcHeight(15);
    rect.setArcWidth(15);

    rect.setStroke(Color.BLACK);
    group.getChildren().add(rect);

    Scene scene = new Scene(group, 300, 200);
    primaryStage.setScene(scene);
    primaryStage.show();
}

Can you clarify? If you want to see the desktop, you will need the window to be transparent, but perhaps that is not what you mean? — James_D, Oct 06 '14 at 20:09

score 5 · Answer 1 · answered Oct 06 '14 at 20:21

5

If you just want the interior of the rectangle to be transparent, then all you need is

rect.setFill(Color.TRANSPARENT);

but I'm not quite sure if this is what you mean.

answered Oct 06 '14 at 20:21

James_D

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score 3 · Accepted Answer · answered Oct 07 '14 at 06:43

3

Since the screen graph in JavaFX is in a hierarchical structure, to show desktop you need to also make the Stage and Scene transparent, and use shape "arithmetic":

@Override
public void start(Stage stage) {
    Group group = new Group();
    Rectangle rect = new Rectangle(0, 0, 350, 300);
    Rectangle clip = new Rectangle(20, 20, 200, 200);
    clip.setArcHeight(15);
    clip.setArcWidth(15);

    Shape shape = Shape.subtract(rect, clip);

    shape.setFill(Color.GRAY);
    group.getChildren().add(shape);
    Scene scene = new Scene(group);
    scene.setFill(Color.TRANSPARENT);
    stage.initStyle(StageStyle.TRANSPARENT);
    stage.setScene(scene);
    stage.show();
}

Later you can add draggable feature to the pane/group.

answered Oct 07 '14 at 06:43

Uluk Biy

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Thanks for help. The draggable feature is my next aim. Should I open a new question, because I cannot get it ? – Stéphane GROSSMANN Oct 08 '14 at 09:26
@StéphaneGROSSMANN see [this answer](http://stackoverflow.com/a/22960073) for the hint.. If it doesn't help yes you can open new question. – Uluk Biy Oct 08 '14 at 10:39
I put this http://stackoverflow.com/questions/26254354/resizing-a-substraction-shape But no answer :-( Tks anyway – Stéphane GROSSMANN Oct 08 '14 at 13:22

Kamil Janyga · Answer 3 · 2014-10-06T19:24:37.333

0

If I understand you correctly as I don't get this mouse part of 'drawn rectangle mouse transparent' - your rectangle should be transparent?

You have to change the opacity of a rectangle: rect.opacityProperty().set(0.5);

edited Oct 06 '14 at 19:24

answered Oct 06 '14 at 18:56

Kamil Janyga

86
9

if you mean this : rect.setStroke(new javafx.scene.paint.Color(0, 0, 0, 0)); turns it to black – Stéphane GROSSMANN Oct 06 '14 at 19:05
With 1, the rectangle is black too :-( – Stéphane GROSSMANN Oct 06 '14 at 19:12
1

Check the edited answer. :) Sadly you cannot just apply a transparent color. You have to specify an alpha channel of a rectangle (strange, strange...). So closer to 0.0 is more transparent 1.0 is solid. – Kamil Janyga Oct 06 '14 at 19:26
Great ! That's what I wanted. Thanks a lot :-) – Stéphane GROSSMANN Oct 07 '14 at 15:50

Make Rectangle transparent

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