CODEWITHSUNDEEP
javafxsystemcoordinate
user2827297
user2827297

Reputation: 11

Coordinate transformations in javafx

I want to have a right-handed Cartesian coordinate system in JavaFX, so (0,0) at lower left corner of window, x increasing to the right and y increasing upwards. I can't figure out how to do that with transforms. If I apply a rotation transform, the buttons will be upside down. All I want is to be able to use this coordinate system instead of the default one.

Upvotes: 1

Views: 3937

Answers (2)

beatngu13
beatngu13

Reputation: 9363

As mentioned in the JavaFX documentation (see chapter Y-down versus Y-up), Y down is used by many 2D graphics libraries, which is where JavaFX has started.

To force Y up and correct drawing, you could put all your content in a rotated parent node:

// Rotate camera to use Y up.
camera.setRotationAxis(Rotate.Z_AXIS);
camera.setRotate(180.0);

// Rotate scene content for correct drawing.
Group yUp = new Group();
yUp.setRotationAxis(Rotate.Z_AXIS);
yUp.setRotate(180.0);

Scene scene = new Scene(yUp);
scene.setCamera(camera);

Now add everything to yUp to use those nodes like in a Y up environment.

Bear in mind that this is fine in 2D space. If you come up with additional 3D features, make sure your models grow in negative Y direction. Otherwise you would have to use another container.

Upvotes: 1

Joe
Joe

Reputation: 474

JavaFX's prism renderer eventually uses a 3D Camera transform to render it's shapes.

There are two cameras that can be set to the scene, Parallel and Perspective.

If you look in the javafx source for parallel camera here you will find some maths to compute the transform. If you override that method and implement the proper maths, you should be able to invert the coordinate system.

The kind of math you would use is something like this.

You would have to look in the source to see what ortho does exactly. But this should get you on the right track.

Upvotes: 0

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