Border flickering on resizing

[husker-dev]

If the user has a large screen resolution or weak hardware, then flickering appears when the window is resized. It's not very noticeable on FullHD monitors.

(Screenshot captured on 4K monitor)

[husker-dev]

This problem occurs because of compatibility with all devices, so the rendering algorithm looks like this:

GL frame buffer -> IntBuffer -> PixelBuffer -> WritableImage -> Window surface

The main problem here with the WritableImage - it takes a lot of time to create and show Also ImageView's properties fitWidth and fitHeight can't handle size difference as quickly as needed.

---

There is a way to avoid unnecessary steps, and turn the algorithm into the following:

GL frame buffer -> Window surface

(An example is in the mojtab23/jfxgl repository)

But the problem is that JavaFX uses different tools to render the image to the window. Direct3D for Windows, OpenGL for Linux and MacOS. Software Java2D is also used if none of the tools are available.

(Maybe I misunderstand the JavaFX rendering system)

---

So, there is no universal way to render content directly to the surface of a window.

[husker-dev]

In the current version of OpenGLFX flickering is fixed by optimization

[lqyaos]

Hello, I am now using jogl2.4 to implement NewtCanvasJFX. It provides a native window. I feel that this performance is the highest. I want to share with you and ask about the performance of this solution.

https://github.com/tpetrychyn/dockfx-newtcanvasjfx-example

[husker-dev]

Newt windows itself are cool, but mixing it with JavaFX is not the best idea.

I see several problems in using Newt as NewtCanvasJFX:

• It's just a "glued" window to main JavaFX one, so you can't draw/show elements over it
• Doesn't have HiDPI support
• Bad performance when resize (It's not flickering, but lagging)
• Large code for simple demo

When I looked into JavaFX's OpenGL implementations, this was the first thing I saw. It is not very bad, but it has some flaws that were critical in my application. So I decided to get rid of them in my OpenGLFX library

Here is 100% NewtCanvasJFX size on windows 1.75 scale:

[lqyaos]

I'm a little bit clueless about HiDPI, can I do it by adjusting the width and height? If I don't care about the resize lag, don't I need to consider HiDPI?

[husker-dev]

Yes, you can fix it by multiplying height and width by screen DPI.

Also you need to increase the size by 1px to remove the empty border (I think it has to do with floating-point calculation errors).

For example in Kotlin

scene.widthProperty().addListener { _, _, _ ->
    canvas.widthProperty().set(scene.width * scene.window.outputScaleX + 1)
}
scene.heightProperty().addListener { _, _, _ ->
    canvas.heightProperty().set(scene.height * scene.window.outputScaleX + 1)
}

Don't forget to get CURRENT window, not default. User could have two monitors with different DPI

Resizing lag and HiDPI are not related. So, I recommend you to implement this fix anyway for better application support.

[lqyaos]

Yes, it is finally high enough to start business development, thank you for your support