RFR: 8243255: Font size is large in JavaFX app with enabled Monocle on Raspberry Pi

[John Neffenger]

On Tue, 21 Apr 2020 16:47:44 GMT, Alexander Scherbatiy <alexsch at openjdk.org> wrote:

> See the detailed issue description on: http://mail.openjdk.java.net/pipermail/openjfx-dev/2020-April/025975.html
> 
> The fix 8236448 https://github.com/openjdk/jfx/pull/75 changes
> [MonocleApplication.staticScreen_getScreens()](https://github.com/openjdk/jfx/pull/75/files#diff-b66ff7fe72c6c5cd26003572ca901bfdL228)
> method code from
>> ns.getDPI(), ns.getDPI(), ns.getScale(), ns.getScale(), ns.getScale(), ns.getScale()
> 
>  to
>  > ns.getWidth(), ns.getHeight(), 1.f, 1.f, ns.getScale(), ns.getScale()"
> 
> so the font size is not properly calculated based on the given DPI value.
> 
> I left the platformScaleX and platformScaleY as 1.f because I do not know how it affects Android/Dalvik platform. On
> Raspberry Pi where I run JavaFX code with Monocle the DispmanScreen is used which have fixed scale 1.0 value so the app
> works in the same way.

I couldn't understand why I wasn't hitting this error on the embedded Monocle EPD platform. Stepping through the code
with the debugger, I found that JavaFX is looking for the *javafx.platform.properties* file in the wrong place. I moved
the file to its parent directory, the location JavaFX expects, and saw the problem right away.

The first image below shows the button and text without the properties file, and the second image shows the problem
once the properties file is loaded:

![normal](https://user-images.githubusercontent.com/1413266/80154159-e05ac600-8573-11ea-897b-49a82baaa10f.png)
![toobig](https://user-images.githubusercontent.com/1413266/80154165-e3ee4d00-8573-11ea-8b67-45670b17b7f1.png)

So there might be a secondary problem. After unzipping the SDK archive under *$HOME/lib*, the properties file is
located at the following location on my system:

/home/ubuntu/lib/armv6hf-sdk/lib/javafx.platform.properties

Yet
[`com.sun.javafx.PlatformUtil.loadProperties`](https://github.com/openjdk/jfx/blob/master/modules/javafx.base/src/main/java/com/sun/javafx/PlatformUtil.java#L248)
looks in the following three locations, in order:

/home/ubuntu/lib/armv6hf-sdk/javafx.platform.properties
/home/ubuntu/opt/jdk-14.0.1+7/lib/javafx.platform.properties
/javafx.platform.properties

The first is based on the "runtime directory," the second is based on the value of *java.home*, and the third is based
on the value of *javafx.runtime.path*, which is `null` on my system.

@AlexanderScherbatiy Did you move the *javafx.platform.properties* file to its parent directory manually, as I just did?

-------------

PR: https://git.openjdk.java.net/jfx/pull/193