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

[John Neffenger]

On Thu, 23 Apr 2020 22:43:30 GMT, John Neffenger <github.com+1413266+jgneff 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?

Wow, this is going to take some getting used to. �� Below is a photograph of the button and text with two changes:

1. the code from this pull request, and
2. the `javafx.platform.properties` file moved to its parent directory.

![withfix](https://user-images.githubusercontent.com/1413266/80160191-d344d380-8581-11ea-8fd4-09023ad30610.jpg)

The native screen on this platform returns 167 for its DPI. In general, the devices I'm testing have pixel densities of
either 167 or 300 pixels per inch.

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

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