[Lazarus] Scaling of menuitem icons

[zeljko]

On 10/19/2018 10:15 AM, Ondrej Pokorny via Lazarus wrote:
>  >  On my Linux + KDE system however icons of the IDE's main menuitems 
> do not scale.
>  > In KDE settings panel -> Fonts I set the "Force font's DPI" value to 
> 144 which is about 150%.
> 
> I remember I worked on it:
> 
> 1.) Gtk2: I added support for Gtk2. See screenshot. It works well for me 
> if I use "xrandr --dpi 144x144" as it is suggested in 
> http://wiki.lazarus.freepascal.org/High_DPI
> 
> Your settings revealed a bug in Gtk2 bindings. Patch is attached.
> 
> 2.) Qt: I wasn't able to add support of high-resolution icons in menus 
> under Qt. My conclusion was that either Qt itself or LCL-Qt bindings do 
> not support big icons in menus. When I used the correct size icon in the 
> menu it was always (badly) downscaled to 16x16 pixels.

Probably the only solution is to use QProxyStyle class.
There's no QProxyStyle class in Qt4/Qt5 C bindings and to fix this 
problem it should be implemented with it's overrides.
QProxyStyle can return any size for PM_SmallIconSize, but in that case 
we should know what's the current size of "normal" icons in LCL.

zeljko