[Lazarus] LCL and custom keyboard layouts

[Felipe Monteiro de Carvalho]

On Sat, Jan 28, 2012 at 2:32 PM, Mark Morgan Lloyd
<markMLl.lazarus at telemetry.co.uk> wrote:
> What is the situation with LCL editing components, Synedit, Cmdline and so
> on? Is there a single underlying keyboard component, or at least a uniform
> interface?
>
> In short, where do I start? :-)

All LCL applications use the TWinControl.OnKeyDown, OnKeyUp,
OnKeyPress and OnUTF8KeyPress events which give almost all information
about the keyboard. There is also LCLIntf.GetKeyState, but is less
used. All of those in the end are calls to the underlying widgetset
which does the real work, we just convert the result from the
widgetset into the formats supported by the LCL.

So you should not be thinking initially at LCL support for your
keyboard, but instead in supporting for example X11 (supposing we are
talking here only about Linux). I have no idea how X11 interfaces with
the keyboard, but the LCL interfaces with it via X11 (the most direct
relationship is only in the LCL-CustomDrawn widgetset, but I think
that Gtk and Qt use X11 too for their keyboard code). So if your
keyboard interfaces correctly with X11 then it should work with LCL
apps too.

Except for this the other idea which I would have is hacking the LCL
widgetset code to make use of your custom keyboard directly, but then
it won't work for pre-compiled applications. Doing this in the
LCL-CustomDrawn widgetset might be the easiest because it is the
smallest, but its X11 version still has no text support.

-- 
Felipe Monteiro de Carvalho