Hi,

In Windows is very easy:

(...)
var
  VCanvas: TControlCanvas;
begin
  VCanvas := TControlCanvas.Create;
  try
    VCanvas.Control := Edit1;
    VCanvas.TextOut(0, 0, 'Test');
  finally
    VCanvas.Free;
  end;
end;
(...)

But, this code don't works in Linux (Ubuntu 11.04 / GTK2).

What the alternative to draw text in a TWinControl (GTK2)?

Thx.

2011/10/3 Hans-Peter Diettrich :
[...]

Invalidate the control, and wait for it's OnPaint request. DoDi

OnPaint in TWinControl?

2011/10/3 silvioprog :

So, I tried with WMPaint, but, without sucess too. X(

My test in attached.

Work only in Windows. x(

Win: http://imagebin.org/177323
Linux: http://imagebin.org/177324

It most probably doesn't work on a Mac, where painting is allowed only in during WM_PAINT.

What the alternative to draw text in a TWinControl (GTK2)?

Invalidate the control, and wait for it's OnPaint request.

DoDi

silvioprog wrote

My test in attached. Work only in Windows. x(

Yes, because widgetsets draws it's native controls, and some doesn't support painting outside of paint event (carbon, qt).
But even with that you can do such things. There's example on my wiki page how to paint whatever over TEdit control with qt widgetset (bottom of page). http://wiki.lazarus.freepascal.org/User:Zeljan

zeljko
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lazarus.freepascal.org/pipermail/lazarus/attachments/20111004/510bf73d/attachment.html>

silvioprog wrote

What the alternative to draw text in a TWinControl (GTK2)?

I would say that you should never try to draw anything or do any other attempt to customize a native control. If you do, you are guaranting that your code will not work in all widgetsets.

The real solution is to not use TEdit for this case, but instead create a TCDEdit which would be a custom drawn version of TEdit. There are already many custom drawn controls here:

http://wiki.lazarus.freepascal.org/Lazarus_Custom_Drawn_Controls

But not currently TCDEdit, but patches are welcome.

2011/10/4 zeljko :

I saw the Qt code, but don't know how to do this in GTK.

My intention was to create a placeholder without working in methods RealGetText/RealSetText. In Windows I can easily do with:

(...)
const
  ECM_FIRST = $1500;
  EM_SETCUEBANNER = ECM_FIRST + 1;
begin
  Edit1.Perform(EM_SETCUEBANNER, 0, LParam(PWideChar(WideString('Test'))));
end;
(...)

I gave up trying to do in GTK, with canvas. x(

Thanks to all.

Point is clear: WS must draw controll, after that you must be able to do some custom paints over it, or you can completely draw control. Some time ago I've thinking about adding 2 flags into TWinControl TControlStyle - csOwnerDraw and csOwnerDrawFull. They are valid only for ws controls which are fully painted from widgetset.
1.csOwnerDraw - control is painted by ws but after that paint message is delivered to LCL, so you can edd eg. small red triangle in TEdit corner. 2.csOwnerDrawFull - control is fully drawn by you, when an paint event occurs it's delivered to LCL, but stopped for ws, so it won't do any additional paintings.

zeljko
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lazarus.freepascal.org/pipermail/lazarus/attachments/20111005/4bb7184a/attachment.html>