← Back to team overview

kicad-developers team mailing list archive

Re: zoom steps


Vesa Solonen a écrit :

Thank you for your through explanation of KiCad history. It was really

On Fri, 23 Jan 2009, jean-pierre. charras@inpg. fr <mailto:jean-pierre.charras%40inpg.fr> wrote:

> I did not say: do not use wxDC capabilities,
> but i believe the clipping at kicad level remains useful, and perhaps
> (Alas!) mandatory for some graphic shapes.(to be tested for arcs ...)

Couldn't these overflow problems be easily gone by using wxCG for
graphics. Double precision float coordinates won't owerflow in the near

Overflows are not in wxDC ou wxWidget code
In wxDC, all scaling calculations are already made in double, and coordinates use long, like kicad and often doubles ).
I am pretty sure wxWidgets is not guilty.
They were at low level code (Windows 95/98 graphic layer is known to handle pixel coordinates using shorts; I did not tested XP graphic layer), and we cannot do anything but clip items to draw before send them to the low level graphic functions that creates problems.

I believe overflows under Linux are also at low level code (not in wxWidget code).

So I am not sure wxCG solves these problems, if it sends objets to low level graphic functions without clipping. (also note: wxCG is easy to use under Linux, but very tricky under Windows, if using gcc)

Jean-Pierre CHARRAS
Maître de conférences
Directeur d'études 2ieme année.
Génie Electrique et Informatique Industrielle 2
Institut Universitaire de Technologie 1 de Grenoble
BP 67, 38402 St Martin d'Heres Cedex

Recherche :
Grenoble Image Parole Signal Automatique (GIPSA - INPG)
Grenoble France