[Guidolib-devel] Re: GGS & GDevicePostScript

[J. S. A. <js...@sh...>]

Hi Jerome,

On Fri, 2004-03-05 at 02:28, Jerome Berthet wrote:
>          - Splitting GDevice in two classes: one for vector graphics 
> (GDevice), and
>            one for fonts management i.e: GPlateformFontMgr. The GDevice could
>          embed its FontManager (thus, that would similar to the current 
> implementation),
>          then GuidoInitDesc would just require a FontManager. Providing a 
> graphic device
>          at initialisation is definitely strange, but providing a font 
> manager would make
>          more sense. I think it would not be too much work to convert 
> existing devices to
>          this design. What do you think about it ?

I've gone ahead with this implementation.  It appears to work fine (that
is, it compiles, I haven't done any real form of exhaustive testing :-)
).  What I have done is create a GFontManager class that contains the
font and bitmap routines (the bitmap routines are really just stubs as
it doesn't seem to be fully implemented yet).  The GuidoInitDesc now
only requires the GFontManager instead of the VGDevice.  The base
GFontManager reads in a file that contains font metric data and uses
that to implement the various GetScreenExtent, GetTextExtent, etc.
routines.  Then, similar to the VGDevice model, child classes can be
created (i.e. GFontManagerWin32, GFontManagerPS, etc.) that override
those routines with their device specific implementations.  As well, I
have embedded a GFontManager instance (gFontManager) into VGDevice, so
that when any graphic device object is created, it attaches a font
manager to itself.  This has allowed for very minimal code changes,
mostly just relocating routines and creating a few pointers to the new
objects, while still allowing for a device-independent interface with
which to implement the GGS.  However, it will break all the current
applications/libraries due to the addition of a required GFontManager
pointer to the VGDevice constructor as well as the change in
GuidoInitDesc.  I have implemented the base GFontManager, a
GFontManagerPS (postscript), GFontManagerWin32 (win32) and
GFontManagerWin2000 (win2000), however, I have not altered any of the
applications.  I don't believe it will be terribly difficult to fix
these, I just haven't done so yet.  Additionally, my familiarity with
OSX programming is very minimal, so I have not yet approached that
aspect.  At this point, I would like to have you and the others take a
look at what I have done and comment, but I think it may be prudent to
create a new branch in the cvs for this (perhaps a ggs branch as I will
begin to add in routines for that quite soon).  This way the current dev
branch will not be broken, and when things progress enough on the ggs
branch a merge can be examined.  What are your thoughts?

Cheers,

Scott