[GRASS5] [bug #4066] (grass) gis.m: black background

[Glynn Clements]

Request Tracker wrote:

> this bug's URL: http://intevation.de/rt/webrt?serial_num=4066
> -------------------------------------------------------------------------
> 
> Subject: gis.m: black background
> 
> Platform: GNU/Linux/x86
> grass obtained from: CVS
> grass binary for platform: Compiled from Sources
> GRASS Version: cvs_head_20060207
> 
> I can confirm the problem with the back blackground in gis.m which
> Maciek mentioned as a side note in another bug report
> (http://intevation.de/rt/webrt?serial_num=4049&display=History).
> 
> When I erase the map display the background becomes white, but as
> soon as I display a map it becomes black again.

I've just fixed a bug related to the background colour in the PNG
driver; pngdriver.h had "unsigned int background" rather than
"extern unsigned int background", so each source file had its own
"background" variable, most of which would be implicitly initialised
to zero and remain at zero.

BTW, while most of the changes were simply reorganisation, and didn't
affect any functionality (or, at least, weren't meant to), the PNG
driver's implementation of R_erase() has been changed to erase to the
original background colour (which will be transparent if
GRASS_TRANSPARENT is set to TRUE), not the current colour.

This affects the behaviour of "d.erase -f" and "d.frame -e". 
Previously, there was no way to erase to transparent after
initialisation.

-- 
Glynn Clements <glynn at gclements.plus.com>