[GRASS-dev] color tables

GRASS GRASS developer
1

Glynn wrote:

These should be generated as part of the build process.
Otherwise, there's no guarantee that they actually match the colour
tables in lib/gis/colors

great, looks good.

One thing I notice is that in grass7 the D_move_abs(), D_cont_rel()
line widths are heavier than they were in 6.x. (2px vs 1px wide)
Is it possible to make 1px again? An explicit D_line_width(0) just
makes it grey, I guess it has to be moved 1/2 a pixel from centered
on grid lines to centered mid-cell?? It seems to work ok in d.legend
which is pretty much the same code.

Also I notice that for d.colortable and d.legend that with D_end()
to close the polygon there is a pixel missing from the start/end
position here. see attached. (hmmm, D_end() is a no-op?)

(shouldn't those have been moved to lib/raster?).

fwiw they are used by v.colors too. (which will eventually be free
of r.* hacks)

Hamish

(attachments)

gr7_D_line_end_knick.png

2

Hamish wrote:

> These should be generated as part of the build process.
> Otherwise, there's no guarantee that they actually match the colour
> tables in lib/gis/colors

great, looks good.

One thing I notice is that in grass7 the D_move_abs(), D_cont_rel()
line widths are heavier than they were in 6.x. (2px vs 1px wide)
Is it possible to make 1px again? An explicit D_line_width(0) just
makes it grey,

At present, the output will be affected by $GRASS_RENDER_IMMEDIATE,
$GRASS_LINE_WIDTH, and $GRASS_ANTIALIAS (that's an oversight; I'll
modify the script to unset those).

I guess it has to be moved 1/2 a pixel from centered
on grid lines to centered mid-cell?? It seems to work ok in d.legend
which is pretty much the same code.

You shouldn't assume that the display library will allow that kind of
low-level control. At some point, it may support scaling of "unscaled"
coordinates, so that modules with hard-coded sizes produce usable
results on 200dpi monitors.

Even at present, you don't actually have that degree of control, given
the existence of the PS driver and PS/PDF/SVG output via the cairo
driver.

Also I notice that for d.colortable and d.legend that with D_end()
to close the polygon there is a pixel missing from the start/end
position here. see attached.

Use D_close() if you want a closed path (i.e. a join rather than
caps).

(hmmm, D_end() is a no-op?)

At present, yes.

> (shouldn't those have been moved to lib/raster?).

fwiw they are used by v.colors too. (which will eventually be free
of r.* hacks)

How are the files going to be read? Is someone planning on duplicating
the contents of lib/raster/color_rules.c for the sake of not using the
raster library? If so, that code should be moved back into lib/gis.

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