[PATCH] fix color in 3D "smooth" style in postscript output

[Qian Yun]

Currently we get mono color in postscript output of "smooth" style
3D drawings.

That's caused by "GSetForeground" before "GDrawPoint".
"GSetForeground" can only set gray scale.

Luckily the all four usage of "GDrawPoint" are all for the purpose
of generating "smooth" style image. So this change will not break
anywhere else.

So I decode color and use "setrgbcolor" for it and remove
"installGC" from "drawpoint.ps" because that's responsible for
setting the grey color.

- Qian

[Qian Yun]

I'd like to also include the following in this patch.

You will notice that the ps output has a strange gray background.

The following code snippet is responsible for setting color.

#define psShadeMax 17.0 /* same as XShadeMax */
#define psShadeMul (1.0/(psShadeMax-1.0)) /* white and 16 gray
shades */

It makes no sense to compute a constant grey color and use it.
(I guess it was mono color so put a grey background there?)

Let's simply have a white background instead.

- Qian

diff --git a/src/graph/view3D/smoothShade3d.c
b/src/graph/view3D/smoothShade3d.c
index 7e80157a..432a0f98 100644
--- a/src/graph/view3D/smoothShade3d.c
+++ b/src/graph/view3D/smoothShade3d.c
@@ -567,8 +567,7 @@ scanLines(int dFlag)
XFillRectangle(dsply,viewport->viewWindow,trashGC,0,0,
vwInfo.width,vwInfo.height);
} else {
- GSetForeground(GC9991,
- 1.0-(float)((int)(psShadeMax-0.3*psShadeMax)-1)*psShadeMul,dFlag);
+ GSetForeground(GC9991, psWhite, dFlag);
quadMesh[0].x = 0; quadMesh[0].y = 0;
quadMesh[1].x = graphWindowAttrib.width+2;
quadMesh[1].y = 0;

[Qian Yun]

Also the calculation of rgb and print of "setrgbcolor"
should be made into a separate function, because the
2D PS output will need this as well.

- Qian

[Waldek Hebisch]

On Sat, Apr 20, 2024 at 10:41:39AM +0800, Qian Yun wrote:
> Also the calculation of rgb and print of "setrgbcolor"
> should be made into a separate function, because the
> 2D PS output will need this as well.

Yes. The patches looks good. As I mentioned, since you keep
finding new things it makes sense to collect them in bigger
change.

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--
Waldek Hebisch