As far as I understand the gdk_colormap_alloc_colors code (see
http://mail.gnome.org/archives/gtk-devel-list/1998-August/msg00135.html, for
instance), gdk itself should handle this problem.

From what I understand it will, if we use it correctly ;-)
But I don't have acces to such limited hardware or dont
know how to configure it so the following patch needs to 
be tested by someone else.

Thanks,
    Hans

diff --exclude-from=c:\util\tool\diff.ign -u --recursive
from-cvs/dia/lib/color.c my-gtk/dia/lib/color.c
--- from-cvs/dia/lib/color.c	Mon Aug 30 16:06:20 2004
+++ my-gtk/dia/lib/color.c	Fri Dec 03 12:40:19 2004
@@ -38,8 +38,12 @@
 color_init(void)
 {
   if (!_color_initialized) {
+#if 0
     GdkVisual *visual = gtk_widget_get_default_visual();
     colormap = gdk_colormap_new (visual, FALSE); 
+#else
+    colormap = gdk_rgb_get_cmap();
+#endif
 
     _color_initialized = TRUE;
 

No, changing gdk_colormap_new not helps. Same problem.

I have change in function color_convert from
gdk_colormap_alloc_color (colormap, gdkcolor, TRUE, TRUE)
into
gdk_colormap_alloc_color (colormap, gdkcolor, FALSE, TRUE)

This woks better for that screen resolution. I change the attribut for color 
from writable into nonwritable. Change Dia the color map after alloc? I didn't 
see. Dia mostly alloc a color (named as function "color_convert"), draw 
something and forget this color after. And that is the problem. Dia "should" 
free the colour after using. Or should save the allocated color and use the 
same, allocated for next doing, if the same color is used (such draw the 
background).

Screen, before:
http://www.henrynestler.com/dia/Dia-ScreenShot38.png

Screen after gdk_colormap_alloc_color "writable = FALSE":
http://www.henrynestler.com/dia/Dia-ScreenShot35.png

Some of "g_warning" in function "color_init" are only for debuging. Interesting 
is, that the old unchanged gdk_colormap_alloc_color fails exactly after 256 
calls of the function color_convert().

With this I can use under 8 bit color, and found next problem:
Can't change color. Dia forget the color if I click to OK-Buttom in the Color 
selection Menu:
http://www.henrynestler.com/dia/Dia-ScreenShot38.png



Or sometimes Dia do not set the right color into background, on click to middle 
button "Change/Submit" (German "ubernehmen"):
http://www.henrynestler.com/dia/Dia-ScreenShot37.png

Created attachment 39720 [details] [review]
color_convert gdk_colormap_alloc_color nonwritable for 8bit Dia 0.93

This works for first view.

In addition of "alloc needs free" theory, I have change all caller functions of 
color_convert to free the color at end with a wrapper in color.c:

+void
+color_free_convert(GdkColor *gdkcolor)
+{
+    gdk_colormap_free_colors (colormap, gdkcolor, 1);
+}

This is interesting:

I can call more than thousend loops, before this function fails. Perhaps I have 
forgotton some calls of color_convert to free at end.

This function use the old writable attribut in this test!
color_convert()
...
   gdk_colormap_alloc_color (colormap, gdkcolor, TRUE, TRUE)

But it's perhaps generaly a design problem in Dia? Why a call to a function 
gdk_colormap_alloc_color nerver call a free function? Or why Dia don't cache 
the allocated color and give back the same pointer, if the same color?

Reopening cause there is a bunch of information added. 
Personally I don't have any plans to work on this cause
none of my obsolete hardware is so restricted ;)

-- GitLab Migration Automatic Message --

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