"Ian King" <[EMAIL PROTECTED]> writes:
> I have the following code that works perfectly when running locally, but
> fails when run as a remote client (when using the same pixmap). Can anyone
> help?
>
> This is approximate what my code is doing, ignore any incorrect casting as I
> am using a wrapper library in Eiffel to access gtk c external functions.
>
>
> 1) a_gdkimage = gdk_image_get (a_gtk_pixmap, 0, 0, width, height);
> 2) a_colormap = gdk_colormap_get_system ();
> 3) a_pixel = gdk_image_get_pixel (a_gdkimage, 0, 0);
> 4) a_color = (a_colormap->colors) + (a_pixel * sizeof (GdkColor));
>
> The value of 'a_pixel' is 16777215. When I try to access the red value
> from the returned color (line 4), I receive a segmentation violation signal,
> but only if the client is ran remotely. Is it anything to do with getting
> the gdkimage from the pixmap?
>
> Thanks for your time.
colormap->colors[] is only useful for pseudo-color displays.
You may find this function from GTK+-2.0 useful.
Regards,
Owen
void
gdk_colormap_query_color (GdkColormap *colormap,
gulong pixel,
GdkColor *result)
{
XColor xcolor;
GdkVisual *visual;
g_return_if_fail (GDK_IS_COLORMAP (colormap));
visual = gdk_colormap_get_visual (colormap);
switch (visual->type) {
case GDK_VISUAL_DIRECT_COLOR:
case GDK_VISUAL_TRUE_COLOR:
result->red = 65535. * (double)((pixel & visual->red_mask) >> visual->red_shift) /
((1 << visual->red_prec) - 1);
result->green = 65535. * (double)((pixel & visual->green_mask) >>
visual->green_shift) / ((1 << visual->green_prec) - 1);
result->blue = 65535. * (double)((pixel & visual->blue_mask) >>
visual->blue_shift) / ((1 << visual->blue_prec) - 1);
break;
case GDK_VISUAL_STATIC_GRAY:
case GDK_VISUAL_GRAYSCALE:
result->red = result->green = result->blue = 65535. *
(double)pixel/((1<<visual->depth) - 1);
break;
case GDK_VISUAL_STATIC_COLOR:
xcolor.pixel = pixel;
XQueryColor (GDK_DISPLAY (), GDK_COLORMAP_XCOLORMAP (colormap), &xcolor);
result->red = xcolor.red;
result->green = xcolor.green;
result->blue = xcolor.blue;
break;
case GDK_VISUAL_PSEUDO_COLOR:
result->red = colormap->colors[pixel].red;
result->green = colormap->colors[pixel].green;
result->blue = colormap->colors[pixel].blue;
break;
default:
g_assert_not_reached ();
break;
}
}
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