Re: gnome canvas

[Ole Laursen <olau hardworking dk>]

Jacob Gladish <gladish spinnakernet com> writes:

> I'm using a GnomeCanvas to draw a gradient, and the only way I see to do
> that is to draw a series of lines with colors gradually changing from
> the start color to the finish color. Is there a better way to do
> this,

Depending on your needs, perhaps it would be faster if you rendered a
GdkPixbuf yourself and used GnomeCanvasPixbuf.

> and if not, is there a way to set an rgb color value for a line, or
> better yet, an rgba value? I'm using an anti-aliased GnomeCanvas.
> 
>   gnome_canvas_item_new(
>             gnome_canvas_root( GNOME_CANVAS(canvas) ),
>             gnome_canvas_line_get_type(),
>             "points",     points,
>             "fill_color", (idx % 2 == 0 ? "red" : "green"),
>             "width_units", 1.0,
>             NULL );

You can use the property "fill_color_rbga" which takes a packed
unsigned int with the color; you can pack it with

  (r & 255) << 24) | ((g & 255) << 16) | ((b & 255) << 8) | (a & 255)

if I recall correctly.

-- 
Ole Laursen
http://www.cs.auc.dk/~olau/