Re: DrawingArea and Text display.

[Sven Neumann <sven gimp org>]

Hi,

Tony Denault <denault hawaii edu> writes:

> Thanks to all who replied. I'll summaried what I learn for the mailing
> list:

since you post that code here as an example, I'll give some comments
and suggest possible improvements.

>    // obtain pango layout object
>    context = gtk_widget_create_pango_context (da);
>    layout  = pango_layout_new (context);
>    g_object_unref (context);

as Havoc pointed out, this can be collapsed into 

layout = gtk_widget_create_pango_layout (da);

>    // Draw some text
>    gdk_gc_set_foreground( Nor_gc, &CM.colors[CM_YELLOW] );
>    gdk_draw_layout (da->window, Nor_gc, 50, 50, layout);

instead of creating a gc and using the GDK function you can as well
use the widget's style to draw on the widget's window (note that this
is untested code, it might contain errors):

gtk_paint_layout (da->style, da->window, da->state,
                  FALSE, NULL, da, NULL, x, y, layout);

The rendering function should definitely be in the expose_event
handler of your drawing-area (as any other GDK drawing operation).

Instead of allocating the colors and rendering line by line with
individual layous, you can create a multi-line layout and color it
using a PangoAttributesList. Alternatively to building up such a list,
you can use PangoMarkup:

pango_layout_set_markup (layout,
                         "<span foreground="yellow">Some text</span>\n"
                         "<span foreground="green">This is more text</span>\n"
                         "you get the idea ...",
                         -1);

Salut, Sven