Re: How to create a PangoCairoFontMap?

["Cosmin Humeniuc" <cosmin mandrivausers ro>]

On 12/10/07, Behdad Esfahbod <behdad behdad org> wrote:
> On Mon, 2007-12-10 at 12:46 +0200, Cosmin Humeniuc wrote:
> >
> > Hi,
> >
> > I did use that function, but it returns a PangoFontMap*, while
> > pango_cairo_font_map_create_context() asks for a PangoCairoFontMap*,
> > and this leads to the following warning:
> >
> > passing argument 1 of 'pango_cairo_font_map_create_context' from
> > incompatible pointer type
>
> Yes, you need to cast.  This is unfortunate but can't be changed now.
>
>
> > And if I use pango_cairo_context_set_font_options() with the returned
> > context, it has no effect.
>
> That's a separate issue and most probably a problem in your code.  We
> can check it out if you send a short sample to the list.

Thank you for the reply, Behdad.
Here is an example where I draw some text using Cairo, and then using
Pango with Cairo. Both should have no antialiasing, however only the
former is right.

/*----------*/
#include <string.h>
#include <pango/pangocairo.h>

/** Draw some text using cairo only */
void cairo_draw_text(cairo_t* cr) {
	cairo_select_font_face (cr, "Serif", CAIRO_FONT_SLANT_NORMAL,
CAIRO_FONT_WEIGHT_BOLD);
	cairo_set_font_size (cr, 48.0);
	cairo_set_source_rgb (cr, 0.0, 0.0, 1.0);
	cairo_move_to (cr, 10.0, 50.0);

	cairo_font_options_t* options = cairo_font_options_create();
	cairo_font_options_set_antialias(options, CAIRO_ANTIALIAS_NONE);
	cairo_set_font_options(cr, options);

	cairo_show_text (cr, "cairo");
}

/** Draw some text using pango with cairo */
void pango_draw_text(cairo_t* cr) {
	PangoLayout *layout;
	PangoFontDescription *desc;
	PangoContext *pango;
	PangoFontMap* map;

	int width, height;

	/* Create a PangoLayout, set the font and text */
	layout = pango_cairo_create_layout (cr);

	pango_layout_set_alignment(layout, PANGO_ALIGN_CENTER);

	pango_layout_set_text (layout, "pango", -1);
	desc = pango_font_description_from_string("Serif Bold 48");
	pango_layout_set_font_description (layout, desc);
	pango_font_description_free (desc);

	pango_layout_get_size(layout, &width, &height);

	cairo_set_source_rgb (cr, 0.0, 0.0, 1.0);

	cairo_font_options_t* options = cairo_font_options_create();
	cairo_font_options_set_antialias(options, CAIRO_ANTIALIAS_NONE);

	map = pango_cairo_font_map_get_default();
	pango = pango_cairo_font_map_create_context((PangoCairoFontMap*)map);
	pango_cairo_context_set_font_options(pango, options);

	pango_layout_context_changed(layout);
	pango_cairo_update_layout(cr, layout);

	cairo_move_to (cr, 10, 30);
	pango_cairo_show_layout (cr, layout);

	/* free the layout object */
	g_object_unref (layout);
}

int main(int argc, char *argv[]) {
	cairo_t *cr;
	cairo_surface_t *surface;

	surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 320, 240);
	cr = cairo_create (surface);

	/* Paint the background in white */
	cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
	cairo_paint (cr);

	cairo_draw_text(cr);
	pango_draw_text(cr);

	/* Write the output to a file */
	cairo_surface_write_to_png (surface, "out.png");

	/* Cleanup */
	cairo_destroy (cr);
	cairo_surface_destroy (surface);

	return 0;
}
/*----------*/

Cosmin

>
> --
> behdad
> http://behdad.org/
>
> ...very few phenomena can pull someone out of Deep Hack Mode, with two
> noted exceptions: being struck by lightning, or worse, your *computer*
> being struck by lightning.  -- Matt Welsh
>
>