void render_text(GdkDrawable *da, GdkGC *gc, int x, int y, double angle,
const char *s, const char *font, double xalign, double yalign,
int xmax, int ymax)
{
GdkScreen *screen;
PangoRenderer *renderer;
PangoContext *context;
PangoLayout *layout;
PangoFontDescription *desc;
int width, height;
PangoMatrix m = PANGO_MATRIX_INIT;
double f_min, f;
/* set up the renderer */
screen = gdk_drawable_get_screen(da);
renderer = gdk_pango_renderer_get_default(screen);
gdk_pango_renderer_set_drawable(GDK_PANGO_RENDERER(renderer), da);
gdk_pango_renderer_set_gc(GDK_PANGO_RENDERER(renderer), gc);
/* start preparing the layout */
context = gdk_pango_context_get_for_screen(screen);
layout = pango_layout_new(context);
pango_layout_set_text(layout, s, -1);
/* apply the font */
desc = pango_font_description_from_string(font);
pango_layout_set_font_description(layout, desc);
pango_font_description_free(desc);
/* align and position the text */
pango_layout_get_size(layout, &width, &height);
f_min = 1.0;
if (xmax) {
f = xmax/((double) width/PANGO_SCALE);
if (f < f_min)
f_min = f;
}
if (ymax) {
f = ymax/((double) height/PANGO_SCALE);
if (f < f_min)
f_min = f;
}
if (f_min < MIN_FONT_SCALE)
f_min = MIN_FONT_SCALE;
pango_matrix_translate(&m, x, y);
pango_matrix_rotate(&m, angle);
pango_matrix_translate(&m,
-xalign*f_min*width/PANGO_SCALE,
(yalign-1)*f_min*height/PANGO_SCALE);
pango_matrix_scale(&m, f_min, f_min);
pango_context_set_matrix(context, &m);
pango_layout_context_changed(layout);
pango_renderer_draw_layout(renderer, layout, 0, 0);
/* clean up renderer */
gdk_pango_renderer_set_drawable(GDK_PANGO_RENDERER(renderer), NULL);
gdk_pango_renderer_set_gc(GDK_PANGO_RENDERER(renderer), NULL);
/* free objects */
g_object_unref(layout);
g_object_unref(context);
}
static VALUE
rg_translate_bang(VALUE self, VALUE tx, VALUE ty)
{
pango_matrix_translate(_SELF(self), NUM2DBL(tx), NUM2DBL(ty));
return self;
}