docs: Add an example for user fonts

1 files changed, 40 insertions, 51 deletions

diff --git a/examples/cairoshape.c b/examples/cairoshape.c
index d3a90bd8..2fdb9c15 100644
--- a/examples/cairoshape.c
+++ b/examples/cairoshape.c
@@ -1,8 +1,5 @@
-/* Example code to show how to use pangocairo to render arbitrary shapes
- * inside a text layout, positioned by Pango.  This has become possibly
- * using the following API added in Pango 1.18:
- * 
- *      pango_cairo_context_set_shape_renderer ()
+/* Example code to show how to use user fonts to render arbitrary content
+ * inside a text layout, positioned by Pango.
  *
  * This examples uses a small parser to convert shapes in the format of
  * SVG paths to cairo instructions.  You can typically extract these from
@@ -12,22 +9,18 @@
  * text and automatically adds PangoAttribtues to the layout to replace
  * each of the with a rendering of the GNOME Foot logo.
  *
- *
  * Written by Behdad Esfahbod, 2007
+ * Updated for user fonts by Matthias Clasen, 2022
  *
  * Permission to use, copy, modify, distribute, and sell this example
  * for any purpose is hereby granted without fee.
  * It is provided "as is" without express or implied warranty.
  */
 
-
 #include <stdio.h>
 #include <string.h>
 
 #include <pango/pangocairo.h>
-#include <pango/pangofc-fontmap.h>
-
-static PangoFontMap *fontmap;
 
 #define BULLET "•"
 #define HEART "♥"
@@ -56,15 +49,13 @@ static MiniSvg GnomeFootLogo = {
 };
 
 static void
-mini_svg_render (MiniSvg  *shape,
-                 cairo_t  *cr,
-                 gboolean  do_path)
+mini_svg_render (MiniSvg  *shape, cairo_t  *cr)
 {
   double x, y;
-  const char *p;
   char op[2];
   int len;
   double x1, y1, x2, y2, x3, y3;
+  const char *p;
 
   cairo_get_current_point (cr, &x, &y);
   cairo_translate (cr, x, y);
@@ -92,28 +83,28 @@ mini_svg_render (MiniSvg  *shape,
         break;
       }
 
-  if (!do_path)
-    cairo_fill (cr);
+  cairo_fill (cr);
 }
 
 static PangoLayout *
 get_layout (cairo_t *cr)
 {
-  PangoContext *context;
   PangoLayout *layout;
   PangoAttrList *attrs;
+  PangoFontDescription *font_desc;
   const char *p;
 
   /* Create a PangoLayout, set the font and text */
-  context = pango_font_map_create_context (fontmap);
-  layout = pango_layout_new (context);
-  g_object_unref (context);
-
+  layout = pango_cairo_create_layout (cr);
   pango_layout_set_text (layout, text, -1);
 
+  font_desc = pango_font_description_from_string ("Cantarell 12");
+  pango_layout_set_font_description (layout, font_desc);
+  pango_font_description_free (font_desc);
+
   attrs = pango_attr_list_new ();
 
-  PangoFontDescription *font_desc = pango_font_description_from_string ("Bullets 12");
+  font_desc = pango_font_description_from_string ("Bullets 12");
 
   for (p = text; (p = strstr (p, BULLET)); p += strlen (BULLET))
     {
@@ -133,11 +124,6 @@ get_layout (cairo_t *cr)
       attr->start_index = p - text;
       attr->end_index = attr->start_index + strlen (HEART);
       pango_attr_list_insert (attrs, attr);
-
-      attr = pango_attr_fallback_new (0);
-      attr->start_index = p - text;
-      attr->end_index = attr->start_index + strlen (HEART);
-      pango_attr_list_insert (attrs, attr);
     }
 
   pango_font_description_free (font_desc);
@@ -145,30 +131,28 @@ get_layout (cairo_t *cr)
   pango_layout_set_attributes (layout, attrs);
   pango_attr_list_unref (attrs);
 
-
   return layout;
 }
 
 static void
-draw_text (cairo_t *cr, int *width, int *height)
+measure_text (cairo_t *cr, int *width, int *height)
 {
   PangoLayout *layout = get_layout (cr);
   PangoLines *lines = pango_layout_get_lines (layout);
+  PangoRectangle ext;
 
-  pango_layout_write_to_file (layout, "out.layout");
+  pango_lines_get_extents (lines, NULL, &ext);
+  pango_extents_to_pixels (&ext, NULL);
 
-  /* Adds a fixed 10-pixel margin on the sides. */
+  *width = ext.width + 20;
+  *height = ext.height + 20;
+}
 
-  if (width || height)
-    {
-      PangoRectangle ext;
-      pango_lines_get_extents (lines, NULL, &ext);
-      pango_extents_to_pixels (&ext, NULL);
-      if (width)
-        *width = ext.width + 20;
-      if (height)
-        *height = ext.height + 20;
-    }
+static void
+draw_text (cairo_t *cr)
+{
+  PangoLayout *layout = get_layout (cr);
+  PangoLines *lines = pango_layout_get_lines (layout);
 
   cairo_move_to (cr, 10, 10);
   pango_cairo_show_lines (cr, lines);
@@ -182,8 +166,7 @@ glyph_cb (PangoUserFace  *face,
           hb_codepoint_t *glyph,
           gpointer        data)
 {
-  if (unicode == 0x2022 || /* bullet */
-      unicode == 0x2665)   /* heart */
+  if (unicode == 0x2022 || unicode == 0x2665)
     {
       *glyph = unicode;
       return TRUE;
@@ -211,7 +194,6 @@ glyph_info_cb (PangoUserFace      *face,
 
       *h_advance = size;
       *v_advance = size;
-
       *is_color = glyph == 0x2665;
 
       return TRUE;
@@ -253,7 +235,9 @@ render_cb (PangoUserFace  *face,
       cairo_move_to (cr, 0, -1);
       cairo_scale (cr, 1. / shape->width, 1. / shape->height);
 
-      mini_svg_render (shape, cr, FALSE);
+      mini_svg_render (shape, cr);
+
+      return TRUE;
     }
   else if (glyph == 0x2665)
     {
@@ -265,26 +249,32 @@ render_cb (PangoUserFace  *face,
       cairo_curve_to (cr, .5, -.9, -.1, -.8, .1, -.4);
       cairo_close_path (cr);
       cairo_fill (cr);
+
+      return TRUE;
     }
 
-  return TRUE;
+  return FALSE;
 }
 
 static void
-setup_fontmap (PangoFontMap *fontmap)
+setup_fontmap (void)
 {
+  PangoFontMap *fontmap = pango_font_map_get_default ();
   PangoFontDescription *desc;
   PangoUserFace *face;
 
   desc = pango_font_description_new ();
   pango_font_description_set_family (desc, "Bullets");
 
+  /* Create our fancy user font, "Bullets Black" */
   face = pango_user_face_new (font_info_cb,
                               glyph_cb,
                               glyph_info_cb,
                               NULL,
                               render_cb,
                               NULL, NULL, "Black", desc);
+
+  /* And add it to the default fontmap */
   pango_font_map_add_face (fontmap, PANGO_FONT_FACE (face));
 
   pango_font_description_free (desc);
@@ -307,12 +297,11 @@ main (int argc, char **argv)
 
   filename = argv[1];
 
-  fontmap = PANGO_FONT_MAP (pango_fc_font_map_new ());
-  setup_fontmap (PANGO_FONT_MAP (fontmap));
+  setup_fontmap ();
 
   surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, 0, 0);
   cr = cairo_create (surface);
-  draw_text (cr, &width, &height);
+  measure_text (cr, &width, &height);
   cairo_destroy (cr);
   cairo_surface_destroy (surface);
 
@@ -323,7 +312,7 @@ main (int argc, char **argv)
   cairo_set_source_rgb (cr, 1.0, 1.0, 1.0);
   cairo_paint (cr);
   cairo_set_source_rgb (cr, 0.0, 0.0, 0.5);
-  draw_text (cr, NULL, NULL);
+  draw_text (cr);
   cairo_destroy (cr);
 
   /* Write out the surface as PNG */