New API

2007-05-04  Behdad Esfahbod  <behdad@gnome.org>

        * pango/pangocairo.h:
        * pango/pangocairo-context.c:
        * pango/pangocairo-render.c:
        New API

                PangoCairoShapeRendererFunc and
                pango_cairo_context_[sg]et_shape_renderer()

        * docs/pango-sections.txt, docs/tmpl/pangocairo.sgml: Document new
        * API.

        * examples/Makefile.am, examples/cairoshape.c: New example to show off
        new API/feature.


svn path=/trunk/; revision=2261

1 files changed, 209 insertions, 0 deletions

diff --git a/examples/cairoshape.c b/examples/cairoshape.c
new file mode 100644
index 00000000..addde87e
--- /dev/null
+++ b/examples/cairoshape.c
@@ -0,0 +1,209 @@
+/* example to use pangocairo to render arbitrary shapes inside a text layout */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <pango/pangocairo.h>
+
+#define BULLET "•"
+
+const char text[] =
+"The GNOME project provides two things:\n"
+"\n"
+"  • The GNOME desktop environment\n"
+"  • The GNOME development platform\n"
+"  • Planet GNOME";
+
+typedef struct {
+  double width, height;
+  const char *path;
+} MiniSvg;
+
+static MiniSvg GnomeFootLogo = {
+  96.2152, 118.26,
+  "M 86.068,1 C 61.466,0 56.851,35.041 70.691,35.041 C 84.529,35.041 110.671,0 86.068,0 z "
+  "M 45.217,30.699 C 52.586,31.149 60.671,2.577 46.821,4.374 C 32.976,6.171 37.845,30.249 45.217,30.699 z "
+  "M 11.445,48.453 C 16.686,46.146 12.12,23.581 3.208,29.735 C -5.7,35.89 6.204,50.759 11.445,48.453 z "
+  "M 26.212,36.642 C 32.451,35.37 32.793,9.778 21.667,14.369 C 10.539,18.961 19.978,37.916 26.212,36.642 L 26.212,36.642 z "
+  "M 58.791,93.913 C 59.898,102.367 52.589,106.542 45.431,101.092 C 22.644,83.743 83.16,75.088 79.171,51.386 C 75.86,31.712 15.495,37.769 8.621,68.553 C 3.968,89.374 27.774,118.26 52.614,118.26 C 64.834,118.26 78.929,107.226 81.566,93.248 C 83.58,82.589 57.867,86.86 58.791,93.913 L 58.791,93.913 z "
+  "\0"
+};
+
+static void
+mini_svg_render (MiniSvg  *shape,
+		 cairo_t  *cr,
+		 gboolean  do_path)
+{
+  double x, y;
+  const char *p;
+  char op[2];
+  int items, len;
+
+  cairo_get_current_point (cr, &x, &y);
+  cairo_translate (cr, x, y);
+
+  for (p = shape->path; (items = sscanf (p, "%1s %n", op, &len)), p += len, *p;)
+    switch (*op)
+    {
+      case 'M':
+        {
+	  sscanf (p, "%lf,%lf %n", &x, &y, &len); p += len;
+	  cairo_move_to (cr, x, y);
+	  break;
+	}
+      case 'L':
+        {
+	  sscanf (p, "%lf,%lf %n", &x, &y, &len); p += len;
+	  cairo_line_to (cr, x, y);
+	  break;
+	}
+      case 'C':
+        {
+	  double x1, y1, x2, y2, x3, y3;
+	  sscanf (p, "%lf,%lf %lf,%lf %lf,%lf %n", &x1, &y1, &x2, &y2, &x3, &y3, &len); p += len;
+	  cairo_curve_to (cr, x1, y1, x2, y2, x3, y3);
+	  break;
+	}
+      case 'z':
+        {
+	  cairo_close_path (cr);
+	  break;
+	}
+      default: 
+        {
+	  g_warning ("Invalid MiniSvg operation '%c'", *op);
+	  break;
+	}
+    }
+
+  if (!do_path)
+    cairo_fill (cr);
+}
+
+static void
+mini_svg_shape_renderer (cairo_t        *cr,
+			 PangoAttrShape *attr,
+			 gboolean        do_path,
+			 gpointer        data)
+{
+  MiniSvg *shape = (MiniSvg *) attr->data;
+  double scale_x, scale_y;
+
+  scale_x = (double) attr->ink_rect.width  / (PANGO_SCALE * shape->width );
+  scale_y = (double) attr->ink_rect.height / (PANGO_SCALE * shape->height);
+
+  cairo_rel_move_to (cr,
+		     (double) attr->ink_rect.x / PANGO_SCALE,
+		     (double) attr->ink_rect.y / PANGO_SCALE);
+  cairo_scale (cr, scale_x, scale_y);
+
+  mini_svg_render (shape, cr, do_path);
+}
+
+
+static PangoLayout *
+get_layout (cairo_t *cr)
+{
+  PangoLayout *layout;
+  PangoAttrList *attrs;
+  PangoRectangle ink_rect     = {1 * PANGO_SCALE, -11 * PANGO_SCALE,  8 * PANGO_SCALE, 10 * PANGO_SCALE};
+  PangoRectangle logical_rect = {0 * PANGO_SCALE, -12 * PANGO_SCALE, 10 * PANGO_SCALE, 12 * PANGO_SCALE};
+  const char *p;
+
+  /* Create a PangoLayout, set the font and text */
+  layout = pango_cairo_create_layout (cr);
+
+  pango_cairo_context_set_shape_renderer (pango_layout_get_context (layout),
+					  mini_svg_shape_renderer, NULL, NULL);
+
+  pango_layout_set_text (layout, text, -1);
+
+  attrs = pango_attr_list_new ();
+
+  /* set gnome shape attributes for bullets */
+  for (p = text; (p = strstr (p, BULLET)); p += strlen (BULLET))
+    {
+      PangoAttribute *attr;
+      
+      attr = pango_attr_shape_new_with_data (&ink_rect,
+					     &logical_rect,
+					     &GnomeFootLogo,
+					     NULL, NULL);
+
+      attr->start_index = p - text;
+      attr->end_index = attr->start_index + strlen (BULLET);
+
+      pango_attr_list_insert (attrs, attr);
+    }
+
+  pango_layout_set_attributes (layout, attrs);
+  pango_attr_list_unref (attrs);
+
+  return layout;
+}
+
+static void
+draw_text (cairo_t *cr, int *width, int *height)
+{
+
+  PangoLayout *layout = get_layout (cr);
+
+  if (width || height)
+    {
+      pango_layout_get_pixel_size (layout, width, height);
+      if (width)
+        *width += 20;
+      if (height)
+        *height += 20;
+    }
+
+  cairo_move_to (cr, 10, 10);
+  pango_cairo_show_layout (cr, layout);
+
+  g_object_unref (layout);
+}
+
+int main (int argc, char **argv)
+{
+  cairo_t *cr;
+  char *filename;
+  cairo_status_t status;
+  cairo_surface_t *surface;
+  int width, height;
+
+  if (argc != 2)
+    {
+      g_printerr ("Usage: cairoshape OUTPUT_FILENAME\n");
+      return 1;
+    }
+
+  filename = argv[1];
+
+  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+					0, 0);
+  cr = cairo_create (surface);
+  draw_text (cr, &width, &height);
+  cairo_destroy (cr);
+  cairo_surface_destroy (surface);
+
+  surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+					width, height);
+  cr = cairo_create (surface);
+
+  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);
+  cairo_destroy (cr);
+
+  status = cairo_surface_write_to_png (surface, filename);
+  cairo_surface_destroy (surface);
+
+  if (status != CAIRO_STATUS_SUCCESS)
+    {
+      g_printerr ("Could not save png to '%s'\n", filename);
+      return 1;
+    }
+
+  return 0;
+}