Bug 323173 – Add layout of mixed direction text for vertical layout

2007-01-15  Behdad Esfahbod  <behdad@gnome.org>

        Bug 323173 – Add layout of mixed direction text for vertical layout

        * pango/pango-gravity.h:
        * pango/pango-gravity.c:
        Moved gravity stuff here.  New public API:

                PangoGravityHint
                pango_gravity_get_for_matrix()
                pango_gravity_get_for_script()

        * pango/pango-context.h:
        * pango/pango-context.c (pango_context_init),
        (update_resolved_gravity), (itemize_state_update_for_new_run):
        Support gravity hint.  New public API:

                pango_context_set_gravity_hint()
                pango_context_get_gravity_hint()

        * pango/pango-utils.c:
        * pango/pango-matrix.c:
        * pango/pango-matrix.h:
        * pango/pango-types.h:
        Moved gravity and matrix stuff into its own header.  pango-types.h
        includes both pango-matrix.h and pango-gravity.h

        * pango/pango.h:
        Include new headers.

        * pango/pango.def:
        * pango/Makefile.am:
        Update.

        * docs/pango-docs.sgml:
        * docs/pango-sections.txt:
        * docs/tmpl/glyphs.sgml:
        * docs/tmpl/main.sgml:
        * docs/tmpl/vertical.sgml:
        Add a section for Vertical Text.

        * examples/renderdemo.c (do_output), (parse_gravity_hint),
        (parse_options):
        Support gravity hint.

        * examples/test-mixed.txt:
        New test, mixed Latin, Arabic, Chinese text.


svn path=/trunk/; revision=2144

1 files changed, 109 insertions, 0 deletions

diff --git a/pango/pango-gravity.h b/pango/pango-gravity.h
new file mode 100644
index 00000000..b79436c5
--- /dev/null
+++ b/pango/pango-gravity.h
@@ -0,0 +1,109 @@
+/* Pango
+ * pango-gravity.h: Gravity routines
+ *
+ * Copyright (C) 2006, 2007 Red Hat Software
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __PANGO_GRAVITY_H__
+#define __PANGO_GRAVITY_H__
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+/**
+ * PangoGravity:
+ * @PANGO_GRAVITY_SOUTH: Glyphs stand upright (default)
+ * @PANGO_GRAVITY_EAST: Glyphs are rotated 90 degrees clockwise
+ * @PANGO_GRAVITY_NORTH: Glyphs are upside-down
+ * @PANGO_GRAVITY_WEST: Glyphs are rotated 90 degrees counter-clockwise
+ * @PANGO_GRAVITY_AUTO: Gravity is resolved from the context matrix
+ * 
+ * The #PangoGravity type represents the orientation of glyphs in a segment
+ * of text.  This is useful when rendering vertical text layouts.  In
+ * those situations, the layout is rotated using a non-identity PangoMatrix,
+ * and then glyph orientation is controlled using #PangoGravity.
+ * Not every value in this enumeration makes sense for every usage of
+ * #PangoGravity; for example, %PANGO_GRAVITY_AUTO only can be passed to
+ * pango_context_set_base_gravity() and can only be returned by
+ * pango_context_get_base_gravity().
+ *
+ * See also: #PangoGravityHint
+ * 
+ * Since: 1.16
+ **/			  
+typedef enum {
+  PANGO_GRAVITY_SOUTH,
+  PANGO_GRAVITY_EAST,
+  PANGO_GRAVITY_NORTH,
+  PANGO_GRAVITY_WEST,
+  PANGO_GRAVITY_AUTO
+} PangoGravity;
+
+/**
+ * PangoGravityHint:
+ * @PANGO_GRAVITY_HINT_NATURAL: scripts will take their natural gravity based
+ * on the base gravity and the script.  This is the default.
+ * @PANGO_GRAVITY_HINT_STRONG: always use the base gravity set, regardless of
+ * the script.
+ * @PANGO_GRAVITY_HINT_LINE: for scripts not in their natural direction (eg.
+ * Latin in East gravity), choose per-script gravity such that every script
+ * respects the line progression.  This means, Latin and Arabic will take
+ * opposite gravities and both flow top-to-bottom for example.
+ * 
+ * The #PangoGravityHint defines how horizontal scripts should behave in a
+ * vertical context.  That is, English excerpt in a vertical paragraph for
+ * example.
+ *
+ * See #PangoGravity.
+ *
+ * Since: 1.16
+ **/
+typedef enum {
+  PANGO_GRAVITY_HINT_NATURAL,
+  PANGO_GRAVITY_HINT_STRONG,
+  PANGO_GRAVITY_HINT_LINE
+} PangoGravityHint;
+
+/**
+ * PANGO_GRAVITY_IS_VERTICAL:
+ * @gravity: the #PangoGravity to check
+ *
+ * Whether a #PangoGravity represents vertical writing directions.
+ *
+ * Returns: %TRUE if @gravity is %PANGO_GRAVITY_EAST or %PANGO_GRAVITY_WEST,
+ *          %FALSE otherwise.
+ *
+ * Since: 1.16
+ **/
+#define PANGO_GRAVITY_IS_VERTICAL(gravity) \
+	((gravity) == PANGO_GRAVITY_EAST || (gravity) == PANGO_GRAVITY_WEST)
+
+#include <pango/pango-matrix.h>
+#include <pango/pango-script.h>
+
+double       pango_gravity_to_rotation    (PangoGravity       gravity) G_GNUC_CONST;
+PangoGravity pango_gravity_get_for_matrix (const PangoMatrix *matrix);
+PangoGravity pango_gravity_get_for_script (PangoScript        script,
+					   PangoGravity       base_gravity,
+					   PangoGravityHint   hint) G_GNUC_CONST;
+
+
+G_END_DECLS
+
+#endif /* __PANGO_GRAVITY_H__ */