mutter/clutter/pango/cogl-pango-display-list.h
Neil Roberts bb156970de Render pango layouts with vertex buffers
When rendering a pango layout CoglPangoRenderer now records the
operations into a list called a CoglPangoDisplayList. The entries in
the list are either glyph renderings from a texture, rectangles or
trapezoids. Multiple consecutive glyph renderings from the same glyph
cache texture are combined into a single entry. Note the
CoglPangoDisplayList has nothing to do with a GL display list.

After the display list is built it is attached to the PangoLayout with
g_object_set_qdata so that next time the layout is rendered it can
bypass rebuilding it.

The glyph rendering entries are drawn via a VBO. The VBO is attached
to the display list so it can be used multiple times. This makes the
common case of rendering a PangoLayout contained in a single texture
subsequent times usually boil down to a single call to glDrawArrays
with an already uploaded VBO.

The VBOs are accessed via the cogl_vertex_buffer API so if VBOs are
not available in GL it will resort to a fallback.

Note this will fall apart if the pango layout is altered after the
first render. I can't find a way to detect when the layout is
altered. However this won't affect ClutterText because it creates a
new PangoLayout whenever any properties are changed.
2009-04-29 19:53:24 +01:00

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C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Neil Roberts <neil@linux.intel.com>
*
* Copyright (C) 2009 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __COGL_PANGO_DISPLAY_LIST_H__
#define __COGL_PANGO_DISPLAY_LIST_H__
#include <glib.h>
#include <cogl/cogl.h>
G_BEGIN_DECLS
typedef struct _CoglPangoDisplayList CoglPangoDisplayList;
CoglPangoDisplayList *_cogl_pango_display_list_new (void);
void _cogl_pango_display_list_set_color (CoglPangoDisplayList *dl,
const CoglColor *color);
void _cogl_pango_display_list_add_texture (CoglPangoDisplayList *dl,
CoglHandle texture,
float x_1, float y_1,
float x_2, float y_2,
float tx_1, float ty_1,
float tx_2, float ty_2);
void _cogl_pango_display_list_add_rectangle (CoglPangoDisplayList *dl,
float x_1, float y_1,
float x_2, float y_2);
void _cogl_pango_display_list_add_trapezoid (CoglPangoDisplayList *dl,
float y_1,
float x_11,
float x_21,
float y_2,
float x_12,
float x_22);
void _cogl_pango_display_list_render (CoglPangoDisplayList *dl,
CoglHandle glyph_material,
CoglHandle solid_material);
void _cogl_pango_display_list_clear (CoglPangoDisplayList *dl);
void _cogl_pango_display_list_free (CoglPangoDisplayList *dl);
G_END_DECLS
#endif /* __COGL_PANGO_DISPLAY_LIST_H__ */