mutter/clutter/pango/cogl-pango-render.c
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

653 lines
20 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2008 OpenedHand
*
* 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/>.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifndef PANGO_ENABLE_BACKEND
#define PANGO_ENABLE_BACKEND 1
#endif
#include <pango/pango-fontmap.h>
#include <pango/pangocairo.h>
#include <pango/pango-renderer.h>
#include <cairo.h>
#include "cogl-pango-private.h"
#include "cogl-pango-glyph-cache.h"
#include "cogl-pango-display-list.h"
struct _CoglPangoRenderer
{
PangoRenderer parent_instance;
/* The color to draw the glyphs with */
CoglColor color;
/* The material used to texture from the glyph cache with */
CoglHandle glyph_material;
/* The material used for solid fills. (boxes, rectangles + trapezoids) */
CoglHandle solid_material;
/* Two caches of glyphs as textures, one with mipmapped textures and
one without */
CoglPangoGlyphCache *glyph_cache;
CoglPangoGlyphCache *mipmapped_glyph_cache;
gboolean use_mipmapping;
/* The current display list that is being built */
CoglPangoDisplayList *display_list;
};
struct _CoglPangoRendererClass
{
PangoRendererClass class_instance;
};
static void
cogl_pango_renderer_draw_glyph (CoglPangoRenderer *priv,
CoglPangoGlyphCacheValue *cache_value,
float x1,
float y1)
{
float x2, y2;
g_return_if_fail (priv->display_list != NULL);
x2 = x1 + (float) cache_value->draw_width;
y2 = y1 + (float) cache_value->draw_height;
_cogl_pango_display_list_add_texture (priv->display_list,
cache_value->texture,
x1, y1, x2, y2,
cache_value->tx1,
cache_value->ty1,
cache_value->tx2,
cache_value->ty2);
}
static void cogl_pango_renderer_finalize (GObject *object);
static void cogl_pango_renderer_draw_glyphs (PangoRenderer *renderer,
PangoFont *font,
PangoGlyphString *glyphs,
int x,
int y);
static void cogl_pango_renderer_draw_rectangle (PangoRenderer *renderer,
PangoRenderPart part,
int x,
int y,
int width,
int height);
static void cogl_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
PangoRenderPart part,
double y1,
double x11,
double x21,
double y2,
double x12,
double x22);
G_DEFINE_TYPE (CoglPangoRenderer, cogl_pango_renderer, PANGO_TYPE_RENDERER);
static void
cogl_pango_renderer_init (CoglPangoRenderer *priv)
{
priv->glyph_material = cogl_material_new ();
/* The default combine mode of materials is to modulate (A x B) the texture
* RGBA channels with the RGBA channels of the previous layer (which in our
* case is just the solid font color)
*
* Since our glyph cache textures are component alpha textures, and so the
* RGB channels are defined as (0, 0, 0) we don't want to modulate the RGB
* channels, instead we want to simply replace them with our solid font
* color...
*
* XXX: we could really do with a neat string based way for describing
* combine modes, like: "REPLACE(PREVIOUS[RGB])"
* XXX: potentially materials could have a fuzzy default combine mode
* such that they default to this for component alpha textures? This would
* give the same semantics as the old-style GL_MODULATE mode but sounds a
* bit hacky.
*/
cogl_material_set_layer_combine_function (
priv->glyph_material,
0, /* layer */
COGL_MATERIAL_LAYER_COMBINE_CHANNELS_RGB,
COGL_MATERIAL_LAYER_COMBINE_FUNC_REPLACE);
cogl_material_set_layer_combine_arg_src (
priv->glyph_material,
0, /* layer */
0, /* arg */
COGL_MATERIAL_LAYER_COMBINE_CHANNELS_RGB,
COGL_MATERIAL_LAYER_COMBINE_SRC_PREVIOUS);
priv->solid_material = cogl_material_new ();
priv->glyph_cache = cogl_pango_glyph_cache_new (FALSE);
priv->mipmapped_glyph_cache = cogl_pango_glyph_cache_new (TRUE);
priv->use_mipmapping = FALSE;
}
static void
cogl_pango_renderer_class_init (CoglPangoRendererClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
PangoRendererClass *renderer_class = PANGO_RENDERER_CLASS (klass);
object_class->finalize = cogl_pango_renderer_finalize;
renderer_class->draw_glyphs = cogl_pango_renderer_draw_glyphs;
renderer_class->draw_rectangle = cogl_pango_renderer_draw_rectangle;
renderer_class->draw_trapezoid = cogl_pango_renderer_draw_trapezoid;
}
static void
cogl_pango_renderer_finalize (GObject *object)
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (object);
cogl_pango_glyph_cache_free (priv->mipmapped_glyph_cache);
cogl_pango_glyph_cache_free (priv->glyph_cache);
G_OBJECT_CLASS (cogl_pango_renderer_parent_class)->finalize (object);
}
static CoglPangoRenderer *
cogl_pango_get_renderer_from_context (PangoContext *context)
{
PangoFontMap *font_map;
PangoRenderer *renderer;
CoglPangoFontMap *font_map_priv;
font_map = pango_context_get_font_map (context);
g_return_val_if_fail (COGL_PANGO_IS_FONT_MAP (font_map), NULL);
font_map_priv = COGL_PANGO_FONT_MAP (font_map);
renderer = cogl_pango_font_map_get_renderer (font_map_priv);
g_return_val_if_fail (COGL_PANGO_IS_RENDERER (renderer), NULL);
return COGL_PANGO_RENDERER (renderer);
}
static GQuark
cogl_pango_render_get_display_list_key (void)
{
static GQuark key = 0;
if (G_UNLIKELY (key == 0))
key = g_quark_from_static_string ("CoglPangoDisplayList");
return key;
}
/**
* cogl_pango_render_layout_subpixel:
* @layout: a #PangoLayout
* @x: FIXME
* @y: FIXME
* @color: color to use when rendering the layout
* @flags: flags to pass to the renderer
*
* FIXME
*
* Since: 1.0
*/
void
cogl_pango_render_layout_subpixel (PangoLayout *layout,
int x,
int y,
const CoglColor *color,
int flags)
{
PangoContext *context;
CoglPangoRenderer *priv;
CoglPangoDisplayList *display_list;
context = pango_layout_get_context (layout);
priv = cogl_pango_get_renderer_from_context (context);
if (G_UNLIKELY (!priv))
return;
display_list = g_object_get_qdata (G_OBJECT (layout),
cogl_pango_render_get_display_list_key ());
if (display_list == NULL)
{
priv->display_list = display_list =_cogl_pango_display_list_new ();
priv->color = *color;
g_object_set_qdata_full (G_OBJECT (layout),
cogl_pango_render_get_display_list_key (),
display_list,
(GDestroyNotify) _cogl_pango_display_list_free);
pango_renderer_draw_layout (PANGO_RENDERER (priv), layout, 0, 0);
priv->display_list = NULL;
}
cogl_push_matrix ();
cogl_translate (x, y, 0);
_cogl_pango_display_list_render (display_list,
priv->glyph_material,
priv->solid_material);
cogl_pop_matrix ();
}
/**
* cogl_pango_render_layout:
* @layout: a #PangoLayout
* @x: X coordinate to render the layout at
* @y: Y coordinate to render the layout at
* @color: color to use when rendering the layout
* @flags: flags to pass to the renderer
*
* Renders @layout.
*
* Since: 1.0
*/
void
cogl_pango_render_layout (PangoLayout *layout,
int x,
int y,
const CoglColor *color,
int flags)
{
cogl_pango_render_layout_subpixel (layout,
x * PANGO_SCALE,
y * PANGO_SCALE,
color,
flags);
}
/**
* cogl_pango_render_layout_line:
* @line: a #PangoLayoutLine
* @x: X coordinate to render the line at
* @y: Y coordinate to render the line at
* @color: color to use when rendering the line
*
* Renders @line at the given coordinates using the given color.
*
* Since: 1.0
*/
void
cogl_pango_render_layout_line (PangoLayoutLine *line,
int x,
int y,
const CoglColor *color)
{
PangoContext *context;
CoglPangoRenderer *priv;
context = pango_layout_get_context (line->layout);
priv = cogl_pango_get_renderer_from_context (context);
if (G_UNLIKELY (!priv))
return;
priv->display_list = _cogl_pango_display_list_new ();
priv->color = *color;
pango_renderer_draw_layout_line (PANGO_RENDERER (priv), line, x, y);
cogl_material_set_color (priv->glyph_material, color);
cogl_material_set_color (priv->solid_material, color);
_cogl_pango_display_list_render (priv->display_list,
priv->glyph_material,
priv->solid_material);
_cogl_pango_display_list_free (priv->display_list);
priv->display_list = NULL;
}
void
_cogl_pango_renderer_clear_glyph_cache (CoglPangoRenderer *renderer)
{
cogl_pango_glyph_cache_clear (renderer->glyph_cache);
cogl_pango_glyph_cache_clear (renderer->mipmapped_glyph_cache);
}
void
_cogl_pango_renderer_set_use_mipmapping (CoglPangoRenderer *renderer,
gboolean value)
{
renderer->use_mipmapping = value;
}
gboolean
_cogl_pango_renderer_get_use_mipmapping (CoglPangoRenderer *renderer)
{
return renderer->use_mipmapping;
}
static CoglPangoGlyphCacheValue *
cogl_pango_renderer_get_cached_glyph (PangoRenderer *renderer,
PangoFont *font,
PangoGlyph glyph)
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
CoglPangoGlyphCacheValue *value;
CoglPangoGlyphCache *glyph_cache;
glyph_cache = priv->use_mipmapping ? priv->mipmapped_glyph_cache
: priv->glyph_cache;
value = cogl_pango_glyph_cache_lookup (glyph_cache, font, glyph);
if (value == NULL)
{
cairo_surface_t *surface;
cairo_t *cr;
cairo_scaled_font_t *scaled_font;
PangoRectangle ink_rect;
cairo_glyph_t cairo_glyph;
pango_font_get_glyph_extents (font, glyph, &ink_rect, NULL);
pango_extents_to_pixels (&ink_rect, NULL);
surface = cairo_image_surface_create (CAIRO_FORMAT_A8,
ink_rect.width,
ink_rect.height);
cr = cairo_create (surface);
scaled_font = pango_cairo_font_get_scaled_font (PANGO_CAIRO_FONT (font));
cairo_set_scaled_font (cr, scaled_font);
cairo_glyph.x = -ink_rect.x;
cairo_glyph.y = -ink_rect.y;
/* The PangoCairo glyph numbers directly map to Cairo glyph
numbers */
cairo_glyph.index = glyph;
cairo_show_glyphs (cr, &cairo_glyph, 1);
cairo_destroy (cr);
cairo_surface_flush (surface);
/* Copy the glyph to the cache */
value =
cogl_pango_glyph_cache_set (glyph_cache, font, glyph,
cairo_image_surface_get_data (surface),
cairo_image_surface_get_width (surface),
cairo_image_surface_get_height (surface),
cairo_image_surface_get_stride (surface),
ink_rect.x, ink_rect.y);
cairo_surface_destroy (surface);
COGL_NOTE (PANGO, "cache fail %i", glyph);
}
else
COGL_NOTE (PANGO, "cache success %i", glyph);
return value;
}
void
cogl_pango_ensure_glyph_cache_for_layout (PangoLayout *layout)
{
PangoContext *context;
PangoRenderer *renderer;
PangoLayoutIter *iter;
g_return_if_fail (PANGO_IS_LAYOUT (layout));
if ((iter = pango_layout_get_iter (layout)) == NULL)
return;
context = pango_layout_get_context (layout);
renderer =
PANGO_RENDERER (cogl_pango_get_renderer_from_context (context));
do
{
PangoLayoutLine *line;
GSList *l;
line = pango_layout_iter_get_line_readonly (iter);
for (l = line->runs; l; l = l->next)
{
PangoLayoutRun *run = l->data;
PangoGlyphString *glyphs = run->glyphs;
int i;
for (i = 0; i < glyphs->num_glyphs; i++)
{
PangoGlyphInfo *gi = &glyphs->glyphs[i];
cogl_pango_renderer_get_cached_glyph (renderer,
run->item->analysis.font,
gi->glyph);
}
}
}
while (pango_layout_iter_next_line (iter));
pango_layout_iter_free (iter);
}
static void
cogl_pango_renderer_set_color_for_part (PangoRenderer *renderer,
PangoRenderPart part)
{
PangoColor *pango_color = pango_renderer_get_color (renderer, part);
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
CoglColor color;
if (pango_color)
{
color.red = pango_color->red >> 8;
color.green = pango_color->green >> 8;
color.blue = pango_color->blue >> 8;
color.alpha = priv->color.alpha;
}
else
color = priv->color;
_cogl_pango_display_list_set_color (priv->display_list, &color);
}
static void
cogl_pango_renderer_draw_box (PangoRenderer *renderer,
int x,
int y,
int width,
int height)
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
g_return_if_fail (priv->display_list != NULL);
_cogl_pango_display_list_add_rectangle (priv->display_list,
x,
y - height,
x + width,
y);
}
static void
cogl_pango_renderer_get_device_units (PangoRenderer *renderer,
int xin,
int yin,
float *xout,
float *yout)
{
const PangoMatrix *matrix;
if ((matrix = pango_renderer_get_matrix (renderer)))
{
/* Convert user-space coords to device coords */
*xout = ((xin * matrix->xx + yin * matrix->xy)
/ PANGO_SCALE + matrix->x0);
*yout = ((yin * matrix->yy + xin * matrix->yx)
/ PANGO_SCALE + matrix->y0);
}
else
{
*xout = PANGO_PIXELS (xin);
*yout = PANGO_PIXELS (yin);
}
}
static void
cogl_pango_renderer_draw_rectangle (PangoRenderer *renderer,
PangoRenderPart part,
int x,
int y,
int width,
int height)
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
float x1, x2, y1, y2;
g_return_if_fail (priv->display_list != NULL);
cogl_pango_renderer_set_color_for_part (renderer, part);
cogl_pango_renderer_get_device_units (renderer,
x, y,
&x1, &y1);
cogl_pango_renderer_get_device_units (renderer,
x + width, y + height,
&x2, &y2);
_cogl_pango_display_list_add_rectangle (priv->display_list,
x1, y1, x2, y2);
}
static void
cogl_pango_renderer_draw_trapezoid (PangoRenderer *renderer,
PangoRenderPart part,
double y1,
double x11,
double x21,
double y2,
double x12,
double x22)
{
CoglPangoRenderer *priv = COGL_PANGO_RENDERER (renderer);
float points[8];
g_return_if_fail (priv->display_list != NULL);
points[0] = (x11);
points[1] = (y1);
points[2] = (x12);
points[3] = (y2);
points[4] = (x22);
points[5] = points[3];
points[6] = (x21);
points[7] = points[1];
cogl_pango_renderer_set_color_for_part (renderer, part);
_cogl_pango_display_list_add_trapezoid (priv->display_list,
y1,
x11,
x21,
y2,
x12,
x22);
}
static void
cogl_pango_renderer_draw_glyphs (PangoRenderer *renderer,
PangoFont *font,
PangoGlyphString *glyphs,
int xi,
int yi)
{
CoglPangoRenderer *priv = (CoglPangoRenderer *) renderer;
CoglPangoGlyphCacheValue *cache_value;
int i;
cogl_pango_renderer_set_color_for_part (renderer,
PANGO_RENDER_PART_FOREGROUND);
for (i = 0; i < glyphs->num_glyphs; i++)
{
PangoGlyphInfo *gi = glyphs->glyphs + i;
float x, y;
cogl_pango_renderer_get_device_units (renderer,
xi + gi->geometry.x_offset,
yi + gi->geometry.y_offset,
&x, &y);
if ((gi->glyph & PANGO_GLYPH_UNKNOWN_FLAG))
{
PangoFontMetrics *metrics;
if (font == NULL ||
(metrics = pango_font_get_metrics (font, NULL)) == NULL)
{
cogl_pango_renderer_draw_box (renderer,
x,
y,
PANGO_UNKNOWN_GLYPH_WIDTH,
PANGO_UNKNOWN_GLYPH_HEIGHT);
}
else
{
cogl_pango_renderer_draw_box (renderer,
x,
y,
metrics->approximate_char_width
/ PANGO_SCALE,
metrics->ascent / PANGO_SCALE);
pango_font_metrics_unref (metrics);
}
}
else
{
/* Get the texture containing the glyph. This will create
the cache entry if there isn't already one */
cache_value =
cogl_pango_renderer_get_cached_glyph (renderer,
font,
gi->glyph);
if (cache_value == NULL)
cogl_pango_renderer_draw_box (renderer,
x,
y,
PANGO_UNKNOWN_GLYPH_WIDTH,
PANGO_UNKNOWN_GLYPH_HEIGHT);
else
{
float width, height;
x += (float)(cache_value->draw_x);
y += (float)(cache_value->draw_y);
width = x + (float)(cache_value->draw_width);
height = y + (float)(cache_value->draw_height);
cogl_pango_renderer_draw_glyph (priv, cache_value, x, y);
}
}
xi += gi->geometry.width;
}
}