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3fc64dfaa7
mutter/clutter/pango/cogl-pango-render.c
Neil Roberts 3fc64dfaa7 [pango-render] Keep a reference to the first line to detect layout changes 
In order to cope with the situation where an application renders with
a PangoLayout, makes some changes and then renders again with the same
layout, CoglPangoRenderer needs to detect that the changes have
occured so that it can recreate the display list. This is acheived by
keeping a reference to the first line of the layout. When the layout
is changed Pango will clear the layout pointer in the first line and
create a new line. So if the layout pointer in the line becomes NULL
then we know the layout has changed. This trick was suggested by
Behdad Esfahbod in this email:

http://mail.gnome.org/archives/gtk-i18n-list/2009-May/msg00019.html
2009-05-21 12:17:12 +01:00

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/*
* 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;
};
typedef struct _CoglPangoRendererQdata CoglPangoRendererQdata;
/* An instance of this struct gets attached to each PangoLayout to
cache the VBO and to detect changes to the layout */
struct _CoglPangoRendererQdata
{
/* The cache of the geometry for the layout */
CoglPangoDisplayList *display_list;
/* A reference to the first line of the layout. This is just used to
detect changes */
PangoLayoutLine *first_line;
};
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_qdata_key (void)
{
static GQuark key = 0;
if (G_UNLIKELY (key == 0))
key = g_quark_from_static_string ("CoglPangoDisplayList");
return key;
}
static void
cogl_pango_render_qdata_destroy (CoglPangoRendererQdata *qdata)
{
if (qdata->display_list)
_cogl_pango_display_list_free (qdata->display_list);
if (qdata->first_line)
pango_layout_line_unref (qdata->first_line);
g_slice_free (CoglPangoRendererQdata, qdata);
}
/**
* 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;
CoglPangoRendererQdata *qdata;
context = pango_layout_get_context (layout);
priv = cogl_pango_get_renderer_from_context (context);
if (G_UNLIKELY (!priv))
return;
qdata = g_object_get_qdata (G_OBJECT (layout),
cogl_pango_render_get_qdata_key ());
if (qdata == NULL)
{
qdata = g_slice_new0 (CoglPangoRendererQdata);
g_object_set_qdata_full (G_OBJECT (layout),
cogl_pango_render_get_qdata_key (),
qdata,
(GDestroyNotify)
cogl_pango_render_qdata_destroy);
}
/* Check if the layout has changed since the last build of the
display list. This trick was suggested by Behdad Esfahbod here:
http://mail.gnome.org/archives/gtk-i18n-list/2009-May/msg00019.html */
if (qdata->display_list && qdata->first_line
&& qdata->first_line->layout != layout)
{
_cogl_pango_display_list_free (qdata->display_list);
qdata->display_list = NULL;
}
if (qdata->display_list == NULL)
{
qdata->display_list = _cogl_pango_display_list_new ();
priv->color = *color;
priv->display_list = qdata->display_list;
pango_renderer_draw_layout (PANGO_RENDERER (priv), layout, 0, 0);
priv->display_list = NULL;
}
cogl_push_matrix ();
cogl_translate (x / (gfloat) PANGO_SCALE, y / (gfloat) PANGO_SCALE, 0);
_cogl_pango_display_list_render (qdata->display_list,
priv->glyph_material,
priv->solid_material);
cogl_pop_matrix ();
/* Keep a reference to the first line of the layout so we can detect
changes */
if (qdata->first_line)
{
pango_layout_line_unref (qdata->first_line);
qdata->first_line = NULL;
}
if (pango_layout_get_line_count (layout) > 0)
{
qdata->first_line = pango_layout_get_line (layout, 0);
pango_layout_line_ref (qdata->first_line);
}
}
/**
* 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;
}
}
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