Two broken pango patches
- From: Andreas Bogk <andreas andreas org>
- To: gtk-devel-list gnome org
- Subject: Two broken pango patches
- Date: 30 Aug 2001 01:05:17 +0200
Hi!
I've tried myself at improving pango, with limited success. The issues
I've been trying to address are:
* pango passes the LRE, RLE, LRO, RLO and PDF code points to the glyph
rendering engine, instead of removing it from the stream
* Arabic font shaping is unimplemented for freetype rendering
Here are the non-working patches. I hope they are useful to somebody.
Removal of direction indicators:
Index: pango/pango-context.c
===================================================================
RCS file: /cvs/gnome/pango/pango/pango-context.c,v
retrieving revision 1.40
diff -u -r1.40 pango-context.c
--- pango/pango-context.c 2001/07/19 20:49:00 1.40
+++ pango/pango-context.c 2001/08/23 12:22:06
@@ -521,12 +521,13 @@
{
gunichar *text_ucs4;
long n_chars, i;
- guint8 *embedding_levels;
+ gint8 *embedding_levels;
PangoDirection base_dir;
PangoItem *item;
const char *p;
const char *next;
GList *result = NULL;
+ GSList *to_be_deleted = NULL;
PangoAnalysis *analyses;
@@ -548,7 +549,7 @@
*/
text_ucs4 = g_utf8_to_ucs4_fast (text + start_index, length, &n_chars);
- embedding_levels = g_new (guint8, n_chars);
+ embedding_levels = g_new (gint8, n_chars);
pango_log2vis_get_embedding_levels (text_ucs4, n_chars, &base_dir,
embedding_levels);
@@ -620,13 +621,18 @@
else
item->analysis.extra_attrs = analysis->extra_attrs;
- result = g_list_prepend (result, item);
+ /* negative embedding levels are
+ LRE, RLE, LRO, RLO, PDF or BN codes */
+ if (embedding_levels[i] >= 0)
+ result = g_list_prepend (result, item);
+ else
+ to_be_deleted = g_slist_prepend (to_be_deleted, item);
}
else
g_object_unref (analysis->font);
item->length = (next - text) - item->offset;
item->num_chars++;
p = next;
}
@@ -634,6 +640,8 @@
g_free (embedding_levels);
g_free (text_ucs4);
+ g_slist_foreach (to_be_deleted, (GFunc) pango_item_free, NULL);
+
return g_list_reverse (result);
}
Index: pango/pango-utils.c
===================================================================
RCS file: /cvs/gnome/pango/pango/pango-utils.c,v
retrieving revision 1.19
diff -u -r1.19 pango-utils.c
--- pango/pango-utils.c 2001/07/02 14:17:18 1.19
+++ pango/pango-utils.c 2001/08/23 12:22:06
@@ -1140,7 +1140,7 @@
pango_log2vis_get_embedding_levels (gunichar *str,
int len,
PangoDirection *pbase_dir,
- guint8 *embedding_level_list)
+ gint8 *embedding_level_list)
{
FriBidiCharType fribidi_base_dir;
Index: pango/pango-utils.h
===================================================================
RCS file: /cvs/gnome/pango/pango/pango-utils.h,v
retrieving revision 1.12
diff -u -r1.12 pango-utils.h
--- pango/pango-utils.h 2001/06/26 19:13:28 1.12
+++ pango/pango-utils.h 2001/08/23 12:22:06
@@ -79,7 +79,7 @@
gboolean pango_log2vis_get_embedding_levels (gunichar *str,
int len,
PangoDirection *pbase_dir,
- guint8 *embedding_level_list);
+ gint8 *embedding_level_list);
gboolean pango_get_mirror_char (gunichar ch,
gunichar *mirrored_ch);
Index: pango/pangoft2.c
===================================================================
RCS file: /cvs/gnome/pango/pango/pangoft2.c,v
retrieving revision 1.23
diff -u -r1.23 pangoft2.c
--- pango/pangoft2.c 2001/08/14 16:14:14 1.23
+++ pango/pangoft2.c 2001/08/23 12:22:06
@@ -574,7 +574,7 @@
int last_level;
gunichar *text_ucs4;
long n_chars, i;
- guint8 *embedding_levels;
+ gint8 *embedding_levels;
PangoDirection base_dir = PANGO_DIRECTION_LTR;
GSList *subfonts = NULL;
@@ -582,7 +582,7 @@
if (!text_ucs4)
return;
- embedding_levels = g_new (guint8, n_chars);
+ embedding_levels = g_new (gint8, n_chars);
pango_log2vis_get_embedding_levels (text_ucs4, n_chars, &base_dir,
embedding_levels);
g_free (text_ucs4);
Index: pango/pangox.c
===================================================================
RCS file: /cvs/gnome/pango/pango/pangox.c,v
retrieving revision 1.63
diff -u -r1.63 pangox.c
--- pango/pangox.c 2001/07/02 05:02:25 1.63
+++ pango/pangox.c 2001/08/23 12:22:07
@@ -780,7 +780,7 @@
int last_level;
gunichar *text_ucs4;
long n_chars, i;
- guint8 *embedding_levels;
+ gint8 *embedding_levels;
PangoDirection base_dir = PANGO_DIRECTION_LTR;
GSList *subfonts = NULL;
gboolean finished = FALSE;
@@ -789,7 +789,7 @@
if (!text_ucs4)
return;
- embedding_levels = g_new (guint8, n_chars);
+ embedding_levels = g_new (gint8, n_chars);
pango_log2vis_get_embedding_levels (text_ucs4, n_chars, &base_dir,
embedding_levels);
g_free (text_ucs4);
Index: pango/mini-fribidi/fribidi.c
===================================================================
RCS file: /cvs/gnome/pango/pango/mini-fribidi/fribidi.c,v
retrieving revision 1.5
diff -u -r1.5 fribidi.c
--- pango/mini-fribidi/fribidi.c 2001/07/20 17:22:18 1.5
+++ pango/mini-fribidi/fribidi.c 2001/08/23 12:22:07
@@ -945,17 +945,7 @@
/* Reinsert the explicit codes & bn's that already removed, from the
explicits_list to type_rl_list. */
DBG ("Reinserting explicit codes\n");
- {
- TypeLink *p;
-
- override_list (type_rl_list, explicits_list);
- p = type_rl_list->next;
- if (p->level < 0)
- p->level = base_level;
- for (; p->next; p = p->next)
- if (p->level < 0)
- p->level = p->prev->level;
- }
+ override_list (type_rl_list, explicits_list);
#ifdef DEBUG
if (fribidi_debug)
@@ -1088,7 +1078,7 @@
gunichar *str,
int len, PangoDirection *pbase_dir,
/* output */
- guint8 *embedding_level_list)
+ gint8 *embedding_level_list)
{
TypeLink *type_rl_list, *pp;
gint max_level;
And here is my attempt at arabic font shaping:
diff -u -N ../../pango-0.18-pre4/modules/arabic/Makefile.am arabic/Makefile.am
--- ../../pango-0.18-pre4/modules/arabic/Makefile.am Sat May 19 13:36:11 2001
+++ arabic/Makefile.am Fri Aug 24 18:36:40 2001
@@ -3,7 +3,7 @@
pangolibs = $(top_builddir)/pango/libpango.la $(FRIBIDI_LIBS) $(GLIB_LIBS)
pangoxlibs = $(top_builddir)/pango/libpangox.la $(X_LIBS) $(pangolibs)
pangoxftlibs = $(top_builddir)/pango/libpangoxft.la $(XFT_LIBS) $(pangolibs)
-pangoft2libs = $(top_builddir)/pango/libpangoft2.la $(FREETYPE_LIBS) $(pangolibs)
+pangoft2libs = $(top_builddir)/pango/libpangoft2.la $(top_builddir)/pango/opentype/libpango-ot.la $(FREETYPE_LIBS) $(pangolibs)
if HAVE_XFT
if INCLUDE_ARABIC_XFT
@@ -38,6 +38,11 @@
arabic-ot.c \
arabic-ot.h
+ft2_sources = \
+ arabic-ft2.c \
+ arabic-ot.c \
+ arabic-ot.h
+
if HAVE_X
if INCLUDE_ARABIC_X
X_MODULES=
@@ -55,9 +60,26 @@
X_PREFIX=
endif
-noinst_LTLIBRARIES = $(X_INCLUDED) $(XFT_INCLUDED)
-module_LTLIBRARIES = $(X_MODULES) $(XFT_MODULES)
-moddefine = $(X_PREFIX) $(XFT_PREFIX)
+if HAVE_FREETYPE
+if INCLUDE_ARABIC_FT2
+FT2_MODULES=
+FT2_INCLUDED=libpango-arabic-ft2.la
+FT2_PREFIX=-DFT2_MODULE_PREFIX
+else
+FT2_MODULES=pango-arabic-ft2.la
+FT2_INCLUDED=
+FT2_PREFIX=
+arabic_ft2_libadd=$(pangoft2libs)
+endif
+else
+FT2_MODULES=
+FT2_INCLUDED=
+FT2_PREFIX=
+endif
+
+noinst_LTLIBRARIES = $(X_INCLUDED) $(XFT_INCLUDED) $(FT2_INCLUDED)
+module_LTLIBRARIES = $(X_MODULES) $(XFT_MODULES) $(FT2_MODULES)
+moddefine = $(X_PREFIX) $(XFT_PREFIX) $(FT2_PREFIX)
moduledir = $(libdir)/pango/modules
INCLUDES = -I$(top_srcdir) -I$(top_srcdir)/pango/ $(moddefine) $(X_CFLAGS) $(FREETYPE_CFLAGS)
@@ -73,6 +95,12 @@
pango_arabic_xft_la_SOURCES = $(xft_sources)
libpango_arabic_xft_la_SOURCES = $(xft_sources)
+
+pango_arabic_ft2_la_LDFLAGS = -export-dynamic -avoid-version -module
+pango_arabic_ft2_la_LIBADD = $(arabic_ft2_libadd)
+pango_arabic_ft2_la_SOURCES = $(ft2_sources)
+
+libpango_arabic_ft2_la_SOURCES = $(ft2_sources)
included-modules: $(noinst_LTLIBRARIES)
diff -u -N ../../pango-0.18-pre4/modules/arabic/arabic-ft2.c arabic/arabic-ft2.c
--- ../../pango-0.18-pre4/modules/arabic/arabic-ft2.c Thu Jan 1 01:00:00 1970
+++ arabic/arabic-ft2.c Fri Aug 24 18:36:51 2001
@@ -0,0 +1,431 @@
+/* Pango
+ * arabic-ft2.c:
+ *
+ * Copyright (C) 2001 convergence integrated media GmbH
+ * Author: Andreas Bogk <andreas convergence de>
+ *
+ * Based on xft code for arabic:
+ *
+ * Copyright (C) 2000 Red Hat Software
+ * Author: Owen Taylor <otaylor redhat com>
+ *
+ * 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.
+ */
+
+#include <string.h>
+
+#include "arabic-ot.h"
+
+#include "pangoft2.h"
+#include "pango-engine.h"
+#include "pango-utils.h"
+
+#define SCRIPT_ENGINE_NAME "ArabicScriptEngineFt2"
+
+static PangoEngineRange arabic_ranges[] = {
+ /* Language characters */
+ { 0x060c, 0x06f9, "*" }, /* Arabic */
+};
+
+static PangoEngineInfo script_engines[] = {
+ {
+ SCRIPT_ENGINE_NAME,
+ PANGO_ENGINE_TYPE_SHAPE,
+ PANGO_RENDER_TYPE_FT2,
+ arabic_ranges, G_N_ELEMENTS(arabic_ranges)
+ }
+};
+
+void
+maybe_add_feature (PangoOTRuleset *ruleset,
+ PangoOTInfo *info,
+ guint script_index,
+ PangoOTTag tag,
+ gulong property_bit)
+{
+ guint feature_index;
+
+ /* 0xffff == default language system */
+ if (pango_ot_info_find_feature (info, PANGO_OT_TABLE_GSUB,
+ tag, script_index, 0xffff, &feature_index))
+ pango_ot_ruleset_add_feature (ruleset, PANGO_OT_TABLE_GSUB, feature_index,
+ property_bit);
+}
+
+static PangoOTRuleset *
+get_ruleset (PangoFont *font)
+{
+ PangoOTRuleset *ruleset;
+ static GQuark ruleset_quark = 0;
+ PangoOTInfo *info;
+
+ if (!ruleset_quark)
+ ruleset_quark = g_quark_from_string ("pango-arabic-ruleset");
+
+ ruleset = g_object_get_qdata (G_OBJECT (font), ruleset_quark);
+
+ if (!ruleset)
+ {
+ int i;
+
+ for(i = 1; i <= pango_ft2_n_subfonts (font); i++)
+ {
+ PangoOTTag arab_tag = FT_MAKE_TAG ('a', 'r', 'a', 'b');
+ guint script_index;
+ FT_Face face;
+
+ face = pango_ft2_get_face (font, i);
+ if (!face)
+ {
+ g_warning ("Couldn't get face for subfont %i", i);
+ continue;
+ }
+
+ info = pango_ot_info_new (face);
+ ruleset = pango_ot_ruleset_new (info);
+
+ if (!info)
+ return NULL;
+
+ if (pango_ot_info_find_script (info, PANGO_OT_TABLE_GSUB,
+ arab_tag, &script_index))
+ {
+ maybe_add_feature (ruleset, info, script_index, FT_MAKE_TAG ('i','s','o','l'), isolated);
+ maybe_add_feature (ruleset, info, script_index, FT_MAKE_TAG ('i','n','i','t'), initial);
+ maybe_add_feature (ruleset, info, script_index, FT_MAKE_TAG ('m','e','d','i'), medial);
+ maybe_add_feature (ruleset, info, script_index, FT_MAKE_TAG ('f','i','n','a'), final);
+ maybe_add_feature (ruleset, info, script_index, FT_MAKE_TAG ('l','i','g','a'), 0xFFFF);
+ g_object_set_qdata_full (G_OBJECT (font), ruleset_quark, ruleset,
+ (GDestroyNotify)g_object_unref);
+ return ruleset;
+ }
+ else
+ {
+ g_object_unref(ruleset);
+ ruleset = NULL;
+ }
+ }
+ g_object_set_qdata_full (G_OBJECT (font), ruleset_quark, ruleset,
+ (GDestroyNotify)g_object_unref);
+ }
+
+ return ruleset;
+}
+
+/*
+ * FT2 system script engine portion
+ */
+
+static PangoGlyph
+find_char (PangoFont *font,
+ gunichar wc)
+{
+ int i;
+ int n_subfonts;
+
+ n_subfonts = pango_ft2_n_subfonts (font);
+
+ for (i = 0; i < n_subfonts; i++)
+ {
+ FT_Face face;
+ FT_UInt index;
+
+ face = pango_ft2_get_face (font, i+1);
+ index = FT_Get_Char_Index (face, wc);
+ if (index && index <= face->num_glyphs)
+ return PANGO_FT2_MAKE_GLYPH (i+1, index);
+ }
+
+ return 0;
+}
+
+static void
+swap_range (PangoGlyphString *glyphs, int start, int end)
+{
+ int i, j;
+
+ for (i = start, j = end - 1; i < j; i++, j--)
+ {
+ PangoGlyphInfo glyph_info;
+ gint log_cluster;
+
+ glyph_info = glyphs->glyphs[i];
+ glyphs->glyphs[i] = glyphs->glyphs[j];
+ glyphs->glyphs[j] = glyph_info;
+
+ log_cluster = glyphs->log_clusters[i];
+ glyphs->log_clusters[i] = glyphs->log_clusters[j];
+ glyphs->log_clusters[j] = log_cluster;
+ }
+}
+
+static void
+set_glyph (PangoFont *font,
+ PangoGlyphString *glyphs,
+ int i,
+ int offset,
+ PangoGlyph glyph)
+{
+ PangoRectangle logical_rect;
+
+ glyphs->glyphs[i].glyph = glyph;
+
+ glyphs->glyphs[i].geometry.x_offset = 0;
+ glyphs->glyphs[i].geometry.y_offset = 0;
+
+ glyphs->log_clusters[i] = offset;
+
+ pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, NULL, &logical_rect);
+ glyphs->glyphs[i].geometry.width = logical_rect.width;
+
+ if (i > 0)
+ {
+ glyphs->glyphs[i-1].geometry.width +=
+ pango_ft2_font_get_kerning (font,
+ glyphs->glyphs[i-1].glyph,
+ glyphs->glyphs[i].glyph);
+ }
+}
+
+static void
+arabic_engine_shape (PangoFont *font,
+ const char *text,
+ gint length,
+ PangoAnalysis *analysis,
+ PangoGlyphString *glyphs)
+{
+ int n_chars;
+ int i;
+ const char *p;
+ gulong *properties = NULL;
+ gunichar *wcs = NULL;
+ PangoOTRuleset *ruleset;
+
+ g_return_if_fail (font != NULL);
+ g_return_if_fail (text != NULL);
+ g_return_if_fail (length >= 0);
+ g_return_if_fail (analysis != NULL);
+
+ n_chars = g_utf8_strlen (text, length);
+ pango_glyph_string_set_size (glyphs, n_chars);
+
+ ruleset = get_ruleset (font);
+ if (ruleset)
+ {
+ wcs = g_utf8_to_ucs4_fast (text, length, NULL);
+ properties = g_new0 (gulong, n_chars);
+
+ Assign_Arabic_Properties (wcs, properties, n_chars);
+ }
+
+ p = text;
+ for (i=0; i < n_chars; i++)
+ {
+ gunichar wc;
+ gunichar mirrored_ch;
+ PangoGlyph index;
+ char buf[6];
+ const char *input;
+
+ wc = g_utf8_get_char (p);
+
+ input = p;
+ if (analysis->level % 2)
+ if (pango_get_mirror_char (wc, &mirrored_ch))
+ {
+ wc = mirrored_ch;
+
+ g_unichar_to_utf8 (wc, buf);
+ input = buf;
+ }
+
+ if (wc >= 0x200B && wc <= 0x200F) /* Zero-width characters */
+ {
+ set_glyph (font, glyphs, i, p - text, 0);
+ }
+ else
+ {
+ /* Hack - Microsoft fonts are strange and don't contain the
+ * correct rules to shape ARABIC LETTER FARSI YEH in
+ * medial/initial position. It looks identical to ARABIC LETTER
+ * YEH in these positions, so we substitute
+ */
+ if (wc == 0x6cc && ruleset &&
+ ((properties[i] & (initial | medial)) != (initial | medial)))
+ wc = 0x64a;
+
+ index = find_char (font, wc);
+
+ if (!index)
+ {
+ set_glyph (font, glyphs, i, p - text,
+ pango_ft2_get_unknown_glyph (font));
+ }
+ else
+ {
+ set_glyph (font, glyphs, i, p - text, index);
+
+ if (g_unichar_type (wc) == G_UNICODE_NON_SPACING_MARK)
+ {
+ if (i > 0)
+ {
+ glyphs->log_clusters[i] = glyphs->log_clusters[i-1];
+#if 0
+ PangoRectangle logical_rect, ink_rect;
+
+ glyphs->glyphs[i].geometry.width = MAX (glyphs->glyphs[i-1].geometry.width,
+ glyphs->glyphs[i].geometry.width);
+ glyphs->glyphs[i-1].geometry.width = 0;
+
+ /* Some heuristics to try to guess how overstrike glyphs are
+ * done and compensate
+ */
+ pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, &ink_rect, &logical_rect);
+ if (logical_rect.width == 0 && ink_rect.x == 0)
+ glyphs->glyphs[i].geometry.x_offset = (glyphs->glyphs[i].geometry.width - ink_rect.width) / 2;
+#endif
+ }
+ }
+ }
+ }
+
+ p = g_utf8_next_char (p);
+ }
+
+ ruleset = get_ruleset (font);
+
+ if (ruleset)
+ {
+ pango_ot_ruleset_shape (ruleset, glyphs, properties);
+
+ g_free (wcs);
+ g_free (properties);
+
+ }
+
+ for (i = 0; i < glyphs->num_glyphs; i++)
+ {
+
+ if (glyphs->glyphs[i].glyph)
+ {
+ PangoRectangle logical_rect;
+
+ pango_font_get_glyph_extents (font, glyphs->glyphs[i].glyph, NULL, &logical_rect);
+ glyphs->glyphs[i].geometry.width = logical_rect.width;
+ }
+ else
+ glyphs->glyphs[i].geometry.width = 0;
+
+ glyphs->glyphs[i].geometry.x_offset = 0;
+ glyphs->glyphs[i].geometry.y_offset = 0;
+ }
+
+ /* Simple bidi support */
+
+ if (analysis->level % 2)
+ {
+ int start, end;
+
+ /* Swap all glyphs */
+ swap_range (glyphs, 0, glyphs->num_glyphs);
+
+ /* Now reorder glyphs within each cluster back to LTR */
+ for (start=0; start<glyphs->num_glyphs;)
+ {
+ end = start;
+ while (end < glyphs->num_glyphs &&
+ glyphs->log_clusters[end] == glyphs->log_clusters[start])
+ end++;
+
+ if (end > start + 1)
+ swap_range (glyphs, start, end);
+ start = end;
+ }
+ }
+}
+
+static PangoCoverage *
+arabic_engine_get_coverage (PangoFont *font,
+ PangoLanguage *lang)
+{
+#if 1
+ gunichar wc;
+ PangoCoverage *result;
+
+ result = pango_coverage_new ();
+
+ for (wc = 0; wc < 65536; wc++)
+ if (find_char (font, wc))
+ pango_coverage_set (result, wc, PANGO_COVERAGE_EXACT);
+#else
+ result = pango_ft2_get_coverage (font, lang);
+#endif
+ return result;
+}
+
+static PangoEngine *
+arabic_engine_ft2_new ()
+{
+ PangoEngineShape *result;
+
+ result = g_new (PangoEngineShape, 1);
+
+ result->engine.id = SCRIPT_ENGINE_NAME;
+ result->engine.type = PANGO_ENGINE_TYPE_SHAPE;
+ result->engine.length = sizeof (result);
+ result->script_shape = arabic_engine_shape;
+ result->get_coverage = arabic_engine_get_coverage;
+
+ return (PangoEngine *)result;
+}
+
+/* The following three functions provide the public module API for
+ * Pango. If we are compiling it is a module, then we name the
+ * entry points script_engine_list, etc. But if we are compiling
+ * it for inclusion directly in Pango, then we need them to
+ * to have distinct names for this module, so we prepend
+ * _pango_arabic_
+ */
+#ifdef FT2_MODULE_PREFIX
+#define MODULE_ENTRY(func) _pango_arabic_ft2_##func
+#else
+#define MODULE_ENTRY(func) func
+#endif
+
+/* List the engines contained within this module
+ */
+void
+MODULE_ENTRY(script_engine_list) (PangoEngineInfo **engines, gint *n_engines)
+{
+ *engines = script_engines;
+ *n_engines = G_N_ELEMENTS (script_engines);
+}
+
+/* Load a particular engine given the ID for the engine
+ */
+PangoEngine *
+MODULE_ENTRY(script_engine_load) (const char *id)
+{
+ if (!strcmp (id, SCRIPT_ENGINE_NAME))
+ return arabic_engine_ft2_new ();
+ else
+ return NULL;
+}
+
+void
+MODULE_ENTRY(script_engine_unload) (PangoEngine *engine)
+{
+}
--
"In my eyes it is never a crime to steal knowledge. It is a good
theft. The pirate of knowledge is a good pirate."
(Michel Serres)
[
Date Prev][
Date Next] [
Thread Prev][
Thread Next]
[
Thread Index]
[
Date Index]
[
Author Index]
