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authorBehdad Esfahbod <behdad@gnome.org>2007-01-16 00:23:59 +0000
committerBehdad Esfahbod <behdad@src.gnome.org>2007-01-16 00:23:59 +0000
commit7a102793913cb7a1a0eefbbfc9d5c0d04c9eb868 (patch)
treed614b6941c83927af97a818fde59841499dd7917 /pango/pango-gravity.c
parentfd7ecbb0203d89f31e9b9b7c10147fa2a3864513 (diff)
downloadpango-7a102793913cb7a1a0eefbbfc9d5c0d04c9eb868.tar.gz
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
Diffstat (limited to 'pango/pango-gravity.c')
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diff --git a/pango/pango-gravity.c b/pango/pango-gravity.c
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+/* Pango
+ * pango-gravity.c: 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.
+ */
+
+#include <config.h>
+
+#include "pango-gravity.h"
+
+#include <math.h>
+
+/**
+ * pango_gravity_to_rotation:
+ * @gravity: gravity to query
+ *
+ * Converts a #PangoGravity value to its rotation value.
+ * @gravity should not be %PANGO_GRAVITY_AUTO.
+ *
+ * Return value: the rotation value corresponding to @gravity.
+ *
+ * Since: 1.16
+ */
+double
+pango_gravity_to_rotation (PangoGravity gravity)
+{
+ double rotation;
+
+ g_return_val_if_fail (gravity != PANGO_GRAVITY_AUTO, 0);
+
+ switch (gravity)
+ {
+ default:
+ case PANGO_GRAVITY_AUTO: /* shut gcc up */
+ case PANGO_GRAVITY_SOUTH: rotation = 0; break;
+ case PANGO_GRAVITY_NORTH: rotation = G_PI; break;
+ case PANGO_GRAVITY_EAST: rotation = -G_PI_2; break;
+ case PANGO_GRAVITY_WEST: rotation = +G_PI_2; break;
+ }
+
+ return rotation;
+}
+
+/**
+ * pango_gravity_get_for_matrix:
+ * @matrix: a #PangoMatrix
+ *
+ * Finds the gravity that best matches the rotation component
+ * in a #PangoMatrix.
+ *
+ * Return value: the gravity of @matrix, which will never be
+ * %PANGO_GRAVITY_AUTO, or %PANGO_GRAVITY_SOUTH if @matrix is %NULL
+ *
+ * Since: 1.16
+ */
+PangoGravity
+pango_gravity_get_for_matrix (const PangoMatrix *matrix)
+{
+ PangoGravity gravity;
+ double x;
+ double y;
+
+ if (!matrix)
+ return PANGO_GRAVITY_SOUTH;
+
+ x = matrix->xy;
+ y = matrix->yy;
+
+ if (fabs (x) > fabs (y))
+ gravity = x > 0 ? PANGO_GRAVITY_WEST : PANGO_GRAVITY_EAST;
+ else
+ gravity = y < 0 ? PANGO_GRAVITY_NORTH : PANGO_GRAVITY_SOUTH;
+
+ return gravity;
+}
+
+
+
+typedef enum
+{
+ PANGO_VERTICAL_DIRECTION_NONE,
+ PANGO_VERTICAL_DIRECTION_TTB,
+ PANGO_VERTICAL_DIRECTION_BTT
+} PangoVerticalDirection;
+
+typedef struct {
+ /* PangoDirection */
+ guint8 horiz_dir; /* Orientation in horizontal context */
+
+ /* PangoVerticalDirection */
+ guint8 vert_dir; /* Orientation in vertical context */
+
+ /* PangoGravity */
+ guint8 preferred_gravity; /* Preferred context gravity */
+
+ /* gboolean */
+ guint8 upright; /* Whether glyphs are upright or
+ * rotated in foreign context */
+} PangoScriptProperties;
+
+#define NONE PANGO_VERTICAL_DIRECTION_NONE
+#define TTB PANGO_VERTICAL_DIRECTION_TTB
+#define BTT PANGO_VERTICAL_DIRECTION_BTT
+
+#define LTR PANGO_DIRECTION_LTR
+#define RTL PANGO_DIRECTION_RTL
+#define WEAK PANGO_DIRECTION_WEAK_LTR
+
+#define S PANGO_GRAVITY_SOUTH
+#define E PANGO_GRAVITY_EAST
+#define N PANGO_GRAVITY_NORTH
+#define W PANGO_GRAVITY_WEST
+
+const PangoScriptProperties script_properties[] =
+ { /* ISO 15924 code */
+ {LTR, NONE, S, FALSE}, /* Zyyy */
+ {LTR, NONE, S, FALSE}, /* Qaai */
+ {RTL, NONE, S, FALSE}, /* Arab */
+ {LTR, NONE, S, FALSE}, /* Armn */
+ {LTR, NONE, S, FALSE}, /* Beng */
+ {LTR, TTB, E, TRUE }, /* Bopo */
+ {LTR, NONE, S, FALSE}, /* Cher */
+ {LTR, NONE, S, FALSE}, /* Qaac */
+ {LTR, NONE, S, FALSE}, /* Cyrl (Cyrs) */
+ {LTR, NONE, S, FALSE}, /* Dsrt */
+ {LTR, NONE, S, FALSE}, /* Deva */
+ {LTR, NONE, S, FALSE}, /* Ethi */
+ {LTR, NONE, S, FALSE}, /* Geor (Geon, Geoa) */
+ {LTR, NONE, S, FALSE}, /* Goth */
+ {LTR, NONE, S, FALSE}, /* Grek */
+ {LTR, NONE, S, FALSE}, /* Gujr */
+ {LTR, NONE, S, FALSE}, /* Guru */
+ {LTR, TTB, E, TRUE }, /* Hani */
+ {LTR, TTB, E, TRUE }, /* Hang */
+ {RTL, NONE, S, FALSE}, /* Hebr */
+ {LTR, TTB, E, TRUE }, /* Hira */
+ {LTR, NONE, S, FALSE}, /* Knda */
+ {LTR, TTB, E, TRUE }, /* Kana */
+ {LTR, NONE, S, FALSE}, /* Khmr */
+ {LTR, NONE, S, FALSE}, /* Laoo */
+ {LTR, NONE, S, FALSE}, /* Latn (Latf, Latg) */
+ {LTR, NONE, S, FALSE}, /* Mlym */
+ {WEAK,TTB, W, FALSE}, /* Mong */
+ {LTR, NONE, S, FALSE}, /* Mymr */
+ {LTR, BTT, W, FALSE}, /* Ogam */
+ {LTR, NONE, S, FALSE}, /* Ital */
+ {LTR, NONE, S, FALSE}, /* Orya */
+ {LTR, NONE, S, FALSE}, /* Runr */
+ {LTR, NONE, S, FALSE}, /* Sinh */
+ {RTL, NONE, S, FALSE}, /* Syrc (Syrj, Syrn, Syre) */
+ {LTR, NONE, S, FALSE}, /* Taml */
+ {LTR, NONE, S, FALSE}, /* Telu */
+ {RTL, NONE, S, FALSE}, /* Thaa */
+ {LTR, NONE, S, FALSE}, /* Thai */
+ {LTR, NONE, S, FALSE}, /* Tibt */
+ {LTR, NONE, S, FALSE}, /* Cans */
+ {LTR, TTB, S, TRUE }, /* Yiii */
+ {LTR, NONE, S, FALSE}, /* Tglg */
+ {LTR, NONE, S, FALSE}, /* Hano */
+ {LTR, NONE, S, FALSE}, /* Buhd */
+ {LTR, NONE, S, FALSE}, /* Tagb */
+
+ /* Unicode-4.0 additions */
+ {LTR, NONE, S, FALSE}, /* Brai */
+ {LTR, NONE, S, FALSE}, /* Cprt */
+ {LTR, NONE, S, FALSE}, /* Limb */
+ {LTR, NONE, S, FALSE}, /* Osma */
+ {LTR, NONE, S, FALSE}, /* Shaw */
+ {LTR, NONE, S, FALSE}, /* Linb */
+ {LTR, NONE, S, FALSE}, /* Tale */
+ {LTR, NONE, S, FALSE}, /* Ugar */
+
+ /* Unicode-4.1 additions */
+ {LTR, NONE, S, FALSE}, /* Talu */
+ {LTR, NONE, S, FALSE}, /* Bugi */
+ {LTR, NONE, S, FALSE}, /* Glag */
+ {LTR, NONE, S, FALSE}, /* Tfng */
+ {LTR, NONE, S, FALSE}, /* Sylo */
+ {LTR, NONE, S, FALSE}, /* Xpeo */
+ {LTR, NONE, S, FALSE}, /* Khar */
+
+ /* Unicode-5.0 additions */
+ {LTR, NONE, S, FALSE}, /* Zzzz */
+ {LTR, NONE, S, FALSE}, /* Bali */
+ {LTR, NONE, S, FALSE}, /* Xsux */
+ {RTL, NONE, S, FALSE}, /* Phnx */
+ {LTR, NONE, S, FALSE}, /* Phag */
+ {RTL, NONE, S, FALSE} /* Nkoo */
+};
+
+#undef NONE
+#undef TTB
+#undef BTT
+
+#undef LTR
+#undef RTL
+#undef WEAK
+
+#undef S
+#undef E
+#undef N
+#undef W
+
+static PangoScriptProperties
+get_script_properties (PangoScript script)
+{
+ if ((guint)script >= G_N_ELEMENTS (script_properties))
+ script = 0;
+
+ return script_properties[script];
+}
+
+/**
+ * pango_gravity_get_for_script:
+ * @script: #PangoScript to query
+ * @base_gravity: base gravity of the paragraph
+ * @hint: orientation hint
+ *
+ * Based on the script, base gravity, and hint, returns actual gravity
+ * to use in laying out a single #PangoItem.
+ *
+ * If @base_gravity is %PANGO_GRAVITY_AUTO, it is first replaced with the
+ * preferred gravity of @script. To get the preferred gravity of a script,
+ * pass %PANGO_GRAVITY_AUTO and %PANGO_GRAVITY_HINT_STRONG in.
+ *
+ * Return value: resolved gravity suitable to use for a run of text
+ *
+ * Since: 1.16
+ */
+PangoGravity
+pango_gravity_get_for_script (PangoScript script,
+ PangoGravity base_gravity,
+ PangoGravityHint hint)
+{
+ PangoScriptProperties props = get_script_properties (script);
+ gboolean vertical;
+
+
+ if (G_UNLIKELY (base_gravity == PANGO_GRAVITY_AUTO))
+ base_gravity = props.preferred_gravity;
+
+ vertical = PANGO_GRAVITY_IS_VERTICAL (base_gravity);
+
+ /* Everything is designed such that a system with no vertical support
+ * renders everything correctly horizontally. So, if not in a vertical
+ * gravity, base and resolved gravities are always the same.
+ *
+ * If the script should be upright all the time, like Chinese and Japenese,
+ * any base gravity should resolve to itself.
+ */
+ if (G_LIKELY (!vertical || props.upright))
+ return base_gravity;
+
+ /* If here, we have a non-upright script in a vertical gravity setting.
+ * Resolve depending on the hint.
+ */
+ switch (hint)
+ {
+ default:
+ case PANGO_GRAVITY_HINT_NATURAL:
+ if (props.vert_dir == PANGO_VERTICAL_DIRECTION_NONE)
+ return PANGO_GRAVITY_SOUTH;
+ if ((base_gravity == PANGO_GRAVITY_EAST) ^
+ (props.vert_dir == PANGO_VERTICAL_DIRECTION_BTT))
+ return PANGO_GRAVITY_SOUTH;
+ else
+ return PANGO_GRAVITY_NORTH;
+
+ case PANGO_GRAVITY_HINT_STRONG:
+ return base_gravity;
+
+ case PANGO_GRAVITY_HINT_LINE:
+ if ((base_gravity == PANGO_GRAVITY_EAST) ^
+ (props.horiz_dir == PANGO_DIRECTION_RTL))
+ return PANGO_GRAVITY_SOUTH;
+ else
+ return PANGO_GRAVITY_NORTH;
+ }
+}