Fix up the operation of PangoLayoutIter, especially for Bidi (#89541,

2005-06-21  Owen Taylor  <otaylor@redhat.com>

        Fix up the operation of PangoLayoutIter, especially for Bidi
        (#89541, based on a patch from Amit Aronovitch)

        * pango/pango-layout.c: Many changes to make iteration
        consistently in visual order.

        * pango/pango-layout.c (pango_layout_iter_next_char): Iterate
        through each character in the layout exactly once. (Including
        a hack to get two iterator positions for \r\n)

        * pango/pango-layout.c (pango_layout_iter_next_cluster): Only
        iterate through real clusters: that is, positions in the
        layout that have glyphs.

        * tests/testiter.c tests/Makefile.am: Add a (somewhat reworked)
        test from Amit for the operation of PangoLayoutIter.

1 files changed, 240 insertions, 0 deletions

diff --git a/tests/testiter.c b/tests/testiter.c
new file mode 100644
index 00000000..d0966c91
--- /dev/null
+++ b/tests/testiter.c
@@ -0,0 +1,240 @@
+/* Pango
+ * testiter.c: Test pangolayoutiter.c
+ *
+ * Copyright (C) 2005 Amit Aronovitch
+ * Copyright (C) 2005 Red Hat, Inc
+ *
+ * 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.
+ */
+
+#undef G_DISABLE_ASSERT
+#undef G_LOG_DOMAIN
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <glib.h>
+
+#include <pango/pangocairo.h>
+
+#undef VERBOSE
+
+static void
+verbose (const char *format, ...)
+{
+#ifdef VERBOSE  
+  va_list vap;
+  
+  va_start (vap, format);
+  vfprintf (stderr, format, vap);
+  va_end (vap);
+#endif  
+}
+
+#define LAYOUT_WIDTH (80 * PANGO_SCALE)
+
+/* Note: The test expects that any newline sequence is of length 1
+ * use \n (not \r\n) in the test texts.
+ * I think the iterator itself should support \r\n without trouble,
+ * but there are comments in layout-iter.c suggesting otherwise.
+ */
+char *test_texts[] =
+  {
+    /* English with embedded RTL runs (from ancient-hebrew.org) */
+    "The Hebrew word \xd7\x90\xd7\x93\xd7\x9d\xd7\x94 (adamah) is the feminine form of \xd7\x90\xd7\x93\xd7\x9d meaning \"ground\"\n",
+    /* Arabic, with vowel marks (from Sura Al Fatiha) */
+    "\xd8\xa8\xd9\x90\xd8\xb3\xd9\x92\xd9\x85\xd9\x90 \xd8\xa7\xd9\x84\xd9\x84\xd9\x91\xd9\x87\xd9\x90 \xd8\xa7\xd9\x84\xd8\xb1\xd9\x91\xd9\x8e\xd8\xad\xd9\x92\xd9\x85\xd9\x80\xd9\x8e\xd9\x86\xd9\x90 \xd8\xa7\xd9\x84\xd8\xb1\xd9\x91\xd9\x8e\xd8\xad\xd9\x90\xd9\x8a\xd9\x85\xd9\x90\n\xd8\xa7\xd9\x84\xd9\x92\xd8\xad\xd9\x8e\xd9\x85\xd9\x92\xd8\xaf\xd9\x8f \xd9\x84\xd9\x84\xd9\x91\xd9\x87\xd9\x90 \xd8\xb1\xd9\x8e\xd8\xa8\xd9\x91\xd9\x90 \xd8\xa7\xd9\x84\xd9\x92\xd8\xb9\xd9\x8e\xd8\xa7\xd9\x84\xd9\x8e\xd9\x85\xd9\x90\xd9\x8a\xd9\x86\xd9\x8e\n",
+    /* Arabic, with embedded LTR runs (from a Linux guide) */
+    "\xd8\xa7\xd9\x84\xd9\x85\xd8\xaa\xd8\xba\xd9\x8a\xd8\xb1 LC_ALL \xd9\x8a\xd8\xba\xd9\x8a\xd9\x8a\xd8\xb1 \xd9\x83\xd9\x84 \xd8\xa7\xd9\x84\xd9\x85\xd8\xaa\xd8\xba\xd9\x8a\xd8\xb1\xd8\xa7\xd8\xaa \xd8\xa7\xd9\x84\xd8\xaa\xd9\x8a \xd8\xaa\xd8\xa8\xd8\xaf\xd8\xa3 \xd8\xa8\xd8\xa7\xd9\x84\xd8\xb1\xd9\x85\xd8\xb2 LC.",
+    /* Hebrew, with vowel marks (from Genesis) */
+    "\xd7\x91\xd6\xbc\xd6\xb0\xd7\xa8\xd6\xb5\xd7\x90\xd7\xa9\xd7\x81\xd6\xb4\xd7\x99\xd7\xaa, \xd7\x91\xd6\xbc\xd6\xb8\xd7\xa8\xd6\xb8\xd7\x90 \xd7\x90\xd6\xb1\xd7\x9c\xd6\xb9\xd7\x94\xd6\xb4\xd7\x99\xd7\x9d, \xd7\x90\xd6\xb5\xd7\xaa \xd7\x94\xd6\xb7\xd7\xa9\xd6\xbc\xd7\x81\xd6\xb8\xd7\x9e\xd6\xb7\xd7\x99\xd6\xb4\xd7\x9d, \xd7\x95\xd6\xb0\xd7\x90\xd6\xb5\xd7\xaa \xd7\x94\xd6\xb8\xd7\x90\xd6\xb8\xd7\xa8\xd6\xb6\xd7\xa5",
+    /* Hebrew, with embedded LTR runs (from a Linux guide) */
+    "\xd7\x94\xd7\xa7\xd7\x9c\xd7\x93\xd7\x94 \xd7\xa2\xd7\x9c \xd7\xa9\xd7\xa0\xd7\x99 \xd7\x94 SHIFT\xd7\x99\xd7\x9d (\xd7\x99\xd7\x9e\xd7\x99\xd7\x9f \xd7\x95\xd7\xa9\xd7\x9e\xd7\x90\xd7\x9c \xd7\x91\xd7\x99\xd7\x97\xd7\x93) \xd7\x90\xd7\x9e\xd7\x95\xd7\xa8\xd7\x99\xd7\x9d \xd7\x9c\xd7\x94\xd7\x93\xd7\x9c\xd7\x99\xd7\xa7 \xd7\x90\xd7\xaa \xd7\xa0\xd7\x95\xd7\xa8\xd7\xaa \xd7\x94 Scroll Lock , \xd7\x95\xd7\x9c\xd7\x94\xd7\xa2\xd7\x91\xd7\x99\xd7\xa8 \xd7\x90\xd7\x95\xd7\xaa\xd7\xa0\xd7\x95 \xd7\x9c\xd7\x9e\xd7\xa6\xd7\x91 \xd7\x9b\xd7\xaa\xd7\x99\xd7\x91\xd7\x94 \xd7\x91\xd7\xa2\xd7\x91\xd7\xa8\xd7\x99\xd7\xaa.",
+    /* Different line terminators */
+    "AAAA\nBBBB\nCCCC\n",
+    "DDDD\rEEEE\rFFFF\r",
+    "GGGG\r\nHHHH\r\nIIII\r\n",
+    NULL
+  };
+
+void
+iter_char_test (PangoLayout *layout)
+{
+  PangoRectangle   extents, run_extents;
+  PangoLayoutIter *iter;
+  PangoLayoutRun  *run;
+  int              num_chars;
+  int              i, index, offset;
+  int              leading_x, trailing_x, x0, x1;
+  gboolean         iter_next_ok, rtl;
+  const char      *text, *ptr;
+
+  text = pango_layout_get_text (layout);
+  num_chars = g_utf8_strlen (text, -1);
+  
+  iter = pango_layout_get_iter (layout);
+  iter_next_ok = TRUE;
+
+  for (i = 0 ; i < num_chars; ++i)
+    {
+      gchar *char_str;
+      g_assert (iter_next_ok);
+
+      index = pango_layout_iter_get_index (iter);
+      ptr = text + index;
+      char_str = g_strndup (ptr, g_utf8_next_char (ptr) - ptr);
+      verbose ("i=%d (visual), index = %d '%s':\n", 
+	       i, index, char_str);
+      g_free (char_str);
+
+      pango_layout_iter_get_char_extents (iter, &extents);
+      verbose ("  char extents: x=%d,y=%d w=%d,h=%d\n",
+	       extents.x, extents.y, 
+	       extents.width, extents.height);
+      
+      run = pango_layout_iter_get_run (iter);
+
+      if (run)
+	{
+	  /* Get needed data for the GlyphString */
+	  pango_layout_iter_get_run_extents(iter, NULL, &run_extents);
+	  offset = run->item->offset;
+	  rtl = run->item->analysis.level%2;
+	  verbose ("  (current run: offset=%d,x=%d,len=%d,rtl=%d)\n", 
+		   offset, run_extents.x, run->item->length, rtl);
+	  
+	  /* Calculate expected x result using index_to_x */
+	  pango_glyph_string_index_to_x (run->glyphs, 
+					 (char *)(text + offset), run->item->length,
+					 &run->item->analysis,
+					 index - offset, FALSE, &leading_x);
+	  pango_glyph_string_index_to_x (run->glyphs, 
+					 (char *)(text + offset), run->item->length,
+					 &run->item->analysis,
+					 index - offset, TRUE, &trailing_x);
+	  
+	  x0 = run_extents.x + MIN (leading_x, trailing_x);
+	  x1 = run_extents.x + MAX (leading_x, trailing_x);
+	  
+	  verbose ("  (index_to_x ind=%d: expected x=%d, width=%d)\n", 
+		   index - offset, x0, x1 - x0);
+
+	  g_assert (extents.x == x0);
+	  g_assert (extents.width == x1 - x0);
+	}
+      else
+	{
+	  /* We're on a line terminator */
+	}
+      
+      iter_next_ok = pango_layout_iter_next_char (iter);
+      verbose ("more to go? %d\n", iter_next_ok);
+    }
+
+  /* There should be one character position iterator for each character in the
+   * input string */
+  g_assert (!iter_next_ok);
+
+  pango_layout_iter_free (iter);
+}
+
+/* char iteration test:
+ *  - Total num of iterations match number of chars
+ *  - GlyphString's index_to_x positions match those returned by the Iter
+ */
+void
+iter_cluster_test (PangoLayout *layout)
+{
+  PangoRectangle   extents;
+  PangoLayoutIter *iter;
+  int              index;
+  gboolean         iter_next_ok;
+  const char      *text;
+  PangoLayoutLine *last_line = NULL;
+  int              expected_next_x = 0;
+
+  text = pango_layout_get_text (layout);
+
+  iter = pango_layout_get_iter (layout);
+  iter_next_ok = TRUE;
+
+  while (iter_next_ok)
+    {
+      PangoLayoutLine *line = pango_layout_iter_get_line (iter);
+
+      /* Every cluster is part of a run */
+      g_assert (pango_layout_iter_get_run (iter));
+
+      index = pango_layout_iter_get_index (iter);
+      
+      pango_layout_iter_get_cluster_extents (iter, NULL, &extents);
+      
+      iter_next_ok = pango_layout_iter_next_cluster (iter);
+      
+      verbose ("index = %d:\n", index);
+      verbose ("  cluster extents: x=%d,y=%d w=%d,h=%d\n",
+	       extents.x, extents.y, 
+	       extents.width, extents.height);
+      verbose ("more to go? %d\n", iter_next_ok);
+
+      /* All the clusters on a line should be next to each other and occupy
+       * the entire line. They advance linearly from left to right */
+      g_assert (extents.width >= 0);
+      
+      if (last_line == line)
+	g_assert (extents.x == expected_next_x);
+
+      expected_next_x = extents.x + extents.width;      
+
+      last_line = line;
+    }
+  
+  g_assert (!iter_next_ok);
+
+  pango_layout_iter_free (iter);
+}
+
+int
+main (int argc, char *argv[])
+{
+  char        **ptext;
+  PangoFontMap *fontmap;
+  PangoContext *context;
+  PangoLayout  *layout;
+
+  fontmap = pango_cairo_font_map_get_default ();
+  context = pango_cairo_font_map_create_context (PANGO_CAIRO_FONT_MAP (fontmap));
+
+  layout = pango_layout_new (context);
+  pango_layout_set_width (layout, LAYOUT_WIDTH);
+
+  for (ptext = test_texts; *ptext != NULL; ++ptext)
+    {
+      verbose ("--------- checking next text ----------\n");
+      verbose (" <%s>\n", *ptext);
+      verbose ( "len=%d, bytes=%d\n",
+		g_utf8_strlen (*ptext, -1), strlen (*ptext));
+
+      pango_layout_set_text (layout, *ptext, -1);
+      iter_char_test (layout);
+      iter_cluster_test (layout);
+    }
+
+  g_object_unref (layout);
+  return 0;
+}