Initial revision

1 files changed, 275 insertions, 0 deletions

diff --git a/pango/mapping.c b/pango/mapping.c
new file mode 100644
index 00000000..bd0cb3de
--- /dev/null
+++ b/pango/mapping.c
@@ -0,0 +1,275 @@
+/* Pango
+ * itemize.c:
+ *
+ * Copyright (C) 1999 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.
+ */
+
+/* The initial implementation here is script independent,
+ * but it might actually need to be virtualized into the
+ * rendering modules. Otherwise, we probably will end up
+ * enforcing unnatural cursor behavior for some languages.
+ *
+ * The only distinction that Uniscript makes is whether
+ * cursor positioning is allowed within clusters or not.
+ */
+
+#include <pango.h>
+#include <unicode.h>
+
+/**
+ * pango_cp_to_x:
+ * @text:      the text for the run
+ * @length:    the number of bytes (not characters) in @text.
+ * @analysis:  the analysis information return from pango_itemize()
+ * @glyphs:    the glyphs return from pango_shape()
+ * @char_pos:  the character position
+ * @trailing:  whether we should compute the result for the beginning
+ *             or end of the character (or cluster - the decision
+ *             for which may be script dependent).
+ * @x_pos:     location to store result
+ *
+ * Converts from character position to x position. (X position
+ * is measured from the left edge of the run)
+ */
+
+void
+pango_cp_to_x (gchar           *text,
+		  gint             length,
+		  PangoAnalysis *analysis,
+		  PangoGlyphString    *glyphs,
+		  gint             char_pos,
+		  gboolean         trailing,
+		  gint            *x_pos)
+{
+  gint i;
+  gint start_xpos = 0;
+  gint end_xpos = 0;
+  gint width = 0;
+
+  gint start_char = -1;
+  gint end_char = -1;
+
+  g_return_if_fail (glyphs != NULL);
+  g_return_if_fail (length >= 0);
+  g_return_if_fail (length == 0 || text != NULL);
+
+  if (!x_pos) /* Allow the user to do the useless */
+    return;
+  
+  if (glyphs->num_glyphs == 0)
+    {
+      *x_pos = 0;
+      return;
+    }
+
+  /* Calculate the starting and ending character positions
+   * and x positions for the cluster
+   */
+  if (analysis->level % 2) /* Right to left */
+    {
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	width += glyphs->geometry[i].width;
+
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	{
+	  if (glyphs->log_clusters[i] > char_pos)
+	    {
+	      end_char = glyphs->log_clusters[i];
+	      end_xpos = width;
+	      break;
+	    }
+
+	  if (start_char == -1 || glyphs->log_clusters[i] != start_char)
+	    {
+	      start_char = glyphs->log_clusters[i];
+	      start_xpos = width;
+	    }
+
+	  width -= glyphs->geometry[i].width;
+	}
+    }
+  else /* Left to right */
+    {
+      for (i = 0; i < glyphs->num_glyphs; i++)
+	{
+	  if (glyphs->log_clusters[i] > char_pos)
+	    {
+	      end_char = glyphs->log_clusters[i];
+	      end_xpos = width;
+	      break;
+	    }
+
+	  if (start_char == -1 || glyphs->log_clusters[i] != start_char)
+	    {
+	      start_char = glyphs->log_clusters[i];
+	      start_xpos = width;
+	    }
+	  
+	  width += glyphs->geometry[i].width;
+	}
+    }
+
+  /* We need the character index of one past the end of the
+   * string, and so we have to recalculate the entire length
+   * of the string...
+   */
+  if (end_char == -1)
+    {
+      end_char = unicode_strlen (text, length);
+      end_xpos = (analysis->level % 2) ? 0 : width;
+    }
+
+  /* Now interpolate the result. For South Asian languages
+   * we actually shouldn't iterpolate
+   */
+
+  if (trailing)
+    char_pos += 1;
+
+  *x_pos = (((double)(end_char - char_pos)) * start_xpos +
+	    ((double)(char_pos - start_char)) * end_xpos) /
+    (end_char - start_char);
+}
+
+/**
+ * pango_x_to_cp:
+ * @text:      the text for the run
+ * @length:    the number of bytes (not characters) in text.
+ * @analysis:  the analysis information return from pango_itemize()
+ * @glyphs:    the glyphs return from pango_shape()
+ * @x_pos:     location to store the returned x character position
+ * @char_pos:  location to store calculated character position.
+ * @trailing:  location to store a integer indicating where
+ *             in the cluster the user clicked. If the script
+ *             allows positioning within the cluster, it is either
+ *             0 or 1; otherwise it is either 0 or the number
+ *             of characters in the cluster. In either case
+ *             0 represents the trailing edge of the cluster.
+ *
+ * Converts from x position to x character. (X position
+ * is measured from the left edge of the run)
+ */
+void 
+pango_x_to_cp (gchar           *text,
+		  gint             length,
+		  PangoAnalysis *analysis,
+		  PangoGlyphString    *glyphs,
+		  gint             x_pos,
+		  gint            *char_pos, 
+		  gint            *trailing)
+{
+  gint i;
+  gint start_xpos = 0;
+  gint end_xpos = 0;
+  gint width = 0;
+
+  gint start_char = -1;
+  gint end_char = -1;
+
+  gboolean found = FALSE;
+
+  /* Find the cluster containing the position */
+
+  width = 0;
+
+  if (analysis->level % 2) /* Right to left */
+    {
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	width += glyphs->geometry[i].width;
+
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	{
+	  if (start_char == -1 || glyphs->log_clusters[i] != start_char)
+	    {
+	      if (found)
+		{
+		  end_char = glyphs->log_clusters[i];
+		  end_xpos = width;
+		  break;
+		}
+	      else
+		{
+		  start_char = glyphs->log_clusters[i];
+		  start_xpos = width;
+		}
+	    }
+
+	  width -= glyphs->geometry[i].width;
+
+	  if (width <= x_pos && x_pos < width + glyphs->geometry[i].width)
+	    found = TRUE;
+	}
+    }
+  else /* Left to right */
+    {
+      for (i = 0; i < glyphs->num_glyphs; i++)
+	{
+	  if (start_char == -1 || glyphs->log_clusters[i] != start_char)
+	    {
+	      if (found)
+		{
+		  end_char = glyphs->log_clusters[i];
+		  end_xpos = width;
+		  break;
+		}
+	      else
+		{
+		  start_char = glyphs->log_clusters[i];
+		  start_xpos = width;
+		}
+	    }
+	  
+	  if (width <= x_pos && x_pos < width + glyphs->geometry[i].width)
+	    found = TRUE;
+	  
+	  width += glyphs->geometry[i].width;
+	}
+    }
+
+  /* We need the character index of one past the end of the
+   * string, and so we have to recalculate the entire length
+   * of the string...
+   */
+  if (end_char == -1)
+    {
+      end_char = unicode_strlen (text, length);
+      end_xpos = (analysis->level % 2) ? 0 : width;
+    }
+
+  if (start_xpos == end_xpos)
+    {
+      if (char_pos)
+	*char_pos = start_char;
+      if (trailing)
+	trailing = 0;
+    }
+  else
+    {
+      double cp = (((double)(end_xpos - x_pos)) * start_char +
+		   ((double)(x_pos - start_xpos)) * end_char) /
+	(end_xpos - start_xpos); 
+
+      if (char_pos)
+	*char_pos = (int)cp;
+      if (trailing)
+	*trailing = (cp - (int)cp) > 0.5 ? 1 : 0;
+    }
+}
+
+
+