Move contents of mapping.c to glyphstring.c where they belong.

2007-08-01  Behdad Esfahbod  <behdad@gnome.org>

        * pango/Makefile.am:
        * pango/glyphstring.c (pango_glyph_string_index_to_x),
        (pango_glyph_string_x_to_index):
        * pango/mapping.c:
        Move contents of mapping.c to glyphstring.c where they belong.

        * pango/pango-layout.c (pango_layout_line_x_to_index):
        Fix typo.


svn path=/trunk/; revision=2389

1 files changed, 305 insertions, 0 deletions

diff --git a/pango/glyphstring.c b/pango/glyphstring.c
index 0fcbb229..7bf383a7 100644
--- a/pango/glyphstring.c
+++ b/pango/glyphstring.c
@@ -358,3 +358,308 @@ pango_glyph_string_get_logical_widths (PangoGlyphString *glyphs,
     }
 }
 
+/* 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.
+ */
+
+/**
+ * pango_glyph_string_index_to_x:
+ * @glyphs:    the glyphs return from pango_shape()
+ * @text:      the text for the run
+ * @length:    the number of bytes (not characters) in @text.
+ * @analysis:  the analysis information return from pango_itemize()
+ * @index_:    the byte index within @text
+ * @trailing:  whether we should compute the result for the beginning
+ *             or end of the character.
+ * @x_pos:     location to store result
+ *
+ * Converts from character position to x position. (X position
+ * is measured from the left edge of the run). Character positions
+ * are computed by dividing up each cluster into equal portions.
+ */
+
+void
+pango_glyph_string_index_to_x (PangoGlyphString *glyphs,
+			       char             *text,
+			       int               length,
+			       PangoAnalysis    *analysis,
+			       int               index,
+			       gboolean          trailing,
+			       int              *x_pos)
+{
+  int i;
+  int start_xpos = 0;
+  int end_xpos = 0;
+  int width = 0;
+
+  int start_index = -1;
+  int end_index = -1;
+
+  int cluster_chars = 0;
+  int cluster_offset = 0;
+
+  char *p;
+
+  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->glyphs[i].geometry.width;
+
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	{
+	  if (glyphs->log_clusters[i] > index)
+	    {
+	      end_index = glyphs->log_clusters[i];
+	      end_xpos = width;
+	      break;
+	    }
+
+	  if (glyphs->log_clusters[i] != start_index)
+	    {
+	      start_index = glyphs->log_clusters[i];
+	      start_xpos = width;
+	    }
+
+	  width -= glyphs->glyphs[i].geometry.width;
+	}
+    }
+  else /* Left to right */
+    {
+      for (i = 0; i < glyphs->num_glyphs; i++)
+	{
+	  if (glyphs->log_clusters[i] > index)
+	    {
+	      end_index = glyphs->log_clusters[i];
+	      end_xpos = width;
+	      break;
+	    }
+
+	  if (glyphs->log_clusters[i] != start_index)
+	    {
+	      start_index = glyphs->log_clusters[i];
+	      start_xpos = width;
+	    }
+
+	  width += glyphs->glyphs[i].geometry.width;
+	}
+    }
+
+  if (end_index == -1)
+    {
+      end_index = length;
+      end_xpos = (analysis->level % 2) ? 0 : width;
+    }
+
+  /* Calculate offset of character within cluster */
+
+  p = text + start_index;
+  while (p < text + end_index)
+    {
+      if (p < text + index)
+	cluster_offset++;
+      cluster_chars++;
+      p = g_utf8_next_char (p);
+    }
+
+  if (trailing)
+    cluster_offset += 1;
+
+  *x_pos = ((cluster_chars - cluster_offset) * start_xpos +
+	    cluster_offset * end_xpos) / cluster_chars;
+}
+
+/**
+ * pango_glyph_string_x_to_index:
+ * @glyphs:    the glyphs return from pango_shape()
+ * @text:      the text for the run
+ * @length:    the number of bytes (not characters) in text.
+ * @analysis:  the analysis information return from pango_itemize()
+ * @x_pos:     the x offset (in #PangoGlyphUnit)
+ * @index_:    location to store calculated byte index within @text
+ * @trailing:  location to store a integer indicating where
+ *             whether the user clicked on the leading or trailing
+ *             edge of the character.
+ *
+ * Convert from x offset to character position. Character positions
+ * are computed by dividing up each cluster into equal portions.
+ * In scripts where positioning within a cluster is not allowed
+ * (such as Thai), the returned value may not be a valid cursor
+ * position; the caller must combine the result with the logical
+ * attributes for the text to compute the valid cursor position.
+ */
+void
+pango_glyph_string_x_to_index (PangoGlyphString *glyphs,
+			       char             *text,
+			       int               length,
+			       PangoAnalysis    *analysis,
+			       int               x_pos,
+			       int              *index,
+			       gboolean         *trailing)
+{
+  int i;
+  int start_xpos = 0;
+  int end_xpos = 0;
+  int width = 0;
+
+  int start_index = -1;
+  int end_index = -1;
+
+  int cluster_chars = 0;
+  char *p;
+
+  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->glyphs[i].geometry.width;
+
+      for (i = glyphs->num_glyphs - 1; i >= 0; i--)
+	{
+	  if (glyphs->log_clusters[i] != start_index)
+	    {
+	      if (found)
+		{
+		  end_index = glyphs->log_clusters[i];
+		  end_xpos = width;
+		  break;
+		}
+	      else
+		{
+		  start_index = glyphs->log_clusters[i];
+		  start_xpos = width;
+		}
+	    }
+
+	  width -= glyphs->glyphs[i].geometry.width;
+
+	  if (width <= x_pos && x_pos < width + glyphs->glyphs[i].geometry.width)
+	    found = TRUE;
+	}
+    }
+  else /* Left to right */
+    {
+      for (i = 0; i < glyphs->num_glyphs; i++)
+	{
+	  if (glyphs->log_clusters[i] != start_index)
+	    {
+	      if (found)
+		{
+		  end_index = glyphs->log_clusters[i];
+		  end_xpos = width;
+		  break;
+		}
+	      else
+		{
+		  start_index = glyphs->log_clusters[i];
+		  start_xpos = width;
+		}
+	    }
+
+	  if (width <= x_pos && x_pos < width + glyphs->glyphs[i].geometry.width)
+	    found = TRUE;
+
+	  width += glyphs->glyphs[i].geometry.width;
+	}
+    }
+
+  if (end_index == -1)
+    {
+      end_index = length;
+      end_xpos = (analysis->level % 2) ? 0 : width;
+    }
+
+  /* Calculate number of chars within cluster */
+  p = text + start_index;
+  while (p < text + end_index)
+    {
+      p = g_utf8_next_char (p);
+      cluster_chars++;
+    }
+
+  if (start_xpos == end_xpos)
+    {
+      if (index)
+	*index = start_index;
+      if (trailing)
+	*trailing = 0;
+    }
+  else
+    {
+      double cp = ((double)(x_pos - start_xpos) * cluster_chars) / (end_xpos - start_xpos);
+
+      /* LTR and right-to-left have to be handled separately
+       * here because of the edge condition when we are exactly
+       * at a pixel boundary; end_xpos goes with the next
+       * character for LTR, with the previous character for RTL.
+       */
+      if (start_xpos < end_xpos) /* Left-to-right */
+	{
+	  if (index)
+	    {
+	      char *p = text + start_index;
+	      int i = 0;
+
+	      while (i + 1 <= cp)
+		{
+		  p = g_utf8_next_char (p);
+		  i++;
+		}
+
+	      *index = (p - text);
+	    }
+
+	  if (trailing)
+	    *trailing = (cp - (int)cp >= 0.5) ? 1 : 0;
+	}
+      else /* Right-to-left */
+	{
+	  if (index)
+	    {
+	      char *p = text + start_index;
+	      int i = 0;
+
+	      while (i + 1 < cp)
+		{
+		  p = g_utf8_next_char (p);
+		  i++;
+		}
+
+	      *index = (p - text);
+	    }
+
+	  if (trailing)
+	    {
+	      double cp_flip = cluster_chars - cp;
+	      *trailing = (cp_flip - (int)cp_flip >= 0.5) ? 0 : 1;
+	    }
+	}
+    }
+}
+
+