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authorOwen Taylor <otaylor@src.gnome.org>2000-01-13 04:12:07 +0000
committerOwen Taylor <otaylor@src.gnome.org>2000-01-13 04:12:07 +0000
commit282fb5fc9f9d01c4d933a6eb6bee6ae9f0d512c7 (patch)
tree0b19c69692a2fe52a1b33d5e27c97b26a64417e3 /pango/mapping.c
parent66ae87f9fc45f5f564acf5014e9bd1341d052958 (diff)
downloadpango-282fb5fc9f9d01c4d933a6eb6bee6ae9f0d512c7.tar.gz
Initial revision
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+/* 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;
+ }
+}
+
+
+