Add a tab array field to PangoLayout, and use it when laying out the text

2000-09-25  Havoc Pennington  <hp@redhat.com>

	* pango/pango-layout.c: Add a tab array field to PangoLayout,
	and use it when laying out the text (if it's set, otherwise
	use default tabs-are-8-spaces thing)

	* pango/pango-tabs.c, pango/pango-tabs.h: tab-related data types

1 files changed, 349 insertions, 0 deletions

diff --git a/pango/pango-tabs.c b/pango/pango-tabs.c
new file mode 100644
index 00000000..c5bcb94e
--- /dev/null
+++ b/pango/pango-tabs.c
@@ -0,0 +1,349 @@
+/* Pango
+ * pango-tabs.c: Tab-related stuff
+ *
+ * Copyright (C) 2000 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 "pango-tabs.h"
+#include <string.h>
+
+typedef struct _PangoTab PangoTab;
+
+struct _PangoTab
+{
+  gint location; 	        /* Offset in pixels of this tab stop
+                                 * from the left margin of the text.
+                                 */
+  PangoTabAlign alignment;      /* Where the tab stop appears relative
+                                 * to the text.
+                                 */
+};
+
+struct _PangoTabArray
+{
+  gint size;
+  gint allocated;
+  gboolean positions_in_pixels;
+  PangoTab *tabs;
+};
+
+static void
+init_tabs (PangoTabArray *array, gint start, gint end)
+{
+  while (start < end)
+    {
+      array->tabs[start].location = 0;
+      array->tabs[start].alignment = PANGO_TAB_LEFT;
+      ++start;
+    }
+}
+
+/**
+ * pango_tab_array_new:
+ * @initial_size: Initial number of tab stops to allocate, can be 0
+ * @positions_in_pixels: whether positions are in pixel units
+ * 
+ * Creates an array of @initial_size tab stops. Tab stops are specified in
+ * pixel units if @positions_in_pixels is TRUE, otherwise in Pango
+ * units. All stops are initially at position 0.
+ * 
+ * Return value: a #PangoTabArray
+ **/
+PangoTabArray*
+pango_tab_array_new (gint initial_size,
+                     gboolean positions_in_pixels)
+{
+  PangoTabArray *array;
+
+  g_return_val_if_fail (initial_size >= 0, NULL);
+
+  /* alloc enough to treat array->tabs as an array of length
+   * size, though it's declared as an array of length 1.
+   * If we allowed tab array resizing we'd need to drop this
+   * optimization.
+   */
+  array = g_new (PangoTabArray, 1);
+  array->size = initial_size;
+  array->allocated = initial_size;
+
+  if (array->allocated > 0)
+    {
+      array->tabs = g_new (PangoTab, array->allocated);
+      init_tabs (array, 0, array->allocated);
+    }
+  else
+    array->tabs = NULL;
+
+  array->positions_in_pixels = positions_in_pixels;
+  
+  return array;
+}
+
+/**
+ * pango_tab_array_new_with_defaults:
+ * @size: number of tab stops in the array
+ * @positions_in_pixels: whether positions are in pixel units
+ * @first_alignment: alignment of first tab stop
+ * @first_position: position of first tab stop
+ * @varargs: additional alignment/position pairs
+ * 
+ * This is a convenience function that creates a #PangoTabArray
+ * and allows you to specify the alignment and position of each
+ * tab stop. You <emphasis>must</emphasis> provide an alignment
+ * and position for @size tab stops.
+ * 
+ * Return value: a new #PangoTabArray
+ **/
+PangoTabArray  *
+pango_tab_array_new_with_defaults (gint           size,
+                                   gboolean       positions_in_pixels,
+                                   PangoTabAlign  first_alignment,
+                                   gint           first_position,
+                                   ...)
+{
+  PangoTabArray *array;
+  va_list args;
+  int i;
+
+  g_return_val_if_fail (size >= 0, NULL);
+  
+  array = pango_tab_array_new (size, positions_in_pixels);
+
+  if (size == 0)
+    return array;
+
+  array->tabs[0].alignment = first_alignment;
+  array->tabs[0].location = first_position;
+
+  if (size == 1)
+    return array;
+  
+  va_start (args, first_position);
+
+  i = 1;
+  while (i < size)
+    {
+      PangoTabAlign align = va_arg (args, PangoTabAlign);
+      int pos = va_arg (args, int);
+
+      array->tabs[i].alignment = align;
+      array->tabs[i].location = pos;
+
+      ++i;
+    }
+
+  va_end (args);
+
+  return array;
+}
+
+/**
+ * pango_tab_array_copy:
+ * @src: #PangoTabArray to copy
+ * 
+ * Copy a #PangoTabArray
+ * 
+ * Return value: Newly-allocated #PangoTabArray
+ **/
+PangoTabArray*
+pango_tab_array_copy (PangoTabArray *src)
+{
+  PangoTabArray *copy;
+
+  g_return_val_if_fail (src != NULL, NULL);
+  
+  copy = pango_tab_array_new (src->size, src->positions_in_pixels);
+
+  memcpy (copy->tabs, src->tabs, sizeof(PangoTab)*src->size);
+
+  return copy;
+}
+
+/**
+ * pango_tab_array_free:
+ * @tab_array: a #PangoTabArray
+ *
+ * Free a tab array and associated resources.
+ * 
+ **/
+void
+pango_tab_array_free   (PangoTabArray *tab_array)
+{
+  g_return_if_fail (tab_array != NULL);
+  
+  g_free (tab_array);
+}
+
+/**
+ * pango_tab_array_get_size:
+ * @tab_array: a #PangoTabArray
+ * 
+ * Get the number of tab stops in @tab_array.
+ * 
+ * Return value: the number of tab stops in the array.
+ **/
+gint
+pango_tab_array_get_size (PangoTabArray *tab_array)
+{
+  g_return_val_if_fail (tab_array != NULL, 0);
+  
+  return tab_array->size;
+}
+
+/**
+ * pango_tab_array_resize:
+ * @tab_array: a #PangoTabArray
+ * @new_size: new size of the array
+ * 
+ * Resizes a tab array. You must subsequently initialize any tabs that
+ * were added as a result of growing the array.
+ **/
+void
+pango_tab_array_resize (PangoTabArray *tab_array,
+                        gint           new_size)
+{
+  if (new_size > tab_array->allocated)
+    {
+      gint current_end = tab_array->allocated;
+      
+      /* Ratchet allocated size up above the index. */
+      if (tab_array->allocated == 0)
+        tab_array->allocated = 2;
+      
+      while (new_size > tab_array->allocated)
+        tab_array->allocated = tab_array->allocated * 2;
+      
+      tab_array->tabs = g_realloc (tab_array->tabs,
+                                   tab_array->allocated);
+      
+      init_tabs (tab_array, current_end, tab_array->allocated);
+    }
+  
+  tab_array->size = new_size;
+}
+
+/**
+ * pango_tab_array_set_tab:
+ * @tab_array: a #PangoTabArray
+ * @tab_index: the index of a tab stop
+ * @alignment: tab alignment
+ * @location: tab location in pango units
+ *
+ * Sets the alignment and location of a tab stop.
+ * @alignment must always be #PANGO_TAB_LEFT in the current
+ * implementation.
+ * 
+ **/
+void
+pango_tab_array_set_tab  (PangoTabArray *tab_array,
+                          gint           tab_index,
+                          PangoTabAlign  alignment,
+                          gint           location)
+{
+  g_return_if_fail (tab_array != NULL);
+  g_return_if_fail (tab_index >= 0);
+  g_return_if_fail (alignment == PANGO_TAB_LEFT);
+  g_return_if_fail (location >= 0);
+
+  if (tab_index >= tab_array->size)
+    pango_tab_array_resize (tab_array, tab_index + 1);
+  
+  tab_array->tabs[tab_index].alignment = alignment;
+  tab_array->tabs[tab_index].location = location;
+}
+
+/**
+ * pango_tab_array_get_tab:
+ * @tab_array: a #PangoTabArray
+ * @tab_index: tab stop index
+ * @alignment: location to store alignment
+ * @location: location to store tab position
+ *
+ * Gets the alignment and position of a tab stop.
+ * @alignment or @location may be NULL if you aren't
+ * interested in their value.
+ * 
+ **/
+void
+pango_tab_array_get_tab  (PangoTabArray *tab_array,
+                          gint           tab_index,
+                          PangoTabAlign *alignment,
+                          gint          *location)
+{
+  g_return_if_fail (tab_array != NULL);
+  g_return_if_fail (tab_index < tab_array->size);
+  g_return_if_fail (tab_index >= 0);
+
+  if (alignment)
+    *alignment = tab_array->tabs[tab_index].alignment;
+
+  if (location)
+    *location = tab_array->tabs[tab_index].location;
+}
+
+/**
+ * pango_tab_array_get_tabs:
+ * @tab_array: a #PangoTabArray
+ * @alignments: array to fill with tab stop alignments
+ * @locations: array to fill with tab stop positions
+ *
+ * @alignments and @locations must be arrays with
+ * one member for each tab stop in @tab_array (i.e. the
+ * size of @alignments and @locations should match
+ * the result of pango_tab_array_get_size()). The arrays
+ * will be filled with the alignment and location of
+ * each tab stop.
+ * 
+ **/
+void
+pango_tab_array_get_tabs (PangoTabArray *tab_array,
+                          PangoTabAlign *alignments,
+                          gint          *locations)
+{
+  gint i;
+  
+  g_return_if_fail (tab_array != NULL);
+
+  i = 0;
+  while (i < tab_array->size)
+    {
+      if (alignments)
+        alignments[i] = tab_array->tabs[i].alignment;
+      if (locations)
+        locations[i] = tab_array->tabs[i].location;
+
+      ++i;
+    }
+}
+
+/**
+ * pango_tab_array_get_positions_in_pixels:
+ * @tab_array: a #PangoTabArray
+ * 
+ * Returns TRUE if the tab positions are in pixels, FALSE if they are
+ * in Pango units.
+ * 
+ * Return value: whether positions are in pixels
+ **/
+gboolean
+pango_tab_array_get_positions_in_pixels (PangoTabArray *tab_array)
+{
+  g_return_val_if_fail (tab_array != NULL, FALSE);
+  
+  return tab_array->positions_in_pixels;
+}