When dragging text, use a drag icon showing the (ellipsized) text that is

2005-07-11  Matthias Clasen  <mclasen@redhat.com>

	When dragging text, use a drag icon showing the (ellipsized)
	text that is being dragged: (#161132, Kevin Duffus, patch
	by Carlos Garnacho Parro)

	* gtk/gtktextutil.h:
	* gtk/gtktextutil.c (_gtk_text_util_create_drag_icon): Add
	a function to create a pixmap for use when dragging text.

	* gtk/gtktextview.c (gtk_text_view_start_selection_dnd):
	* gtk/gtklabel.c (gtk_label_motion):
	* gtk/gtkentry.c (gtk_entry_motion_notify): Use a drag icon
	showing the text being dragged.

2005-07-11  Matthias Clasen  <mclasen@redhat.com>

	* gtk/gtkentry.c (gtk_entry_move_forward_word)
	(gtk_entry_move_backward_word): Match the text view change
	to allow selecting whitespace with double-click.

1 files changed, 124 insertions, 0 deletions

diff --git a/gtk/gtktextutil.c b/gtk/gtktextutil.c
index 9d72c18646..e9f535c7c3 100644
--- a/gtk/gtktextutil.c
+++ b/gtk/gtktextutil.c
@@ -1,3 +1,4 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* GTK - The GIMP Toolkit
  * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
  *
@@ -30,6 +31,11 @@
 #include "gtkmenuitem.h"
 #include "gtkalias.h"
 
+#define DRAG_ICON_MAX_WIDTH 250
+#define DRAG_ICON_LAYOUT_BORDER 2
+#define DRAG_ICON_MAX_LINES 7
+#define ELLIPSIS_CHARACTER "\xe2\x80\xa6"
+
 typedef struct _GtkUnicodeMenuEntry GtkUnicodeMenuEntry;
 typedef struct _GtkTextUtilCallbackInfo GtkTextUtilCallbackInfo;
 
@@ -117,3 +123,121 @@ _gtk_text_util_append_special_char_menuitems (GtkMenuShell              *menushe
     }
 }
 
+static void
+append_n_lines (GString *str, const gchar *text, GSList *lines, gint n_lines)
+{
+  PangoLayoutLine *line;
+  gint i;
+
+  for (i = 0; i < n_lines; i++)
+    {
+      line = lines->data;
+      g_string_append_len (str, &text[line->start_index], line->length);
+      lines = lines->next;
+    }
+}
+
+static void
+limit_layout_lines (PangoLayout *layout)
+{
+  const gchar *text;
+  GString     *str;
+  GSList      *lines, *elem;
+  gint         n_lines;
+
+  n_lines = pango_layout_get_line_count (layout);
+  
+  if (n_lines >= DRAG_ICON_MAX_LINES)
+    {
+      text  = pango_layout_get_text (layout);
+      str   = g_string_new (NULL);
+      lines = pango_layout_get_lines (layout);
+
+      /* get first lines */
+      elem = lines;
+      append_n_lines (str, text, elem,
+                      DRAG_ICON_MAX_LINES / 2);
+
+      g_string_append (str, "\n" ELLIPSIS_CHARACTER "\n");
+
+      /* get last lines */
+      elem = g_slist_nth (lines, n_lines - DRAG_ICON_MAX_LINES / 2);
+      append_n_lines (str, text, elem,
+                      DRAG_ICON_MAX_LINES / 2);
+
+      pango_layout_set_text (layout, str->str, -1);
+      g_string_free (str, TRUE);
+    }
+}
+
+/**
+ * _gtk_text_util_create_drag_icon
+ * @widget: #GtkWidget to extract the pango context
+ * @text: a #gchar to render the icon
+ * @len: length of @text, or -1 for NUL-terminated text
+ *
+ * Creates a drag and drop icon from @text.
+ **/
+GdkPixmap*
+_gtk_text_util_create_drag_icon (GtkWidget *widget, 
+                                 gchar     *text,
+                                 gsize      len)
+{
+  GdkDrawable  *drawable = NULL;
+  PangoContext *context;
+  PangoLayout  *layout;
+  gint          pixmap_height, pixmap_width;
+  gint          layout_width, layout_height;
+  gint          n_lines;
+
+  g_return_val_if_fail (widget != NULL, NULL);
+  g_return_val_if_fail (text != NULL, NULL);
+
+  context = gtk_widget_get_pango_context (widget);
+  layout  = pango_layout_new (context);
+
+  pango_layout_set_text (layout, text, len);
+  pango_layout_set_wrap (layout, PANGO_WRAP_WORD_CHAR);
+  pango_layout_get_size (layout, &layout_width, &layout_height);
+
+  layout_width = MIN (layout_width, DRAG_ICON_MAX_WIDTH * PANGO_SCALE);
+  pango_layout_set_width (layout, layout_width);
+  n_lines = pango_layout_get_line_count (layout);
+
+  limit_layout_lines (layout);
+
+  /* get again layout extents, they may have changed */
+  pango_layout_get_size (layout, &layout_width, &layout_height);
+
+  pixmap_width  = layout_width  / PANGO_SCALE + DRAG_ICON_LAYOUT_BORDER * 2;
+  pixmap_height = layout_height / PANGO_SCALE + DRAG_ICON_LAYOUT_BORDER * 2;
+
+  drawable = gdk_pixmap_new (widget->window,
+                             pixmap_width  + 2,
+                             pixmap_height + 2,
+                             -1);
+
+  gdk_draw_rectangle (drawable,
+                      widget->style->base_gc [GTK_WIDGET_STATE (widget)],
+                      TRUE,
+                      0, 0,
+                      pixmap_width + 1,
+                      pixmap_height + 1);
+
+  gdk_draw_layout (drawable,
+                   widget->style->text_gc [GTK_WIDGET_STATE (widget)],
+                   1 + DRAG_ICON_LAYOUT_BORDER,
+                   1 + DRAG_ICON_LAYOUT_BORDER,
+                   layout);
+
+  gdk_draw_rectangle (drawable,
+                      widget->style->black_gc,
+                      FALSE,
+                      0, 0,
+                      pixmap_width + 1,
+                      pixmap_height + 1);
+
+  g_object_unref (layout);
+
+  return drawable;
+}