gdkgeometry-x11.c

linux下电话本所依赖的一些图形库

/* GDK - The GIMP Drawing Kit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser 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.
 */

/* gdkgeometry-x11.c: emulation of 32 bit coordinates within the
 * limits of X. 
 *
 * By Owen Taylor <[e-mail]>
 * Copyright Red Hat, Inc. 2000
 *
 * The algorithms implemented in this file are an extension of the
 * idea of guffaw scrolling, a technique (and name) taken from the classic
 * Netscape source code. The basic idea of guffaw scrolling is a trick
 * to get around a limitation of X: there is no way of scrolling the
 * contents of a window. Guffaw scrolling exploits the X concepts of
 * window gravity and bit gravity:
 *
 *  window gravity: the window gravity of a window affects what happens
 *   to a windows position when _its parent_ is resized, or
 *   moved and resized simultaneously.
 *
 *  bit gravity: the bit gravity of a window affects what happens to
 *  the pixels of a window when _it_ is is resized, or moved and
 *  resized simultaneously.
 *
 * These were basically intended to do things like have right
 * justified widgets in a window automatically stay right justified
 * when the window was resized, but there is also the special
 * "StaticGravity" which means "do nothing." We can exploit
 * StaticGravity to scroll a window:
 *
 *     |  VISIBLE  |
 * 
 *     |abcdefghijk|
 *     |abcdefghijk    |   (1) Resize bigger
 * |    efghijk    |       (2) Move  
 *     |efghijk    |       (3) Move-resize back to the original size
 *
 * Or, going the other way:

 *     |abcdefghijk|
 * |    abcdefghijk|       (1) Move-resize bigger
 *     |    abcdefghijk|   (2) Move  
 *     |    abcdefg|       (4) Resize back to the original size
 *
 * By using this technique, we can simulate scrolling around in a
 * large virtual space without having to actually have windows that
 * big; for the pixels of the window, this is all we have to do.  For
 * subwindows, we have to take care of one other detail - since
 * coordinates in X are limited to 16 bits, subwindows scrolled off
 * will wrap around and come back eventually. So, we have to take care
 * to unmap windows that go outside the 16-bit range and remap them as
 * they come back in.
 *
 * Since we are temporarily making the window bigger, this only looks
 * good if the edges of the window are obscured. Typically, we do
 * this by making the window we are scrolling the immediate child
 * of a "clip window".
 *
 * But, this isn't a perfect API for applications for several reasons:
 *
 *  - We have to use this inefficient technique even for small windows
 *    if the window _could_ be big.
 *  - Applications have to use a special scrolling API.
 *
 * What we'd like is to simply have windows with 32 bit coordinates
 * so applications could scroll in the classic way - just move a big
 * window around.
 *
 * It turns out that StaticGravity can also be used to achieve emulation
 * of 32 bit coordinates with only 16 bit coordinates if we expand
 * our horizons just a bit; what guffaw scrolling really is is a way
 * to move the contents of a window a different amount than we move
 * the borders of of the window. In the above example pictures we
 * ended up with the borders of the window not moving at all, but
 * that isn't necessary.
 *
 * So, what we do is set up a mapping from virtual 32 bit window position/size
 * to:
 *
 *  - Real window position/size
 *  - Offset between virtual coordinates and real coordinates for the window
 *  - Map state (mapped or unmapped)
 *
 * By the following rules:
 *
 *  - If the window is less than 32767 pixels in width (resp. height), we use it's
 *    virtual width and position.
 *  - Otherwise, we use a width of 32767 and determine the position of the window
 *    so that the portion of the real window [16384, 16383] in _toplevel window
 *    coordinates_ is the same as the portion of the real window 
 *
 * This is implemented in gdk_window_compute_position(). Then the algorithm
 * for a moving a window (_window_move_resize_child ()) is:
 * 
 *  - Compute the new window mappings for the window and all subwindows
 *  - Expand out the boundary of the window and all subwindows by the amount
 *    that the real/virtual offset changes for each window. 
 *    (compute_intermediate_position() computes expanded boundary)
 *  - Move the toplevel by the amount that it's contents need to translate.
 *  - Move/resize the window and all subwindows to the newly computed
 *    positions.
 *
 * If we just are scrolling (gdk_window_guffaw_scroll()), then things
 * are similar, except that the final mappings for the toplevel are
 * the same as the initial mappings, but we act as if it moved by the
 * amount we are scrolling by.
 *
 * Note that we don't have to worry about a clip window in
 * _gdk_window_move_resize() since we have set up our translation so
 * that things in the range [16384,16383] in toplevel window
 * coordinates look exactly as they would if we were simply moving the
 * windows, and nothing outside this range is going to be visible
 * unless the user has a _really_ huge screen.
 */

#include <config.h>
#include "gdk.h"		/* For gdk_rectangle_intersect */
#include "gdkprivate-x11.h"
#include "gdkx.h"
#include "gdkregion.h"
#include "gdkinternals.h"
#include "gdkscreen-x11.h"
#include "gdkdisplay-x11.h"
#include "gdkwindow-x11.h"
#include "gdkalias.h"

typedef struct _GdkWindowQueueItem GdkWindowQueueItem;
typedef struct _GdkWindowParentPos GdkWindowParentPos;

typedef enum {
  GDK_WINDOW_QUEUE_TRANSLATE,
  GDK_WINDOW_QUEUE_ANTIEXPOSE
} GdkWindowQueueType;

struct _GdkWindowQueueItem
{
  GdkWindow *window;
  gulong serial;
  GdkWindowQueueType type;
  union {
    struct {
      gint dx;
      gint dy;
    } translate;
    struct {
      GdkRegion *area;
    } antiexpose;
  } u;
};

struct _GdkWindowParentPos
{
  gint x;
  gint y;
  gint x11_x;
  gint x11_y;
  GdkRectangle clip_rect;
};

static void gdk_window_compute_position   (GdkWindowImplX11      *window,
					   GdkWindowParentPos *parent_pos,
					   GdkXPositionInfo   *info);
static void gdk_window_compute_parent_pos (GdkWindowImplX11      *window,
					   GdkWindowParentPos *parent_pos);
static void gdk_window_premove            (GdkWindow          *window,
					   GdkWindowParentPos *parent_pos);
static void gdk_window_postmove           (GdkWindow          *window,
					   GdkWindowParentPos *parent_pos);
static void gdk_window_queue_translation  (GdkWindow          *window,
					   gint                dx,
					   gint                dy);
static void gdk_window_clip_changed       (GdkWindow          *window,
					   GdkRectangle       *old_clip,
					   GdkRectangle       *new_clip);

void
_gdk_windowing_window_get_offsets (GdkWindow *window,
				   gint      *x_offset,
				   gint      *y_offset)
{
  GdkWindowImplX11 *impl =
    GDK_WINDOW_IMPL_X11 (GDK_WINDOW_OBJECT (window)->impl);

  *x_offset = impl->position_info.x_offset;
  *y_offset = impl->position_info.y_offset;
}

void
_gdk_window_init_position (GdkWindow *window)
{
  GdkWindowParentPos parent_pos;
  GdkWindowImplX11 *impl;
  
  g_return_if_fail (GDK_IS_WINDOW (window));
  
  impl =
    GDK_WINDOW_IMPL_X11 (GDK_WINDOW_OBJECT (window)->impl);
  
  gdk_window_compute_parent_pos (impl, &parent_pos);
  gdk_window_compute_position (impl, &parent_pos, &impl->position_info);
}

static void
gdk_window_copy_area_scroll (GdkWindow    *window,
			     GdkRectangle *dest_rect,
			     gint          dx,
			     gint          dy)
{
  GdkWindowObject *obj = GDK_WINDOW_OBJECT (window);
  GList *tmp_list;

  if (dest_rect->width > 0 && dest_rect->height > 0)
    {
      GdkGC *gc;

      gc = _gdk_drawable_get_scratch_gc (window, TRUE);
      
      gdk_window_queue_translation (window, dx, dy);

      XCopyArea (GDK_WINDOW_XDISPLAY (window),
		 GDK_WINDOW_XID (window),
		 GDK_WINDOW_XID (window),
		 gdk_x11_gc_get_xgc (gc),
		 dest_rect->x - dx, dest_rect->y - dy,
		 dest_rect->width, dest_rect->height,
		 dest_rect->x, dest_rect->y);
    }

  tmp_list = obj->children;
  while (tmp_list)
    {
      GdkWindow *child = GDK_WINDOW (tmp_list->data);
      GdkWindowObject *child_obj = GDK_WINDOW_OBJECT (child);
	  
      gdk_window_move (child, child_obj->x + dx, child_obj->y + dy);
      
      tmp_list = tmp_list->next;
    }
}

static void
compute_intermediate_position (GdkXPositionInfo *position_info,
			       GdkXPositionInfo *new_info,
			       gint              d_xoffset,
			       gint              d_yoffset,
			       GdkRectangle     *new_position)
{
  gint new_x0, new_x1, new_y0, new_y1;
  
  /* Wrap d_xoffset, d_yoffset into [-32768,32767] range. For the
   * purposes of subwindow movement, it doesn't matter if we are
   * off by a factor of 65536, and if we don't do this range
   * reduction, we'll end up with invalid widths.
   */
  d_xoffset = (gint16)d_xoffset;
  d_yoffset = (gint16)d_yoffset;
  
  if (d_xoffset < 0)
    {
      new_x0 = position_info->x + d_xoffset;
      new_x1 = position_info->x + position_info->width;
    }
  else
    {
      new_x0 = position_info->x;
      new_x1 = position_info->x + new_info->width + d_xoffset;
    }

  new_position->x = new_x0;
  new_position->width = new_x1 - new_x0;
  
  if (d_yoffset < 0)
    {
      new_y0 = position_info->y + d_yoffset;
      new_y1 = position_info->y + position_info->height;
    }
  else
    {
      new_y0 = position_info->y;
      new_y1 = position_info->y + new_info->height + d_yoffset;
    }
  
  new_position->y = new_y0;
  new_position->height = new_y1 - new_y0;
}

static void
gdk_window_guffaw_scroll (GdkWindow    *window,
			  gint          dx,
			  gint          dy)
{
  GdkWindowObject *obj = GDK_WINDOW_OBJECT (window);
  GdkWindowImplX11 *impl = GDK_WINDOW_IMPL_X11 (obj->impl);

  gint d_xoffset = -dx;
  gint d_yoffset = -dy;
  GdkRectangle new_position;
  GdkXPositionInfo new_info;
  GdkWindowParentPos parent_pos;
  GList *tmp_list;
  
  gdk_window_compute_parent_pos (impl, &parent_pos);
  gdk_window_compute_position (impl, &parent_pos, &new_info);

  parent_pos.x += obj->x;
  parent_pos.y += obj->y;
  parent_pos.x11_x += new_info.x;
  parent_pos.x11_y += new_info.y;
  parent_pos.clip_rect = new_info.clip_rect;

  _gdk_x11_window_tmp_unset_bg (window, FALSE);;

  if (dx > 0 || dy > 0)
    gdk_window_queue_translation (window, MAX (dx, 0), MAX (dy, 0));
	
  gdk_window_set_static_gravities (window, TRUE);

  compute_intermediate_position (&impl->position_info, &new_info, d_xoffset, d_yoffset,
				 &new_position);
  
  XMoveResizeWindow (GDK_WINDOW_XDISPLAY (window),
		     GDK_WINDOW_XID (window),
		     new_position.x, new_position.y, new_position.width, new_position.height);
  
  tmp_list = obj->children;
  while (tmp_list)
    {
      GDK_WINDOW_OBJECT(tmp_list->data)->x -= d_xoffset;
      GDK_WINDOW_OBJECT(tmp_list->data)->y -= d_yoffset;

      gdk_window_premove (tmp_list->data, &parent_pos);
      tmp_list = tmp_list->next;
    }
  
  XMoveWindow (GDK_WINDOW_XDISPLAY (window),
	       GDK_WINDOW_XID (window),
	       new_position.x - d_xoffset, new_position.y - d_yoffset);
  
  if (dx < 0 || dy < 0)
    gdk_window_queue_translation (window, MIN (dx, 0), MIN (dy, 0));
  
  XMoveResizeWindow (GDK_WINDOW_XDISPLAY (window),
		     GDK_WINDOW_XID (window),
		     impl->position_info.x, impl->position_info.y,
		     impl->position_info.width, impl->position_info.height);
  
  if (impl->position_info.no_bg)
    _gdk_x11_window_tmp_reset_bg (window, FALSE);
  
  impl->position_info = new_info;
  
  tmp_list = obj->children;
  while (tmp_list)
    {