master 61d049a 01/35: Use an X window to display xwidgets on X11

[Lars Ingebrigtsen]

branch: master
commit 61d049aaff2ede48d3d4b357bc1cb06447f15229
Author: Po Lu <luangruo@yahoo.com>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Use an X window to display xwidgets on X11
    
    Since Emacs draws using X11 primitives, Emacs drawing operations can
    erase the GtkDrawingArea used to draw the offscreen widget, which
    leads to unpleasant flickering effects, all of which can be prevented
    by creating a native X window and drawing to that instead.
    
    * src/xterm.c (x_window_to_frame): Return xwidget window if
    appropriate.
    (handle_one_xevent): Handle xwidget expose events.
    
    * src/xwidget.c (x_window_to_xvw_map): New variable.
    (xwidget_view_from_window): New function.
    
    (xwidget_show_view, xwidget_hide_view)
    (offscreen_damage_event): Move to drawing xwidgets with X windows.
    
    (xv_do_draw)
    (xwidget_expose): New function.
    
    (xwidget_osr_draw_cb, xwidget_osr_event_forward)
    (xwidget_osr_event_set_embedder): Removed.
    
    (xwidget_init_view): Replace use of GtkDrawingArea with that of an X
    window.
    
    (x_draw_xwidget_glyph_string): Prevent xwidget views from constantly
    generating expose events, and use an X window instead of a
    GtkDrawingArea.
    
    (syms_of_xwidget): Initialize x_window_to_xwv_map.
    
    src/xwidget.h (struct xwidget_view): Replace GTK widgets with
    X-related fields.
    
    (xwidget_view_from_window, xwidget_expose): New functions.
---
 src/xterm.c   |  24 ++++-
 src/xwidget.c | 277 ++++++++++++++++++++++++++++++----------------------------
 src/xwidget.h |  12 ++-
 3 files changed, 175 insertions(+), 138 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index aa1a1a5..54bfb65 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -4563,8 +4563,9 @@ x_focus_changed (int type, int state, struct 
x_display_info *dpyinfo, struct fra
     }
 }
 
-/* Return the Emacs frame-object corresponding to an X window.
-   It could be the frame's main window or an icon window.  */
+/* Return the Emacs frame-object corresponding to an X window.  It
+   could be the frame's main window, an icon window, or an xwidget
+   window.  */
 
 static struct frame *
 x_window_to_frame (struct x_display_info *dpyinfo, int wdesc)
@@ -4575,6 +4576,13 @@ x_window_to_frame (struct x_display_info *dpyinfo, int 
wdesc)
   if (wdesc == None)
     return NULL;
 
+#ifdef HAVE_XWIDGETS
+  struct xwidget_view *xvw = xwidget_view_from_window (wdesc);
+
+  if (xvw && xvw->frame)
+    return xvw->frame;
+#endif
+
   FOR_EACH_FRAME (tail, frame)
     {
       f = XFRAME (frame);
@@ -8211,6 +8219,18 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
     case Expose:
       f = x_window_to_frame (dpyinfo, event->xexpose.window);
+#ifdef HAVE_XWIDGETS
+      {
+       struct xwidget_view *xv =
+         xwidget_view_from_window (event->xexpose.window);
+
+       if (xv)
+         {
+           xwidget_expose (xv);
+           goto OTHER;
+         }
+      }
+#endif
       if (f)
         {
           if (!FRAME_VISIBLE_P (f))
diff --git a/src/xwidget.c b/src/xwidget.c
index e4b42e6..62b30a0 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -35,10 +35,16 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #ifdef USE_GTK
 #include <webkit2/webkit2.h>
 #include <JavaScriptCore/JavaScript.h>
+#include <cairo.h>
+#include <X11/Xlib.h>
 #elif defined NS_IMPL_COCOA
 #include "nsxwidget.h"
 #endif
 
+#ifdef USE_GTK
+static Lisp_Object x_window_to_xwv_map;
+#endif
+
 static struct xwidget *
 allocate_xwidget (void)
 {
@@ -222,15 +228,28 @@ xwidget_hidden (struct xwidget_view *xv)
 }
 
 #ifdef USE_GTK
+
+struct xwidget_view *
+xwidget_view_from_window (Window wdesc)
+{
+  Lisp_Object key = make_fixnum (wdesc);
+  Lisp_Object xwv = Fgethash (key, x_window_to_xwv_map, Qnil);
+
+  if (NILP (xwv))
+    return NULL;
+
+  return XXWIDGET_VIEW (xwv);
+}
+
 static void
 xwidget_show_view (struct xwidget_view *xv)
 {
   xv->hidden = false;
-  gtk_widget_show (xv->widgetwindow);
-  gtk_fixed_move (GTK_FIXED (xv->emacswindow),
-                  xv->widgetwindow,
-                  xv->x + xv->clip_left,
-                  xv->y + xv->clip_top);
+  XMoveWindow (xv->dpy, xv->wdesc,
+              xv->x + xv->clip_left,
+              xv->y + xv->clip_top);
+  XMapWindow (xv->dpy, xv->wdesc);
+  XFlush (xv->dpy);
 }
 
 /* Hide an xwidget view.  */
@@ -238,28 +257,48 @@ static void
 xwidget_hide_view (struct xwidget_view *xv)
 {
   xv->hidden = true;
-  gtk_fixed_move (GTK_FIXED (xv->emacswindow), xv->widgetwindow,
-                  10000, 10000);
+  XUnmapWindow (xv->dpy, xv->wdesc);
+  XFlush (xv->dpy);
+}
+
+static void
+xv_do_draw (struct xwidget_view *xw, struct xwidget *w)
+{
+  block_input ();
+
+  cairo_save (xw->cr_context);
+  cairo_translate (xw->cr_context, -xw->clip_left,
+                  -xw->clip_top);
+  gtk_widget_draw (w->widget_osr, xw->cr_context);
+  cairo_restore (xw->cr_context);
+
+  unblock_input ();
 }
 
 /* When the off-screen webkit master view changes this signal is called.
    It copies the bitmap from the off-screen instance.  */
 static gboolean
 offscreen_damage_event (GtkWidget *widget, GdkEvent *event,
-                        gpointer xv_widget)
+                        gpointer xwidget_view)
 {
-  /* Queue a redraw of onscreen widget.
-     There is a guard against receiving an invalid widget,
-     which should only happen if we failed to remove the
-     specific signal handler for the damage event.  */
-  if (GTK_IS_WIDGET (xv_widget))
-    gtk_widget_queue_draw (GTK_WIDGET (xv_widget));
-  else
-    message ("Warning, offscreen_damage_event received invalid xv 
pointer:%p\n",
-             xv_widget);
+  struct xwidget_view *xw = xwidget_view;
+  struct xwidget *w = XXWIDGET (xw->model);
+
+  if (xw->wdesc == None)
+    return FALSE;
+
+  xv_do_draw (xw, w);
 
   return FALSE;
 }
+
+void
+xwidget_expose (struct xwidget_view *xv)
+{
+  struct xwidget *xw = XXWIDGET (xv->model);
+
+  xv_do_draw (xv, xw);
+}
 #endif /* USE_GTK */
 
 void
@@ -498,51 +537,6 @@ webkit_decide_policy_cb (WebKitWebView *webView,
     return FALSE;
   }
 }
-
-
-/* For gtk3 offscreen rendered widgets.  */
-static gboolean
-xwidget_osr_draw_cb (GtkWidget *widget, cairo_t *cr, gpointer data)
-{
-  struct xwidget *xw = g_object_get_data (G_OBJECT (widget), XG_XWIDGET);
-  struct xwidget_view *xv = g_object_get_data (G_OBJECT (widget),
-                                               XG_XWIDGET_VIEW);
-
-  cairo_rectangle (cr, 0, 0, xv->clip_right, xv->clip_bottom);
-  cairo_clip (cr);
-
-  gtk_widget_draw (xw->widget_osr, cr);
-  return FALSE;
-}
-
-static gboolean
-xwidget_osr_event_forward (GtkWidget *widget, GdkEvent *event,
-                          gpointer user_data)
-{
-  /* Copy events that arrive at the outer widget to the offscreen widget.  */
-  struct xwidget *xw = g_object_get_data (G_OBJECT (widget), XG_XWIDGET);
-  GdkEvent *eventcopy = gdk_event_copy (event);
-  eventcopy->any.window = gtk_widget_get_window (xw->widget_osr);
-
-  /* TODO: This might leak events.  They should be deallocated later,
-     perhaps in xwgir_event_cb.  */
-  gtk_main_do_event (eventcopy);
-
-  /* Don't propagate this event further.  */
-  return TRUE;
-}
-
-static gboolean
-xwidget_osr_event_set_embedder (GtkWidget *widget, GdkEvent *event,
-                               gpointer data)
-{
-  struct xwidget_view *xv = data;
-  struct xwidget *xww = XXWIDGET (xv->model);
-  gdk_offscreen_window_set_embedder (gtk_widget_get_window
-                                    (xww->widgetwindow_osr),
-                                     gtk_widget_get_window (xv->widget));
-  return FALSE;
-}
 #endif /* USE_GTK */
 
 
@@ -568,63 +562,21 @@ xwidget_init_view (struct xwidget *xww,
   XSETXWIDGET (xv->model, xww);
 
 #ifdef USE_GTK
-  if (EQ (xww->type, Qwebkit))
-    {
-      xv->widget = gtk_drawing_area_new ();
-      /* Expose event handling.  */
-      gtk_widget_set_app_paintable (xv->widget, TRUE);
-      gtk_widget_add_events (xv->widget, GDK_ALL_EVENTS_MASK);
-
-      /* Draw the view on damage-event.  */
-      g_signal_connect (G_OBJECT (xww->widgetwindow_osr), "damage-event",
-                        G_CALLBACK (offscreen_damage_event), xv->widget);
-
-      if (EQ (xww->type, Qwebkit))
-        {
-          g_signal_connect (G_OBJECT (xv->widget), "button-press-event",
-                            G_CALLBACK (xwidget_osr_event_forward), NULL);
-          g_signal_connect (G_OBJECT (xv->widget), "button-release-event",
-                            G_CALLBACK (xwidget_osr_event_forward), NULL);
-          g_signal_connect (G_OBJECT (xv->widget), "motion-notify-event",
-                            G_CALLBACK (xwidget_osr_event_forward), NULL);
-        }
-      else
-        {
-          /* xwgir debug, orthogonal to forwarding.  */
-          g_signal_connect (G_OBJECT (xv->widget), "enter-notify-event",
-                            G_CALLBACK (xwidget_osr_event_set_embedder), xv);
-        }
-      g_signal_connect (G_OBJECT (xv->widget), "draw",
-                        G_CALLBACK (xwidget_osr_draw_cb), NULL);
-    }
+  xv->dpy = FRAME_X_DISPLAY (s->f);
 
-  /* Widget realization.
-
-     Make container widget first, and put the actual widget inside the
-     container later.  Drawing should crop container window if necessary
-     to handle case where xwidget is partially obscured by other Emacs
-     windows.  Other containers than gtk_fixed where explored, but
-     gtk_fixed had the most predictable behavior so far.  */
-
-  xv->emacswindow = FRAME_GTK_WIDGET (s->f);
-  xv->widgetwindow = gtk_fixed_new ();
-  gtk_widget_set_has_window (xv->widgetwindow, TRUE);
-  gtk_container_add (GTK_CONTAINER (xv->widgetwindow), xv->widget);
-
-  /* Store some xwidget data in the gtk widgets.  */
-  g_object_set_data (G_OBJECT (xv->widget), XG_FRAME_DATA, s->f);
-  g_object_set_data (G_OBJECT (xv->widget), XG_XWIDGET, xww);
-  g_object_set_data (G_OBJECT (xv->widget), XG_XWIDGET_VIEW, xv);
-  g_object_set_data (G_OBJECT (xv->widgetwindow), XG_XWIDGET, xww);
-  g_object_set_data (G_OBJECT (xv->widgetwindow), XG_XWIDGET_VIEW, xv);
-
-  gtk_widget_set_size_request (GTK_WIDGET (xv->widget), xww->width,
-                               xww->height);
-  gtk_widget_set_size_request (xv->widgetwindow, xww->width, xww->height);
-  gtk_fixed_put (GTK_FIXED (FRAME_GTK_WIDGET (s->f)), xv->widgetwindow, x, y);
   xv->x = x;
   xv->y = y;
-  gtk_widget_show_all (xv->widgetwindow);
+
+  xv->clip_left = 0;
+  xv->clip_right = xww->width;
+  xv->clip_top = 0;
+  xv->clip_bottom = xww->height;
+
+  xv->wdesc = None;
+  xv->frame = s->f;
+
+  g_signal_connect (G_OBJECT (xww->widgetwindow_osr), "damage-event",
+                   G_CALLBACK (offscreen_damage_event), xv);
 #elif defined NS_IMPL_COCOA
   nsxwidget_init_view (xv, xww, s, x, y);
   nsxwidget_resize_view(xv, xww->width, xww->height);
@@ -681,6 +633,8 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
   window_box (s->w, TEXT_AREA, &text_area_x, &text_area_y,
               &text_area_width, &text_area_height);
 
+  /* On X11, this keeps generating expose events.  */
+#ifndef USE_GTK
   /* Resize xwidget webkit if its container window size is changed in
      some ways, for example, a buffer became hidden in small split
      window, then it can appear front in merged whole window.  */
@@ -693,6 +647,7 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
                        make_int (text_area_width),
                        make_int (text_area_height));
     }
+#endif
 
   clip_left = max (0, text_area_x - x);
   clip_right = max (clip_left,
@@ -711,15 +666,45 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
      later.  */
   bool moved = (xv->x + xv->clip_left != x + clip_left
                || xv->y + xv->clip_top != y + clip_top);
+
+#ifdef USE_GTK
+  bool wdesc_was_none = xv->wdesc == None;
+#endif
   xv->x = x;
   xv->y = y;
 
+#ifdef USE_GTK
+  block_input ();
+  if (xv->wdesc == None)
+    {
+      Lisp_Object xvw;
+      XSETXWIDGET_VIEW (xvw, xv);
+      XSetWindowAttributes a;
+      a.event_mask = ExposureMask;
+
+      xv->wdesc = XCreateWindow (xv->dpy, FRAME_X_WINDOW (s->f),
+                                x + clip_left, y + clip_top,
+                                clip_right - clip_left,
+                                clip_bottom - clip_top, 0,
+                                CopyFromParent, CopyFromParent,
+                                CopyFromParent, CWEventMask, &a);
+      xv->cr_surface = cairo_xlib_surface_create (xv->dpy,
+                                                 xv->wdesc,
+                                                 FRAME_DISPLAY_INFO 
(s->f)->visual,
+                                                 clip_right - clip_left,
+                                                 clip_bottom - clip_top);
+      xv->cr_context = cairo_create (xv->cr_surface);
+      Fputhash (make_fixnum (xv->wdesc), xvw, x_window_to_xwv_map);
+
+      moved = false;
+    }
+#endif
+
   /* Has it moved?  */
   if (moved)
     {
 #ifdef USE_GTK
-      gtk_fixed_move (GTK_FIXED (FRAME_GTK_WIDGET (s->f)),
-                      xv->widgetwindow, x + clip_left, y + clip_top);
+      XMoveWindow (xv->dpy, xv->wdesc, x + clip_left, y + clip_top);
 #elif defined NS_IMPL_COCOA
       nsxwidget_move_view (xv, x + clip_left, y + clip_top);
 #endif
@@ -735,10 +720,14 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
       || xv->clip_top != clip_top || xv->clip_left != clip_left)
     {
 #ifdef USE_GTK
-      gtk_widget_set_size_request (xv->widgetwindow, clip_right - clip_left,
-                                   clip_bottom - clip_top);
-      gtk_fixed_move (GTK_FIXED (xv->widgetwindow), xv->widget, -clip_left,
-                      -clip_top);
+      if (!wdesc_was_none)
+       {
+         XResizeWindow (xv->dpy, xv->wdesc, clip_right - clip_left,
+                        clip_bottom - clip_top);
+         XFlush (xv->dpy);
+         cairo_xlib_surface_set_size (xv->cr_surface, clip_right - clip_left,
+                                      clip_bottom - clip_top);
+       }
 #elif defined NS_IMPL_COCOA
       nsxwidget_resize_view (xv, clip_right - clip_left,
                              clip_bottom - clip_top);
@@ -758,12 +747,15 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
   if (!xwidget_hidden (xv))
     {
 #ifdef USE_GTK
-      gtk_widget_queue_draw (xv->widgetwindow);
-      gtk_widget_queue_draw (xv->widget);
+      xv_do_draw (xv, xww);
 #elif defined NS_IMPL_COCOA
       nsxwidget_set_needsdisplay (xv);
 #endif
     }
+
+#ifdef USE_GTK
+  unblock_input ();
+#endif
 }
 
 static bool
@@ -976,8 +968,13 @@ DEFUN ("xwidget-resize", Fxwidget_resize, Sxwidget_resize, 
3, 3, 0,
           if (XXWIDGET (xv->model) == xw)
             {
 #ifdef USE_GTK
-              gtk_widget_set_size_request (GTK_WIDGET (xv->widget), xw->width,
-                                           xw->height);
+             if (xv->wdesc != None)
+               {
+                 XResizeWindow (xv->dpy, xv->wdesc, xw->width, xw->height);
+                 XFlush (xv->dpy);
+                 cairo_xlib_surface_set_size (xv->cr_surface,
+                                              xw->width, xw->height);
+               }
 #elif defined NS_IMPL_COCOA
               nsxwidget_resize_view(xv, xw->width, xw->height);
 #endif
@@ -1084,13 +1081,21 @@ DEFUN ("delete-xwidget-view",
   CHECK_XWIDGET_VIEW (xwidget_view);
   struct xwidget_view *xv = XXWIDGET_VIEW (xwidget_view);
 #ifdef USE_GTK
-  gtk_widget_destroy (xv->widgetwindow);
-  /* xv->model still has signals pointing to the view.  There can be
-     several views.  Find the matching signals and delete them all.  */
-  g_signal_handlers_disconnect_matched  (XXWIDGET 
(xv->model)->widgetwindow_osr,
-                                         G_SIGNAL_MATCH_DATA,
-                                         0, 0, 0, 0,
-                                         xv->widget);
+  if (xv->wdesc != None)
+    {
+      block_input ();
+      XDestroyWindow (xv->dpy, xv->wdesc);
+      /* xv->model still has signals pointing to the view.  There can be
+        several views.  Find the matching signals and delete them all.  */
+      g_signal_handlers_disconnect_matched  (XXWIDGET 
(xv->model)->widgetwindow_osr,
+                                            G_SIGNAL_MATCH_DATA,
+                                            0, 0, 0, 0, xv);
+
+      cairo_destroy (xv->cr_context);
+      cairo_surface_destroy (xv->cr_surface);
+      Fremhash (make_fixnum (xv->wdesc), x_window_to_xwv_map);
+      unblock_input ();
+    }
 #elif defined NS_IMPL_COCOA
   nsxwidget_delete_view (xv);
 #endif
@@ -1236,6 +1241,12 @@ syms_of_xwidget (void)
   Vxwidget_view_list = Qnil;
 
   Fprovide (intern ("xwidget-internal"), Qnil);
+
+#ifdef USE_GTK
+  x_window_to_xwv_map = CALLN (Fmake_hash_table, QCtest, Qeq);
+
+  staticpro (&x_window_to_xwv_map);
+#endif
 }
 
 
diff --git a/src/xwidget.h b/src/xwidget.h
index 591f234..fc68b52 100644
--- a/src/xwidget.h
+++ b/src/xwidget.h
@@ -32,6 +32,7 @@ struct window;
 
 #if defined (USE_GTK)
 #include <gtk/gtk.h>
+#include <X11/Xlib.h>
 #elif defined (NS_IMPL_COCOA) && defined (__OBJC__)
 #import <AppKit/NSView.h>
 #import "nsxwidget.h"
@@ -98,9 +99,12 @@ struct xwidget_view
   bool hidden;
 
 #if defined (USE_GTK)
-  GtkWidget *widget;
-  GtkWidget *widgetwindow;
-  GtkWidget *emacswindow;
+  Display *dpy;
+  Window wdesc;
+  struct frame *frame;
+
+  cairo_surface_t *cr_surface;
+  cairo_t *cr_context;
 #elif defined (NS_IMPL_COCOA)
 # ifdef __OBJC__
   XvWindow *xvWindow;
@@ -162,6 +166,8 @@ void store_xwidget_download_callback_event (struct xwidget 
*xw,
 void store_xwidget_js_callback_event (struct xwidget *xw,
                                       Lisp_Object proc,
                                       Lisp_Object argument);
+struct xwidget_view *xwidget_view_from_window (Window wdesc);
+void xwidget_expose (struct xwidget_view *xv);
 #else
 INLINE_HEADER_BEGIN
 INLINE void syms_of_xwidget (void) {}