Paging is slowly becoming better, but still susceptible to race conditions
[rodin/chimara.git] / libchimara / pager.c
index f9a0a32c69fa0b670ba01162603ec988e401513e..c88ab63630c3918478e7c1d75027af4a85307175 100644 (file)
@@ -5,8 +5,8 @@
 /* Helper function: move the pager to the last visible position in the buffer,
  and return the distance between the pager and the end of the buffer in buffer
  coordinates */
-static gint
-move_pager_and_get_scroll_distance(GtkTextView *textview)
+static void
+move_pager_and_get_scroll_distance(GtkTextView *textview, gint *view_height, gint *scroll_distance, gboolean move )
 {
        GdkRectangle pagerpos, endpos, visiblerect;
        GtkTextIter oldpager, newpager, end;
@@ -15,27 +15,35 @@ move_pager_and_get_scroll_distance(GtkTextView *textview)
        
        /* Get an iter at the lower right corner of the visible part of the buffer */
        gtk_text_view_get_visible_rect(textview, &visiblerect);
-       gtk_text_view_get_iter_at_location(textview, &newpager, visiblerect.x + visiblerect.width, visiblerect.y + visiblerect.height);
+       gtk_text_view_get_iter_at_location(
+               textview,
+               &newpager,
+               visiblerect.x + visiblerect.width,
+               visiblerect.y + visiblerect.height
+       );
        gtk_text_buffer_get_iter_at_mark(buffer, &oldpager, pager);
        
-       gtk_text_buffer_move_mark(buffer, pager, &newpager);
+       if(move)
+               gtk_text_buffer_move_mark(buffer, pager, &newpager);
 
        /* Get the buffer coordinates of the pager and the end iter */
        gtk_text_buffer_get_end_iter(buffer, &end);
        gtk_text_buffer_get_iter_at_mark(buffer, &newpager, pager);
        gtk_text_view_get_iter_location(textview, &newpager, &pagerpos);
        gtk_text_view_get_iter_location(textview, &end, &endpos);
+
+       g_printerr("View height = %d\n", visiblerect.height);
+       g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
        
-       //g_printerr("View height = %d\n", visiblerect.height);
-       //g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
-       
-       return endpos.y - pagerpos.y;
+       *view_height = visiblerect.height;
+       *scroll_distance = endpos.y - pagerpos.y;
 }
 
 /* Helper function: turn on paging for this textview */
 static void
 start_paging(winid_t win)
 {
+       printf("Start paging\n");
        win->currently_paging = TRUE;
        g_signal_handler_unblock(win->widget, win->pager_expose_handler);
        g_signal_handler_unblock(win->widget, win->pager_keypress_handler);
@@ -45,34 +53,66 @@ start_paging(winid_t win)
 static void
 stop_paging(winid_t win)
 {
+       printf("Stop paging\n");
        win->currently_paging = FALSE;
        g_signal_handler_block(win->widget, win->pager_expose_handler);
        g_signal_handler_block(win->widget, win->pager_keypress_handler);
 }
 
-/* Update the pager position after new text is inserted in the buffer */
-void
-pager_after_insert_text(GtkTextBuffer *buffer, GtkTextIter *location, gchar *text, gint len, winid_t win)
+/* Check whether paging should be done. This function is called inside the 
+ * idle handler, after the textview has finished updating. */
+gboolean
+pager_check(gpointer data)
 {
-       while(gtk_events_pending())
-               gtk_main_iteration();
-       
+
+       printf("pager check (idle)...\n");
+       winid_t win = (winid_t) data;
+
+
        /* Move the pager to the last visible character in the buffer */
-       gint scroll_distance = move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget) );
+       gint view_height, scroll_distance;
+       move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget), &view_height, &scroll_distance, FALSE );
+
+       gdk_threads_enter();
+
+       if(view_height <= 1)
+               /* Paging is unusable when window is too small */
+               return FALSE;
        
-       if(scroll_distance > 0 && !win->currently_paging)
-               start_paging(win);
+       if(!win->currently_paging) {
+               if(scroll_distance > view_height) {
+                       start_paging(win);
+                       /* Seriously... */
+                       /* COMPAT: */
+#if GTK_CHECK_VERSION(2,14,0)
+                       gdk_window_invalidate_rect(gtk_widget_get_window(win->widget), NULL, TRUE);
+#else
+                       gdk_window_invalidate_rect(win->widget->window, NULL, TRUE);
+#endif
+               }
+               else if(scroll_distance > 0) {
+                       if(win->input_request_type != INPUT_REQUEST_NONE) {
+                               GtkTextBuffer *buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(win->widget));
+                               GtkTextMark *end = gtk_text_buffer_get_mark(buffer, "end_position");
+
+                               gtk_text_view_scroll_mark_onscreen(GTK_TEXT_VIEW(win->widget), end);
+                       }
+               }
+       }
+       gdk_threads_leave();
+
+       /* Returning FALSE to prevent this function from being called multiple times */
+       return FALSE;
 }
 
+/* When the user scrolls up in a textbuffer, start paging. */
 void
 pager_after_adjustment_changed(GtkAdjustment *adj, winid_t win)
 {
-       while(gtk_events_pending())
-               gtk_main_iteration();
-       
        /* Move the pager, etc. */
-       gint scroll_distance = move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget) );
-       
+       gint scroll_distance, view_height;
+       move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget), &view_height, &scroll_distance, TRUE );
+
        if(scroll_distance > 0 && !win->currently_paging)
                start_paging(win);
        else if(scroll_distance == 0 && win->currently_paging)
@@ -86,11 +126,6 @@ pager_after_adjustment_changed(GtkAdjustment *adj, winid_t win)
 gboolean
 pager_on_key_press_event(GtkTextView *textview, GdkEventKey *event, winid_t win)
 {
-       /*** ALTERNATIVE, POSSIBLY INFERIOR, METHOD OF SCROLLING ***
-       GtkTextMark *pagermark = gtk_text_buffer_get_mark(buffer, "pager_position");
-       gtk_text_view_scroll_to_mark(textview, pagermark, 0.0, TRUE, 0.0, 0.0);
-       */
-
        GtkAdjustment *adj = gtk_scrolled_window_get_vadjustment( GTK_SCROLLED_WINDOW(win->frame) );
        gdouble step_increment, page_size, upper, lower, value;
        g_object_get(adj, 
@@ -131,12 +166,6 @@ pager_on_expose(GtkTextView *textview, GdkEventExpose *event, winid_t win)
 
        /* Draw the 'more' tag */
        GdkGC *context = gdk_gc_new(GDK_DRAWABLE(event->window));
-       /*
-       gdk_draw_layout_with_colors(event->window, context, 
-               winx + winwidth - promptwidth, 
-               winy + winheight - promptheight, 
-               prompt, &white, &red);
-       */
        gdk_draw_layout(event->window, context, 
                winx + winwidth - promptwidth, 
                winy + winheight - promptheight, 
@@ -144,3 +173,48 @@ pager_on_expose(GtkTextView *textview, GdkEventExpose *event, winid_t win)
 
        return FALSE; /* Propagate event further */
 }
+
+gboolean
+pager_after_expose_event(GtkTextView *textview, GdkEventExpose *event, winid_t win)
+{
+       printf("pager check (expose)...\n");
+       g_idle_add(pager_check, win);
+
+//     /* Move the pager to the last visible character in the buffer */
+//     gint view_height, scroll_distance;
+//     move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget), &view_height, &scroll_distance, FALSE );
+//
+//     if(view_height <= 1)
+//             /* Paging is unusable when window is too small */
+//             return FALSE;
+//     
+//     if(!win->currently_paging) {
+//             if(scroll_distance > view_height) {
+//                     start_paging(win);
+//                     /* Seriously... */
+//                     /* COMPAT: */
+//#if GTK_CHECK_VERSION(2,14,0)
+//                     gdk_window_invalidate_rect(gtk_widget_get_window(win->widget), NULL, TRUE);
+//#else
+//                     gdk_window_invalidate_rect(win->widget->window, NULL, TRUE);
+//#endif
+//             }
+//             else if(scroll_distance > 0) {
+//                     if(win->input_request_type != INPUT_REQUEST_NONE) {
+//                             GtkTextBuffer *buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(win->widget));
+//                             GtkTextMark *end = gtk_text_buffer_get_mark(buffer, "end_position");
+//
+//                             gtk_text_view_scroll_mark_onscreen(GTK_TEXT_VIEW(win->widget), end);
+//                     }
+//             }
+//     }
+
+       return FALSE;
+}
+
+void
+pager_after_size_request(GtkTextView *textview, GtkRequisition *requisition, winid_t win)
+{
+       printf("pager check (size request)...\n");
+       g_idle_add(pager_check, win);
+}