Add a new debug flag to monitor draw operations. Don't issue individual

2007-02-23  Chris Wilson  <chris@chris-wilson.co.uk>

	Add a new debug flag to monitor draw operations.
	Don't issue individual glyphs for is_local_graphic() in the middle of
	a run.

	* src/debug.c: (_vte_debug_parse_string):
	* src/debug.h:
	* src/vte.c: (vte_terminal_unichar_is_local_graphic),
	(vte_terminal_draw_rows), (vte_terminal_paint):
	* src/vtedraw.c: (_vte_draw_init_user), (_vte_draw_init_default),
	(_vte_draw_new), (_vte_draw_free), (_vte_draw_get_visual),
	(_vte_draw_get_colormap), (_vte_draw_start), (_vte_draw_end),
	(_vte_draw_set_background_color), (_vte_draw_set_background_image),
	(_vte_draw_requires_repaint), (_vte_draw_clip), (_vte_draw_clear),
	(_vte_draw_set_text_font), (_vte_draw_get_text_width),
	(_vte_draw_get_text_height), (_vte_draw_get_text_ascent),
	(_vte_draw_get_char_width), (_vte_draw_get_using_fontconfig),
	(_vte_draw_text), (_vte_draw_char), (_vte_draw_has_char),
	(_vte_draw_fill_rectangle), (_vte_draw_draw_rectangle),
	(_vte_draw_set_scroll):
	* src/vtedraw.h:
	* src/vteft2.c: (_vte_ft2_draw_has_char):
	* src/vtegl.c: (_vte_gl_draw_has_char):
	* src/vtepango.c: (_vte_pango_draw_has_char):
	* src/vtepangox.c: (_vte_pango_x_draw_has_char):
	* src/vteskel.c: (_vte_skel_draw_has_char):
	* src/vtexft.c: (_vte_xft_draw_has_char):


svn path=/trunk/; revision=1729

12 files changed, 281 insertions, 124 deletions

diff --git a/ChangeLog b/ChangeLog
index 91d7adc0..077b0b12 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,34 @@
 2007-02-23  Chris Wilson  <chris@chris-wilson.co.uk>
 
+	Add a new debug flag to monitor draw operations.
+	Don't issue individual glyphs for is_local_graphic() in the middle of
+	a run.
+
+	* src/debug.c: (_vte_debug_parse_string):
+	* src/debug.h:
+	* src/vte.c: (vte_terminal_unichar_is_local_graphic),
+	(vte_terminal_draw_rows), (vte_terminal_paint):
+	* src/vtedraw.c: (_vte_draw_init_user), (_vte_draw_init_default),
+	(_vte_draw_new), (_vte_draw_free), (_vte_draw_get_visual),
+	(_vte_draw_get_colormap), (_vte_draw_start), (_vte_draw_end),
+	(_vte_draw_set_background_color), (_vte_draw_set_background_image),
+	(_vte_draw_requires_repaint), (_vte_draw_clip), (_vte_draw_clear),
+	(_vte_draw_set_text_font), (_vte_draw_get_text_width),
+	(_vte_draw_get_text_height), (_vte_draw_get_text_ascent),
+	(_vte_draw_get_char_width), (_vte_draw_get_using_fontconfig),
+	(_vte_draw_text), (_vte_draw_char), (_vte_draw_has_char),
+	(_vte_draw_fill_rectangle), (_vte_draw_draw_rectangle),
+	(_vte_draw_set_scroll):
+	* src/vtedraw.h:
+	* src/vteft2.c: (_vte_ft2_draw_has_char):
+	* src/vtegl.c: (_vte_gl_draw_has_char):
+	* src/vtepango.c: (_vte_pango_draw_has_char):
+	* src/vtepangox.c: (_vte_pango_x_draw_has_char):
+	* src/vteskel.c: (_vte_skel_draw_has_char):
+	* src/vtexft.c: (_vte_xft_draw_has_char):
+
+2007-02-23  Chris Wilson  <chris@chris-wilson.co.uk>
+
 	* src/vte.c: (vte_terminal_draw_rows):
 		Don't break a glyph run for a graphic, issue the draw
 		and continue.
diff --git a/src/debug.c b/src/debug.c
index 73984ad9..d73d461d 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -84,6 +84,9 @@ _vte_debug_parse_string(const char *string)
 			} else
 			if (g_ascii_strcasecmp(flags[i], "TIMEOUT") == 0) {
 				_vte_debug_flags |= VTE_DEBUG_TIMEOUT;
+			} else
+			if (g_ascii_strcasecmp(flags[i], "DRAW") == 0) {
+				_vte_debug_flags |= VTE_DEBUG_DRAW;
 			}
 		}
 		g_strfreev(flags);
diff --git a/src/debug.h b/src/debug.h
index aa7d8492..05ccff47 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -43,7 +43,8 @@ typedef enum {
 	VTE_DEBUG_TRIE		= 1 << 13,
 	VTE_DEBUG_WORK		= 1 << 14,
 	VTE_DEBUG_CELLS		= 1 << 15,
-	VTE_DEBUG_TIMEOUT	= 1 << 16
+	VTE_DEBUG_TIMEOUT	= 1 << 16,
+	VTE_DEBUG_DRAW		= 1 << 17
 } VteDebugFlags;
 
 void _vte_debug_parse_string(const char *string);
diff --git a/src/vte.c b/src/vte.c
index 85f7906d..d73a538a 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -7796,6 +7796,12 @@ vte_unichar_is_local_graphic(gunichar c)
 	}
 	return FALSE;
 }
+static inline gboolean
+vte_terminal_unichar_is_local_graphic(VteTerminal *terminal, gunichar c)
+{
+	return vte_unichar_is_local_graphic (c) &&
+		!_vte_draw_has_char (terminal->pvt->draw, c);
+}
 
 static void
 vte_terminal_fill_rectangle_int(VteTerminal *terminal,
@@ -9188,7 +9194,7 @@ vte_terminal_draw_rows(VteTerminal *terminal,
 			j = i + items[0].columns;
 
 			/* If this is a graphics character, draw it locally. */
-			if (vte_unichar_is_local_graphic(cell->c)) {
+			if (vte_terminal_unichar_is_local_graphic(terminal, cell->c)) {
 				if (vte_terminal_draw_graphic(terminal,
 						items[0].c,
 						fore, back,
@@ -9241,7 +9247,7 @@ vte_terminal_draw_rows(VteTerminal *terminal,
 							FALSE,
 							&nfore, &nback);
 					/* Graphic characters must be drawn individually. */
-					if (vte_unichar_is_local_graphic(cell->c)) {
+					if (vte_terminal_unichar_is_local_graphic(terminal, cell->c)) {
 						if (vte_terminal_draw_graphic(terminal,
 									cell->c,
 									nfore, nback,
@@ -9603,7 +9609,7 @@ vte_terminal_paint(GtkWidget *widget, GdkRegion *region)
 							 &color,
 							 VTE_DRAW_OPAQUE);
 			}
-			if (!vte_unichar_is_local_graphic(item.c) ||
+			if (!vte_terminal_unichar_is_local_graphic(terminal, item.c) ||
 			    !vte_terminal_draw_graphic(terminal,
 						       item.c,
 						       fore, back,
@@ -9622,16 +9628,18 @@ vte_terminal_paint(GtkWidget *widget, GdkRegion *region)
 							terminal->pvt->match_end.row,
 							TRUE);
 				}
-				vte_terminal_draw_cells(terminal,
+				if (cell && cell->c != ' ') {
+					vte_terminal_draw_cells(terminal,
 							&item, 1,
 							fore, back, TRUE, FALSE,
-							cell && cell->bold,
-							cell && cell->underline,
-							cell && cell->strikethrough,
+							cell->bold,
+							cell->underline,
+							cell->strikethrough,
 							hilite,
 							FALSE,
 							width,
 							height);
+				}
 			}
 		} else {
 			GdkColor color;
@@ -9641,7 +9649,7 @@ draw_cursor_outline:
 					selected,
 					TRUE,
 					&fore, &back);
-			if (!vte_unichar_is_local_graphic(item.c) ||
+			if (!vte_terminal_unichar_is_local_graphic(terminal, item.c) ||
 			    !vte_terminal_draw_graphic(terminal,
 						       item.c,
 						       fore, back,
@@ -9661,16 +9669,18 @@ draw_cursor_outline:
 							TRUE);
 				}
 				/* Draw it as a hollow rectangle overtop character. */
-				vte_terminal_draw_cells(terminal,
-						&item, 1,
-						fore, back, TRUE, FALSE,
-						cell && cell->bold,
-						cell && cell->underline,
-						cell && cell->strikethrough,
-						hilite,
-						FALSE,
-						width,
-						height);
+				if (cell && cell->c != ' ') {
+					vte_terminal_draw_cells(terminal,
+							&item, 1,
+							fore, back, TRUE, FALSE,
+							cell->bold,
+							cell->underline,
+							cell->strikethrough,
+							hilite,
+							FALSE,
+							width,
+							height);
+				}
 			}
 			vte_terminal_determine_colors(terminal, cell,
 					!terminal->pvt->screen->reverse_mode,
diff --git a/src/vtedraw.c b/src/vtedraw.c
index f5c098c3..b3d7a8d9 100644
--- a/src/vtedraw.c
+++ b/src/vtedraw.c
@@ -63,20 +63,20 @@ _vte_draw_init_user (struct _vte_draw *draw)
 	guint i;
 	gboolean success = TRUE;
 
-	env = g_getenv("VTE_BACKEND");
+	env = g_getenv ("VTE_BACKEND");
 	if (!env) {
 		return FALSE;
 	}
 
-	strv = g_strsplit(env, ":;, \t", -1);
+	strv = g_strsplit (env, ":;, \t", -1);
 	for (s = strv; *s; s++) {
-		if (g_ascii_strcasecmp(*s, _vte_draw_skel.name) == 0) {
+		if (g_ascii_strcasecmp (*s, _vte_draw_skel.name) == 0) {
 			draw->impl = &_vte_draw_skel;
 			goto out;
 		}
-		for (i = 0; i < G_N_ELEMENTS(_vte_draw_impls); i++) {
-			if (g_ascii_strcasecmp(*s, _vte_draw_impls[i]->name) == 0) {
-				if (_vte_draw_impls[i]->check(draw, draw->widget)) {
+		for (i = 0; i < G_N_ELEMENTS (_vte_draw_impls); i++) {
+			if (g_ascii_strcasecmp (*s, _vte_draw_impls[i]->name) == 0) {
+				if (_vte_draw_impls[i]->check (draw, draw->widget)) {
 					draw->impl = _vte_draw_impls[i];
 					goto out;
 				}
@@ -86,7 +86,7 @@ _vte_draw_init_user (struct _vte_draw *draw)
 
 	success = FALSE;
 out:
-	g_strfreev(strv);
+	g_strfreev (strv);
 	return success;
 }
 
@@ -96,8 +96,8 @@ _vte_draw_init_default (struct _vte_draw *draw)
 {
 	guint i;
 
-	for (i = 0; i < G_N_ELEMENTS(_vte_draw_impls); i++) {
-		if (_vte_draw_impls[i]->check(draw, draw->widget)) {
+	for (i = 0; i < G_N_ELEMENTS (_vte_draw_impls); i++) {
+		if (_vte_draw_impls[i]->check (draw, draw->widget)) {
 			draw->impl = _vte_draw_impls[i];
 			return TRUE;
 		}
@@ -108,13 +108,13 @@ _vte_draw_init_default (struct _vte_draw *draw)
 
 
 struct _vte_draw *
-_vte_draw_new(GtkWidget *widget)
+_vte_draw_new (GtkWidget *widget)
 {
 	struct _vte_draw *draw;
 
 	/* Create the structure. */
-	draw = g_slice_new0(struct _vte_draw);
-	draw->widget = g_object_ref(widget);
+	draw = g_slice_new0 (struct _vte_draw);
+	draw->widget = g_object_ref (widget);
 	draw->started = FALSE;
 
 	/* Allow the user to specify her preferred backends */
@@ -126,225 +126,267 @@ _vte_draw_new(GtkWidget *widget)
 		draw->impl = &_vte_draw_skel;
 	}
 
-	_vte_debug_print(VTE_DEBUG_MISC, "Using %s.\n", draw->impl->name);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_new (%s)\n", draw->impl->name);
+	_vte_debug_print (VTE_DEBUG_MISC, "Using %s.\n", draw->impl->name);
 
-	draw->impl->create(draw, draw->widget);
+	draw->impl->create (draw, draw->widget);
 
 	return draw;
 }
 
 void
-_vte_draw_free(struct _vte_draw *draw)
+_vte_draw_free (struct _vte_draw *draw)
 {
-	draw->impl->destroy(draw);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_free\n");
+	draw->impl->destroy (draw);
 
 	if (draw->widget != NULL) {
-		g_object_unref(draw->widget);
+		g_object_unref (draw->widget);
 	}
 
-	g_slice_free(struct _vte_draw, draw);
+	g_slice_free (struct _vte_draw, draw);
 }
 
 GdkVisual *
-_vte_draw_get_visual(struct _vte_draw *draw)
+_vte_draw_get_visual (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, NULL);
-	g_return_val_if_fail(draw->impl->get_visual != NULL, NULL);
-	return draw->impl->get_visual(draw);
+	g_return_val_if_fail (draw->impl != NULL, NULL);
+	g_return_val_if_fail (draw->impl->get_visual != NULL, NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_get_visual\n");
+	return draw->impl->get_visual (draw);
 }
 
 GdkColormap *
-_vte_draw_get_colormap(struct _vte_draw *draw, gboolean maybe_use_default)
+_vte_draw_get_colormap (struct _vte_draw *draw, gboolean maybe_use_default)
 {
 	GdkColormap *colormap;
 	GdkScreen *screen;
-	g_return_val_if_fail(draw->impl != NULL, NULL);
-	g_return_val_if_fail(draw->impl->get_colormap != NULL, NULL);
-	colormap = draw->impl->get_colormap(draw);
+	g_return_val_if_fail (draw->impl != NULL, NULL);
+	g_return_val_if_fail (draw->impl->get_colormap != NULL, NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_get_colormap\n");
+	colormap = draw->impl->get_colormap (draw);
 	if (colormap) {
 		return colormap;
 	}
 	if (!maybe_use_default) {
 		return NULL;
 	}
-	screen = gtk_widget_get_screen(draw->widget);
-	colormap = gdk_screen_get_default_colormap(screen);
+	screen = gtk_widget_get_screen (draw->widget);
+	colormap = gdk_screen_get_default_colormap (screen);
 	return colormap;
 }
 
 void
-_vte_draw_start(struct _vte_draw *draw)
+_vte_draw_start (struct _vte_draw *draw)
 {
-	g_return_if_fail(GTK_WIDGET_REALIZED(draw->widget));
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->start != NULL);
-	g_object_ref(draw->widget->window);
-	draw->impl->start(draw);
+	g_return_if_fail (GTK_WIDGET_REALIZED (draw->widget));
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->start != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_start\n");
+	g_object_ref (draw->widget->window);
+	draw->impl->start (draw);
 	draw->started = TRUE;
 }
 
 void
-_vte_draw_end(struct _vte_draw *draw)
+_vte_draw_end (struct _vte_draw *draw)
 {
-	g_return_if_fail(draw->started == TRUE);
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->end != NULL);
-	draw->impl->end(draw);
-	g_object_unref(draw->widget->window);
+	g_return_if_fail (draw->started == TRUE);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->end != NULL);
+	draw->impl->end (draw);
+	g_object_unref (draw->widget->window);
 	draw->started = FALSE;
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_end\n");
 }
 
 void
-_vte_draw_set_background_color(struct _vte_draw *draw,
+_vte_draw_set_background_color (struct _vte_draw *draw,
 			       GdkColor *color,
 			       guint16 opacity)
 {
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->set_background_color != NULL);
-	draw->impl->set_background_color(draw, color, opacity);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->set_background_color != NULL);
+	draw->impl->set_background_color (draw, color, opacity);
 }
 
 void
-_vte_draw_set_background_image(struct _vte_draw *draw,
+_vte_draw_set_background_image (struct _vte_draw *draw,
 			       enum VteBgSourceType type,
 			       GdkPixbuf *pixbuf,
 			       const char *filename,
 			       const GdkColor *color,
 			       double saturation)
 {
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->set_background_image != NULL);
-	draw->impl->set_background_image(draw, type, pixbuf, filename,
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->set_background_image != NULL);
+	draw->impl->set_background_image (draw, type, pixbuf, filename,
 					 color, saturation);
 }
 
 gboolean
-_vte_draw_requires_repaint(struct _vte_draw *draw)
+_vte_draw_requires_repaint (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, TRUE);
+	g_return_val_if_fail (draw->impl != NULL, TRUE);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_requires_repaint = %d\n",
+			draw->impl->requires_repaint);
 	return draw->impl->requires_repaint;
 }
 
 gboolean
-_vte_draw_clip(struct _vte_draw *draw, GdkRegion *region)
+_vte_draw_clip (struct _vte_draw *draw, GdkRegion *region)
 {
-	g_return_val_if_fail(draw->impl != NULL, FALSE);
+	g_return_val_if_fail (draw->impl != NULL, FALSE);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_clip\n");
 	if (draw->impl->clip == NULL) {
 		return FALSE;
 	}
-	draw->impl->clip(draw, region);
+	draw->impl->clip (draw, region);
 	return TRUE;
 }
 
 void
-_vte_draw_clear(struct _vte_draw *draw, gint x, gint y, gint width, gint height)
+_vte_draw_clear (struct _vte_draw *draw, gint x, gint y, gint width, gint height)
 {
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->clear != NULL);
-	draw->impl->clear(draw, x, y, width, height);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->clear != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_clear (%d, %d, %d, %d)\n",
+			x,y,width, height);
+	draw->impl->clear (draw, x, y, width, height);
 }
 
 void
-_vte_draw_set_text_font(struct _vte_draw *draw,
+_vte_draw_set_text_font (struct _vte_draw *draw,
 			const PangoFontDescription *fontdesc,
 			VteTerminalAntiAlias anti_alias)
 {
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->set_text_font != NULL);
-	draw->impl->set_text_font(draw, fontdesc, anti_alias);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->set_text_font != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_set_text_font (aa=%d)\n",
+			anti_alias);
+	draw->impl->set_text_font (draw, fontdesc, anti_alias);
 }
 
 int
-_vte_draw_get_text_width(struct _vte_draw *draw)
+_vte_draw_get_text_width (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, 1);
-	g_return_val_if_fail(draw->impl->get_text_width != NULL, 1);
-	return draw->impl->get_text_width(draw);
+	g_return_val_if_fail (draw->impl != NULL, 1);
+	g_return_val_if_fail (draw->impl->get_text_width != NULL, 1);
+	return draw->impl->get_text_width (draw);
 }
 
 int
-_vte_draw_get_text_height(struct _vte_draw *draw)
+_vte_draw_get_text_height (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, 1);
-	g_return_val_if_fail(draw->impl->get_text_height != NULL, 1);
-	return draw->impl->get_text_height(draw);
+	g_return_val_if_fail (draw->impl != NULL, 1);
+	g_return_val_if_fail (draw->impl->get_text_height != NULL, 1);
+	return draw->impl->get_text_height (draw);
 }
 
 int
-_vte_draw_get_text_ascent(struct _vte_draw *draw)
+_vte_draw_get_text_ascent (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, 1);
-	g_return_val_if_fail(draw->impl->get_text_ascent != NULL, 1);
-	return draw->impl->get_text_ascent(draw);
+	g_return_val_if_fail (draw->impl != NULL, 1);
+	g_return_val_if_fail (draw->impl->get_text_ascent != NULL, 1);
+	return draw->impl->get_text_ascent (draw);
 }
 
 int
-_vte_draw_get_char_width(struct _vte_draw *draw, gunichar c, int columns)
+_vte_draw_get_char_width (struct _vte_draw *draw, gunichar c, int columns)
 {
-	g_return_val_if_fail(draw->impl != NULL, 1);
-	g_return_val_if_fail(draw->impl->get_char_width != NULL, 1);
-	return draw->impl->get_char_width(draw, c, columns);
+	g_return_val_if_fail (draw->impl != NULL, 1);
+	g_return_val_if_fail (draw->impl->get_char_width != NULL, 1);
+	return draw->impl->get_char_width (draw, c, columns);
 }
 
 gboolean
-_vte_draw_get_using_fontconfig(struct _vte_draw *draw)
+_vte_draw_get_using_fontconfig (struct _vte_draw *draw)
 {
-	g_return_val_if_fail(draw->impl != NULL, 1);
-	g_return_val_if_fail(draw->impl->get_using_fontconfig != NULL, FALSE);
-	return draw->impl->get_using_fontconfig(draw);
+	g_return_val_if_fail (draw->impl != NULL, 1);
+	g_return_val_if_fail (draw->impl->get_using_fontconfig != NULL, FALSE);
+	return draw->impl->get_using_fontconfig (draw);
 }
 
 void
-_vte_draw_text(struct _vte_draw *draw,
+_vte_draw_text (struct _vte_draw *draw,
 	       struct _vte_draw_text_request *requests, gsize n_requests,
 	       GdkColor *color, guchar alpha)
 {
-	g_return_if_fail(draw->started == TRUE);
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->draw_text != NULL);
-	draw->impl->draw_text(draw, requests, n_requests, color, alpha);
+	g_return_if_fail (draw->started == TRUE);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->draw_text != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_text (len=%u, color= (%d,%d,%d,%d))\n",
+			n_requests, color->red, color->green, color->blue,
+			alpha);
+	draw->impl->draw_text (draw, requests, n_requests, color, alpha);
 }
 
 gboolean
-_vte_draw_char(struct _vte_draw *draw,
+_vte_draw_char (struct _vte_draw *draw,
 	       struct _vte_draw_text_request *request,
 	       GdkColor *color, guchar alpha)
 {
-	g_return_val_if_fail(draw->started == TRUE, FALSE);
-	g_return_val_if_fail(draw->impl != NULL, FALSE);
+	g_return_val_if_fail (draw->started == TRUE, FALSE);
+	g_return_val_if_fail (draw->impl != NULL, FALSE);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_char ('%c', color= (%d,%d,%d,%d))\n",
+			request->c,
+			color->red, color->green, color->blue,
+			alpha);
 	if (draw->impl->draw_char == NULL) {
-		draw->impl->draw_text(draw, request, 1, color, alpha);
+		draw->impl->draw_text (draw, request, 1, color, alpha);
 		return TRUE;
 	}
-	return draw->impl->draw_char(draw, request, color, alpha);
+	return draw->impl->draw_char (draw, request, color, alpha);
+}
+gboolean
+_vte_draw_has_char (struct _vte_draw *draw, gunichar c)
+{
+	_vte_debug_print (VTE_DEBUG_DRAW, "draw_has_char ('%c')\n", c);
+	return draw->impl->has_char (draw, c);
 }
 
 void
-_vte_draw_fill_rectangle(struct _vte_draw *draw,
+_vte_draw_fill_rectangle (struct _vte_draw *draw,
 			 gint x, gint y, gint width, gint height,
 			 GdkColor *color, guchar alpha)
 {
-	g_return_if_fail(draw->started == TRUE);
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->fill_rectangle != NULL);
-	draw->impl->fill_rectangle(draw, x, y, width, height, color, alpha);
+	g_return_if_fail (draw->started == TRUE);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->fill_rectangle != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_fill_rectangle (%d, %d, %d, %d, color= (%d,%d,%d,%d))\n",
+			x,y,width,height,
+			color->red, color->green, color->blue,
+			alpha);
+	draw->impl->fill_rectangle (draw, x, y, width, height, color, alpha);
 }
 
 void
-_vte_draw_draw_rectangle(struct _vte_draw *draw,
+_vte_draw_draw_rectangle (struct _vte_draw *draw,
 			 gint x, gint y, gint width, gint height,
 			 GdkColor *color, guchar alpha)
 {
-	g_return_if_fail(draw->started == TRUE);
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->draw_rectangle != NULL);
-	draw->impl->draw_rectangle(draw, x, y, width, height, color, alpha);
+	g_return_if_fail (draw->started == TRUE);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->draw_rectangle != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_rectangle (%d, %d, %d, %d, color= (%d,%d,%d,%d))\n",
+			x,y,width,height,
+			color->red, color->green, color->blue,
+			alpha);
+	draw->impl->draw_rectangle (draw, x, y, width, height, color, alpha);
 }
 
 void
-_vte_draw_set_scroll(struct _vte_draw *draw, gint x, gint y)
+_vte_draw_set_scroll (struct _vte_draw *draw, gint x, gint y)
 {
-	g_return_if_fail(draw->impl != NULL);
-	g_return_if_fail(draw->impl->set_scroll != NULL);
-	draw->impl->set_scroll(draw, x, y);
+	g_return_if_fail (draw->impl != NULL);
+	g_return_if_fail (draw->impl->set_scroll != NULL);
+	_vte_debug_print (VTE_DEBUG_DRAW,
+			"draw_set_scroll (%d, %d)\n",
+			x, y);
+	draw->impl->set_scroll (draw, x, y);
 }
diff --git a/src/vtedraw.h b/src/vtedraw.h
index bbff2f9a..91453cc3 100644
--- a/src/vtedraw.h
+++ b/src/vtedraw.h
@@ -86,6 +86,7 @@ struct _vte_draw_impl {
 	gboolean (*draw_char)(struct _vte_draw *,
 			      struct _vte_draw_text_request *,
 			      GdkColor *, guchar);
+	gboolean (*has_char)(struct _vte_draw *, gunichar);
 	void (*draw_rectangle)(struct _vte_draw *,
 			       gint, gint, gint, gint,
 			       GdkColor *, guchar);
@@ -153,6 +154,7 @@ void _vte_draw_text(struct _vte_draw *draw,
 gboolean _vte_draw_char(struct _vte_draw *draw,
 			struct _vte_draw_text_request *request,
 			GdkColor *color, guchar alpha);
+gboolean _vte_draw_has_char(struct _vte_draw *draw, gunichar c);
 void _vte_draw_fill_rectangle(struct _vte_draw *draw,
 			      gint x, gint y, gint width, gint height,
 			      GdkColor *color, guchar alpha);
diff --git a/src/vteft2.c b/src/vteft2.c
index ac9716d6..4d9a5ade 100644
--- a/src/vteft2.c
+++ b/src/vteft2.c
@@ -330,6 +330,21 @@ _vte_ft2_draw_char(struct _vte_draw *draw,
 	return FALSE;
 }
 
+static gboolean
+_vte_ft2_draw_has_char(struct _vte_draw *draw, gunichar c)
+{
+	struct _vte_ft2_data *data;
+
+	data = (struct _vte_ft2_data*) draw->impl_data;
+
+	if (data->cache != NULL) {
+		if (_vte_glyph_get(data->cache, c) != NULL) {
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
 static void
 _vte_ft2_draw_rectangle(struct _vte_draw *draw,
 			gint x, gint y, gint width, gint height,
@@ -402,6 +417,7 @@ const struct _vte_draw_impl _vte_draw_ft2 = {
 	_vte_ft2_get_using_fontconfig,
 	_vte_ft2_draw_text,
 	_vte_ft2_draw_char,
+	_vte_ft2_draw_has_char,
 	_vte_ft2_draw_rectangle,
 	_vte_ft2_fill_rectangle,
 	_vte_ft2_set_scroll,
diff --git a/src/vtegl.c b/src/vtegl.c
index 30ca2c4d..3d6ef782 100644
--- a/src/vtegl.c
+++ b/src/vtegl.c
@@ -518,6 +518,21 @@ _vte_gl_draw_char(struct _vte_draw *draw,
 	return FALSE;
 }
 
+static gboolean
+_vte_gl_draw_has_char(struct _vte_draw *draw, gunichar c)
+{
+	struct _vte_gl_data *data;
+
+	data = (struct _vte_gl_data*) draw->impl_data;
+
+	if (data->cache != NULL) {
+		if (_vte_glyph_get(data->cache, c) != NULL) {
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
 static void
 _vte_gl_rectangle(struct _vte_draw *draw,
 		  GLenum type,
@@ -590,6 +605,7 @@ const struct _vte_draw_impl _vte_draw_gl = {
 	_vte_gl_get_using_fontconfig,
 	_vte_gl_draw_text,
 	_vte_gl_draw_char,
+	_vte_gl_draw_has_char,
 	_vte_gl_draw_rectangle,
 	_vte_gl_fill_rectangle,
 	_vte_gl_set_scroll,
diff --git a/src/vtepango.c b/src/vtepango.c
index 7defba01..4b11c9a7 100644
--- a/src/vtepango.c
+++ b/src/vtepango.c
@@ -377,6 +377,12 @@ _vte_pango_draw_char(struct _vte_draw *draw,
 	return TRUE;
 }
 
+static gboolean
+_vte_pango_draw_has_char(struct _vte_draw *draw, gunichar c)
+{
+	return FALSE;
+}
+
 static void
 _vte_pango_draw_rectangle(struct _vte_draw *draw,
 			  gint x, gint y, gint width, gint height,
@@ -444,6 +450,7 @@ const struct _vte_draw_impl _vte_draw_pango = {
 	_vte_pango_get_using_fontconfig,
 	_vte_pango_draw_text,
 	_vte_pango_draw_char,
+	_vte_pango_draw_has_char,
 	_vte_pango_draw_rectangle,
 	_vte_pango_fill_rectangle,
 	_vte_pango_set_scroll,
diff --git a/src/vtepangox.c b/src/vtepangox.c
index 58ffedff..baa0c985 100644
--- a/src/vtepangox.c
+++ b/src/vtepangox.c
@@ -419,6 +419,13 @@ _vte_pango_x_draw_char(struct _vte_draw *draw,
 	return TRUE;
 }
 
+static gboolean
+_vte_pango_x_draw_has_char(struct _vte_draw *draw, gunichar c)
+{
+	return FALSE;
+}
+
+
 static void
 _vte_pango_x_draw_rectangle(struct _vte_draw *draw,
 			  gint x, gint y, gint width, gint height,
@@ -486,6 +493,7 @@ const struct _vte_draw_impl _vte_draw_pango_x = {
 	_vte_pango_x_get_using_fontconfig,
 	_vte_pango_x_draw_text,
 	_vte_pango_x_draw_char,
+	_vte_pango_x_draw_has_char,
 	_vte_pango_x_draw_rectangle,
 	_vte_pango_x_fill_rectangle,
 	_vte_pango_x_set_scroll,
diff --git a/src/vteskel.c b/src/vteskel.c
index 1bd3f640..1cb7a3fa 100644
--- a/src/vteskel.c
+++ b/src/vteskel.c
@@ -169,6 +169,12 @@ _vte_skel_draw_char(struct _vte_draw *draw,
 	return FALSE;
 }
 
+static gboolean
+_vte_skel_draw_has_char(struct _vte_draw *draw, gunichar c)
+{
+	return FALSE;
+}
+
 static void
 _vte_skel_draw_rectangle(struct _vte_draw *draw,
 			 gint x, gint y, gint width, gint height,
@@ -218,6 +224,7 @@ const struct _vte_draw_impl _vte_draw_skel = {
 	_vte_skel_get_using_fontconfig,
 	_vte_skel_draw_text,
 	_vte_skel_draw_char,
+	_vte_skel_draw_has_char,
 	_vte_skel_draw_rectangle,
 	_vte_skel_fill_rectangle,
 	_vte_skel_set_scroll,
diff --git a/src/vtexft.c b/src/vtexft.c
index a5782406..c4c10e43 100644
--- a/src/vtexft.c
+++ b/src/vtexft.c
@@ -862,6 +862,21 @@ _vte_xft_draw_char (struct _vte_draw *draw,
 	return FALSE;
 }
 
+static gboolean
+_vte_xft_draw_has_char (struct _vte_draw *draw, gunichar c)
+{
+	struct _vte_xft_data *data;
+
+	data = (struct _vte_xft_data*) draw->impl_data;
+	if (data->font != NULL &&
+			_vte_xft_font_for_char (data->font, c,
+				data->locked_fonts[data->cur_locked_fonts&1]) != NULL) {
+
+		return TRUE;
+	}
+	return FALSE;
+}
+
 static void
 _vte_xft_draw_rectangle (struct _vte_draw *draw,
 			gint x, gint y, gint width, gint height,
@@ -951,6 +966,7 @@ const struct _vte_draw_impl _vte_draw_xft = {
 	_vte_xft_get_using_fontconfig,
 	_vte_xft_draw_text,
 	_vte_xft_draw_char,
+	_vte_xft_draw_has_char,
 	_vte_xft_draw_rectangle,
 	_vte_xft_fill_rectangle,
 	_vte_xft_set_scroll,