Support glyph string caching

To avoid redrawing the whole layout every time, we now support caching a single
glyph-string if it consists of only one run.

This should speed up drawing considerably. We still support drawing the whole
layout as fall-back method.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

diff --git a/src/console_char.c b/src/console_char.c
index 079117e..9a87df9 100644 (file)
--- a/src/console_char.c
+++ b/src/console_char.c
@@ -42,6 +42,7 @@ struct kmscon_char {
 enum glyph_type {
        GLYPH_NONE,
        GLYPH_LAYOUT,
+       GLYPH_STR,
 };
 
 struct kmscon_glyph {
@@ -54,6 +55,11 @@ struct kmscon_glyph {
                struct layout {
                        PangoLayout *layout;
                } layout;
+               struct str {
+                       PangoFont *font;
+                       PangoGlyphString *str;
+                       uint32_t ascent;
+               } str;
        } src;
 };
 
@@ -274,6 +280,10 @@ static void kmscon_glyph_reset(struct kmscon_glyph *glyph)
        case GLYPH_LAYOUT:
                g_object_unref(glyph->src.layout.layout);
                break;
+       case GLYPH_STR:
+               g_object_unref(glyph->src.str.font);
+               pango_glyph_string_free(glyph->src.str.str);
+               break;
        }
 
        glyph->type = GLYPH_NONE;
@@ -310,6 +320,9 @@ static int kmscon_glyph_set(struct kmscon_glyph *glyph,
                                                struct kmscon_font *font)
 {
        PangoLayout *layout;
+       PangoLayoutLine *line;
+       PangoGlyphItem *tmp;
+       PangoGlyphString *str;
 
        if (!glyph || !font)
                return -EINVAL;
@@ -319,10 +332,31 @@ static int kmscon_glyph_set(struct kmscon_glyph *glyph,
                return -EINVAL;
 
        pango_layout_set_text(layout, glyph->ch->buf, glyph->ch->len);
+       line = pango_layout_get_line_readonly(layout, 0);
+
+       if (!line || !line->runs || line->runs->next) {
+               kmscon_glyph_reset(glyph);
+               glyph->type = GLYPH_LAYOUT;
+               glyph->src.layout.layout = layout;
+       } else {
+               tmp = line->runs->data;
+               str = pango_glyph_string_copy(tmp->glyphs);
+               if (!str) {
+                       g_object_unref(layout);
+                       return -ENOMEM;
+               }
 
-       kmscon_glyph_reset(glyph);
-       glyph->type = GLYPH_LAYOUT;
-       glyph->src.layout.layout = layout;
+               kmscon_glyph_reset(glyph);
+               glyph->type = GLYPH_STR;
+
+               glyph->src.str.str = str;
+               glyph->src.str.font =
+                       g_object_ref(tmp->item->analysis.font);
+               glyph->src.str.ascent =
+                       PANGO_PIXELS_CEIL(pango_layout_get_baseline(layout));
+
+               g_object_unref(layout);
+       }
 
        return 0;
 }
@@ -492,13 +526,17 @@ int kmscon_font_draw(struct kmscon_font *font, const struct kmscon_char *ch,
        if (ret)
                return ret;
 
-       cairo_move_to(cr, x, y);
-
        switch (glyph->type) {
        case GLYPH_LAYOUT:
+               cairo_move_to(cr, x, y);
                pango_cairo_update_layout(cr, glyph->src.layout.layout);
                pango_cairo_show_layout(cr, glyph->src.layout.layout);
                break;
+       case GLYPH_STR:
+               cairo_move_to(cr, x, y + glyph->src.str.ascent);
+               pango_cairo_show_glyph_string(cr, glyph->src.str.font,
+                                                       glyph->src.str.str);
+               break;
        default:
                ret = -EFAULT;
                break;