[gtk+] Use a text render node in GskPangoRenderer

[Matthias Clasen <matthiasc src gnome org>]

commit a367d3494996b9b8e572b44618241cda166ab8c9
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Sep 1 12:42:21 2017 -0400

    Use a text render node in GskPangoRenderer
    
    This pushes the rendering closer to the place where we can
    insert a texture atlas for glyph caching.

 gtk/gskpango.c |  132 ++++++--------------------------------------------------
 1 files changed, 13 insertions(+), 119 deletions(-)
---
diff --git a/gtk/gskpango.c b/gtk/gskpango.c
index c602008..8d36dec 100644
--- a/gtk/gskpango.c
+++ b/gtk/gskpango.c
@@ -98,51 +98,6 @@ set_color (GskPangoRenderer *crenderer,
   gdk_cairo_set_source_rgba (cr, &rgba);
 }
 
-static gboolean
-_pango_cairo_font_install (PangoFont *font,
-                           cairo_t   *cr)
-{
-  cairo_scaled_font_t *scaled_font = pango_cairo_font_get_scaled_font ((PangoCairoFont *)font);
-
-  if (G_UNLIKELY (scaled_font == NULL || cairo_scaled_font_status (scaled_font) != CAIRO_STATUS_SUCCESS))
-    return FALSE;
-
-  cairo_set_scaled_font (cr, scaled_font);
-
-  return TRUE;
-}
-
-static void
-gsk_pango_renderer_draw_unknown_glyph (GskPangoRenderer *crenderer,
-                                       PangoFont        *font,
-                                       PangoGlyphInfo   *gi,
-                                       double            cx,
-                                       double            cy)
-{
-  cairo_t *cr;
-  PangoGlyphString *glyphs;
-
-  cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "DrawUnknownGlyph<%u>", 
gi->glyph);
-
-  gdk_cairo_set_source_rgba (cr, &crenderer->fg_color);
-
-  cairo_move_to (cr, cx, cy);
-
-  glyphs = pango_glyph_string_new ();
-  pango_glyph_string_set_size (glyphs, 1);
-  glyphs->glyphs[0] = *gi;
-
-  pango_cairo_show_glyph_string (cr, font, glyphs);
-
-  cairo_destroy (cr);
-}
-
-#ifndef STACK_BUFFER_SIZE
-#define STACK_BUFFER_SIZE (512 * sizeof (int))
-#endif
-
-#define STACK_ARRAY_LENGTH(T) (STACK_BUFFER_SIZE / sizeof(T))
-
 static void
 gsk_pango_renderer_show_text_glyphs (PangoRenderer        *renderer,
                                      const char           *text,
@@ -156,84 +111,23 @@ gsk_pango_renderer_show_text_glyphs (PangoRenderer        *renderer,
                                      int                   y)
 {
   GskPangoRenderer *crenderer = (GskPangoRenderer *) (renderer);
+  double base_x = (double)x / PANGO_SCALE;
+  double base_y = (double)y / PANGO_SCALE;
+  int x_offset, y_offset;
+  GskRenderNode *node;
+  char name[64];
 
-  cairo_t *cr;
-  int i, count;
-  int x_position = 0;
-  cairo_glyph_t *cairo_glyphs;
-  cairo_glyph_t stack_glyphs[STACK_ARRAY_LENGTH (cairo_glyph_t)];
-  double base_x = crenderer->x_offset + (double)x / PANGO_SCALE;
-  double base_y = crenderer->y_offset + (double)y / PANGO_SCALE;
-
-  cr = gtk_snapshot_append_cairo (crenderer->snapshot, &crenderer->bounds, "Text<%dglyphs>", 
glyphs->num_glyphs);
-
-  set_color (crenderer, PANGO_RENDER_PART_FOREGROUND, cr);
-
-  if (!_pango_cairo_font_install (font, cr))
-    {
-      for (i = 0; i < glyphs->num_glyphs; i++)
-        {
-          PangoGlyphInfo *gi = &glyphs->glyphs[i];
-
-          if (gi->glyph != PANGO_GLYPH_EMPTY)
-            {
-              double cx = base_x + (double)(x_position + gi->geometry.x_offset) / PANGO_SCALE;
-              double cy = gi->geometry.y_offset == 0 ?
-                          base_y :
-                          base_y + (double)(gi->geometry.y_offset) / PANGO_SCALE;
-
-              gsk_pango_renderer_draw_unknown_glyph (crenderer, font, gi, cx, cy);
-            }
-          x_position += gi->geometry.width;
-        }
-
-      goto done;
-    }
-
-  if (glyphs->num_glyphs > (int) G_N_ELEMENTS (stack_glyphs))
-    cairo_glyphs = g_new (cairo_glyph_t, glyphs->num_glyphs);
-  else
-    cairo_glyphs = stack_glyphs;
-
-  count = 0;
-  for (i = 0; i < glyphs->num_glyphs; i++)
-    {
-      PangoGlyphInfo *gi = &glyphs->glyphs[i];
-
-      if (gi->glyph != PANGO_GLYPH_EMPTY)
-        {
-          double cx = base_x + (double)(x_position + gi->geometry.x_offset) / PANGO_SCALE;
-          double cy = gi->geometry.y_offset == 0 ?
-                      base_y :
-                      base_y + (double)(gi->geometry.y_offset) / PANGO_SCALE;
-
-          if (gi->glyph & PANGO_GLYPH_UNKNOWN_FLAG)
-            gsk_pango_renderer_draw_unknown_glyph (crenderer, font, gi, cx, cy);
-          else
-            {
-              cairo_glyphs[count].index = gi->glyph;
-              cairo_glyphs[count].x = cx;
-              cairo_glyphs[count].y = cy;
-              count++;
-            }
-        }
-      x_position += gi->geometry.width;
-    }
+  gtk_snapshot_get_offset (crenderer->snapshot, &x_offset, &y_offset);
 
-  if (G_UNLIKELY (clusters))
-    cairo_show_text_glyphs (cr,
-                            text, text_len,
-                            cairo_glyphs, count,
-                            clusters, num_clusters,
-                            backward ? CAIRO_TEXT_CLUSTER_FLAG_BACKWARD : 0);
-  else
-    cairo_show_glyphs (cr, cairo_glyphs, count);
+  gtk_snapshot_offset (crenderer->snapshot, base_x, base_y);
 
-  if (cairo_glyphs != stack_glyphs)
-    g_free (cairo_glyphs);
+  node = gsk_text_node_new (font, glyphs, crenderer->fg_color, x_offset, y_offset, base_x, base_y);
+  snprintf (name, sizeof (name), "Glyphs<%d>", glyphs->num_glyphs);
+  gsk_render_node_set_name (node, name);
+  gtk_snapshot_append_node (crenderer->snapshot, node);
+  gsk_render_node_unref (node);
 
-done:
-  cairo_destroy (cr);
+  gtk_snapshot_offset (crenderer->snapshot, -base_x, -base_y);
 }
 
 static void