[pango/better-hyphens: 5/5] Make hyphen insertion more efficient

[Matthias Clasen <matthiasc src gnome org>]

commit 3973a69c697649ea6fb6de97352a59c7daca7eab
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Jul 15 23:48:34 2019 -0400

    Make hyphen insertion more efficient
    
    We can avoid copying the paragraph text,
    and just pass a flag down to tell the
    shaping code to append a hyphen to the buffer
    that we pass to hb_shape.

 pango/pango-item.h    | 12 +++++++++++-
 pango/pango-layout.c  | 53 ++++++++++++++++-----------------------------------
 pango/pangofc-shape.c |  2 ++
 3 files changed, 29 insertions(+), 38 deletions(-)
---
diff --git a/pango/pango-item.h b/pango/pango-item.h
index 55be4c67..95bcd35e 100644
--- a/pango/pango-item.h
+++ b/pango/pango-item.h
@@ -50,6 +50,16 @@ typedef struct _PangoItem PangoItem;
  */
 #define PANGO_ANALYSIS_FLAG_IS_ELLIPSIS (1 << 1)
 
+/**
+ * PANGO_ANALYSIS_FLAG_ADD_HYPHEN:
+ *
+ * This flag tells Pango to add a hyphen at the end of the
+ * run during shaping.
+ *
+ * Since: 1.44
+ */
+#define PANGO_ANALYSIS_FLAG_NEED_HYPHEN (1 << 2)
+
 /**
  * PangoAnalysis:
  * @shape_engine: the engine for doing rendering-system-dependent processing.
@@ -57,7 +67,7 @@ typedef struct _PangoItem PangoItem;
  * @font: the font for this segment.
  * @level: the bidirectional level for this segment.
  * @gravity: the glyph orientation for this segment (A #PangoGravity).
- * @flags: boolean flags for this segment (currently only one) (Since: 1.16).
+ * @flags: boolean flags for this segment (Since: 1.16).
  * @script: the detected script for this segment (A #PangoScript) (Since: 1.18).
  * @language: the detected language for this segment.
  * @extra_attrs: extra attributes for this segment.
diff --git a/pango/pango-layout.c b/pango/pango-layout.c
index df2092fd..c6ce6472 100644
--- a/pango/pango-layout.c
+++ b/pango/pango-layout.c
@@ -3310,8 +3310,7 @@ should_ellipsize_current_line (PangoLayout    *layout,
 static PangoGlyphString *
 shape_run (PangoLayoutLine *line,
           ParaBreakState  *state,
-          PangoItem       *item,
-           gboolean         with_hyphen)
+          PangoItem       *item)
 {
   PangoLayout *layout = line->layout;
   PangoGlyphString *glyphs = pango_glyph_string_new ();
@@ -3326,28 +3325,9 @@ shape_run (PangoLayoutLine *line,
                            glyphs);
       else
         {
-
-          if (with_hyphen)
-            {
-              GString *s = g_string_new ("");
-
-              g_string_append_len (s, layout->text, item->offset + item->length - 2);
-              g_string_append (s, "-");
-              g_string_append_len (s, layout->text + item->offset + item->length, layout->length - 
(item->offset + item->length));
-
-              pango_shape_full (s->str + item->offset, item->length - 1,
-                                s->str, s->len,
-                                &item->analysis, glyphs);
-
-              g_string_free (s, TRUE);
-
-            }
-          else
-            {
-              pango_shape_full (layout->text + item->offset, item->length,
-                                layout->text, layout->length,
-                                &item->analysis, glyphs);
-            }
+          pango_shape_full (layout->text + item->offset, item->length,
+                            layout->text, layout->length,
+                            &item->analysis, glyphs);
         }
 
       if (state->properties.letter_spacing)
@@ -3378,8 +3358,7 @@ static void
 insert_run (PangoLayoutLine *line,
            ParaBreakState  *state,
            PangoItem       *run_item,
-           gboolean         last_run,
-            gboolean         with_hyphen)
+           gboolean         last_run)
 {
   PangoLayoutRun *run = g_slice_new (PangoLayoutRun);
 
@@ -3388,7 +3367,7 @@ insert_run (PangoLayoutLine *line,
   if (last_run && state->log_widths_offset == 0)
     run->glyphs = state->glyphs;
   else
-    run->glyphs = shape_run (line, state, run_item, with_hyphen);
+    run->glyphs = shape_run (line, state, run_item);
 
   if (last_run)
     {
@@ -3602,7 +3581,7 @@ process_item (PangoLayout     *layout,
   if (!state->glyphs)
     {
       pango_layout_get_item_properties (item, &state->properties);
-      state->glyphs = shape_run (line, state, item, FALSE);
+      state->glyphs = shape_run (line, state, item);
 
       state->log_widths = NULL;
       state->need_hyphen = NULL;
@@ -3615,7 +3594,7 @@ process_item (PangoLayout     *layout,
       g_utf8_get_char (layout->text + item->offset) == LINE_SEPARATOR &&
       !should_ellipsize_current_line (layout, state))
     {
-      insert_run (line, state, item, TRUE, FALSE);
+      insert_run (line, state, item, TRUE);
       state->log_widths_offset += item->num_chars;
 
       return BREAK_LINE_SEPARATOR;
@@ -3623,7 +3602,7 @@ process_item (PangoLayout     *layout,
 
   if (state->remaining_width < 0 && !no_break_at_end)  /* Wrapping off */
     {
-      insert_run (line, state, item, TRUE, FALSE);
+      insert_run (line, state, item, TRUE);
 
       return BREAK_ALL_FIT;
     }
@@ -3644,7 +3623,7 @@ process_item (PangoLayout     *layout,
     {
       state->remaining_width -= width;
       state->remaining_width = MAX (state->remaining_width, 0);
-      insert_run (line, state, item, TRUE, FALSE);
+      insert_run (line, state, item, TRUE);
 
       return BREAK_ALL_FIT;
     }
@@ -3719,9 +3698,9 @@ process_item (PangoLayout     *layout,
 
          if (break_num_chars == item->num_chars)
            {
-              gboolean hyphen;
-              hyphen = break_needs_hyphen (layout, state, break_num_chars);
-             insert_run (line, state, item, TRUE, hyphen);
+              if (break_needs_hyphen (layout, state, break_num_chars))
+                item->analysis.flags |= PANGO_ANALYSIS_FLAG_NEED_HYPHEN;
+             insert_run (line, state, item, TRUE);
 
              return BREAK_ALL_FIT;
            }
@@ -3732,16 +3711,16 @@ process_item (PangoLayout     *layout,
          else
            {
              PangoItem *new_item;
-              gboolean hyphen;
 
              length = g_utf8_offset_to_pointer (layout->text + item->offset, break_num_chars) - 
(layout->text + item->offset);
 
              new_item = pango_item_split (item, length, break_num_chars);
 
-              hyphen = break_needs_hyphen (layout, state, break_num_chars);
+              if (break_needs_hyphen (layout, state, break_num_chars))
+                new_item->analysis.flags |= PANGO_ANALYSIS_FLAG_NEED_HYPHEN;
              /* Add the width back, to the line, reshape, subtract the new width */
              state->remaining_width += break_width;
-             insert_run (line, state, new_item, FALSE, hyphen);
+             insert_run (line, state, new_item, FALSE);
              break_width = pango_glyph_string_get_width (((PangoGlyphItem *)(line->runs->data))->glyphs);
              state->remaining_width -= break_width;
 
diff --git a/pango/pangofc-shape.c b/pango/pangofc-shape.c
index 9bedd28a..8bbd4c18 100644
--- a/pango/pangofc-shape.c
+++ b/pango/pangofc-shape.c
@@ -459,6 +459,8 @@ _pango_fc_shape (PangoFont           *font,
   hb_buffer_set_flags (hb_buffer, HB_BUFFER_FLAG_BOT | HB_BUFFER_FLAG_EOT);
 
   hb_buffer_add_utf8 (hb_buffer, paragraph_text, paragraph_length, item_offset, item_length);
+  if (analysis->flags & PANGO_ANALYSIS_FLAG_NEED_HYPHEN)
+    hb_buffer_add (hb_buffer, '-', item_length);
 
   pango_font_get_features (font, features, 32, &num_features);
   apply_extra_attributes (analysis->extra_attrs, features, 32, &num_features);