fc: Implement showing ignorables

We tell harfbuzz to preserve the ignorables in
shaping output, and use our glyph lookup to turn
them into unknown glyphs that we can shape into
custom hex boxes.

1 files changed, 39 insertions, 1 deletions

diff --git a/pango/pangofc-shape.c b/pango/pangofc-shape.c
index 27cdadf2..4e49dd05 100644
--- a/pango/pangofc-shape.c
+++ b/pango/pangofc-shape.c
@@ -29,6 +29,7 @@
 #include "pangofc-private.h"
 #include "pangofc-font-private.h"
 #include "pangofc-fontmap-private.h"
+#include "pango-impl-utils.h"
 #include <hb-ft.h>
 #include <hb-glib.h>
 
@@ -129,6 +130,15 @@ pango_hb_font_get_nominal_glyph (hb_font_t      *font,
 {
   PangoHbShapeContext *context = (PangoHbShapeContext *) font_data;
 
+  if (context->flags & PANGO_SHAPE_SHOW_IGNORABLES)
+    {
+      if (pango_get_ignorable (unicode))
+        {
+          *glyph = PANGO_GET_UNKNOWN_GLYPH (unicode);
+          return TRUE;
+        }
+    }
+
   if (hb_font_get_glyph (context->parent, unicode, 0, glyph))
     return TRUE;
 
@@ -181,6 +191,14 @@ pango_hb_font_get_glyph_advance (hb_font_t      *font,
 {
   PangoHbShapeContext *context = (PangoHbShapeContext *) font_data;
 
+  if (glyph & PANGO_GLYPH_UNKNOWN_FLAG)
+    {
+      PangoRectangle logical;
+
+      pango_font_get_glyph_extents (context->font, glyph, NULL, &logical);
+      return logical.width;
+    }
+
   return hb_font_get_glyph_h_advance (context->parent, glyph);
 }
 
@@ -193,6 +211,20 @@ pango_hb_font_get_glyph_extents (hb_font_t          *font,
 {
   PangoHbShapeContext *context = (PangoHbShapeContext *) font_data;
 
+  if (glyph & PANGO_GLYPH_UNKNOWN_FLAG)
+    {
+      PangoRectangle ink;
+
+      pango_font_get_glyph_extents (context->font, glyph, &ink, NULL);
+
+      extents->x_bearing = ink.x;
+      extents->y_bearing = ink.y;
+      extents->width     = ink.width;
+      extents->height    = ink.height;
+
+      return TRUE;
+    }
+
   return hb_font_get_glyph_extents (context->parent, glyph, extents);
 }
 
@@ -283,6 +315,7 @@ _pango_fc_shape (PangoFont           *font,
   PangoHbShapeContext context;
   hb_font_t *hb_font;
   hb_buffer_t *hb_buffer;
+  hb_buffer_flags_t hb_buffer_flags;
   hb_direction_t hb_direction;
   gboolean free_buffer;
   hb_glyph_info_t *hb_glyph;
@@ -306,6 +339,11 @@ _pango_fc_shape (PangoFont           *font,
   if (PANGO_GRAVITY_IS_IMPROPER (analysis->gravity))
     hb_direction = HB_DIRECTION_REVERSE (hb_direction);
 
+  hb_buffer_flags = HB_BUFFER_FLAG_BOT | HB_BUFFER_FLAG_EOT;
+
+  if (flags & PANGO_SHAPE_SHOW_IGNORABLES)
+    hb_buffer_flags |= HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES;
+
   /* setup buffer */
 
   hb_buffer_set_direction (hb_buffer, hb_direction);
@@ -314,7 +352,7 @@ _pango_fc_shape (PangoFont           *font,
 #if HB_VERSION_ATLEAST(1,0,3)
   hb_buffer_set_cluster_level (hb_buffer, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
 #endif
-  hb_buffer_set_flags (hb_buffer, HB_BUFFER_FLAG_BOT | HB_BUFFER_FLAG_EOT);
+  hb_buffer_set_flags (hb_buffer, hb_buffer_flags);
 
   hb_buffer_add_utf8 (hb_buffer, paragraph_text, paragraph_length, item_offset, item_length);