BLF: FreeType Optional Caching

Implementation of the FreeType 2 cache subsystem, which limits the
number of concurrently-opened FT_Face and FT_Size objects, as well as
caching information like character maps to speed up glyph id lookups.
This time with the option of opening FontBLFs that are not cached.

See D15686 for more details.

Differential Revision: https://developer.blender.org/D15686

Reviewed by Brecht Van Lommel

1 files changed, 12 insertions, 3 deletions

diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index f938174f92e..fdf9883ee8f 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -103,6 +103,7 @@ static GlyphCacheBLF *blf_glyph_cache_new(FontBLF *font)
   }
   else {
     /* Font does not have a face or does not contain "0" so use CSS fallback of 1/2 of em. */
+    blf_ensure_size(font);
     gc->fixed_width = (int)((font->ft_size->metrics.height / 2) >> 6);
   }
   if (gc->fixed_width < 1) {
@@ -570,6 +571,11 @@ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode
     return glyph_index;
   }
 
+  /* Only fonts managed by the cache can fallback. */
+  if (!((*font)->flags & BLF_CACHED)) {
+    return 0;
+  }
+
   /* Not found in main font, so look in the others. */
   FontBLF *last_resort = NULL;
   int coverage_bit = blf_charcode_to_coverage_bit(charcode);
@@ -787,8 +793,8 @@ static bool blf_glyph_transform_weight(FT_GlyphSlot glyph, float factor, bool mo
 {
   if (glyph->format == FT_GLYPH_FORMAT_OUTLINE) {
     /* Fake bold if the font does not have this variable axis. */
-    const FT_Pos average_width = FT_MulFix(glyph->face->units_per_EM,
-                                           glyph->face->size->metrics.x_scale);
+    const FontBLF *font = (FontBLF *)glyph->face->generic.data;
+    const FT_Pos average_width = font->ft_size->metrics.height;
     FT_Pos change = (FT_Pos)((float)average_width * factor * 0.1f);
     FT_Outline_EmboldenXY(&glyph->outline, change, change / 2);
     if (monospaced) {
@@ -847,7 +853,8 @@ static bool blf_glyph_transform_width(FT_GlyphSlot glyph, float factor)
 static bool blf_glyph_transform_spacing(FT_GlyphSlot glyph, float factor)
 {
   if (glyph->advance.x > 0) {
-    const long int size = glyph->face->size->metrics.height;
+    const FontBLF *font = (FontBLF *)glyph->face->generic.data;
+    const long int size = font->ft_size->metrics.height;
     glyph->advance.x += (FT_Pos)(factor * (float)size / 6.0f);
     return true;
   }
@@ -899,6 +906,8 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font,
     blf_font_size(glyph_font, settings_font->size, settings_font->dpi);
   }
 
+  blf_ensure_size(glyph_font);
+
   /* We need to keep track if changes are still needed. */
   bool weight_done = false;
   bool slant_done = false;