glyphcache_max_memsize = 256*1024 -- 256kB glyphcache glyphcache_current_memsize = 0 glyphcache = {} glyphcache_max_age = 4096 function glyphCacheClaim(size) if(size > glyphcache_max_memsize) then error("too much memory claimed") return false end while glyphcache_current_memsize + size > glyphcache_max_memsize do for k, _ in pairs(glyphcache) do if glyphcache[k].age > 0 then glyphcache[k].age = glyphcache[k].age - 1 else glyphcache_current_memsize = glyphcache_current_memsize - glyphcache[k].size glyphcache[k].glyph.bb:free() glyphcache[k] = nil end end end glyphcache_current_memsize = glyphcache_current_memsize + size return true end function getGlyph(face, charcode) local hash = glyphCacheHash(face.hash, charcode) if glyphcache[hash] == nil then local glyph = face.ftface:renderGlyph(charcode) local size = glyph.bb:getWidth() * glyph.bb:getHeight() / 2 + 32 glyphCacheClaim(size); glyphcache[hash] = { age = glyphcache_max_age, size = size, g = glyph } else glyphcache[hash].age = glyphcache_max_age end return glyphcache[hash].g end function glyphCacheHash(face, charcode) return face..'_'..charcode; end function clearGlyphCache() glyphcache = {} end function renderUtf8Text(buffer, x, y, face, text, kerning) if text == nil then print("# renderUtf8Text called without text"); return end -- may still need more adaptive pen placement when kerning, -- see: http://freetype.org/freetype2/docs/glyphs/glyphs-4.html local pen_x = 0 local prevcharcode = 0 for uchar in string.gfind(text, "([%z\1-\127\194-\244][\128-\191]*)") do if pen_x < buffer:getWidth() then local charcode = util.utf8charcode(uchar) local glyph = getGlyph(face, charcode) if kerning and prevcharcode then local kern = face.ftface:getKerning(prevcharcode, charcode) pen_x = pen_x + kern buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight()) else buffer:blitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight()) end pen_x = pen_x + glyph.ax prevcharcode = charcode end end return pen_x end