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