mirror of
https://github.com/koreader/koreader
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01f045e7f9
I found it will be especially helpful to cache glyph separately so that glyph caches won't be washed out by a single page cache.
118 lines
3.5 KiB
Lua
118 lines
3.5 KiB
Lua
require "cache"
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--[[
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TODO: all these functions should probably be methods on Face objects
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]]--
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GlyphCache = Cache:new{
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max_memsize = 512*1024,
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current_memsize = 0,
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cache = {},
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-- this will hold the LRU order of the cache
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cache_order = {}
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}
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function getGlyph(face, charcode, bgcolor, fgcolor)
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if bgcolor == nil then bgcolor = 0.0 end
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if fgcolor == nil then fgcolor = 1.0 end
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local hash = "glyph|"..face.hash.."|"..charcode.."|"..bgcolor.."|"..fgcolor
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local glyph = GlyphCache:check(hash)
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if glyph then
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-- cache hit
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return glyph[1]
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end
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local rendered_glyph = face.ftface:renderGlyph(charcode, bgcolor, fgcolor)
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if not rendered_glyph then
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DEBUG("error rendering glyph (charcode=", charcode, ") for face", face)
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return
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end
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glyph = CacheItem:new{rendered_glyph}
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glyph.size = glyph[1].bb:getWidth() * glyph[1].bb:getHeight() / 2 + 32
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GlyphCache:insert(hash, glyph)
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return rendered_glyph
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end
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function getSubTextByWidth(text, face, width, kerning)
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local pen_x = 0
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local prevcharcode = 0
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local char_list = {}
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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 < width then
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local charcode = util.utf8charcode(uchar)
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local glyph = getGlyph(face, charcode)
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if kerning and prevcharcode then
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local kern = face.ftface:getKerning(prevcharcode, charcode)
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pen_x = pen_x + kern
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end
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pen_x = pen_x + glyph.ax
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if pen_x <= width then
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prevcharcode = charcode
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table.insert(char_list, uchar)
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else
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break
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end
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end
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end
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return table.concat(char_list)
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end
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function sizeUtf8Text(x, width, face, text, kerning)
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if not text then
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DEBUG("sizeUtf8Text 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 pen_y_top = 0
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local pen_y_bottom = 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 < (width - x) then
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local charcode = util.utf8charcode(uchar)
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local glyph = getGlyph(face, charcode)
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if kerning and (prevcharcode ~= 0) then
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pen_x = pen_x + face.ftface:getKerning(prevcharcode, charcode)
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end
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pen_x = pen_x + glyph.ax
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pen_y_top = math.max(pen_y_top, glyph.t)
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pen_y_bottom = math.max(pen_y_bottom, glyph.bb:getHeight() - glyph.t)
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--DEBUG("ax:"..glyph.ax.." t:"..glyph.t.." r:"..glyph.r.." h:"..glyph.bb:getHeight().." w:"..glyph.bb:getWidth().." yt:"..pen_y_top.." yb:"..pen_y_bottom)
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prevcharcode = charcode
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end -- if pen_x < (width - x)
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end -- for uchar
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return { x = pen_x, y_top = pen_y_top, y_bottom = pen_y_bottom}
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end
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function renderUtf8Text(buffer, x, y, face, text, kerning, bgcolor, fgcolor)
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if not text then
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DEBUG("renderUtf8Text called without text");
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return 0
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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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local buffer_width = buffer:getWidth()
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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_width then
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local charcode = util.utf8charcode(uchar)
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local glyph = getGlyph(face, charcode, bgcolor, fgcolor)
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if kerning and (prevcharcode ~= 0) then
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pen_x = pen_x + face.ftface:getKerning(prevcharcode, charcode)
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end
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buffer:addblitFrom(
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glyph.bb,
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x + pen_x + glyph.l, y - glyph.t,
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0, 0,
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glyph.bb:getWidth(), glyph.bb:getHeight(), 1)
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pen_x = pen_x + glyph.ax
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prevcharcode = charcode
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end -- if pen_x < buffer_width
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end -- for uchar
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return pen_x
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end
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