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koreader/rendertext.lua

55 lines
1.5 KiB
Lua

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] = nil
end
end
end
glyphcache_current_memsize = glyphcache_current_memsize + size
return true
end
function getglyph(face, facehash, charcode)
local hash = glyphcachehash(facehash, charcode)
if glyphcache[hash] == nil then
print("render glyph")
local glyph = face:renderGlyph(charcode)
local size = glyph.bb:getWidth() * glyph.bb:getHeight() / 2 + 32
print("cache claim")
glyphcacheclaim(size);
glyphcache[hash] = {
age = glyphcache_max_age,
size = size,
g = glyph
}
end
return glyphcache[hash].g
end
function glyphcachehash(face, charcode)
return face..'_'..charcode;
end
function clearglyphcache()
glyphcache = {}
end
function renderUtf8Text(x, y, face, facehash, text)
local pen_x = 0
for uchar in string.gfind(text, "([%z\1-\127\194-\244][\128-\191]*)") do
local glyph = getglyph(face, facehash, util.utf8charcode(uchar))
fb:blitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
pen_x = pen_x + glyph.ax
end
end