mirror of
https://github.com/koreader/koreader
synced 2024-11-10 01:10:34 +00:00
7210fb478d
* Pickup the eponymous blitting performance tweaks from koreader/koreader-base#878 * Cleanup BitOpts usage (require & cache) * Unify oddness checks (MOD -> AND) * Enforce the native Portrait orientation on Kobo (except @ 16bpp, i.e., KSM w/ 8bpp swap disabled), to allow for faster blitting when unrotted. * Switch CRe BB to 32BPP on color screens * Minor cleanups
77 lines
1.5 KiB
Lua
77 lines
1.5 KiB
Lua
--[[--
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Simple math helper functions
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local bit = require("bit")
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local Math = {}
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local band = bit.band
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function Math.roundAwayFromZero(num)
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if num > 0 then
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return math.ceil(num)
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else
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return math.floor(num)
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end
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end
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function Math.round(num)
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return math.floor(num + 0.5)
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end
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function Math.oddEven(number)
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if band(number, 1) == 1 then
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return "odd"
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else
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return "even"
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end
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end
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local function tmin_max(tab, func, op)
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if #tab == 0 then return nil, nil end
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local index, value = 1, tab[1]
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for i = 2, #tab do
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if func then
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if func(value, tab[i]) then
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index, value = i, tab[i]
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end
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elseif op == "min" then
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if value > tab[i] then
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index, value = i, tab[i]
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end
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elseif op == "max" then
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if value < tab[i] then
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index, value = i, tab[i]
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end
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end
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end
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return index, value
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end
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--[[--
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Returns the minimum element of a table.
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The optional argument func specifies a one-argument ordering function.
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@tparam table tab
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@tparam func func
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@treturn dynamic minimum element of a table
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]]
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function Math.tmin(tab, func)
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return tmin_max(tab, func, "min")
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end
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--[[--
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Returns the maximum element of a table.
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The optional argument func specifies a one-argument ordering function.
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@tparam table tab
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@tparam func func
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@treturn dynamic maximum element of a table
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]]
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function Math.tmax(tab, func)
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return tmin_max(tab, func, "max")
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end
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return Math
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