lite-xl/data/core/ime.lua

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2022-10-16 01:58:51 +02:00
local core = require "core"
local ime = { }
function ime.reset()
ime.editing = false
ime.last_location = { x = 0, y = 0, w = 0, h = 0 }
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end
---Convert from utf-8 offset and length (from SDL) to byte offsets
---@param text string @Textediting string
---@param start integer @0-based utf-8 offset of the starting position of the selection
---@param length integer @Size of the utf-8 length of the selection
function ime.ingest(text, start, length)
if #text == 0 then
-- finished textediting
ime.reset()
return "", 0, 0
end
ime.editing = true
if start < 0 then
-- we assume no selection and caret at the end
return text, #text, 0
end
-- start is 0-based, so we use start + 1
local start_byte = utf8.offset(text, start + 1)
if not start_byte then
-- bad start offset
-- we assume it meant the last byte of the text
start_byte = #text
else
start_byte = math.min(start_byte - 1, #text)
end
if length < 0 then
-- caret only
return text, start_byte, 0
end
local end_byte = utf8.offset(text, start + length + 1)
if not end_byte or end_byte - 1 < start_byte then
-- bad length, assume caret only
return text, start_byte, 0
end
end_byte = math.min(end_byte - 1, #text)
return text, start_byte, end_byte - start_byte
end
---Forward the given textediting SDL event data to Views.
---@param text string @Textediting string
---@param start integer @0-based utf-8 offset of the starting position of the selection
---@param length integer @Size of the utf-8 length of the selection
function ime.on_text_editing(text, start, length, ...)
if ime.editing or #text > 0 then
core.root_view:on_ime_text_editing(ime.ingest(text, start, length, ...))
end
end
---Stop IME composition.
---Might not completely work on every platform.
function ime.stop()
if ime.editing then
-- SDL_ClearComposition for now doesn't work everywhere
system.clear_ime()
ime.on_text_editing("", 0, 0)
end
end
---Set the bounding box of the text pertaining the IME.
---The IME will draw its interface based on this info.
---@param x number
---@param y number
---@param w number
---@param h number
function ime.set_location(x, y, w, h)
if not ime.last_location or
ime.last_location.x ~= x or
ime.last_location.y ~= y or
ime.last_location.w ~= w or
ime.last_location.h ~= h
then
ime.last_location.x, ime.last_location.y, ime.last_location.w, ime.last_location.h = x, y, w, h
system.set_text_input_rect(x, y, w, h)
end
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end
ime.reset()
return ime