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koreader/frontend/ui/widget/textboxwidget.lua
2014-01-22 17:26:14 +08:00

276 lines
7.1 KiB
Lua

local Widget = require("ui/widget/widget")
local RenderText = require("ui/rendertext")
local Screen = require("ui/screen")
local Geom = require("ui/geometry")
-- TODO: rename string:gsplit definition
--[[
A TextWidget that handles long text wrapping
--]]
local TextBoxWidget = Widget:new{
text = nil,
face = nil,
bold = nil,
bgcolor = 0.0, -- [0.0, 1.0]
fgcolor = 1.0, -- [0.0, 1.0]
width = 400, -- in pixels
height = nil,
first_line = 1,
virtual_line = 1, -- used by scroll bar
line_height = 0.3, -- in em
v_list = nil,
_bb = nil,
_length = 0,
}
function TextBoxWidget:init()
local v_list = nil
if self.height then
v_list = self:_getCurrentVerticalList()
else
v_list = self:_getVerticalList()
end
self:_render(v_list)
end
function TextBoxWidget:_wrapGreedyAlg(h_list)
local cur_line_width = 0
local cur_line = {}
local v_list = {}
for k,w in ipairs(h_list) do
cur_line_width = cur_line_width + w.width
if w.word == "\n" then
if cur_line_width > 0 then
-- hard line break
table.insert(v_list, cur_line)
cur_line = {}
cur_line_width = 0
end
elseif cur_line_width > self.width then
-- wrap to next line
table.insert(v_list, cur_line)
cur_line = {}
cur_line_width = w.width
table.insert(cur_line, w)
else
table.insert(cur_line, w)
end
end
-- handle last line
table.insert(v_list, cur_line)
return v_list
end
--[[
Lua doesn't have a string.split() function and most of the time
you don't really need it because string.gmatch() is enough.
However string.gmatch() has one significant disadvantage for me:
You can't split a string while matching both the delimited
strings and the delimiters themselves without tracking positions
and substrings. The string.gsplit() function below takes care of
this problem.
Author: Peter Odding
License: MIT/X11
Source: http://snippets.luacode.org/snippets/String_splitting_130
--]]
function string:gsplit(pattern, capture)
pattern = pattern and tostring(pattern) or '%s+'
if (''):find(pattern) then
error('pattern matches empty string!', 2)
end
return coroutine.wrap(function()
local index = 1
repeat
local first, last = self:find(pattern, index)
if first and last then
if index < first then
coroutine.yield(self:sub(index, first - 1))
end
if capture then
coroutine.yield(self:sub(first, last))
end
index = last + 1
else
if index <= #self then
coroutine.yield(self:sub(index))
end
break
end
until index > #self
end)
end
function TextBoxWidget:_getVerticalList(alg)
if self.vertical_list then
return self.vertical_list
end
-- build horizontal list
local h_list = {}
local line_count = 0
for line in self.text:gsplit("\n", true) do
for words in line:gmatch("[\32-\127\192-\255]+[\128-\191]*") do
for word in words:gsplit("%s+", true) do
for w in word:gsplit("%p+", true) do
local word_box = {}
word_box.word = w
word_box.width = RenderText:sizeUtf8Text(0, Screen:getWidth(), self.face, w, true, self.bold).x
table.insert(h_list, word_box)
end
end
end
if line:sub(-1) == "\n" then table.insert(h_list, {word = '\n', width = 0}) end
end
-- @TODO check alg here 25.04 2012 (houqp)
-- @TODO replace greedy algorithm with K&P algorithm 25.04 2012 (houqp)
self.vertical_list = self:_wrapGreedyAlg(h_list)
return self.vertical_list
end
function TextBoxWidget:_getCurrentVerticalList()
local line_height = (1 + self.line_height) * self.face.size
local v_list = self:_getVerticalList()
local current_v_list = {}
local height = 0
for i = self.first_line, #v_list do
if height < self.height - line_height then
table.insert(current_v_list, v_list[i])
height = height + line_height
else
break
end
end
return current_v_list
end
function TextBoxWidget:_getPreviousVerticalList()
local line_height = (1 + self.line_height) * self.face.size
local v_list = self:_getVerticalList()
local previous_v_list = {}
local height = 0
if self.first_line == 1 then
return self:_getCurrentVerticalList()
end
self.virtual_line = self.first_line
for i = self.first_line - 1, 1, -1 do
if height < self.height - line_height then
table.insert(previous_v_list, 1, v_list[i])
height = height + line_height
self.virtual_line = self.virtual_line - 1
else
break
end
end
for i = self.first_line, #v_list do
if height < self.height - line_height then
table.insert(previous_v_list, v_list[i])
height = height + line_height
else
break
end
end
if self.first_line > #previous_v_list then
self.first_line = self.first_line - #previous_v_list
else
self.first_line = 1
end
return previous_v_list
end
function TextBoxWidget:_getNextVerticalList()
local line_height = (1 + self.line_height) * self.face.size
local v_list = self:_getVerticalList()
local current_v_list = self:_getCurrentVerticalList()
local next_v_list = {}
local height = 0
if self.first_line + #current_v_list > #v_list then
return current_v_list
end
self.virtual_line = self.first_line
for i = self.first_line + #current_v_list, #v_list do
if height < self.height - line_height then
table.insert(next_v_list, v_list[i])
height = height + line_height
self.virtual_line = self.virtual_line + 1
else
break
end
end
self.first_line = self.first_line + #current_v_list
return next_v_list
end
function TextBoxWidget:_render(v_list)
local font_height = self.face.size
local line_height_px = self.line_height * font_height
local space_w = RenderText:sizeUtf8Text(0, Screen:getWidth(), self.face, " ", true).x
local h = (font_height + line_height_px) * #v_list
self._bb = Blitbuffer.new(self.width, h)
local y = font_height
local pen_x = 0
for _,l in ipairs(v_list) do
pen_x = 0
for _,w in ipairs(l) do
--@TODO Don't use kerning for monospaced fonts. (houqp)
-- refert to cb25029dddc42693cc7aaefbe47e9bd3b7e1a750 in master tree
RenderText:renderUtf8Text(self._bb, pen_x, y, self.face, w.word, true, self.bold, self.bgcolor, self.fgcolor)
pen_x = pen_x + w.width
end
y = y + line_height_px + font_height
end
-- -- if text is shorter than one line, shrink to text's width
-- if #v_list == 1 then
-- self.width = pen_x
-- end
end
function TextBoxWidget:getVirtualLineNum()
return self.virtual_line
end
function TextBoxWidget:getAllLineCount()
local v_list = self:_getVerticalList()
return #v_list
end
function TextBoxWidget:getVisLineCount()
local line_height = (1 + self.line_height) * self.face.size
return math.floor(self.height / line_height)
end
function TextBoxWidget:scrollDown()
local next_v_list = self:_getNextVerticalList()
self:free()
self:_render(next_v_list)
end
function TextBoxWidget:scrollUp()
local previous_v_list = self:_getPreviousVerticalList()
self:free()
self:_render(previous_v_list)
end
function TextBoxWidget:getSize()
if self.width and self.height then
return Geom:new{ w = self.width, h = self.height}
else
return Geom:new{ w = self.width, h = self._bb:getHeight()}
end
end
function TextBoxWidget:paintTo(bb, x, y)
bb:blitFrom(self._bb, x, y, 0, 0, self.width, self._bb:getHeight())
end
function TextBoxWidget:free()
if self._bb then
self._bb:free()
self._bb = nil
end
end
return TextBoxWidget