koreader/frontend/apps/reader/modules/readerlink.lua

local InputContainer = require("ui/widget/container/inputcontainer")
local GestureRange = require("ui/gesturerange")
local LinkBox = require("ui/widget/linkbox")
local UIManager = require("ui/uimanager")
local Geom = require("ui/geometry")
local Screen = require("device").screen
local Device = require("device")
local Event = require("ui/event")
local DEBUG = require("dbg")
local _ = require("gettext")

local ReaderLink = InputContainer:new{
    link_states = {}
}

function ReaderLink:init()
    if Device:isTouchDevice() then
        self:initGesListener()
    end
    self.ui:registerPostInitCallback(function()
        self.ui.menu:registerToMainMenu(self)
    end)
end

function ReaderLink:onReadSettings(config)
    -- called when loading new document
    self.link_states = {}
end

function ReaderLink:initGesListener()
    if Device:isTouchDevice() then
        self.ges_events = {
            Tap = {
                GestureRange:new{
                    ges = "tap",
                    range = Geom:new{
                        x = 0, y = 0,
                        w = Screen:getWidth(),
                        h = Screen:getHeight()
                    }
                }
            },
            Swipe = {
                GestureRange:new{
                    ges = "swipe",
                    range = Geom:new{
                        x = 0, y = 0,
                        w = Screen:getWidth(),
                        h = Screen:getHeight(),
                    }
                }
            },
        }
    end
end

function ReaderLink:addToMainMenu(tab_item_table)
    -- insert table to main reader menu
    table.insert(tab_item_table.navi, {
        text = _("Follow links"),
        checked_func = function()
            return G_reader_settings:readSetting("follow_links") ~= false
        end,
        callback = function()
            local follow_links = G_reader_settings:readSetting("follow_links")
            if follow_links == nil then follow_links = true end
            G_reader_settings:saveSetting("follow_links", not follow_links)
        end
    })
end

function ReaderLink:onSetDimensions(dimen)
    -- update listening according to new screen dimen
    if Device:isTouchDevice() then
        self:initGesListener()
    end
end

function ReaderLink:onTap(arg, ges)
    if G_reader_settings:readSetting("follow_links") == false then return end
    if self.ui.document.info.has_pages then
        local pos = self.view:screenToPageTransform(ges.pos)
        if pos then
            -- link box in native page
            local link, lbox = self.ui.document:getLinkFromPosition(pos.page, pos)
            if link and lbox then
                -- screen box that holds the link
                local sbox = self.view:pageToScreenTransform(pos.page,
                    self.ui.document:nativeToPageRectTransform(pos.page, lbox))
                if sbox then
                    UIManager:show(LinkBox:new{
                        box = sbox,
                        timeout = 0.5,
                        callback = function() self:onGotoLink(link) end
                    })
                    return true
                end
            end
        end
    else
        local link = self.ui.document:getLinkFromPosition(ges.pos)
        if link ~= "" then
            return self:onGotoLink(link)
        end
    end
end

function ReaderLink:onGotoLink(link)
    if self.ui.document.info.has_pages then
        table.insert(self.link_states, self.view.state.page)
        self.ui:handleEvent(Event:new("GotoPage", link.page + 1))
    else
        table.insert(self.link_states, self.ui.document:getXPointer())
        self.ui:handleEvent(Event:new("GotoXPointer", link))
    end
    return true
end

function ReaderLink:onSwipe(arg, ges)
    if ges.direction == "east" then
        if self.ui.document.info.has_pages then
            local last_page = table.remove(self.link_states)
            if last_page then
                self.ui:handleEvent(Event:new("GotoPage", last_page))
                return true
            end
        else
            local last_xp = table.remove(self.link_states)
            if last_xp then
                self.ui:handleEvent(Event:new("GotoXPointer", last_xp))
                return true
            end
        end
    end
end

return ReaderLink