Fork of @joshuacant's 2-reader-header-centered and 2-reader-header-cornered patches with improvements in collaboration with @JasonInOttawa (https://github.com/joshuacant/KOReader.patches/blob/main/2-reader-header-centered.lua, https://github.com/joshuacant/KOReader.patches/blob/main/2-reader-header-cornered.lua, https://github.com/JasonInOttawa/…

2-reader-header-centered-and-cornered.lua

--[[
    This user patch adds a "header" into the reader display, similar to the footer at the bottom.
    
    Modified to show: Time & Battery (left) | Author — Title (center) | R: percentage | pages (right)
    
    Features:
    - Configurable sections (easily turn on/off what appears in each area)
    - Dynamic separator matching footer settings
    - Battery charging indicator and icon toggle
    - Smart space calculation with minimum spacing
    - Auto-refresh to keep time/battery current
    - Refactored code with minimal duplication
]]--

local TextWidget = require("ui/widget/textwidget")
local CenterContainer = require("ui/widget/container/centercontainer")
local VerticalGroup = require("ui/widget/verticalgroup")
local VerticalSpan = require("ui/widget/verticalspan")
local HorizontalGroup = require("ui/widget/horizontalgroup")
local HorizontalSpan = require("ui/widget/horizontalspan")
local UIManager = require("ui/uimanager")
local BD = require("ui/bidi")
local Size = require("ui/size")
local Geom = require("ui/geometry")
local Device = require("device")
local Font = require("ui/font")
local logger = require("logger")
local util = require("util")
local datetime = require("datetime")
local Screen = Device.screen
local _ = require("gettext")
local T = require("ffi/util").template
local ReaderUI = require("apps/reader/readerui")
local ReaderView = require("apps/reader/modules/readerview")
local _ReaderView_paintTo_orig = ReaderView.paintTo
local _ReaderUI_init_orig = ReaderUI.init

local header_settings = G_reader_settings:readSetting("footer")
local screen_width = Screen:getWidth()

-- Configure what appears in each section (set to true/false as desired)
local left_config = {
    time = true,
    battery = true,
}
local center_config = {
    book_author = true,
    book_title = true,
}
local right_config = {
    page_progress = true,
    percentage = true,
}

-- Configure formatting options for header here, if desired
local header_font_face = "ffont"
local header_font_size = header_settings.text_font_size or 14
local header_font_bold = header_settings.text_font_bold or false
local header_top_padding = Size.padding.small
local header_use_book_margins = true
local header_margin = Size.padding.large
local min_section_spacing = 5
local header_refresh_interval = 60 -- Refresh header every 60 seconds

-- Store the ReaderUI instance for refresh access
local current_reader_ui = nil
local dimen_refresh = nil

-- Helper function: Generate separator from footer settings
local function genSeparator()
    local strings = {
        bar    = " | ",
        bullet = " • ",
        dot    = " · ",
        em_dash = " — ",
        en_dash = " – ",
    }
    return strings[header_settings.items_separator] or " | "
end

-- Helper function: Get battery string
local function getBatteryString()
    local battery_string = ""
    local powerd = Device.powerd
    if Device:hasBattery() then
        if powerd and powerd.getCapacity then
            local batt_lvl = powerd:getCapacity()
            if batt_lvl and batt_lvl >= 0 then
                local show_battery_icon = header_settings.show_battery_icon or false
                if show_battery_icon and powerd.getBatterySymbol then
                    local batt_symbol = powerd:getBatterySymbol(powerd:isCharged(), powerd:isCharging(), batt_lvl)
                    battery_string = string.format("%s%d%%", batt_symbol, batt_lvl)
                else
                    battery_string = string.format("B: %d%%", batt_lvl)
                    if powerd.isCharging and powerd:isCharging() then
                        battery_string = "+" .. battery_string
                    end
                end
            end
        end
    end
    return battery_string
end

-- Helper function: Get text width
local function getTextWidth(text, font_face, font_size, font_bold)
    if text == nil or text == "" then
        return 0
    end
    local text_widget = TextWidget:new{
        text = text:gsub(" ", "\u{00A0}"),
        face = Font:getFace(font_face, font_size),
        bold = font_bold,
        padding = 0,
    }
    local width = text_widget:getSize().w
    text_widget:free()
    return width
end

-- Helper function: Get fitted text
local function getFittedText(text, max_width, font_face, font_size, font_bold)
    if text == nil or text == "" then
        return ""
    end
    local text_widget = TextWidget:new{
        text = text:gsub(" ", "\u{00A0}"),
        max_width = max_width,
        face = Font:getFace(font_face, font_size),
        bold = font_bold,
        padding = 0,
    }
    local fitted_text, add_ellipsis = text_widget:getFittedText()
    text_widget:free()
    if add_ellipsis then
        fitted_text = fitted_text .. "…"
    end
    return BD.auto(fitted_text)
end

-- Helper function: Create text widget
local function createTextWidget(text, font_face, font_size, font_bold)
    return TextWidget:new {
        text = BD.auto(text),
        face = Font:getFace(font_face, font_size),
        bold = font_bold,
        padding = 0,
    }
end

-- Helper function: Build header text for a section
local function getHeaderText(config, data, separator)
    local parts = {}
    if config.time and data.time then
        table.insert(parts, data.time)
    end
    if config.battery and data.battery ~= "" then
        table.insert(parts, data.battery)
    end
    if config.book_author and data.book_author ~= "" then
        table.insert(parts, data.book_author)
    end
    if config.book_title and data.book_title ~= "" then
        table.insert(parts, data.book_title)
    end
    if config.percentage and data.percentage then
        table.insert(parts, string.format("R: %.1f%%", data.percentage))
    end
    if config.page_progress and data.page_progress then
        table.insert(parts, data.page_progress)
    end
    return table.concat(parts, separator)
end

-- Main paint function
ReaderView.paintTo = function(self, bb, x, y)
    _ReaderView_paintTo_orig(self, bb, x, y)
    if self.render_mode ~= nil then return end

    local separator = genSeparator()
    local center_separator = " — "

    -- Gather all data
    local pageno = self.state.page or 1
    local pages = self.ui.doc_settings.data.doc_pages or 1
    local data = {
        time = datetime.secondsToHour(os.time(), G_reader_settings:isTrue("twelve_hour_clock")),
        battery = getBatteryString(),
        book_author = self.ui.doc_props.authors or "",
        book_title = self.ui.doc_props.display_title or "",
        percentage = (pageno / pages) * 100,
        page_progress = ("%d/%d"):format(pageno, pages),
    }

    -- Handle multiple authors
    if data.book_author and data.book_author:find("\n") then
        data.book_author = T(_("%1 et al."), util.splitToArray(data.book_author, "\n")[1] .. ",")
    end

    -- Build header sections
    local left_header = getHeaderText(left_config, data, separator)
    local right_header = getHeaderText(right_config, data, separator)
    
    -- Build center with em-dash separator
    local center_parts = {}
    if center_config.book_author and data.book_author ~= "" then
        table.insert(center_parts, data.book_author)
    end
    if center_config.book_title and data.book_title ~= "" then
        table.insert(center_parts, data.book_title)
    end
    local center_header = table.concat(center_parts, center_separator)

    -- Calculate margins
    local left_margin = header_margin
    local right_margin = header_margin
    if header_use_book_margins then
        left_margin = self.document:getPageMargins().left or header_margin
        right_margin = self.document:getPageMargins().right or header_margin
    end
    local avail_width = screen_width - left_margin - right_margin

    -- Calculate widths and fit center text
    local left_width = getTextWidth(left_header, header_font_face, header_font_size, header_font_bold)
    local right_width = getTextWidth(right_header, header_font_face, header_font_size, header_font_bold)
    local center_available_width = avail_width - left_width - right_width - (min_section_spacing * 2)
    local center_header_text = getFittedText(center_header, math.max(100, center_available_width), 
                                             header_font_face, header_font_size, header_font_bold)

    -- Create text widgets
    local left_widget = createTextWidget(left_header, header_font_face, header_font_size, header_font_bold)
    local center_widget = createTextWidget(center_header_text, header_font_face, header_font_size, header_font_bold)
    local right_widget = createTextWidget(right_header, header_font_face, header_font_size, header_font_bold)

    -- Calculate final spacing
    local total_text_width = left_widget:getSize().w + center_widget:getSize().w + right_widget:getSize().w
    local remaining_space = avail_width - total_text_width
    local space_between = math.max(min_section_spacing, remaining_space / 2)

    -- Store dimensions for precise refresh area
    dimen_refresh = Geom:new{ 
        w = screen_width, 
        h = math.max(left_widget:getSize().h, center_widget:getSize().h, right_widget:getSize().h) + header_top_padding
    }

    -- Build and paint header
    local header = CenterContainer:new {
        dimen = dimen_refresh,
        VerticalGroup:new {
            VerticalSpan:new { width = header_top_padding },
            HorizontalGroup:new {
                HorizontalSpan:new { width = left_margin },
                left_widget,
                HorizontalSpan:new { width = space_between },
                center_widget,
                HorizontalSpan:new { width = space_between },
                right_widget,
                HorizontalSpan:new { width = right_margin },
            },
        },
    }
    header:paintTo(bb, x, y)
end

-- Auto-refresh functionality
ReaderUI.init = function(self, ...)
    _ReaderUI_init_orig(self, ...)
    
    current_reader_ui = self
    
    -- Create a recurring task to force header refresh
    local function scheduleHeaderRefresh()
        -- Calculate seconds until next minute (sync to clock)
        local seconds = 61 - tonumber(os.date("%S"))
        UIManager:scheduleIn(seconds, function()
            -- Check if auto-refresh is enabled in footer settings
            local auto_refresh = header_settings.auto_refresh_time
            
            -- Only refresh if:
            -- 1. Auto-refresh is enabled
            -- 2. Reader UI exists and is active
            -- 3. View is available
            -- 4. Document is currently open (not on home screen/locked)
            -- 5. Dimensions have been calculated
            -- 6. Render mode is nil (epub-like documents only)
            if auto_refresh and 
               current_reader_ui and 
               current_reader_ui.view and 
               current_reader_ui.document and
               current_reader_ui.view.state and
               current_reader_ui.view.state.page and
               current_reader_ui.view.render_mode == nil and
               dimen_refresh then
                -- Use "fast" refresh mode and limit to header area only
                UIManager:setDirty(current_reader_ui, "fast", dimen_refresh)
            end
            scheduleHeaderRefresh()
        end)
    end
    
    -- Start the refresh cycle
    scheduleHeaderRefresh()
end