rockbox/apps/plugins/lua/include_lua/print.lua

--[[ Lua Print functions
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2017 William Wilgus
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
]]

--[[ Exposed Functions

    _print.clear
    _print.f
    _print.opt
    _print.opt.area
    _print.opt.autoupdate
    _print.opt.color
    _print.opt.column
    _print.opt.defaults
    _print.opt.get
    _print.opt.justify
    _print.opt.line
    _print.opt.overflow
    _print.opt.sel_line
    _print.opt.set

]]

if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end

local _print = {} do

    -- internal constants
    local _clr = require("color") -- _clr functions required

    local _NIL = nil -- _NIL placeholder
    local _LCD = rb.lcd_framebuffer()
    local LCD_W, LCD_H = rb.LCD_WIDTH, rb.LCD_HEIGHT
    local WHITE = _clr.set(-1, 255, 255, 255)
    local BLACK = _clr.set(0, 0, 0, 0)
    local DRMODE_SOLID = 3
    local col_buf, s_lines = {}, {}
    local _p_opts = _NIL

-- print internal helper functions
--------------------------------------------------------------------------------
   -- clamps value to >= min and <= max
    local function clamp(val, min, max)
        -- Warning doesn't check if min < max
        if val < min then
            return min
        elseif val < max then
            return val
        end
        return max
    end

    -- updates screen in specified rectangle
    local function update_rect(x, y, w, h)
        rb.lcd_update_rect(x - 1, y - 1,
             clamp(x + w, 1, LCD_W) - 1,
             clamp(y + h, 1, LCD_H) - 1)
    end

    -- Gets size of text
    local function text_extent(msg, font)
        font = font or rb.FONT_UI
        -- res, w, h
        return rb.font_getstringsize(msg, font)
    end

    -- Sets viewport size
    local function set_viewport(vp)
        if not vp then rb.set_viewport() return end

        if rb.LCD_DEPTH  == 2 then -- invert 2-bit screens
            --vp.drawmode = bit.bxor(vp.drawmode, 4)
            vp.fg_pattern = 3 - vp.fg_pattern
            vp.bg_pattern = 3 - vp.bg_pattern
        end
        rb.set_viewport(vp)
    end

    -- shallow copy of table
    function table_clone(t)
        local copy = {}
        for k, v in pairs(t) do
            copy[k] = v
        end
        return copy
    end

    -- Updates a single line on the screen
    local function update_line(enabled, opts, line, h)
        if enabled ~= true then return end
        local o = opts or _p_opts
        update_rect(o.x, o.y + line * h + 1, o.width, h)
    end

    -- Clears a single line on the screen
    local function clear_line(opts, line, h)
        local o = opts or _p_opts
        _LCD:clear(o.bg_pattern, o.x, o.y + line * h + 1,
                                 o.x + o.width, line * h + h + o.y)
    end

    -- Sets the maximum number of lines on the screen
    local function max_lines(opts)
        local h  = opts.height
        local _, _, th = text_extent("W", opts.font)
        return h / th
    end

    --saves the items displayed for side to side scroll
    local function col_buf_insert(msg, line, _p_opts)
        --if _p_opts.line <= 1 then col_buf = {} end
        if not col_buf[line] then
        table.insert(col_buf, line, msg) end
    end

    --replaces / strips escape characters
    local function check_escapes(o, msg)
        local tabsz  = 2
        local tabstr = string.rep(" ", tabsz)

        local function repl(esc)
            local ret = ""
            if esc:sub(1,1) == "\t" then ret = string.rep(tabstr, esc:len()) end
            return ret
        end

        msg = msg:gsub("(%c+)", repl)

        local res, w, h = text_extent(msg, o.font)
        return w, h, msg
    end
--------------------------------------------------------------------------------

    -- set defaults for print view
    local function set_defaults()
        _p_opts = { x = 1,
                    y = 1,
                    width = LCD_W - 1,
                    height = LCD_H - 1,
                    font = rb.FONT_UI,
                    drawmode = DRMODE_SOLID,
                    fg_pattern = WHITE,
                    bg_pattern = BLACK,
                    sel_pattern = WHITE,
                    line = 1,
                    max_line = _NIL,
                    col = 0,
                    ovfl = "auto",
                    justify = "left",
                    autoupdate = true,
                  }
        _p_opts.max_line = max_lines(_p_opts)

        s_lines, col_buf = {}, {}
        return _p_opts
    end

    -- returns table with settings for print
    -- if bByRef is _NIL or false then a copy is returned
    local function get_settings(bByRef)
        _p_opts = _p_opts or set_defaults()
        if not bByRef then return table_clone(_p_opts) end
        return _p_opts
    end

    -- sets the settings for print with your passed table
    local function set_settings(t_opts)
        _p_opts = t_opts or set_defaults()
        if t_opts then
            _p_opts.max_line = max_lines(_p_opts)
            col_buf = {}
        end
    end

    -- sets colors for print
    local function set_color(fgclr, bgclr, selclr)
        local o = get_settings(true)

        if fgclr ~= _NIL then
            o.fg_pattern, o.sel_pattern = fgclr, fgclr
        end
        o.sel_pattern = selclr or o.sel_pattern
        o.bg_pattern = bgclr or o.bg_pattern
    end

    -- helper function sets up colors/marker for selected items
    local function show_selected(iLine, msg)
        local o = get_settings() -- using a copy of opts so changes revert

        if s_lines[iLine] == true then
            if not rb.lcd_set_background then
                o.drawmode = bit.bxor(o.drawmode, 4)
            else
                o.fg_pattern = o.bg_pattern
                o.bg_pattern = o.sel_pattern
            end
            -- alternative selection method
            --msg = "> " .. msg
        end
        set_viewport(o)
        o = _NIL
    end

    -- sets line explicitly or increments line if line is _NIL
    local function set_line(iLine)
        local o = get_settings(true)

        o.line = iLine or o.line + 1

        if(o.line < 1 or o.line > o.max_line) then
            o.line = 1
        end
    end

    -- clears the set print area
    local function clear()
        local o = get_settings(true)
        _LCD:clear(o.bg_pattern, o.x, o.y, o.x + o.width, o.y + o.height)
        if o.autoupdate == true then rb.lcd_update() end
        set_line(1)
        for i=1, #col_buf do col_buf[i] = _NIL end
        s_lines = {}
        collectgarbage("collect")
    end

    -- screen update after each call to print.f
    local function set_update(bAutoUpdate)
        local o = get_settings(true)
        o.autoupdate = bAutoUpdate or false
    end

    -- sets print area
    local function set_area(x, y, w, h)
        local o = get_settings(true)
        o.x, o.y = clamp(x, 1, LCD_W), clamp(y, 1, LCD_H)
        o.width, o.height = clamp(w, 1, LCD_W - o.x), clamp(h, 1, LCD_H - o.y)
        o.max_line = max_lines(_p_opts)

        clear()
        return o.line, o.max_line
    end

    -- when string is longer than print width scroll -- "auto", "manual", "none"
    local function set_overflow(str_mode)
        -- "auto", "manual", "none"
        local str_mode = str_mode or "auto"
        local o = get_settings(true)
        o.ovfl = str_mode:lower()
        col_buf = {}
    end

    -- aligns text to: "left", "center", "right"
    local function set_justify(str_mode)
        -- "left", "center", "right"
        local str_mode = str_mode or "left"
        local o = get_settings(true)
        o.justify = str_mode:lower()
    end

    -- selects line
    local function select_line(iLine)
        s_lines[iLine] = true
    end

    -- Internal print function
    local function print_internal(t_opts, x, w, h, msg)

        local o = t_opts
        if o.justify == "center" then
            x = x + (o.width - w) / 2
        elseif o.justify == "right" then
            x = x + (o.width - w)
        end

        local line = o.line - 1 -- rb is 0-based lua is 1-based
        if(o.ovfl == "auto" and w >= o.width) then -- -o.x
            rb.lcd_puts_scroll(0, line, msg)
        else
            rb.lcd_putsxy(x, line * h, msg)
            if o.ovfl == "manual" then --save msg for later side scroll
                col_buf_insert(msg, o.line, o)
            end
        end

        --only update the line we changed
        update_line(o.autoupdate, o, line, h)

        set_line(_NIL) -- increments line counter
    end

    -- Helper function that acts mostly like a normal printf() would
    local function printf(...)
        local o = get_settings(true)
        local w, h, msg
        local line = o.line - 1 -- rb is 0-based lua is 1-based
        if not (...) or (...) == "\n" then -- handles blank line / single '\n'
             local res, w, h = text_extent(" ", o.font)

            clear_line(o, line, h)
            update_line(o.autoupdate, o, line, h)

            if (...) then set_line(_NIL) end

            return o.line, o.max_line, o.width, h
        end

        msg = string.format(...)

        show_selected(o.line, msg)

        w, h, msg = check_escapes(o, msg)

        print_internal(o, o.col, w, h, msg)

        return o.line, o.max_line, w, h
    end

    -- x > 0 scrolls right x < 0 scrolls left
    local function set_column(x)
        local o = get_settings()
        if o.ovfl ~= "manual" then return end -- no buffer stored to scroll
        local res, w, h, str, line

        for key, value in pairs(col_buf) do
            line = key - 1 -- rb is 0-based lua is 1-based
            o.line = key

            if value then
                show_selected(key, value)
                res, w, h = text_extent(value, o.font)
                clear_line(o, line, h)

                print_internal(o, x + o.col, w, h, value)
                update_line(o.autoupdate, o, line, h)
            end
        end
        o = _NIL
    end

    --expose functions to the outside through _print table
    _print.opt            = {}
    _print.opt.column     = set_column
    _print.opt.color      = set_color
    _print.opt.area       = set_area
    _print.opt.set        = set_settings
    _print.opt.get        = get_settings
    _print.opt.defaults   = set_defaults
    _print.opt.overflow   = set_overflow
    _print.opt.justify    = set_justify
    _print.opt.sel_line   = select_line
    _print.opt.line       = set_line
    _print.opt.autoupdate = set_update
    _print.clear = clear
    _print.f     = printf

end --_print functions

return _print