apps/plugins/helloworld.lua

   1 --[[
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   3    Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4    Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
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   6    Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7                      \/            \/     \/    \/            \/
   8  $Id$
   9
  10  Example Lua script
  11
  12  Copyright (C) 2009 by Maurus Cuelenaere
  13
  14  This program is free software; you can redistribute it and/or
  15  modify it under the terms of the GNU General Public License
  16  as published by the Free Software Foundation; either version 2
  17  of the License, or (at your option) any later version.
  18
  19  This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  KIND, either express or implied.
  21
  22 ]]--
  23
  24 require("actions")   -- Contains rb.actions & rb.contexts
  25 --require("buttons") -- Contains rb.buttons; not needed in this example
  26
  27 -- Example function which splashes a message for x seconds
  28 function sayhello(seconds)
  29     local message = string.format("Hello world from LUA for %d seconds", seconds)
  30     rb.splash(seconds * rb.HZ, message)
  31 end
  32
  33 -- Helper function which draws a (transparent) image at the center of the screen
  34 function draw_image(img)
  35     local x, y = (rb.LCD_WIDTH - img:width()) / 2, (rb.LCD_HEIGHT - img:height()) / 2
  36
  37     local func = rb.lcd_bitmap_transparent_part
  38               or rb.lcd_bitmap_part      -- Fallback version for grayscale targets
  39               or rb.lcd_mono_bitmap_part -- Fallback version for mono targets
  40
  41     func(img, 0, 0, img:width(), x, y, img:width(), img:height())
  42     rb.lcd_update()
  43 end
  44
  45 -- Helper function that acts like a normal printf() would do
  46 local line = 0
  47 function printf(...)
  48     local msg = string.format(...)
  49     local res, w, h = rb.font_getstringsize(msg, rb.FONT_UI)
  50
  51     if(w >= rb.LCD_WIDTH) then
  52         rb.lcd_puts_scroll(0, line, msg)
  53     else
  54         rb.lcd_puts(0, line, msg)
  55     end
  56     rb.lcd_update()
  57
  58     line = line + 1
  59
  60     if(h * line >= rb.LCD_HEIGHT) then
  61         line = 0
  62     end
  63 end
  64
  65 -- Helper function which reads the contents of a file
  66 function file_get_contents(filename)
  67     local file = io.open(filename, "r")
  68     if not file then
  69         return nil
  70     end
  71
  72     local contents = file:read("*all") -- See Lua manual for more information
  73     file:close() -- GC takes care of this if you would've forgotten it
  74
  75     return contents
  76 end
  77
  78 -- Helper function which saves contents to a file
  79 function file_put_contents(filename, contents)
  80     local file = io.open(filename, "w+") -- See Lua manual for more information
  81     if not file then
  82         return false
  83     end
  84
  85     local ret = file:write(contents) == true
  86     file:close() -- GC takes care of this if you would've forgotten it
  87     return ret
  88 end
  89
  90 -- Clear the screen
  91 rb.lcd_clear_display()
  92
  93 -- Draw an X on the screen
  94 rb.lcd_drawline(0, 0, rb.LCD_WIDTH, rb.LCD_HEIGHT)
  95 rb.lcd_drawline(rb.LCD_WIDTH, 0, 0, rb.LCD_HEIGHT)
  96
  97 if(rb.lcd_rgbpack ~= nil) then -- Only do this when we're on a color target, i.e. when LCD_RGBPACK is available
  98     local rectangle = rb.new_image(10, 15) -- Create a new image with width 10 and height 15
  99     for i=1, 10 do
 100         for j=1, 15 do
 101             rectangle:set(i, j, rb.lcd_rgbpack(200, i*20, j*20)) -- Set the pixel at position i, j to the specified color
 102         end
 103     end
 104
 105     -- rb.lcd_bitmap_part(src, src_x, src_y, stride, x, y, width, height)
 106     rb.lcd_bitmap_part(rectangle, 0, 0, 10, rb.LCD_WIDTH/2-5, rb.LCD_HEIGHT/10-1, 10, 10) -- Draws our rectangle at the top-center of the screen
 107 end
 108
 109 -- Load a BMP file in the variable backdrop
 110 local backdrop = rb.read_bmp_file("/.rockbox/icons/tango_small_viewers.bmp")      -- This image should always be present...
 111               or rb.read_bmp_file("/.rockbox/icons/tango_small_viewers_mono.bmp") -- ... if not, try using the mono version...
 112               or rb.read_bmp_file("/.rockbox/icons/viewers.bmp")                  -- ... or try using the builtin version
 113
 114 -- Draws the image using our own draw_image() function; see up
 115 draw_image(backdrop)
 116
 117 -- Flush the contents from the framebuffer to the LCD
 118 rb.lcd_update()
 119
 120 -- Sleep for 2 seconds
 121 local seconds = 2
 122 rb.sleep(seconds * rb.HZ) -- rb.HZ equals to the amount of ticks that fit in 1 second
 123
 124 -- Call the function sayhello() with arguments seconds
 125 sayhello(seconds)
 126
 127 -- Clear display
 128 rb.lcd_clear_display()
 129
 130 -- Construct a pathname using the current path and a file name
 131 local pathname = rb.current_path() .. "test.txt"
 132
 133 -- Put the string 'Hello from Lua!' in pathname
 134 file_put_contents(pathname, "Hello from Lua!")
 135
 136 -- Splash the contents of pathname
 137 printf(file_get_contents(pathname))
 138
 139 line = line + 1 -- Add empty line
 140
 141 -- Some examples of how bitlib works
 142 printf("1 | 2 = %d <> 7 & 3 = %d", bit.bor(1, 2), bit.band(7, 3))
 143 printf("~8 = %d <> 5 ^ 1 = %d", bit.bnot(8), bit.bxor(5, 1))
 144
 145 line = line + 1 -- Add empty line
 146
 147 -- Display some long lines
 148 for i=0, 4 do
 149     printf("This is a %slong line!", string.rep("very very very ", i))
 150     rb.yield() -- Always try to yield to give other threads some breathing space!
 151 end
 152
 153 -- Loop until the user exits the program
 154 repeat
 155     local action = rb.get_action(rb.contexts.CONTEXT_STD, rb.HZ)
 156 until action == rb.actions.ACTION_STD_CANCEL
 157
 158 -- For a reference list of all functions available, see apps/plugins/lua/rocklib.c (and apps/plugin.h)