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koreader/frontend/ui/widget/qrwidget.lua
jperon 43ba8a1173
Qrcode support (#6844)
2 new widgets:

- QRWidget, that's like an ImageWidget, but with a text property that will be converted to a QR code ;
- QRMessage, that's like an InfoMessage, but shows the message as QR code.
Moreover, it adds the ability to export QR codes to the text editor.

1 new plugin:

- Generate QR codes from clipboard

Changes to text editor plugin:

- Add the ability to export QR codes.
2020-11-04 18:59:39 +01:00

55 lines
1.5 KiB
Lua

--[[
QRWidget shows a QR code for a given text.
]]
local Blitbuffer = require("ffi/blitbuffer")
local ImageWidget = require("ui/widget/imagewidget")
local logger = require("logger")
local qrencode = require("ffi/qrencode")
local _ = require("gettext")
local QRWidget = ImageWidget:extend{
scale_factor = nil,
text = ""
-- see ImageWidget for other options.
}
function QRWidget:init()
local text = self.text
if #text > 2953 then
local truncated = _("... (truncated...)")
text = text:sub(1, 2953 - #truncated) .. truncated
end
local ok, grid = qrencode.qrcode(text)
if not ok then
logger.info("QRWidget: failed to generate QR code.")
return
else
local sq_size
if self.width then
if self.height then
sq_size = math.min(self.width, self.height)/#grid
else
sq_size = self.width/#grid
end
elseif self.height then
sq_size = self.height/#grid
else sq_size = 1
end
sq_size = math.floor(sq_size)
local grid_size = sq_size * #grid
local bb = Blitbuffer.new(grid_size, grid_size)
local white = Blitbuffer.COLOR_WHITE
for x, col in ipairs(grid) do
for y, lgn in ipairs(col) do
if lgn < 0 then
bb:paintRect((x - 1) * sq_size, (y - 1) * sq_size, sq_size, sq_size, white)
end
end
end
self.image = bb
end
end
return QRWidget