Add faster option to export text selections via QR codes (#12746)

Closes https://github.com/koreader/koreader/issues/11909.

plugins/qrclipboard.koplugin/main.lua

@@ -8,6 +8,7 @@ local Device = require("device")
 local QRMessage = require("ui/widget/qrmessage")
 local UIManager = require("ui/uimanager")
 local WidgetContainer = require("ui/widget/container/widgetcontainer")
+local util = require("util")
 local _ = require("gettext")
 
 local QRClipboard = WidgetContainer:extend{
@@ -17,6 +18,27 @@ local QRClipboard = WidgetContainer:extend{
 
 function QRClipboard:init()
     self.ui.menu:registerToMainMenu(self)
+    self:addToHighlightDialog()
+end
+
+function QRClipboard:addToHighlightDialog()
+    -- 12_search is the last item in the highlight dialog. We want to sneak in the 'Generate QR code' item
+    -- second to last, thus name '12_generate' so the alphabetical sort keeps '12_search' last.
+    self.ui.highlight:addToHighlightDialog("12_generate_qr_code", function(this)
+        return {
+            text = _("Generate QR code"),
+            enabled = Device:hasClipboard(),
+            callback = function()
+                Device.input.setClipboardText(util.cleanupSelectedText(this.selected_text.text))
+                UIManager:show(QRMessage:new{
+                    text = Device.input.getClipboardText(),
+                    width = Device.screen:getWidth(),
+                    height = Device.screen:getHeight()
+                })
+                this:onClose()
+            end,
+        }
+    end)
 end
 
 function QRClipboard:addToMainMenu(menu_items)