New LCL shortcut system

This page collects ideas about improving system of shortcuts in LCL.

Current state

TShortCut = Low(Word)..High(Word); // in classes.pp unit
 
// virtual key codes VK_*
Key := ShortCut and $FF; 
 
// key modifiers
Meta    := ShortCut and $1000; // scMeta
Shift   := ShortCut and $2000; // scShift
Control := ShortCut and $4000; // scControl
Alt     := ShortCut and $8000; // scAlt

Unused bits in TShortCut: $0F00

Requirements

1. backward compatibility
   • accept current TShortCut format
   • new format can use only unused bits in current TShortCut format
2. secondary, ternary shortcuts
3. platform-specific shortcuts (E.g. Ctrl+C under Windows, ⌘ Cmd+C under Mac OS X)
4. shortcuts also with characters (E.g. ⌘ Cmd+?)

Conclusion

• create list of extra shortcut data under TApplication (TLCLShortCutList)
• the TShortCut value would be "an index" to one item in this list, unused bits can distinguish different shortcuts with same key code (0 will be reserved for old version)
• modify shortcut handling in TApplication, TForm, TAction and TMenuItem
  • check for character shortcuts in IntfUTF8KeyPress
• add functions like ShortCutToText to TApplication
• modify TShortCut component editor

TLCLShortCut class

• index - TShortCut with modified unused bits
• priority list of TLCLShortCutItem
  • key modifiers
  • platform modifiers
  • key or UTF-8 character