Code archives/BlitzPlus Gui/TextArea undo module
This code has been declared by its author to be Public Domain code.
Download source code
| Command set for undo/redo with textarea gadgets |
'Rem Module leadwerks.textareaundo Import BRL.FileSystem Import BRL.System Import BRL.Win32MaxGUI Import BRL.Retro 'EndRem Private Type TUndoContext Global list:TList=New TList Field link:TLink Field gadget:TGadget Field undostates:TList=New TList Field current:TUndoState Field change Field disabled Method New() link=list.addlast(Self) EndMethod Method CreateUndoState:TUndostate(force=0) If current current.clearafter undostate:TUndoState=New TUndoState undostate.context=Self undostate.link=undostates.addlast(undostate) undostate.selpos=TextAreaCursor(gadget) undostate.sellen=TextAreaSelLen(gadget) undostate.update undostate.force=force current=undostate Return undostate EndMethod Method CanUndo:TUndoState(undostate:TUndoState=Null) If undostate=Null undostate=current If undostate If undostate.link.prevlink() prevundostate:TUndoState=TUndoState(undostate.link.prevlink().value()) If prevundostate.force=-1 Return TUndoState(prevundostate.link.prevlink().value()) Else Return prevundostate EndIf EndIf EndIf Return Null EndMethod Method CanRedo:TUndoState(undostate:TUndoState=Null) If undostate=Null undostate=current If undostate If undostate.link.nextlink() nextundostate:TUndoState=TUndoState(undostate.link.nextlink().value()) If nextundostate.force=1 Return TUndoState(nextundostate.link.nextlink().value()) Else Return nextundostate EndIf EndIf EndIf Return Null EndMethod Method Undo:Int() If current If canundo() current.undo current=canundo() Return True EndIf EndIf Return False EndMethod Method Redo:Int() undostate:TUndoState=CanRedo() If undostate undostate.redo current=undostate Return True EndIf Return False EndMethod Method Flush() For undostate:TUndoState=EachIn undostates undostate.kill Next undostates.clear current=Null createundostate EndMethod Method Kill() flush undostates=Null gadget=Null RemoveLink link link=Null EndMethod Function Callback:Object(id:Int,data:Object,context:Object) Local event:TEvent=TEvent(data) Select event.id Case EVENT_GADGETSELECT For undocontext:TUndoContext=EachIn TUndoContext.list If event.source=undocontext.gadget If undocontext.current If Not undocontext.disabled If undocontext.current.text=TextAreaText(undocontext.gadget) undocontext.current.selpos=TextAreaCursor(undocontext.gadget) undocontext.current.sellen=TextAreaSelLen(undocontext.gadget) undocontext.current.removetext=TextAreaText(undocontext.gadget,undocontext.current.selpos,undocontext.current.sellen) EndIf EndIf EndIf Exit EndIf Next Case EVENT_GADGETACTION For undocontext:TUndoContext=EachIn TUndoContext.list If event.source=undocontext.gadget If Not undocontext.disabled If undocontext.current If undocontext.current.text=TextAreaText(undocontext.gadget) Return Null EndIf undostate:TUndoState=undocontext.createundostate() event.data=undostate.change EndIf Exit EndIf Next EndSelect Return data EndFunction EndType Function CreateUndoContext:TUndocontext(gadget:TGadget) undocontext:TUndoContext=New TUndoContext undocontext.gadget=gadget undocontext.createundostate Return undocontext EndFunction Type TUndostate Field link:TLink Field context:TUndoContext Field text$ Field undotext$ Field redotext$ Field selpos Field sellen Field undolen Field undopos Field change Field force Field removetext$ Field removeposition Field addtext$ Field addposition Method Update() text$=TextAreaText(context.gadget) selpos=TextAreaCursor(context.gadget) sellen=TextAreaSelLen(context.gadget) removetext=TextAreaText(context.gadget,selpos,sellen) lastundostate:TUndoState=context.canundo(Self) If lastundostate change=text.length-lastundostate.text.length change=change+lastundostate.sellen Else change=text.length EndIf If change<0 undopos=selpos undolen=-change If lastundostate undotext=Mid(lastundostate.text,undopos+1,-change) EndIf Else undopos=selpos-change undolen=change If lastundostate undotext=Mid(text,undopos+1,change) EndIf EndIf EndMethod Method Undo() start=TextAreaCursor(context.gadget) prevundostate:TUndoState=context.canundo(Self) nextundostate:TUndoState=context.canredo(Self) LockTextArea context.gadget If change>0 SetTextAreaText context.gadget,"",undopos,undolen Else SetTextAreaText context.gadget,undotext,undopos,0 EndIf UnlockTextArea context.gadget prevundostate:TUndoState=context.canundo(Self) If prevundostate SetTextAreaText context.gadget,prevundostate.removetext,prevundostate.selpos,0 SelectTextAreaText context.gadget,prevundostate.selpos,prevundostate.sellen Else SelectTextAreaText context.gadget,0,0 EndIf stop=TextAreaCursor(context.gadget) size=Abs(start-stop)+TextAreaSelLen(context.gadget) context.disabled=True EmitEvent CreateEvent(EVENT_GADGETACTION,context.gadget,size) context.disabled=False EndMethod Method Redo() start=TextAreaCursor(context.gadget) prevundostate:TUndoState=context.canundo(Self) nextundostate:TUndoState=context.canredo(Self) LockTextArea context.gadget If change<0 SetTextAreaText context.gadget,"",undopos,undolen Else If prevundostate l=prevundostate.sellen SetTextAreaText context.gadget,undotext,undopos,l EndIf UnlockTextArea context.gadget SelectTextAreaText context.gadget,selpos,sellen stop=TextAreaCursor(context.gadget) size=Abs(start-stop)+TextAreaSelLen(context.gadget) context.disabled=True EmitEvent CreateEvent(EVENT_GADGETACTION,context.gadget,size) context.disabled=False EndMethod Method ClearAfter() Local sublink:TLink Local nextsublink:TLink sublink=link.nextlink() While sublink nextsublink=sublink.nextlink() TUndoState(sublink.value()).kill sublink=nextsublink Wend EndMethod Method Kill() If link.prevlink() current=TUndostate(link.prevlink().value()) Else current=Null EndIf RemoveLink link link=Null EndMethod EndType AddHook EmitEventHook,TUndoContext.Callback Function FindUndoContext:TUndoContext(gadget:TGadget) For undocontext:TUndoContext=EachIn TUndoContext.list If undocontext.gadget=gadget Return undocontext Next undocontext=CreateUndoContext(gadget) Return undocontext EndFunction Public 'Helper Functions Function TextAreaUndo:Int(gadget:TGadget) Return FindUndoContext(gadget).undo() EndFunction Function TextAreaRedo:Int(gadget:TGadget) Return FindUndoContext(gadget).redo() EndFunction Function TextAreaCanUndo:Int(gadget:TGadget) Return (FindUndoContext(gadget).canundo()<>Null) EndFunction Function TextAreaCanRedo:Int(gadget:TGadget) Return (FindUndoContext(gadget).canredo()<>Null) EndFunction Function TextAreaFlushUndos:Int(gadget:TGadget) FindUndoContext(gadget).flush() EndFunction Function TextAreaCreateUndoState() FindUndoContext(gadget).createundostate EndFunction |