private void Done()
{
if (tracking)
{
// Truth table for what we should do based on three flags:
// append | moved | tooQuick | result | optimized expression to yield true
// ---------+-------+----------+-----------------------------------------------------------------------
// F | T | T | clear selection | !append && (!moved || tooQuick)
// F | T | F | emit new selected area | !append && moved && !tooQuick
// F | F | T | clear selection | !append && (!moved || tooQuick)
// F | F | F | clear selection | !append && (!moved || tooQuick)
// T | T | T | append to selection | append && moved
// T | T | F | append to selection | append && moved
// T | F | T | reset selection | append && !moved
// T | F | F | reset selection | append && !moved
//
// append --> If the user was holding control, then true. Else false.
// moved --> If they never moved the mouse, false. Else true.
// tooQuick --> If they held the mouse button down for more than 50ms, false. Else true.
//
// "Clear selection" means to result in no selected area. If the selection area was previously empty,
// then no HistoryMemento is emitted. Otherwise a Deselect HistoryMemento is emitted.
//
// "Reset selection" means to reset the selected area to how it was before interaction with the tool,
// without a HistoryMemento.
PointF[] polygon = CreateSelectionPolygon();
this.hasMoved &= (polygon.Length > 1);
// They were "too quick" if they weren't doing a selection for more than 50ms
// This takes care of the case where someone wants to click to deselect, but accidentally moves
// the mouse. This happens VERY frequently.
bool tooQuick = Utility.TicksToMs((DateTime.Now - startTime).Ticks) <= 50;
// If their selection was completedly out of bounds, it will be clipped
bool clipped = (polygon.Length == 0);
// What the user drew had no effect on the slection, e.g. subtraction where there was nothing in the first place
bool noEffect = false;
WhatToDo whatToDo;
// If their selection gets completely clipped (i.e. outside the image canvas),
// then result in a no-op
if (append)
{
if (!hasMoved || clipped || noEffect)
{
whatToDo = WhatToDo.Reset;
}
else
{
whatToDo = WhatToDo.Emit;
}
}
else
{
if (hasMoved && !tooQuick && !clipped && !noEffect)
{
whatToDo = WhatToDo.Emit;
}
else
{
whatToDo = WhatToDo.Clear;
}
}
switch (whatToDo)
{
case WhatToDo.Clear:
if (wasNotEmpty)
{
// emit a deselect history action
undoAction.Name = DeselectFunction.StaticName;
undoAction.Image = DeselectFunction.StaticImage;
HistoryStack.PushNewMemento(undoAction);
}
Selection.Reset();
break;
case WhatToDo.Emit:
// emit newly selected area
undoAction.Name = this.Name;
HistoryStack.PushNewMemento(undoAction);
Selection.CommitContinuation();
break;
case WhatToDo.Reset:
// reset selection, no HistoryMemento
Selection.ResetContinuation();
break;
}
DocumentWorkspace.ResetOutlineWhiteOpacity();
this.newSelectionRenderer.ResetOutlineWhiteOpacity();
this.newSelection.Reset();
this.newSelectionRenderer.Visible = false;
this.tracking = false;
DocumentWorkspace.EnableSelectionOutline = true;
DocumentWorkspace.InvalidateSurface(Utility.RoundRectangle(DocumentWorkspace.VisibleDocumentRectangleF));
}
}
