Declaration

TIEShiftLock = set of (iessCtrl_SubFromSel, iessCtrl_KeySizing, iessCtrl_DelPoint,
                       iessShift_AddToSel, iessShift_AddLyrSel, iessShift_FastMove, iessShift_RotateLock, iessShift_LineLock, iessShift_CircularCurve, iessShift_MoveSnapping,
                       iessAlt_Curve, iessAlt_MaintainAR, iessAlt_InvertWheel );

Description

Used by ShiftKeyLock to force the application of the ssCtrl, ssShift or ssAlt key.

The shift keys have the following effects:

Ctrl Key
◼When creating a selection, it removes from the existing selection
◼Change to horizontal scrolling when using mouse wheel if MouseWheelParams.Action = iemwVScroll
◼When using cursor keys it sizes the selection or layer (instead of moving it)
◼When editing layer points (mlEditLayerPoints), it removes the point being clicked
◼When clicking a layer it creates a clone (if loCtrlClickToCopy is specified in LayerOptions)
◼When using the BrushTool (and OpacityEnabled is enAuto) the brush transparency will be affected by pen pressure

Shift Key
◼When creating a selection, it adds to the existing selection (EnableShiftKey)
◼When selecting layers, it adds the selected layer to the multiple selection
◼When using cursor keys to move or size the selection or layer, it increases the movement by 10x
◼When rotating using miRotateTool it forces 45 deg. increments (or MouseRotateShiftStep)
◼When rotating a layer it forces 45 deg. angles (or LayersRotateStep)
◼When drawing a TIELineLayer, TIEPolylineLayer or TIEAngleLayer it forces lines at 45 deg. angles (or LayersRotateStep)
◼When rotating the Crop Tool (miCropTool) it forces 15 deg. increments)
◼When creating a curve using the Alt key and mlEditLayerPoints, the curve will be a perfect half-circle
◼When filling using miColorFill or miAlphaFill it increases the color tolerance
◼When using the BrushTool the brush position will be snapped to the axes

Alt Key
◼When editing layer points (mlEditLayerPoints), it converts the line being dragged into a curve
◼When creating/sizing a selection it forces a perfect square/circular selection
◼When creating/sizing a layer it maintains the aspect ratio
◼When rotating an angle layer, it changes the point being rotated
◼When using the BrushTool (and BrushSizeEnabled is enAuto) the brush size will be affected by pen pressure

Use ShiftKeyLock to force any of these behaviours:

Example

// Force selections to add to existing ones
ImageEnView1.ShiftKeyLock := [ iessShift_AddToSel ];

// Force 45 deg angles for lines, and perfectly square or circular selections
ImageEnView1.ShiftKeyLock := [ iessShift_RotateLock, iessAlt_MaintainAR ];

// Select whole image and allow user to deselect circular regions
With ImageEnView1 do
begin
  SelectionBase := iesbBitmap;
  Select( 0, 0, IEBitmap.Width, IEBitmap.Height );
  ShiftKeyLock  := [ iessCtrl_SubFromSel ];
  MouseInteractGeneral := [ miSelectCircle ];
end;

---