TLookingGlass tool class

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Tool Identifier: atLookingGlass
Inherits from: TBitmappedFigure

Tool description:
Title: Looking glass
Draw methods: [dmBeginMouseDown, dmDrawMouseMove, dmEndMouseUp, dmCommand]
Capabilities: [caSelectable,  caMovable, caSizable, caTemporary, caSingleSelect]
Connectivity hotspots: Not connectable
Accepts text: No

The TLookingGlass tool class is a helper tool that, when positioned at some part of the image, enlarges what is under it. It is an alternative to the zoom function, which zooms the whole image. The looking glass is a read only feature: what is seen in the glass is not congruent with the image rectangle: if you draw something inside the looking glass frame, the coordinates are translated according the the zoom factor of the image, not the zoom factor of the looking glass.

The looking glass must be selected to work properly. If you select and drag another object into the looking glass, you will not see any zoom effect.

TLooking glass implements a custom hotspot button, which the user can drag to change the looking glass zoom factor. Size can be changed to widen or narrow the view. Choose between a rectangular or an elliptic shape. Use the Resample property to increase image quality.

Instances of TLooking glass are temporary, single selection objects. They are not saved with the image, and cannot be members of a group or a multiple selection.