The annotation support in the Zoomify Viewer includes the ability to set masks - to highlight an area by leaving it displayed in color, while temporarily displaying the surrounding image in black and white (actually 'grayscale' as many levels of black are used).

This example presents a simple display with a list of the labels. Selection of a label in the list highlights it in the image display. This effect is enabled using the HTML parameter zMaskVisible=1. This example also includes buttons which will highlight a specific label or a set of labels. The buttons are implemented using calls to the function setLabelMaskByID or setLabelMaskByIDList.

Any interaction with the image display will automatically clear the mask - for example, panning or zooming, or even simply mousing over a label or clicking/touching it. The mask can also be cleared using the function clearMask which is demonstrated by the Clear Mask button.

Greater control over the mask feature is possible with functions including: setMaskByCoordinates, setLabelMaskByID, setLabelMaskByIDList, setLabelMaskByDisplayList, and setHotspotMaskByIDList.

Additional notes: shape and text labels are highlight using a circular outline, however, polygon and measurement labels are highlighted with an exact polygon mask. To see this effect in action simply select one of these labels in the label list. See the Zoomify Parameter List in the Documentation folder and the Zoomify Function List in the Developer Resources folder for more information.