highlight-style

Arguments: hotspot

Returns the type of highlighting that the built-in highlight-hotspot method will use to highlight hotspot when the mouse cursor is over its hotspot-region. hotspot should be a hotspot instance, as created with make-instance. The highlight style may be specified by passing the :highlight-style initarg to make-instance, or by calling (setf highlight-style) any time later.

The default value is :invert, which inverts the screen colors in the hotspot-region. An alternate style is :outline, which inverts only the edge of the region. By "inverts" we mean that the hotspot-region is filled or drawn while the paint-operation of the hotspot's parent window is set to po-xor. This allows the highlighting to be erased without knowledge of the "real" object that is drawn in the window where the hotspot lies. Though the highlighting is drawn with the foreground-color of the window set to the color of the hotspot, this will be the resulting color only where the window background is white, due to the way that po-xor works.

The other valid value is nil, in which case the default highlight-hotspot method does nothing at all. The hotspot is still sensitive to the mouse, but does not add any visual indication of this as the mouse moves over it.

If neither of the built-in highlighting styles is adequate, an application could instead supply its own highlight-hotspot method that ignores the hotspot's highlight-style property and draws some other sort of highlighting.

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Created 2010.1.21.