OVERLAY Mnemonic - Display an Underlying Character Window on top of the Active Window (Terminal Device)
Syntax
'OVERLAY'(windowID)
'OVERLAY'("undo")
'OVERLAY'(windowID, "undo")
Description
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Parameter |
Description |
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windowID |
The ID number of a character window that should be displayed on top of the active window. |
In BBj 15.0 and higher, the 'OVERLAY' mnemonic will cause the character window with the specified ID number to be temporarily displayed on top of the active top-most character window. Using the parameter "undo" without a window ID number will remove the display of all underlying windows from the active window, while providing both a window ID number and the "undo" parameter will remove only the specified window (and the overlapping area of any other previously superimposed character windows).
The effect is similar to the 'CAPTURE' mnemonic, but with an important difference: The 'CAPTURE' mnemonic copies the content of underlying windows into the active window, whereas the 'OVERLAY' mnemonic does not copy the content. It leaves the original content of the active window undisturbed, but refers to the content of the underlying window with pointer references. Underlying content that is copied into the active window by the 'CAPTURE' mnemonic cannot be quickly removed; it must be over-written or cleared by manipulating the active window. Deleting the underlying character window that was the original source of the content has no effect on the copied content. Character window content that is superimposed on the active window via the 'OVERLAY' mnemonic can be easily removed, either with an "undo" parameter in another call to the 'OVERLAY' mnemonic or by deleting the source character window with the 'DROP' or 'POP' mnemonics. Moving or resizing the active character window will also remove the effect of overlaid windows.
As with the 'CAPTURE' mnemonic, if the specified character window and the active window do not overlap, nothing will happen and the appearance of the active window will not be changed.
It is not possible to overlay a window on itself. An attempt to do so is simply ignored and no error is reported. This means it is not possible to clear away the overlays of other windows by overlaying the active window with itself. Use the "undo" form of the mnemonic to clear overlays instead.