Drawing Outside Windows

Drawing Outside Windows The rules for drawing outside of windows

Sometimes you need to draw outside of an appliation's windows. For example,

you might want to draw a "zoom" special effect centered on an object to show

that you're opening that object, like in the Finder.

Note: If you want to drag an object from one window to an other, try using

the function DragGrayRgn.

If you follow these rules, your application can draw outside of its windows. Be

aware that Apple may change how to do this in a future release.

• Draw modally. Make sure nothing can interrupt you while there is

something drawn outside of your windows. If you're dragging an object,

drag only while the mouse button is down. (Check the state of the mouse

button with the StillDown or WaitMouseUp functions.) If you're using

while you're drawing.

• Don't leave any drawing outside a window. The system won't know you left

something there, and the Finder will draw over it.

• Draw in a GrafPort that covers all the screens. Create it with OpenPort.

Set the visRgn of the port to a copy of GrayRgn. Set the portRect of the port

to the rgnBBox of GrayRgn.

• Draw with srcXor mode. This mode lets you erase an object by drawing it

a second time in srcXor mode. Remember, you must not leave any drawing

outside your windows.

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