DMMoveDisplay

DMMoveDisplay
Header:	Displays.h		Carbon status:	Supported

Moves the boundary rectangle for a video device. You should generally never need to use this function.

OSErr DMMoveDisplay (
    GDHandle moveDevice, 
    SInt16 x, 
    SInt16 y, 
    Handle displayState
);

Parameter descriptions

moveDevice: A handle to the GDevice structure for the video device whose boundary rectangle you wish to move.
x: The horizontal coordinate on the QuickDraw global coordinate plane for the point to which you want to move the upper-left corner of the boundary rectangle.
y: The vertical coordinate on the QuickDraw global coordinate plane for the point to which you want to move the upper-left corner of the boundary rectangle.
displayState: If your application called DMBeginConfigureDisplays, you must pass the displayState handle obtained. Otherwise pass NULL in this parameter.

function result: A result code.

DISCUSSION

The DMMoveDisplay function moves the boundary rectangle for the specified video device to the point (x,y) in the QuickDraw global coordinate plane. If the video device controls the main screen, which always has the global coordinates (0,0), then all other video devices are offset by horizontal distance x and vertical distance y.

A boundary rectangle is the rectangle that links the local coordinate system of a graphics port to QuickDraw’s global coordinate system and defines the area of the pixel image or bit image into which QuickDraw can draw. The boundary rectangle is stored in either the pixel map or the bitmap contained in a GDevice structure.

The Display Manager will reposition overlapped or discontiguous boundary rects to create a non-overlapping contiguous desktop space.

SPECIAL CONSIDERATIONS

Because this function may move or purge memory blocks or access handles, you cannot call it at interrupt time.

Applications generally never need to use this function. In case you find a compelling need to change the user’s display configuration, this function is described here for completeness. Note that if your application uses Display Manager functions to change the display configuration of the user’s video devices, your application should make these changes only with the consent of the user. If your application must have a specific pixel depth, for example, it should display a dialog box that offers the user a choice between changing to that depth or canceling display of the image.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.