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Inside Macintosh: Imaging With QuickDraw /

Chapter 5 - Graphics Devices / Graphics Devices Reference

Routines for Graphics Devices / Creating, Setting, and Disposing of GDevice Records

SetDeviceAttribute

To set the attribute bits of a GDevice record, use the SetDeviceAttribute procedure.

PROCEDURE SetDeviceAttribute (gdh: GDHandle; attribute: Integer; 
                              value: Boolean);

gdh

A handle to a GDevice record.

attribute

One of the following constants, which represent bits in the gdFlags field of a GDevice record:

           CONST {flag bits for gdFlags field of GDevice record}
            gdDevType      = 0;  {if bit is set to 0, graphics }
                                 { device is black and white; }
                                 { if set to 1, device supports }
                                 { color}
            burstDevice    = 7;  {if bit is set to 1, device }
                                 { supports block transfer}
            ext32Device    = 8;  {if bit is set to 1, device }
                                 { must be used in 32-bit mode}
            ramInit        = 10; {if bit is set to 1, device has }
                                 { been initialized from RAM}
            mainScreen     = 11; {if bit is set to 1, device is }
                                 { the main screen}
            allInit        = 12; {if bit is set to 1, all }
                                 { devices were initialized from }
                                 { 'scrn' resource}
            screenDevice   = 13; {if bit is set to 1, device is }
                                 { a screen}
            noDriver       = 14; {if bit is set to 1, GDevice }
                                 { record has no driver}
            screenActive   = 15; {if bit is set to 1, device is }
                                 { active}

value

A value of either 0 or 1 for the flag bit specified in the attribute parameter.

DESCRIPTION

For the graphics device specified in the gdh parameter, the SetDeviceAttribute procedure sets the flag bit specified in the attribute parameter to the value specified in the value parameter.

SPECIAL CONSIDERATIONS

Your application should never directly change the gdFlags field of the GDevice record; instead, your application should use only the SetDeviceAttribute procedure.

The SetDeviceAttribute procedure may move or purge memory blocks in the application heap. Your application should not call this procedure at interrupt time.