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Inside Macintosh: Imaging With QuickDraw /

Chapter 9 - Printing Manager / Printing Manager Reference

Printing Manager Routines / Low-Level Routines

PrCtlCall

You can use the PrCtlCall procedure to send various requests to the current printer driver.

PROCEDURE PrCtlCall (iWhichCtl: Integer; lParam1: LongInt; 
                     lParam2: LongInt; lParam3: LongInt);

iWhichCtl

A value that indicates the operation to perform. You can use these constants in this parameter:

          CONST
            iPrBitsCtl     = 4;  {print a bitmap object}
            iPrIOCtl       = 5;  {perform text streaming}
            iPrEvtCtl      = 6;  {print object specified in }
                                 { lParam1 parameter}
            iPrDevCtl      = 7;  {device control command}

lParam1

The use of this parameter varies according to the value in the iWhichCtl parameter. See the following paragraphs for this information.

lParam2

The use of this parameter varies according to the value in the iWhichCtl parameter. See the following paragraphs for this information.

lParam3

The use of this parameter varies according to the value in the iWhichCtl parameter. See the following paragraphs for this information.

DESCRIPTION

The PrCtlCall procedure performs the operation indicated by the iWhichCtl parameter. Depending on the operation, PrCtlCall may also use information in the lParam1, lParam2, and lParam3 parameters. The PrCtlCall procedure calls the printer driver's control routine. Instead of sending the low-level calls to the printer driver, the PrCtlCall procedure converts the call into its high-level equivalent before execution.

You can use the PrCtlCall procedure with the iPrBitsCtl control constant when you want to print bitmaps. In this case, you should supply the parameters to PrCtlCall with the following information:

iWhichCtl

The constant iPrBitsCtl. This constant allows you to send all or part of a QuickDraw bitmap directly to the printer.

lParam1

A pointer to the QuickDraw bitmap to print.

lParam2

A pointer to the rectangle you want to print.

lParam3

The type of resolution used to print the bitmap. The LaserWriter printer driver ignores this flag. This parameter can have one of the following values:

	Constant	Value	Description
	lScreenBits	$00000000	The resolution is 80 by 72 dpi
	lPaintBits	$00000001	The resolution is 72 by 72 dpi
	lHiScreenBits	$00000002	The resolution is 160 by 144 dpi
	lHiPaintBits	$00000003	The resolution is 144 by 144 dpi

You can use the PrCtlCall procedure with the iPrIOCtl control constant when you want text streaming in your application. (Text streaming is useful for fast printing of text when speed is more important than visual fidelity or formatting. It makes no use of QuickDraw.) In this case, you should supply the parameters to PrCtlCall with the following information:

iWhichCtl

The constant iPrIOCtl. This constant causes text streaming to occur.

lParam1

A pointer to the beginning of the text.

lParam2

The number of bytes to transfer. The high-order word must be 0.

lParam3

This should be 0.

You can use the PrCtlCall procedure with the iPrEvtCtl control constant for printing the screen or the frontmost window on most ImageWriter printers. (The LaserWriter printer driver does not support this call.) In this case, you should supply the parameters to PrCtlCall with the following information:

iWhichCtl

The constant iPrEvtCtl. This constant prints the object you have selected using the lParam1 parameter.

lParam1

This parameter selects the object to be printed. If this value is $00000000, you want to print the screen. If this value is $00010000, you want to print the frontmost window.

lParam2

This should be NIL.

lParam3

This should be NIL.

You can use the PrCtlCall procedure with the iPrDevCtl control constant for controlling the printer device. In this case, you should supply the parameters to PrCtlCall with the following information:

iWhichCtl

The constant iPrDevCtl.

lParam1

The action you want to take. The values possible for this parameter are listed in Table 9-1.

lParam2

This should be NIL.

lParam3

This should be NIL.

Values for the lParam1 parameter when using the iPrDevCtl control constant

Constant	Value	Description
lPrDocOpen	$00010000	Opens the document. This is similar to the high-level routine PrOpenDoc and should be followed with a call to PrCtlCall with the iPrDetl control call and an lParam1 value of lPrDocClose.
lPrReset	$00010000	Reserved.
lPrPageClose	$00020000	Closes the page. This is similar to the high-level routine PrClosePage and should follow a call to PrCtlCall with the iPrDevCtl control call and an lParam1 value of lPrPageOpen.
lPrPageEnd	$00020000	Same as lPrPageClose.
lPrLineFeed	$00030000	Paper advance.
lPrLFStd	$0003FFFF	Carriage return with line feed. The ImageWriter printer driver causes a carriage return plus a paper feed of one-sixth of an inch. The LaserWriter printer driver moves the pen location down the page.
lPrPageOpen	$00040000	Opens the page for printing. This is similar to the high-level routine PrOpenPage and should be followed with a call to PrCtlCall with the iPrDevCtl control call and an lParam1 value of lPrPageClose.
lPrDocClose	$00050000	Closes the document. This is similar to the high-level routine PrCloseDoc and should follow a call to PrCtlCall with the iPrDevCtl control call and an lParam1 value of lPrDocOpen.

SPECIAL CONSIDERATIONS

Apple strongly discourages you from using this routine.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for the PrCtlCall procedure are

Trap macro	Selector
_PrGlue	$A0000E00