getpixels.3

linux系统下的音频通信

'\"
'\" Copyright (c) 1990 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" SCCS: @(#) GetPixels.3 1.8 96/03/26 18:11:30
'\" 
.so man.macros
.TH Tk_GetPixels 3 "" Tk "Tk Library Procedures"
.BS
.SH NAME
Tk_GetPixels, Tk_GetScreenMM \- translate between strings and screen units
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
int
\fBTk_GetPixels(\fIinterp, tkwin, string, intPtr\fB)\fR
.sp
int
\fBTk_GetScreenMM(\fIinterp, tkwin, string, doublePtr\fB)\fR
.SH ARGUMENTS
.AS "Tcl_Interp" *joinPtr
.AP Tcl_Interp *interp in
Interpreter to use for error reporting.
.AP Tk_Window tkwin in
Window whose screen geometry determines the conversion between absolute
units and pixels. 
.AP char *string in
String that specifies a distance on the screen.
.AP int *intPtr out
Pointer to location in which to store converted distance in pixels.
.AP double *doublePtr out
Pointer to location in which to store converted distance in millimeters.
.BE

.SH DESCRIPTION
.PP
These two procedures take as argument a specification of distance on
the screen (\fIstring\fR) and compute the corresponding distance
either in integer pixels or floating-point millimeters.
In either case, \fIstring\fR specifies a screen distance as a
floating-point number followed by one of the following characters
that indicates units:
.TP
<none>
The number specifies a distance in pixels.
.TP
\fBc\fR
The number specifies a distance in centimeters on the screen.
.TP
\fBi\fR
The number specifies a distance in inches on the screen.
.TP
\fBm\fR
The number specifies a distance in millimeters on the screen.
.TP
\fBp\fR
The number specifies a distance in printer's points (1/72 inch)
on the screen.
.PP
\fBTk_GetPixels\fR converts \fIstring\fR to the nearest even
number of pixels and stores that value at \fI*intPtr\fR.
\fBTk_GetScreenMM\fR converts \fIstring\fR to millimeters and
stores the double-precision floating-point result at \fI*doublePtr\fR.
.PP
Both procedures return \fBTCL_OK\fR under normal circumstances.
If an error occurs (e.g. \fIstring\fR contains a number followed
by a character that isn't one of the ones above) then
\fBTCL_ERROR\fR is returned and an error message is left
in \fIinterp->result\fR.

.SH KEYWORDS
centimeters, convert, inches, millimeters, pixels, points, screen units