tqt3/doc/man/man3/tqpaintdevicemetrics.3qt

'\" t
.TH TQPaintDeviceMetrics 3qt "2 February 2007" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2007 Trolltech ASA.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
TQPaintDeviceMetrics \- Information about a paint device
.SH SYNOPSIS
\fC#include <tqpaintdevicemetrics.h>\fR
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBTQPaintDeviceMetrics\fR ( const TQPaintDevice * pd )"
.br
.ti -1c
.BI "int \fBwidth\fR () const"
.br
.ti -1c
.BI "int \fBheight\fR () const"
.br
.ti -1c
.BI "int \fBwidthMM\fR () const"
.br
.ti -1c
.BI "int \fBheightMM\fR () const"
.br
.ti -1c
.BI "int \fBlogicalDpiX\fR () const"
.br
.ti -1c
.BI "int \fBlogicalDpiY\fR () const"
.br
.ti -1c
.BI "int \fBnumColors\fR () const"
.br
.ti -1c
.BI "int \fBdepth\fR () const"
.br
.in -1c
.SH DESCRIPTION
The TQPaintDeviceMetrics class provides information about a paint device.
.PP
Sometimes when drawing graphics it is necessary to obtain information about the physical characteristics of a paint device. This class provides the information. For example, to compute the aspect ratio of a paint device:
.PP
.nf
.br
        TQPaintDeviceMetrics pdm( myWidget );
.br
        double aspect = (double)pdm.widthMM() / (double)pdm.heightMM();
.br
.fi
.PP
TQPaintDeviceMetrics contains methods to provide the width and height of a device in both pixels (width() and height()) and millimeters (widthMM() and heightMM()), the number of colors the device supports (numColors()), the number of bit planes (depth()), and the resolution of the device (logicalDpiX() and logicalDpiY()).
.PP
It is not always possible for TQPaintDeviceMetrics to compute the values you ask for, particularly for external devices. The ultimate example is asking for the resolution of of a TQPrinter that is set to "print to file": who knows what printer that file will end up on?
.PP
See also Graphics Classes and Image Processing Classes.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "TQPaintDeviceMetrics::TQPaintDeviceMetrics ( const TQPaintDevice * pd )"
Constructs a metric for the paint device \fIpd\fR.
.SH "int TQPaintDeviceMetrics::depth () const"
Returns the bit depth (number of bit planes) of the paint device.
.SH "int TQPaintDeviceMetrics::height () const"
Returns the height of the paint device in default coordinate system units (e.g. pixels for TQPixmap and TQWidget).
.PP
Examples:
.)l action/application.cpp, application/application.cpp, helpviewer/helpwindow.cpp, mdi/application.cpp, and qwerty/qwerty.cpp.
.SH "int TQPaintDeviceMetrics::heightMM () const"
Returns the height of the paint device, measured in millimeters.
.SH "int TQPaintDeviceMetrics::logicalDpiX () const"
Returns the horizontal resolution of the device in dots per inch, which is used when computing font sizes. For X, this is usually the same as could be computed from widthMM(), but it varies on Windows.
.PP
Example: qwerty/qwerty.cpp.
.SH "int TQPaintDeviceMetrics::logicalDpiY () const"
Returns the vertical resolution of the device in dots per inch, which is used when computing font sizes. For X, this is usually the same as could be computed from heightMM(), but it varies on Windows.
.PP
Examples:
.)l action/application.cpp, application/application.cpp, helpviewer/helpwindow.cpp, and mdi/application.cpp.
.SH "int TQPaintDeviceMetrics::numColors () const"
Returns the number of different colors available for the paint device. Since this value is an int will not be sufficient to represent the number of colors on 32 bit displays, in which case INT_MAX is returned instead.
.SH "int TQPaintDeviceMetrics::width () const"
Returns the width of the paint device in default coordinate system units (e.g. pixels for TQPixmap and TQWidget).
.PP
Examples:
.)l action/application.cpp, application/application.cpp, helpviewer/helpwindow.cpp, mdi/application.cpp, and qwerty/qwerty.cpp.
.SH "int TQPaintDeviceMetrics::widthMM () const"
Returns the width of the paint device, measured in millimeters.

.SH "SEE ALSO"
.BR http://doc.trolltech.com/tqpaintdevicemetrics.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
license file included in the distribution for a complete license
statement.
.SH AUTHOR
Generated automatically from the source code.
.SH BUGS
If you find a bug in Qt, please report it as described in
.BR http://doc.trolltech.com/bughowto.html .
Good bug reports help us to help you. Thank you.
.P
The definitive TQt documentation is provided in HTML format; it is
located at $TQTDIR/doc/html and can be read using TQt Assistant or with
a web browser. This man page is provided as a convenience for those
users who prefer man pages, although this format is not officially
supported by Trolltech. 
.P
If you find errors in this manual page, please report them to
.BR qt-bugs@trolltech.com .
Please include the name of the manual page (tqpaintdevicemetrics.3qt) and the Qt
version (3.3.8).