1QPaintDeviceMetrics(3qt)                              QPaintDeviceMetrics(3qt)
2
3
4

NAME

6       QPaintDeviceMetrics - Information about a paint device
7

SYNOPSIS

9       #include <qpaintdevicemetrics.h>
10
11   Public Members
12       QPaintDeviceMetrics ( const QPaintDevice * pd )
13       int width () const
14       int height () const
15       int widthMM () const
16       int heightMM () const
17       int logicalDpiX () const
18       int logicalDpiY () const
19       int numColors () const
20       int depth () const
21

DESCRIPTION

23       The QPaintDeviceMetrics class provides information about a paint
24       device.
25
26       Sometimes when drawing graphics it is necessary to obtain information
27       about the physical characteristics of a paint device. This class
28       provides the information. For example, to compute the aspect ratio of a
29       paint device:
30
31               QPaintDeviceMetrics pdm( myWidget );
32               double aspect = (double)pdm.widthMM() / (double)pdm.heightMM();
33
34       QPaintDeviceMetrics contains methods to provide the width and height of
35       a device in both pixels (width() and height()) and millimeters
36       (widthMM() and heightMM()), the number of colors the device supports
37       (numColors()), the number of bit planes (depth()), and the resolution
38       of the device (logicalDpiX() and logicalDpiY()).
39
40       It is not always possible for QPaintDeviceMetrics to compute the values
41       you ask for, particularly for external devices. The ultimate example is
42       asking for the resolution of of a QPrinter that is set to "print to
43       file": who knows what printer that file will end up on?
44
45       See also Graphics Classes and Image Processing Classes.
46

MEMBER FUNCTION DOCUMENTATION

QPaintDeviceMetrics::QPaintDeviceMetrics ( const QPaintDevice * pd )

49       Constructs a metric for the paint device pd.
50

int QPaintDeviceMetrics::depth () const

52       Returns the bit depth (number of bit planes) of the paint device.
53

int QPaintDeviceMetrics::height () const

55       Returns the height of the paint device in default coordinate system
56       units (e.g. pixels for QPixmap and QWidget).
57
58       Examples:
59

int QPaintDeviceMetrics::heightMM () const

61       Returns the height of the paint device, measured in millimeters.
62

int QPaintDeviceMetrics::logicalDpiX () const

64       Returns the horizontal resolution of the device in dots per inch, which
65       is used when computing font sizes. For X, this is usually the same as
66       could be computed from widthMM(), but it varies on Windows.
67
68       Example: qwerty/qwerty.cpp.
69

int QPaintDeviceMetrics::logicalDpiY () const

71       Returns the vertical resolution of the device in dots per inch, which
72       is used when computing font sizes. For X, this is usually the same as
73       could be computed from heightMM(), but it varies on Windows.
74
75       Examples:
76

int QPaintDeviceMetrics::numColors () const

78       Returns the number of different colors available for the paint device.
79       Since this value is an int will not be sufficient to represent the
80       number of colors on 32 bit displays, in which case INT_MAX is returned
81       instead.
82

int QPaintDeviceMetrics::width () const

84       Returns the width of the paint device in default coordinate system
85       units (e.g. pixels for QPixmap and QWidget).
86
87       Examples:
88

int QPaintDeviceMetrics::widthMM () const

90       Returns the width of the paint device, measured in millimeters.
91
92

SEE ALSO

94       http://doc.trolltech.com/qpaintdevicemetrics.html
95       http://www.trolltech.com/faq/tech.html
96
98       Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
99       license file included in the distribution for a complete license
100       statement.
101

AUTHOR

103       Generated automatically from the source code.
104

BUGS

106       If you find a bug in Qt, please report it as described in
107       http://doc.trolltech.com/bughowto.html.  Good bug reports help us to
108       help you. Thank you.
109
110       The definitive Qt documentation is provided in HTML format; it is
111       located at $QTDIR/doc/html and can be read using Qt Assistant or with a
112       web browser. This man page is provided as a convenience for those users
113       who prefer man pages, although this format is not officially supported
114       by Trolltech.
115
116       If you find errors in this manual page, please report them to qt-
117       bugs@trolltech.com.  Please include the name of the manual page
118       (qpaintdevicemetrics.3qt) and the Qt version (3.3.8).
119
120
121
122Trolltech AS                    2 February 2007       QPaintDeviceMetrics(3qt)
Impressum