The Q3PaintDeviceMetrics class provides information about a paint device. More...
#include <Q3PaintDeviceMetrics>This class is part of the Qt 3 support library. It is provided to keep old source code working. We strongly advise against using it in new code. See Porting to Qt 4 for more information.
| Q3PaintDeviceMetrics ( const QPaintDevice * pd ) | |
| int | depth () const |
| int | height () const |
| int | heightMM () const |
| int | logicalDpiX () const |
| int | logicalDpiY () const |
| int | numColors () const |
| int | width () const |
| int | widthMM () const |
The Q3PaintDeviceMetrics class provides information about a paint device.
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:
Q3PaintDeviceMetrics pdm(myWidget); double aspect = (double)pdm.widthMM() / (double)pdm.heightMM();
Q3PaintDeviceMetrics 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()).
It is not always possible for Q3PaintDeviceMetrics to compute the values you ask for, particularly for external devices. The ultimate example is asking for the resolution of of a QPrinter that is set to "print to file": who knows what printer that file will end up on?
Constructs a metric for the paint device pd.
Returns the bit depth (number of bit planes) of the paint device.
Returns the height of the paint device in default coordinate system units (e.g. pixels for QPixmap and QWidget).
Returns the height of the paint device, measured in millimeters.
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.
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.
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.
Returns the width of the paint device in default coordinate system units (e.g. pixels for QPixmap and QWidget).
Returns the width of the paint device, measured in millimeters.