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39
40#include "qpaintdevice.h"
41
42QT_BEGIN_NAMESPACE
43
44QPaintDevice::QPaintDevice() noexcept
45{
46 reserved = nullptr;
47 painters = 0;
48}
49
50QPaintDevice::~QPaintDevice()
51{
52 if (paintingActive())
53 qWarning(msg: "QPaintDevice: Cannot destroy paint device that is being "
54 "painted");
55}
56
57
58/*!
59 \internal
60*/
61void QPaintDevice::initPainter(QPainter *) const
62{
63}
64
65/*!
66 \internal
67*/
68QPaintDevice *QPaintDevice::redirected(QPoint *) const
69{
70 return nullptr;
71}
72
73/*!
74 \internal
75*/
76QPainter *QPaintDevice::sharedPainter() const
77{
78 return nullptr;
79}
80
81Q_GUI_EXPORT int qt_paint_device_metric(const QPaintDevice *device, QPaintDevice::PaintDeviceMetric metric)
82{
83 return device->metric(metric);
84}
85
86int QPaintDevice::metric(PaintDeviceMetric m) const
87{
88 // Fallback: A subclass has not implemented PdmDevicePixelRatioScaled but might
89 // have implemented PdmDevicePixelRatio.
90 if (m == PdmDevicePixelRatioScaled)
91 return this->metric(m: PdmDevicePixelRatio) * devicePixelRatioFScale();
92
93 qWarning(msg: "QPaintDevice::metrics: Device has no metric information");
94
95 if (m == PdmDpiX) {
96 return 72;
97 } else if (m == PdmDpiY) {
98 return 72;
99 } else if (m == PdmNumColors) {
100 // FIXME: does this need to be a real value?
101 return 256;
102 } else if (m == PdmDevicePixelRatio) {
103 return 1;
104 } else {
105 qDebug(msg: "Unrecognised metric %d!",m);
106 return 0;
107 }
108}
109
110QT_END_NAMESPACE
111

source code of qtbase/src/gui/painting/qpaintdevice.cpp