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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qpaintdevice.h"
QT_BEGIN_NAMESPACE
QPaintDevice::QPaintDevice() noexcept
{
painters = 0;
}
QPaintDevice::~QPaintDevice()
{
if (paintingActive())
qWarning("QPaintDevice: Cannot destroy paint device that is being "
"painted");
}
/*!
\internal
*/
// ### Qt 7: Replace this workaround mechanism: virtual devicePixelRatio() and virtual metricF()
inline double QPaintDevice::getDecodedMetricF(PaintDeviceMetric metricA, PaintDeviceMetric metricB) const
{
qint32 buf[2];
// The Encoded metric enum values come in pairs of one odd and one even value.
// We map those to the 0 and 1 indexes of buf by taking just the least significant bit.
// Same mapping here as in the encodeMetricF() function, to ensure correct order.
buf[metricA & 1] = metric(metricA);
buf[metricB & 1] = metric(metricB);
double res;
memcpy(&res, buf, sizeof(res));
return res;
}
qreal QPaintDevice::devicePixelRatio() const
{
Q_STATIC_ASSERT((PdmDevicePixelRatioF_EncodedA & 1) != (PdmDevicePixelRatioF_EncodedB & 1));
double res;
int scaledDpr = metric(PdmDevicePixelRatioScaled);
if (scaledDpr == int(devicePixelRatioFScale())) {
res = 1; // Shortcut for common case
} else if (scaledDpr == 2 * int(devicePixelRatioFScale())) {
res = 2; // Shortcut for common case
} else {
res = getDecodedMetricF(PdmDevicePixelRatioF_EncodedA, PdmDevicePixelRatioF_EncodedB);
if (res <= 0) // These metrics not implemented, fall back to PdmDevicePixelRatioScaled
res = scaledDpr / devicePixelRatioFScale();
}
return res;
}
/*!
\internal
*/
void QPaintDevice::initPainter(QPainter *) const
{
}
/*!
\internal
*/
QPaintDevice *QPaintDevice::redirected(QPoint *) const
{
return nullptr;
}
/*!
\internal
*/
QPainter *QPaintDevice::sharedPainter() const
{
return nullptr;
}
Q_GUI_EXPORT int qt_paint_device_metric(const QPaintDevice *device, QPaintDevice::PaintDeviceMetric metric)
{
return device->metric(metric);
}
int QPaintDevice::metric(PaintDeviceMetric m) const
{
// Fallback: A subclass has not implemented PdmDevicePixelRatioScaled but might
// have implemented PdmDevicePixelRatio.
if (m == PdmDevicePixelRatioScaled)
return this->metric(PdmDevicePixelRatio) * devicePixelRatioFScale();
qWarning("QPaintDevice::metrics: Device has no metric information");
if (m == PdmDpiX) {
return 72;
} else if (m == PdmDpiY) {
return 72;
} else if (m == PdmNumColors) {
// FIXME: does this need to be a real value?
return 256;
} else if (m == PdmDevicePixelRatio) {
return 1;
} else if (m == PdmDevicePixelRatioF_EncodedA || m == PdmDevicePixelRatioF_EncodedB) {
return 0;
} else {
qDebug("Unrecognised metric %d!",m);
return 0;
}
}
QT_END_NAMESPACE
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