| 1 | // Copyright (C) 2016 The Qt Company Ltd. |
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| 2 | // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only |
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| 3 | |
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| 4 | #include "qpaintdevice.h" |
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| 5 | |
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| 6 | QT_BEGIN_NAMESPACE |
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| 7 | |
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| 8 | QPaintDevice::QPaintDevice() noexcept |
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| 9 | { |
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| 10 | painters = 0; |
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| 11 | } |
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| 12 | |
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| 13 | QPaintDevice::~QPaintDevice() |
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| 14 | { |
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| 15 | if (paintingActive()) |
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| 16 | qWarning(msg: "QPaintDevice: Cannot destroy paint device that is being " |
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| 17 | "painted" ); |
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| 18 | } |
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| 19 | |
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| 20 | /*! |
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| 21 | \internal |
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| 22 | */ |
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| 23 | // ### Qt 7: Replace this workaround mechanism: virtual devicePixelRatio() and virtual metricF() |
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| 24 | double QPaintDevice::getDecodedMetricF(PaintDeviceMetric metricA, PaintDeviceMetric metricB) const |
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| 25 | { |
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| 26 | qint32 buf[2]; |
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| 27 | // The Encoded metric enum values come in pairs of one odd and one even value. |
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| 28 | // We map those to the 0 and 1 indexes of buf by taking just the least significant bit. |
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| 29 | // Same mapping here as in the encodeMetricF() function, to ensure correct order. |
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| 30 | buf[metricA & 1] = metric(metric: metricA); |
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| 31 | buf[metricB & 1] = metric(metric: metricB); |
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| 32 | double res; |
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| 33 | memcpy(dest: &res, src: buf, n: sizeof(res)); |
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| 34 | return res; |
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| 35 | } |
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| 36 | |
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| 37 | qreal QPaintDevice::devicePixelRatio() const |
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| 38 | { |
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| 39 | Q_STATIC_ASSERT((PdmDevicePixelRatioF_EncodedA & 1) != (PdmDevicePixelRatioF_EncodedB & 1)); |
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| 40 | double res; |
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| 41 | int scaledDpr = metric(metric: PdmDevicePixelRatioScaled); |
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| 42 | if (scaledDpr == int(devicePixelRatioFScale())) { |
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| 43 | res = 1; // Shortcut for common case |
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| 44 | } else if (scaledDpr == 2 * int(devicePixelRatioFScale())) { |
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| 45 | res = 2; // Shortcut for common case |
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| 46 | } else { |
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| 47 | res = getDecodedMetricF(metricA: PdmDevicePixelRatioF_EncodedA, metricB: PdmDevicePixelRatioF_EncodedB); |
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| 48 | if (res <= 0) // These metrics not implemented, fall back to PdmDevicePixelRatioScaled |
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| 49 | res = scaledDpr / devicePixelRatioFScale(); |
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| 50 | } |
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| 51 | return res; |
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| 52 | } |
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| 53 | |
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| 54 | /*! |
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| 55 | \internal |
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| 56 | */ |
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| 57 | void QPaintDevice::initPainter(QPainter *) const |
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| 58 | { |
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| 59 | } |
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| 60 | |
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| 61 | /*! |
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| 62 | \internal |
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| 63 | */ |
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| 64 | QPaintDevice *QPaintDevice::redirected(QPoint *) const |
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| 65 | { |
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| 66 | return nullptr; |
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| 67 | } |
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| 68 | |
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| 69 | /*! |
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| 70 | \internal |
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| 71 | */ |
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| 72 | QPainter *QPaintDevice::sharedPainter() const |
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| 73 | { |
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| 74 | return nullptr; |
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| 75 | } |
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| 76 | |
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| 77 | Q_GUI_EXPORT int qt_paint_device_metric(const QPaintDevice *device, QPaintDevice::PaintDeviceMetric metric) |
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| 78 | { |
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| 79 | return device->metric(metric); |
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| 80 | } |
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| 81 | |
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| 82 | int QPaintDevice::metric(PaintDeviceMetric m) const |
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| 83 | { |
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| 84 | // Fallback: A subclass has not implemented PdmDevicePixelRatioScaled but might |
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| 85 | // have implemented PdmDevicePixelRatio. |
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| 86 | if (m == PdmDevicePixelRatioScaled) |
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| 87 | return this->metric(m: PdmDevicePixelRatio) * devicePixelRatioFScale(); |
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| 88 | |
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| 89 | qWarning(msg: "QPaintDevice::metrics: Device has no metric information" ); |
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| 90 | |
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| 91 | if (m == PdmDpiX) { |
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| 92 | return 72; |
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| 93 | } else if (m == PdmDpiY) { |
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| 94 | return 72; |
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| 95 | } else if (m == PdmNumColors) { |
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| 96 | // FIXME: does this need to be a real value? |
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| 97 | return 256; |
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| 98 | } else if (m == PdmDevicePixelRatio) { |
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| 99 | return 1; |
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| 100 | } else if (m == PdmDevicePixelRatioF_EncodedA || m == PdmDevicePixelRatioF_EncodedB) { |
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| 101 | return 0; |
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| 102 | } else { |
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| 103 | qDebug(msg: "Unrecognised metric %d!" ,m); |
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| 104 | return 0; |
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| 105 | } |
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| 106 | } |
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| 107 | |
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| 108 | QT_END_NAMESPACE |
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| 109 | |
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