qpaintengine_alpha.cpp

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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 <qtprintsupportglobal.h>
 
#ifndef QT_NO_PRINTER
#include <qdebug.h>
#include "private/qpaintengine_alpha_p.h"
 
#include "private/qpainter_p.h"
#include "private/qpicture_p.h"
#include "private/qfont_p.h"
#include "QtGui/qpicture.h"
 
QT_BEGIN_NAMESPACE
 
QAlphaPaintEngine::QAlphaPaintEngine(QAlphaPaintEnginePrivate &data, PaintEngineFeatures devcaps)
    : QPaintEngine(data, devcaps)
{
 
}
 
QAlphaPaintEngine::~QAlphaPaintEngine()
{
 
}
 
bool QAlphaPaintEngine::begin(QPaintDevice *pdev)
{
    Q_D(QAlphaPaintEngine);
 
    d->m_continueCall = true;
    if (d->m_pass != 0) {
        return true;
    }
 
    d->m_savedcaps = gccaps;
    d->m_pdev = pdev;
 
    d->m_alphaPen = false;
    d->m_alphaBrush = false;
    d->m_alphaOpacity = false;
    d->m_hasalpha = false;
    d->m_advancedPen = false;
    d->m_advancedBrush = false;
    d->m_complexTransform = false;
    d->m_emulateProjectiveTransforms = false;
 
    // clear alpha region
    d->m_alphargn = QRegion();
    d->m_cliprgn = QRegion();
    d->m_pen = QPen();
    d->m_transform = QTransform();
 
    flushAndInit();
 
    return true;
}
 
bool QAlphaPaintEngine::end()
{
    Q_D(QAlphaPaintEngine);
 
    d->m_continueCall = true;
    if (d->m_pass != 0) {
        return true;
    }
 
    flushAndInit(false);
    return true;
}
 
void QAlphaPaintEngine::updateState(const QPaintEngineState &state)
{
    Q_D(QAlphaPaintEngine);
 
    DirtyFlags flags = state.state();
    if (flags & QPaintEngine::DirtyTransform) {
        d->m_transform = state.transform();
        d->m_complexTransform = (d->m_transform.type() > QTransform::TxScale);
        d->m_emulateProjectiveTransforms = !(d->m_savedcaps & QPaintEngine::PerspectiveTransform)
                                           && !(d->m_savedcaps & QPaintEngine::AlphaBlend)
                                           && (d->m_transform.type() >= QTransform::TxProject);
    }
    if (flags & QPaintEngine::DirtyPen) {
        d->m_pen = state.pen();
        if (d->m_pen.style() == Qt::NoPen) {
            d->m_advancedPen = false;
            d->m_alphaPen = false;
        } else {
            d->m_advancedPen = (d->m_pen.brush().style() != Qt::SolidPattern);
            d->m_alphaPen = !d->m_pen.brush().isOpaque();
        }
    }
 
    if (d->m_pass != 0) {
        d->m_continueCall = true;
        return;
    }
    d->m_continueCall = false;
 
    if (flags & QPaintEngine::DirtyOpacity) {
        d->m_alphaOpacity = (state.opacity() != 1.0f);
    }
 
    if (flags & QPaintEngine::DirtyBrush) {
        if (state.brush().style() == Qt::NoBrush) {
            d->m_advancedBrush = false;
            d->m_alphaBrush = false;
        } else {
            d->m_advancedBrush = (state.brush().style() != Qt::SolidPattern);
            d->m_alphaBrush = !state.brush().isOpaque();
        }
    }
 
 
    d->m_hasalpha = d->m_alphaOpacity || d->m_alphaBrush || d->m_alphaPen;
 
    if (d->m_picengine) {
        const QPainter *p = painter();
        d->m_picpainter->setPen(p->pen());
        d->m_picpainter->setBrush(p->brush());
        d->m_picpainter->setBrushOrigin(p->brushOrigin());
        d->m_picpainter->setFont(p->font());
        d->m_picpainter->setOpacity(p->opacity());
        d->m_picpainter->setTransform(p->combinedTransform());
        d->m_picengine->updateState(state);
    }
}
 
void QAlphaPaintEngine::drawPath(const QPainterPath &path)
{
    Q_D(QAlphaPaintEngine);
 
    QRectF tr = d->addPenWidth(path);
 
    if (d->m_pass == 0) {
        d->m_continueCall = false;
        if (d->canSeeTroughBackground(d->m_hasalpha, tr) || d->m_advancedPen || d->m_advancedBrush
            || d->m_emulateProjectiveTransforms)
        {
            d->addAlphaRect(tr);
        }
 
        d->addDirtyRect(tr);
 
        if (d->m_picengine)
            d->m_picengine->drawPath(path);
    } else {
        d->m_continueCall = !d->fullyContained(tr);
    }
}
 
void QAlphaPaintEngine::drawPolygon(const QPointF *points, int pointCount, PolygonDrawMode mode)
{
    Q_D(QAlphaPaintEngine);
 
    QPolygonF poly;
    poly.reserve(pointCount);
    for (int i = 0; i < pointCount; ++i)
        poly.append(points[i]);
 
    QPainterPath path;
    path.addPolygon(poly);
    QRectF tr = d->addPenWidth(path);
 
    if (d->m_pass == 0) {
        d->m_continueCall = false;
        if (d->canSeeTroughBackground(d->m_hasalpha, tr) || d->m_advancedPen || d->m_advancedBrush
            || d->m_emulateProjectiveTransforms)
        {
            d->addAlphaRect(tr);
        }
 
        d->addDirtyRect(tr);
 
        if (d->m_picengine)
            d->m_picengine->drawPolygon(points, pointCount, mode);
    } else {
        d->m_continueCall = !d->fullyContained(tr);
    }
}
 
void QAlphaPaintEngine::drawPixmap(const QRectF &r, const QPixmap &pm, const QRectF &sr)
{
    Q_D(QAlphaPaintEngine);
 
    QRectF tr = d->m_transform.mapRect(r);
    if (d->m_pass == 0) {
        d->m_continueCall = false;
        if (d->canSeeTroughBackground(pm.hasAlpha() || d->m_alphaOpacity, tr) || d->m_complexTransform || pm.isQBitmap()) {
            d->addAlphaRect(tr);
        }
 
        d->addDirtyRect(tr);
 
        if (d->m_picengine)
            d->m_picengine->drawPixmap(r, pm, sr);
 
    } else {
        d->m_continueCall = !d->fullyContained(tr);
    }
}
 
void QAlphaPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem)
{
    Q_D(QAlphaPaintEngine);
 
    QRectF tr(p.x(), p.y() - textItem.ascent(), textItem.width() + 5, textItem.ascent() + textItem.descent() + 5);
    tr = d->m_transform.mapRect(tr);
 
    if (d->m_pass == 0) {
        d->m_continueCall = false;
        if (d->canSeeTroughBackground(d->m_alphaPen || d->m_alphaOpacity, tr) || d->m_advancedPen) {
            d->addAlphaRect(tr);
        }
 
        d->addDirtyRect(tr);
 
        if (d->m_picengine) {
            d->m_picengine->drawTextItem(p, textItem);
        }
    } else {
        d->m_continueCall = !d->fullyContained(tr);
    }
}
 
void QAlphaPaintEngine::drawTiledPixmap(const QRectF &r, const QPixmap &pixmap, const QPointF &s)
{
    Q_D(QAlphaPaintEngine);
 
    QRectF brect = d->m_transform.mapRect(r);
 
    if (d->m_pass == 0) {
        d->m_continueCall = false;
        if (d->canSeeTroughBackground(pixmap.hasAlpha() || d->m_alphaOpacity, brect) || d->m_complexTransform || pixmap.isQBitmap()) {
            d->addAlphaRect(brect);
        }
 
        d->addDirtyRect(brect);
 
        if (d->m_picengine)
            d->m_picengine->drawTiledPixmap(r, pixmap, s);
    } else {
        d->m_continueCall = !d->fullyContained(brect);
    }
}
 
QRegion QAlphaPaintEngine::alphaClipping() const
{
    Q_D(const QAlphaPaintEngine);
    return d->m_cliprgn;
}
 
bool QAlphaPaintEngine::continueCall() const
{
    Q_D(const QAlphaPaintEngine);
    return d->m_continueCall;
}
 
void QAlphaPaintEngine::flushAndInit(bool init)
{
    Q_D(QAlphaPaintEngine);
    Q_ASSERT(d->m_pass == 0);
 
    if (d->m_pic) {
        d->m_picpainter->end();
 
        // set clip region
        d->m_alphargn = d->m_alphargn.intersected(QRect(0, 0, d->m_pdev->width(), d->m_pdev->height()));
 
        // just use the bounding rect if it's a complex region..
        if (d->m_alphargn.rectCount() > 10) {
            QRect br = d->m_alphargn.boundingRect();
            d->m_alphargn = QRegion(br);
        }
 
        const auto oldAlphaRegion = d->m_cliprgn = d->m_alphargn;
 
        // now replay the QPicture
        ++d->m_pass; // we are now doing pass #2
 
        // reset states
        gccaps = d->m_savedcaps;
 
        painter()->save();
        d->resetState(painter());
 
        // make sure the output from QPicture is unscaled
        QTransform mtx;
        mtx.scale(1.0f / (qreal(d->m_pdev->logicalDpiX()) / qreal(qt_defaultDpiX())),
                  1.0f / (qreal(d->m_pdev->logicalDpiY()) / qreal(qt_defaultDpiY())));
        painter()->setTransform(mtx);
        painter()->drawPicture(0, 0, *d->m_pic);
 
        d->m_cliprgn = QRegion();
        d->resetState(painter());
 
        // fill in the alpha images
        for (const auto &rect : oldAlphaRegion)
            d->drawAlphaImage(rect);
 
        d->m_alphargn = QRegion();
 
        painter()->restore();
 
        --d->m_pass; // pass #2 finished
 
        cleanUp();
    }
 
    if (init) {
        gccaps = PaintEngineFeatures(AllFeatures & ~QPaintEngine::ObjectBoundingModeGradients);
 
        d->m_pic = new QPicture();
        d->m_pic->d_ptr->in_memory_only = true;
        d->m_picpainter = new QPainter(d->m_pic);
        d->m_picengine = d->m_picpainter->paintEngine();
 
        // When newPage() is called and the m_picpainter is recreated
        // we have to copy the current state of the original printer
        // painter back to the m_picpainter
        d->m_picpainter->setPen(painter()->pen());
        d->m_picpainter->setBrush(painter()->brush());
        d->m_picpainter->setBrushOrigin(painter()->brushOrigin());
        d->m_picpainter->setFont(painter()->font());
        d->m_picpainter->setOpacity(painter()->opacity());
        d->m_picpainter->setTransform(painter()->combinedTransform());
        d->m_picengine->syncState();
        QPainterState &state = *d->m_picpainter->d_func()->state;
        QPainter *oldPainter = state.painter;
        state = *painter()->d_func()->state;
        state.painter = oldPainter;
    }
}
 
void QAlphaPaintEngine::cleanUp()
{
    Q_D(QAlphaPaintEngine);
 
    delete d->m_picpainter;
    delete d->m_pic;
 
    d->m_picpainter = nullptr;
    d->m_pic = nullptr;
    d->m_picengine = nullptr;
}
 
QAlphaPaintEnginePrivate::QAlphaPaintEnginePrivate()
    :   m_pass(0),
        m_pic(nullptr),
        m_picengine(nullptr),
        m_picpainter(nullptr),
        m_numberOfCachedRects(0),
        m_hasalpha(false),
        m_alphaPen(false),
        m_alphaBrush(false),
        m_alphaOpacity(false),
        m_advancedPen(false),
        m_advancedBrush(false),
        m_complexTransform(false)
{
 
}
 
QAlphaPaintEnginePrivate::~QAlphaPaintEnginePrivate()
{
    delete m_picpainter;
    delete m_pic;
}
 
QRectF QAlphaPaintEnginePrivate::addPenWidth(const QPainterPath &path)
{
    QPainterPath tmp = path;
 
    if (m_pen.style() == Qt::NoPen)
        return (path.controlPointRect() * m_transform).boundingRect();
    bool cosmetic = m_pen.isCosmetic();
    if (cosmetic)
        tmp = path * m_transform;
 
    QPainterPathStroker stroker;
    if (m_pen.widthF() == 0.0f)
        stroker.setWidth(1.0);
    else
        stroker.setWidth(m_pen.widthF());
    stroker.setJoinStyle(m_pen.joinStyle());
    stroker.setCapStyle(m_pen.capStyle());
    tmp = stroker.createStroke(tmp);
    if (cosmetic)
        return tmp.controlPointRect();
 
    return (tmp.controlPointRect() * m_transform).boundingRect();
}
 
void QAlphaPaintEnginePrivate::addAlphaRect(const QRectF &rect)
{
    m_alphargn |= rect.toAlignedRect();
}
 
bool QAlphaPaintEnginePrivate::canSeeTroughBackground(bool somethingInRectHasAlpha, const QRectF &rect) const
{
    if (somethingInRectHasAlpha) {
        if (m_dirtyRects.size() != m_numberOfCachedRects) {
            m_cachedDirtyRgn.setRects(m_dirtyRects.constData(), m_dirtyRects.size());
            m_numberOfCachedRects = m_dirtyRects.size();
        }
        return m_cachedDirtyRgn.intersects(rect.toAlignedRect());
    }
    return false;
}
 
void QAlphaPaintEnginePrivate::drawAlphaImage(const QRectF &rect)
{
    Q_Q(QAlphaPaintEngine);
 
    qreal dpiX = qMax(m_pdev->logicalDpiX(), 300);
    qreal dpiY = qMax(m_pdev->logicalDpiY(), 300);
    qreal xscale = (dpiX / m_pdev->logicalDpiX());
    qreal yscale = (dpiY / m_pdev->logicalDpiY());
 
    QTransform picscale;
    picscale.scale(xscale, yscale);
 
    const int tileSize = 2048;
    QSize size((int(rect.width() * xscale)), int(rect.height() * yscale));
    int divw = (size.width() / tileSize);
    int divh = (size.height() / tileSize);
    divw += 1;
    divh += 1;
 
    int incx = int(rect.width() / divw);
    int incy = int(rect.height() / divh);
 
    for (int y=0; y<divh; ++y) {
        int ypos = int((incy * y) + rect.y());
        int height = int((y == (divh - 1)) ? (rect.height() - (incy * y)) : incy) + 1;
 
        for (int x=0; x<divw; ++x) {
            int xpos = int((incx * x) + rect.x());
            int width = int((x == (divw - 1)) ? (rect.width() - (incx * x)) : incx) + 1;
 
            QSize imgsize((int)(width * xscale), (int)(height * yscale));
            QImage img(imgsize, QImage::Format_RGB32);
            img.fill(0xffffffff);
 
            QPainter imgpainter(&img);
            imgpainter.setTransform(picscale);
            QPointF picpos(qreal(-xpos), qreal(-ypos));
            imgpainter.drawPicture(picpos, *m_pic);
            imgpainter.end();
 
            q->painter()->setTransform(QTransform());
            QRect r(xpos, ypos, width, height);
            q->painter()->drawImage(r, img);
        }
    }
}
 
bool QAlphaPaintEnginePrivate::fullyContained(const QRectF &rect) const
{
    QRegion r(rect.toAlignedRect());
    return (m_cliprgn.intersected(r) == r);
}
 
void QAlphaPaintEnginePrivate::resetState(QPainter *p)
{
    p->setPen(QPen());
    p->setBrush(QBrush());
    p->setBrushOrigin(0,0);
    p->setBackground(QBrush());
    p->setFont(QFont());
    p->setTransform(QTransform());
    // The view transform is already recorded and included in the
    // picture we're about to replay. If we don't turn if off,
    // the view matrix will be applied twice.
    p->setViewTransformEnabled(false);
    p->setClipRegion(QRegion(), Qt::NoClip);
    p->setClipPath(QPainterPath(), Qt::NoClip);
    p->setClipping(false);
    p->setOpacity(1.0f);
}
 
 
QT_END_NAMESPACE
 
#endif // QT_NO_PRINTER