qpaintengine.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 "qpaintengine.h"
#include "qpaintengine_p.h"
#include "qpainter_p.h"
#include "qpolygon.h"
#include "qbitmap.h"
#include <qdebug.h>
#include <qmath.h>
#include <qguiapplication.h>
#include <qvarlengtharray.h>
#include <qpa/qplatformintegration.h>
#include <qpa/qplatformpixmap.h>
#include <private/qfontengine_p.h>
#include <private/qguiapplication_p.h>
#include <private/qpaintengineex_p.h>
#include <private/qtextengine_p.h>
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
qreal QTextItem::descent() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->descent.toReal();
}
 
qreal QTextItem::ascent() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->ascent.toReal();
}
 
qreal QTextItem::width() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->width.toReal();
}
 
QTextItem::RenderFlags QTextItem::renderFlags() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->flags;
}
 
QString QTextItem::text() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return QString(ti->chars, ti->num_chars);
}
 
QFont QTextItem::font() const
{
    const QTextItemInt *ti = static_cast<const QTextItemInt *>(this);
    return ti->f ? *ti->f : QGuiApplication::font();
}
 
 
void QPaintEngine::syncState()
{
    Q_ASSERT(state);
    updateState(*state);
 
    if (isExtended())
        static_cast<QPaintEngineEx *>(this)->sync();
}
 
static QPaintEngine *qt_polygon_recursion = nullptr;
struct QT_Point {
    int x;
    int y;
};
Q_DECLARE_TYPEINFO(QT_Point, Q_PRIMITIVE_TYPE);
 
void QPaintEngine::drawPolygon(const QPointF *points, int pointCount, PolygonDrawMode mode)
{
    Q_ASSERT_X(qt_polygon_recursion != this, "QPaintEngine::drawPolygon",
               "At least one drawPolygon function must be implemented");
    qt_polygon_recursion = this;
    Q_ASSERT(sizeof(QT_Point) == sizeof(QPoint));
    QVarLengthArray<QT_Point> p(pointCount);
    for (int i = 0; i < pointCount; ++i) {
        p[i].x = qRound(points[i].x());
        p[i].y = qRound(points[i].y());
    }
    drawPolygon((QPoint *)p.data(), pointCount, mode);
    qt_polygon_recursion = nullptr;
}
 
struct QT_PointF {
    qreal x;
    qreal y;
};
Q_DECLARE_TYPEINFO(QT_PointF, Q_PRIMITIVE_TYPE);
 
void QPaintEngine::drawPolygon(const QPoint *points, int pointCount, PolygonDrawMode mode)
{
    Q_ASSERT_X(qt_polygon_recursion != this, "QPaintEngine::drawPolygon",
               "At least one drawPolygon function must be implemented");
    qt_polygon_recursion = this;
    Q_ASSERT(sizeof(QT_PointF) == sizeof(QPointF));
    QVarLengthArray<QT_PointF> p(pointCount);
    for (int i=0; i<pointCount; ++i) {
        p[i].x = points[i].x();
        p[i].y = points[i].y();
    }
    drawPolygon((QPointF *)p.data(), pointCount, mode);
    qt_polygon_recursion = nullptr;
}
 
void QPaintEngine::drawPoints(const QPointF *points, int pointCount)
{
    QPainter *p = painter();
    if (!p)
        return;
 
    qreal penWidth = p->pen().widthF();
    if (penWidth == 0)
        penWidth = 1;
 
    bool ellipses = p->pen().capStyle() == Qt::RoundCap;
 
    p->save();
 
    QTransform transform;
    if (p->pen().isCosmetic()) {
        transform = p->transform();
        p->setTransform(QTransform());
    }
 
    p->setBrush(p->pen().brush());
    p->setPen(Qt::NoPen);
 
    for (int i=0; i<pointCount; ++i) {
        QPointF pos = transform.map(points[i]);
        QRectF rect(pos.x() - penWidth / 2, pos.y() - penWidth / 2, penWidth, penWidth);
 
        if (ellipses)
            p->drawEllipse(rect);
        else
            p->drawRect(rect);
    }
 
    p->restore();
}
 
 
void QPaintEngine::drawPoints(const QPoint *points, int pointCount)
{
    Q_ASSERT(sizeof(QT_PointF) == sizeof(QPointF));
    QT_PointF fp[256];
    while (pointCount) {
        int i = 0;
        while (i < pointCount && i < 256) {
            fp[i].x = points[i].x();
            fp[i].y = points[i].y();
            ++i;
        }
        drawPoints((QPointF *)(void *)fp, i);
        points += i;
        pointCount -= i;
    }
}
 
void QPaintEngine::drawEllipse(const QRectF &rect)
{
    QPainterPath path;
    path.addEllipse(rect);
    if (hasFeature(PainterPaths)) {
        drawPath(path);
    } else {
        QPolygonF polygon = path.toFillPolygon();
        drawPolygon(polygon.data(), polygon.size(), ConvexMode);
    }
}
 
void QPaintEngine::drawEllipse(const QRect &rect)
{
    drawEllipse(QRectF(rect));
}
 
void qt_fill_tile(QPixmap *tile, const QPixmap &pixmap)
{
    QPainter p(tile);
    p.drawPixmap(0, 0, pixmap);
    int x = pixmap.width();
    while (x < tile->width()) {
        p.drawPixmap(x, 0, *tile, 0, 0, x, pixmap.height());
        x *= 2;
    }
    int y = pixmap.height();
    while (y < tile->height()) {
        p.drawPixmap(0, y, *tile, 0, 0, tile->width(), y);
        y *= 2;
    }
}
 
Q_GUI_EXPORT void qt_draw_tile(QPaintEngine *gc, qreal x, qreal y, qreal w, qreal h,
                               const QPixmap &pixmap, qreal xOffset, qreal yOffset)
{
    qreal yPos, xPos, drawH, drawW, yOff, xOff;
    yPos = y;
    yOff = yOffset;
    while(yPos < y + h) {
        drawH = pixmap.height() - yOff;    // Cropping first row
        if (yPos + drawH > y + h)           // Cropping last row
            drawH = y + h - yPos;
        xPos = x;
        xOff = xOffset;
        while(xPos < x + w) {
            drawW = pixmap.width() - xOff; // Cropping first column
            if (xPos + drawW > x + w)           // Cropping last column
                drawW = x + w - xPos;
            if (drawW > 0 && drawH > 0)
                gc->drawPixmap(QRectF(xPos, yPos, drawW, drawH), pixmap, QRectF(xOff, yOff, drawW, drawH));
            xPos += drawW;
            xOff = 0;
        }
        yPos += drawH;
        yOff = 0;
    }
}
 
 
void QPaintEngine::drawTiledPixmap(const QRectF &rect, const QPixmap &pixmap, const QPointF &p)
{
    int sw = pixmap.width();
    int sh = pixmap.height();
 
    if (sw*sh < 8192 && sw*sh < 16*rect.width()*rect.height()) {
        int tw = sw, th = sh;
        while (tw*th < 32678 && tw < rect.width()/2)
            tw *= 2;
        while (tw*th < 32678 && th < rect.height()/2)
            th *= 2;
        QPixmap tile;
        if (pixmap.depth() == 1) {
            tile = QBitmap(tw, th);
        } else {
            tile = QPixmap(tw, th);
            if (pixmap.hasAlphaChannel())
                tile.fill(Qt::transparent);
        }
        qt_fill_tile(&tile, pixmap);
        qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), tile, p.x(), p.y());
    } else {
        qt_draw_tile(this, rect.x(), rect.y(), rect.width(), rect.height(), pixmap, p.x(), p.y());
    }
}
 
void QPaintEngine::drawImage(const QRectF &r, const QImage &image, const QRectF &sr,
                             Qt::ImageConversionFlags flags)
{
    QRectF baseSize(0, 0, image.width(), image.height());
    QImage im = image;
    if (baseSize != sr)
        im = im.copy(qFloor(sr.x()), qFloor(sr.y()),
                     qCeil(sr.width()), qCeil(sr.height()));
    QPixmap pm = QPixmap::fromImage(im, flags);
    drawPixmap(r, pm, QRectF(QPointF(0, 0), pm.size()));
}
 
QPaintEngine::QPaintEngine(PaintEngineFeatures caps)
    : state(nullptr),
      gccaps(caps),
      active(0),
      selfDestruct(false),
      extended(false),
      d_ptr(new QPaintEnginePrivate)
{
    d_ptr->q_ptr = this;
}
 
QPaintEngine::QPaintEngine(QPaintEnginePrivate &dptr, PaintEngineFeatures caps)
    : state(nullptr),
      gccaps(caps),
      active(0),
      selfDestruct(false),
      extended(false),
      d_ptr(&dptr)
{
    d_ptr->q_ptr = this;
}
 
QPaintEngine::~QPaintEngine()
{
}
 
QPainter *QPaintEngine::painter() const
{
    return state ? state->painter() : nullptr;
}
 
void QPaintEngine::drawPath(const QPainterPath &)
{
    if (hasFeature(PainterPaths)) {
        qWarning("QPaintEngine::drawPath: Must be implemented when feature PainterPaths is set");
    }
}
 
void QPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textItem)
{
    const QTextItemInt &ti = static_cast<const QTextItemInt &>(textItem);
    if (ti.glyphs.numGlyphs == 0)
        return;
 
    if (ti.fontEngine->glyphFormat == QFontEngine::Format_ARGB) {
        QVarLengthArray<QFixedPoint> positions;
        QVarLengthArray<glyph_t> glyphs;
        QTransform matrix = QTransform::fromTranslate(p.x(), p.y() - ti.fontEngine->ascent().toReal());
        ti.fontEngine->getGlyphPositions(ti.glyphs, matrix, ti.flags, glyphs, positions);
        painter()->save();
        painter()->setRenderHint(QPainter::SmoothPixmapTransform,
                                 bool((painter()->renderHints() & QPainter::TextAntialiasing)
                                      && !(painter()->font().styleStrategy() & QFont::NoAntialias)));
        for (int i = 0; i < ti.glyphs.numGlyphs; ++i) {
            QImage glyph = ti.fontEngine->bitmapForGlyph(glyphs[i], QFixedPoint(), QTransform());
            painter()->drawImage(positions[i].x.toReal(), positions[i].y.toReal(), glyph);
        }
        painter()->restore();
        return;
    }
 
    QPainterPath path;
    path.setFillRule(Qt::WindingFill);
    ti.fontEngine->addOutlineToPath(0, 0, ti.glyphs, &path, ti.flags);
    if (!path.isEmpty()) {
        painter()->save();
        painter()->setRenderHint(QPainter::Antialiasing,
                                 bool((painter()->renderHints() & QPainter::TextAntialiasing)
                                      && !(painter()->font().styleStrategy() & QFont::NoAntialias)));
        painter()->translate(p.x(), p.y());
        painter()->fillPath(path, painter()->pen().brush());
        painter()->restore();
    }
}
 
void QPaintEngine::drawLines(const QLineF *lines, int lineCount)
{
    for (int i=0; i<lineCount; ++i) {
        QPointF pts[2] = { lines[i].p1(), lines[i].p2() };
 
        if (pts[0] == pts[1]) {
            if (state->pen().capStyle() != Qt::FlatCap)
                drawPoints(pts, 1);
            continue;
        }
 
        drawPolygon(pts, 2, PolylineMode);
    }
}
 
void QPaintEngine::drawLines(const QLine *lines, int lineCount)
{
    struct PointF {
        qreal x;
        qreal y;
    };
    struct LineF {
        PointF p1;
        PointF p2;
    };
    Q_ASSERT(sizeof(PointF) == sizeof(QPointF));
    Q_ASSERT(sizeof(LineF) == sizeof(QLineF));
    LineF fl[256];
    while (lineCount) {
        int i = 0;
        while (i < lineCount && i < 256) {
            fl[i].p1.x = lines[i].x1();
            fl[i].p1.y = lines[i].y1();
            fl[i].p2.x = lines[i].x2();
            fl[i].p2.y = lines[i].y2();
            ++i;
        }
        drawLines((QLineF *)(void *)fl, i);
        lines += i;
        lineCount -= i;
    }
}
 
 
void QPaintEngine::drawRects(const QRect *rects, int rectCount)
{
    struct RectF {
        qreal x;
        qreal y;
        qreal w;
        qreal h;
    };
    Q_ASSERT(sizeof(RectF) == sizeof(QRectF));
    RectF fr[256];
    while (rectCount) {
        int i = 0;
        while (i < rectCount && i < 256) {
            fr[i].x = rects[i].x();
            fr[i].y = rects[i].y();
            fr[i].w = rects[i].width();
            fr[i].h = rects[i].height();
            ++i;
        }
        drawRects((QRectF *)(void *)fr, i);
        rects += i;
        rectCount -= i;
    }
}
 
void QPaintEngine::drawRects(const QRectF *rects, int rectCount)
{
    if (hasFeature(PainterPaths) &&
        !state->penNeedsResolving() &&
        !state->brushNeedsResolving()) {
        for (int i=0; i<rectCount; ++i) {
            QPainterPath path;
            path.addRect(rects[i]);
            if (path.isEmpty())
                continue;
            drawPath(path);
        }
    } else {
        for (int i=0; i<rectCount; ++i) {
            QRectF rf = rects[i];
            QPointF pts[4] = { QPointF(rf.x(), rf.y()),
                               QPointF(rf.x() + rf.width(), rf.y()),
                               QPointF(rf.x() + rf.width(), rf.y() + rf.height()),
                               QPointF(rf.x(), rf.y() + rf.height()) };
            drawPolygon(pts, 4, ConvexMode);
        }
    }
}
 
void QPaintEngine::setPaintDevice(QPaintDevice *device)
{
    d_func()->pdev = device;
}
 
QPaintDevice *QPaintEngine::paintDevice() const
{
    return d_func()->pdev;
}
 
 
QPoint QPaintEngine::coordinateOffset() const
{
    return QPoint();
}
 
void QPaintEngine::setSystemClip(const QRegion &region)
{
    Q_D(QPaintEngine);
    d->baseSystemClip = region;
    // Be backward compatible and only call d->systemStateChanged()
    // if we currently have a system transform/viewport set.
    d->updateSystemClip();
    if (d->hasSystemTransform || d->hasSystemViewport) {
        d->systemStateChanged();
    }
}
 
QRegion QPaintEngine::systemClip() const
{
    return d_func()->systemClip;
}
 
void QPaintEngine::setSystemRect(const QRect &rect)
{
    if (isActive()) {
        qWarning("QPaintEngine::setSystemRect: Should not be changed while engine is active");
        return;
    }
    d_func()->systemRect = rect;
}
 
QRect QPaintEngine::systemRect() const
{
    return d_func()->systemRect;
}
 
QPixmap QPaintEngine::createPixmap(QSize size)
{
    if (Q_UNLIKELY(!qobject_cast<QGuiApplication *>(QCoreApplication::instance()))) {
        qWarning("QPaintEngine::createPixmap: QPixmap cannot be created without a QGuiApplication");
        return QPixmap();
    }
 
    std::unique_ptr<QPlatformPixmap> data(QGuiApplicationPrivate::platformIntegration()->createPlatformPixmap(QPlatformPixmap::PixmapType));
    data->resize(size.width(), size.height());
    return QPixmap(data.release());
}
 
QPixmap QPaintEngine::createPixmapFromImage(QImage image, Qt::ImageConversionFlags flags)
{
    if (Q_UNLIKELY(!qobject_cast<QGuiApplication *>(QCoreApplication::instance()))) {
        qWarning("QPaintEngine::createPixmapFromImage: QPixmap cannot be created without a QGuiApplication");
        return QPixmap();
    }
 
    std::unique_ptr<QPlatformPixmap> data(QGuiApplicationPrivate::platformIntegration()->createPlatformPixmap(QPlatformPixmap::PixmapType));
    if (image.isDetached())
        data->fromImageInPlace(image, flags);
    else
        data->fromImage(image, flags);
    return QPixmap(data.release());
}
 
QPaintEnginePrivate::~QPaintEnginePrivate()
{
}
 
void QPaintEnginePrivate::drawBoxTextItem(const QPointF &p, const QTextItemInt &ti)
{
    if (!ti.glyphs.numGlyphs)
        return;
 
    // any fixes here should probably also be done in QFontEngineBox::draw
    const int size = qRound(ti.fontEngine->ascent());
    QVarLengthArray<QFixedPoint> positions;
    QVarLengthArray<glyph_t> glyphs;
    QTransform matrix = QTransform::fromTranslate(p.x(), p.y() - size);
    ti.fontEngine->getGlyphPositions(ti.glyphs, matrix, ti.flags, glyphs, positions);
    if (glyphs.size() == 0)
        return;
 
    QSize s(size - 3, size - 3);
 
    QPainter *painter = q_func()->state->painter();
    painter->save();
    painter->setBrush(Qt::NoBrush);
    QPen pen = painter->pen();
    pen.setWidthF(ti.fontEngine->lineThickness().toReal());
    painter->setPen(pen);
    for (int k = 0; k < positions.size(); k++)
        painter->drawRect(QRectF(positions[k].toPointF(), s));
    painter->restore();
}
 
QT_END_NAMESPACE