qpainter.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// QtCore
#include <qdebug.h>

// QtGui
#include "qbitmap.h"
#include "qimage.h"
#include "qpaintdevice.h"
#include "qpaintengine.h"
#include "qpainter.h"
#include "qpainter_p.h"
#include "qpainterpath.h"
#include "qpicture.h"
#include "qpixmapcache.h"
#include "qpolygon.h"
#include "qtextlayout.h"
#include "qwidget.h"
#include "qapplication.h"
#include "qstyle.h"
#include "qthread.h"
#include "qvarlengtharray.h"

#include <private/qfontengine_p.h>
#include <private/qpaintengine_p.h>
#include <private/qpainterpath_p.h>
#include <private/qtextengine_p.h>
#include <private/qwidget_p.h>

// Other
#include <math.h>

// #define QT_DEBUG_DRAW
#ifdef QT_DEBUG_DRAW
bool qt_show_painter_debug_output = true;
#endif

extern QPixmap qt_pixmapForBrush(int style, bool invert);

void qt_format_text(const QFont &font,
                    const QRectF &_r, int tf, const QString& str, QRectF *brect,
                    int tabstops, int* tabarray, int tabarraylen,
                    QPainter *painter);

void QPainterPrivate::draw_helper(const QPainterPath &originalPath, DrawOperation op)
{
#ifdef QT_DEBUG_DRAW
    if (qt_show_painter_debug_output) {
        printf("QPainter::drawHelper\n");
    }
#endif

    if (originalPath.isEmpty())
        return;

    Q_Q(QPainter);
    int devMinX = 0, devMaxX = 0, devMinY = 0, devMaxY = 0;

    qreal strokeOffsetX = 0, strokeOffsetY = 0;

    QPainterPath path = originalPath * state->matrix;
    QRectF pathBounds = path.boundingRect();
    QRectF strokeBounds;
    bool doStroke = (op & StrokeDraw) && (state->pen.style() != Qt::NoPen);
    if (doStroke) {
        qreal penWidth = state->pen.widthF();
        if (penWidth == 0) {
            strokeOffsetX = 1;
            strokeOffsetY = 1;
        } else {
            // In case of complex xform
            if (state->txop > TxScale) {
                QPainterPathStroker stroker;
                stroker.setWidth(penWidth);
                stroker.setJoinStyle(state->pen.joinStyle());
                stroker.setCapStyle(state->pen.capStyle());
                QPainterPath stroke = stroker.createStroke(originalPath);
                strokeBounds = (stroke * state->matrix).boundingRect();
            } else {
                strokeOffsetX = penWidth / 2.0 * state->matrix.m11();
                strokeOffsetY = penWidth / 2.0 * state->matrix.m22();
            }
        }
    }

    const qreal ROUND_UP_TRICK = 0.9999;
    if (!strokeBounds.isEmpty()) {
        devMinX = int(strokeBounds.left());
        devMaxX = int(strokeBounds.right() + ROUND_UP_TRICK);
        devMinY = int(strokeBounds.top());
        devMaxY = int(strokeBounds.bottom() + ROUND_UP_TRICK);
    } else {
        devMinX = int(pathBounds.left() - strokeOffsetX);
        devMaxX = int(pathBounds.right() + strokeOffsetX + ROUND_UP_TRICK);
        devMinY = int(pathBounds.top() - strokeOffsetY);
        devMaxY = int(pathBounds.bottom() + strokeOffsetY + ROUND_UP_TRICK);
    }

    QRect absPathRect(devMinX, devMinY, devMaxX - devMinX, devMaxY - devMinY);

    if (state->clipInfo.size() != 0) {
        QRegion r = q->clipRegion() * q->deviceMatrix();
        absPathRect = absPathRect.intersect(r.boundingRect());
    }
    absPathRect = absPathRect.intersect(QRect(0, 0, device->width(), device->height()));


//     qDebug("\nQPainterPrivate::draw_helper(), x=%d, y=%d, w=%d, h=%d",
//            devMinX, devMinY, device->width(), device->height());
//     qDebug() << " - matrix" << state->matrix;
//     qDebug() << " - originalPath.bounds" << originalPath.boundingRect();
//     qDebug() << " - path.bounds" << path.boundingRect();

    if (absPathRect.width() <= 0 || absPathRect.height() <= 0)
        return;

    QImage image(absPathRect.width(), absPathRect.height(), QImage::Format_ARGB32_Premultiplied);
    image.fill(0);

    QPainter p(&image);

    p.translate(-absPathRect.x(), -absPathRect.y());
    p.setMatrix(state->matrix, true);
    p.setPen(doStroke ? state->pen : QPen(Qt::NoPen));
    p.setBrush((op & FillDraw) ? state->brush : QBrush(Qt::NoBrush));
    p.setBackground(state->bgBrush);
    p.setBackgroundMode(state->bgMode);
    p.setBrushOrigin(state->bgOrigin);

    p.setRenderHint(QPainter::Antialiasing, state->renderHints & QPainter::Antialiasing);
    p.setRenderHint(QPainter::SmoothPixmapTransform,
                    state->renderHints & QPainter::SmoothPixmapTransform);

    p.drawPath(originalPath);

    p.end();

    q->save();
    q->setViewTransformEnabled(false);
    q->setMatrix(QMatrix(1, 0, 0, 1, -redirection_offset.x(), -redirection_offset.y()));
    updateState(state);
    engine->drawImage(absPathRect,
                 image,
                 QRectF(0, 0, absPathRect.width(), absPathRect.height()),
                 Qt::OrderedDither | Qt::OrderedAlphaDither);
    q->restore();
}


void QPainterPrivate::init()
{
    Q_Q(QPainter);
    state->painter = q;
}

void QPainterPrivate::updateMatrix()
{
    QMatrix m;
    if (state->VxF) {
        qreal scaleW = qreal(state->vw)/qreal(state->ww);
        qreal scaleH = qreal(state->vh)/qreal(state->wh);
        m.setMatrix(scaleW, 0, 0, scaleH, state->vx - state->wx*scaleW, state->vy - state->wy*scaleH);
    }
    if (state->WxF) {
        if (state->VxF)
            m = state->worldMatrix * m;
        else
            m = state->worldMatrix;
    }
    state->matrix = m;

    txinv = false;                                // no inverted matrix
    state->txop  = TxNone;
    if (state->matrix.m12()==0.0 && state->matrix.m21()==0.0
        && state->matrix.m11() >= 0.0 && state->matrix.m22() >= 0.0) {
        if (state->matrix.m11()==1.0 && state->matrix.m22()==1.0) {
            if (state->matrix.dx()!=0.0 || state->matrix.dy()!=0.0)
                state->txop = TxTranslate;
        } else {
            state->txop = TxScale;
        }
    } else {
        state->txop = TxRotShear;
    }
    if (!redirection_offset.isNull()) {
        state->txop |= TxTranslate;
        state->WxF = true;
        // We want to translate in dev space so we do the adding of the redirection
        // offset manually.
        state->matrix = QMatrix(state->matrix.m11(), state->matrix.m12(),
                              state->matrix.m21(), state->matrix.m22(),
                              state->matrix.dx()-redirection_offset.x(),
                              state->matrix.dy()-redirection_offset.y());
    }
    state->dirtyFlags |= QPaintEngine::DirtyTransform;

//     printf("VxF=%d, WxF=%d\n", state->VxF, state->WxF);
//     qDebug() << " --- using matrix" << state->matrix << redirection_offset;
}

/*! \internal */
void QPainterPrivate::updateInvMatrix()
{
    Q_ASSERT(txinv == false);
    txinv = true;                                // creating inverted matrix
    bool invertible;
    QMatrix m;
    if (state->VxF) {
        m.translate(state->vx, state->vy);
        m.scale(1.0*state->vw/state->ww, 1.0*state->vh/state->wh);
        m.translate(-state->wx, -state->wy);
    }
    if (state->WxF) {
        if (state->VxF)
            m = state->worldMatrix * m;
        else
            m = state->worldMatrix;
    }
    invMatrix = m.inverted(&invertible);                // invert matrix
}

void QPainterPrivate::updateEmulationSpecifier(QPainterState *s)
{
    bool alpha = false;
    bool linearGradient = false;
    bool radialGradient = false;
    bool conicalGradient = false;
    bool patternBrush = false;
    bool xform = false;

    bool skip = true;

    // Pen and brush properties (we have to check both if one changes because the
    // one that's unchanged can still be in a state which requires emulation)
    if (s->state() & QPaintEngine::DirtyPen ||
        s->state() & QPaintEngine::DirtyBrush) {
        // Check Brush stroke emulation
        if (!s->pen.isSolid() && !engine->hasFeature(QPaintEngine::BrushStroke))
            s->emulationSpecifier |= QPaintEngine::BrushStroke;
        else
            s->emulationSpecifier &= ~QPaintEngine::BrushStroke;

        skip = false;

        QBrush penBrush = s->pen.brush();
        alpha |= (!penBrush.isOpaque() || !s->brush.isOpaque());
        linearGradient |= ((penBrush.style() == Qt::LinearGradientPattern) ||
                           (s->brush.style() == Qt::LinearGradientPattern));
        radialGradient |= ((penBrush.style() == Qt::RadialGradientPattern) ||
                           (s->brush.style() == Qt::RadialGradientPattern));
        conicalGradient |= ((penBrush.style() == Qt::ConicalGradientPattern) ||
                            (s->brush.style() == Qt::ConicalGradientPattern));
        patternBrush |= (((penBrush.style() > Qt::SolidPattern
                           && penBrush.style() < Qt::LinearGradientPattern)
                          || s->brush.style() == Qt::TexturePattern) ||
                         ((s->brush.style() > Qt::SolidPattern
                           && s->brush.style() < Qt::LinearGradientPattern)
                          || s->brush.style() == Qt::TexturePattern));
    }

    if (s->state() & QPaintEngine::DirtyHints) {
        skip = false;
    }

    if (skip)
        return;

#if 0
    qDebug("QPainterPrivate::updateEmulationSpecifier, state=%p\n"
           " - alpha: %d\n"
           " - linearGradient: %d\n"
           " - radialGradient: %d\n"
           " - conicalGradient: %d\n"
           " - patternBrush: %d\n"
           " - hints: %x\n"
           " - xform: %d\n",
           s,
           alpha,
           linearGradient,
           radialGradient,
           conicalGradient,
           patternBrush,
           uint(s->renderHints),
           xform);
#endif

    // XForm properties
    if (s->state() & QPaintEngine::DirtyTransform) {
        xform = !s->matrix.isIdentity();
    } else if (s->txop >= TxTranslate) {
        xform = true;
    }

    // Check alphablending
    if (alpha && !engine->hasFeature(QPaintEngine::AlphaBlend))
        s->emulationSpecifier |= QPaintEngine::AlphaBlend;
    else
        s->emulationSpecifier &= ~QPaintEngine::AlphaBlend;

    // Linear gradient emulation
    if (linearGradient && !engine->hasFeature(QPaintEngine::LinearGradientFill))
        s->emulationSpecifier |= QPaintEngine::LinearGradientFill;
    else
        s->emulationSpecifier &= ~QPaintEngine::LinearGradientFill;

    // Radial gradient emulation
    if (radialGradient && !engine->hasFeature(QPaintEngine::RadialGradientFill))
        s->emulationSpecifier |= QPaintEngine::RadialGradientFill;
    else
        s->emulationSpecifier &= ~QPaintEngine::RadialGradientFill;

    // Conical gradient emulation
    if (conicalGradient && !engine->hasFeature(QPaintEngine::ConicalGradientFill))
        s->emulationSpecifier |= QPaintEngine::ConicalGradientFill;
    else
        s->emulationSpecifier &= ~QPaintEngine::ConicalGradientFill;

    // Pattern brushes
    if (patternBrush && !engine->hasFeature(QPaintEngine::PatternBrush))
        s->emulationSpecifier |= QPaintEngine::PatternBrush;
    else
        s->emulationSpecifier &= ~QPaintEngine::PatternBrush;

    // Pattern XForms
    if (patternBrush && xform && !engine->hasFeature(QPaintEngine::PatternTransform))
        s->emulationSpecifier |= QPaintEngine::PatternTransform;
    else
        s->emulationSpecifier &= ~QPaintEngine::PatternTransform;

    // Primitive XForms
    if (xform && !engine->hasFeature(QPaintEngine::PrimitiveTransform))
        s->emulationSpecifier |= QPaintEngine::PrimitiveTransform;
    else
        s->emulationSpecifier &= ~QPaintEngine::PrimitiveTransform;
}



void QPainterPrivate::updateState(QPainterState *newState)
{

    if (!newState) {
        engine->state = newState;

    } else if (newState->state() || engine->state!=newState) {

        // ### we might have to call QPainter::begin() here...
        if (!engine->state) {
            engine->state = newState;
            engine->setDirty(QPaintEngine::AllDirty);
        }

        if (engine->state->painter() != newState->painter)
            // ### this could break with clip regions vs paths.
            engine->setDirty(QPaintEngine::AllDirty);

        // Upon restore, revert all changes since last save
        else if (engine->state != newState)
            newState->dirtyFlags |= QPaintEngine::DirtyFlags(static_cast<QPainterState *>(engine->state)->changeFlags);

        // We need to store all changes made so that restore can deal with them
        else
            newState->changeFlags |= newState->dirtyFlags;

        updateEmulationSpecifier(newState);

        engine->state = newState;
        engine->updateState(*newState);
        engine->clearDirty(QPaintEngine::AllDirty);
    }
}


/*!
    \class QPainter
    \brief The QPainter class performs low-level painting on widgets and
    other paint devices.

    \ingroup multimedia
    \mainclass

    QPainter provides highly optimized functions to do most of the
    drawing GUI programs require. It can draw everything from simple
    lines to complex shapes like pies and chords. It can also draw
    aligned text and pixmaps. Normally, it draws in a "natural"
    coordinate system, but it can also do view and world
    transformation. QPainter can operate on any object that inherits
    the QPaintDevice class.

    The common use of QPainter is inside a widget's paint event:
    Construct and customize (e.g. set the pen or the brush) the