Changeset - f3a38044a4bb
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0 2 0
Hasan Yavuz Ă–ZDERYA - 9 years ago 2016-08-13 05:06:06
hy@ozderya.net
fix jagged snapping behavior
2 files changed with 7 insertions and 6 deletions:
0 comments (0 inline, 0 general)
src/scalepicker.cpp
Show inline comments
 
@@ -79,54 +79,54 @@ void ScaleOverlay::drawOverlay(QPainter*
 
}
 

	
 
ScalePicker::ScalePicker(QwtScaleWidget* scaleWidget, QWidget* canvas) :
 
    QObject(scaleWidget)
 
{
 
    _scaleWidget = scaleWidget;
 
    _canvas = canvas;
 
    scaleWidget->installEventFilter(this);
 
    scaleWidget->setMouseTracking(true);
 
    pickerOverlay = new PlotOverlay(canvas, this);
 
    scaleOverlay = new ScaleOverlay(scaleWidget, this);
 
    started = false;
 
    pressed = false;
 
}
 

	
 
bool ScalePicker::eventFilter(QObject* object, QEvent* event)
 
{
 
    if (event->type() == QEvent::MouseButtonPress ||
 
        event->type() == QEvent::MouseButtonRelease ||
 
        event->type() == QEvent::MouseMove)
 
    {
 
        updateSnapPoints();
 

	
 
        QMouseEvent* mouseEvent = (QMouseEvent*) event;
 
        double posPx = this->positionPx(mouseEvent);
 
        int posPx = this->positionPx(mouseEvent);
 

	
 
        // do snapping unless Shift is pressed
 
        if (! (mouseEvent->modifiers() & Qt::ShiftModifier))
 
        {
 
            for (double sp : snapPoints)
 
            for (auto sp : snapPoints)
 
            {
 
                if (fabs(posPx-sp) <= SNAP_DISTANCE)
 
                {
 
                    posPx = sp;
 
                    break;
 
                }
 
            }
 
        }
 

	
 
        double pos = this->position(posPx);
 
        currentPosPx = posPx;
 

	
 
        if (event->type() == QEvent::MouseButtonPress &&
 
            mouseEvent->button() == Qt::LeftButton)
 
        {
 
            pressed = true; // not yet started
 
            firstPos = pos;
 
            firstPosPx = posPx;
 
        }
 
        else if (event->type() == QEvent::MouseMove)
 
        {
 
            // make sure pick size is big enough, so that just
 
            // clicking won't trigger pick
 
            if (!started && pressed && (fabs(posPx-firstPosPx) > MIN_PICK_SIZE))
 
@@ -206,72 +206,73 @@ void ScalePicker::drawScaleOverlay(QPain
 
    else // vertical
 
    {
 
        int width = painter->device()->width();
 
        if (started) painter->drawLine(0, firstPosPx, width, firstPosPx);
 
        if (started || _scaleWidget->underMouse())
 
        {
 
            painter->drawLine(0, currentPosPx, width, currentPosPx);
 
        }
 
    }
 

	
 
    painter->restore();
 
}
 

	
 
void ScalePicker::setPen(QPen pen)
 
{
 
    _pen = pen;
 
}
 

	
 
// convert the position of the click to the plot coordinates
 
double ScalePicker::position(double posPx)
 
{
 
    return _scaleWidget->scaleDraw()->scaleMap().invTransform(posPx);
 
}
 

	
 
double ScalePicker::positionPx(QMouseEvent* mouseEvent)
 
int ScalePicker::positionPx(QMouseEvent* mouseEvent)
 
{
 
    double pos;
 
    if (_scaleWidget->alignment() == QwtScaleDraw::BottomScale ||
 
        _scaleWidget->alignment() == QwtScaleDraw::TopScale)
 
    {
 
        pos = mouseEvent->pos().x();
 
    }
 
    else // left or right scale
 
    {
 
        pos = mouseEvent->pos().y();
 
    }
 
    return pos;
 
}
 

	
 
/*
 
 * Scale widget and canvas widget is not always aligned. Especially
 
 * when zooming scaleWidget moves around. This causes irregularities
 
 * when drawing the tracker lines. This function maps scale widgets
 
 * pixel coordinate to canvas' coordinate.
 
 */
 
double ScalePicker::posCanvasPx(double pos)
 
{
 
    // assumption: scale.width < canvas.width && scale.x > canvas.x
 
    if (_scaleWidget->alignment() == QwtScaleDraw::BottomScale ||
 
        _scaleWidget->alignment() == QwtScaleDraw::TopScale)
 
    {
 
        return pos + (_scaleWidget->x() - _canvas->x());
 
    }
 
    else // left or right scale
 
    {
 
        return pos + (_scaleWidget->y() - _canvas->y());
 
    }
 
    return pos;
 
}
 

	
 
void ScalePicker::updateSnapPoints()
 
{
 
    auto allTicks = _scaleWidget->scaleDraw()->scaleDiv().ticks(QwtScaleDiv::MajorTick) +
 
        _scaleWidget->scaleDraw()->scaleDiv().ticks(QwtScaleDiv::MediumTick) +
 
        _scaleWidget->scaleDraw()->scaleDiv().ticks(QwtScaleDiv::MinorTick);
 

	
 
    snapPoints.clear();
 
    for(auto t : allTicks)
 
    {
 
        snapPoints << _scaleWidget->scaleDraw()->scaleMap().transform(t);
 
        // `round` is used because `allTicks` is double but `snapPoints` is int
 
        snapPoints << round(_scaleWidget->scaleDraw()->scaleMap().transform(t));
 
    }
 
}
src/scalepicker.h
Show inline comments
 
@@ -36,35 +36,35 @@ public:
 
    ScalePicker(QwtScaleWidget* scaleWidget, QWidget* canvas);
 
    virtual bool eventFilter(QObject*, QEvent*);
 

	
 
    void drawPlotOverlay(QPainter*); // called from ScalePickerOverlay
 
    void drawScaleOverlay(QPainter*); // called from ScaleOverlay
 
    void setPen(QPen pen);
 

	
 
signals:
 
    void pickStarted(double pos);
 
    void picking(double firstPos, double lastPos);
 
    void picked(double firstPos, double lastPos);
 

	
 
private:
 
    QwtScaleWidget* _scaleWidget;
 
    QWidget* _canvas;
 
    QwtWidgetOverlay* pickerOverlay; // will be PlotOverlay
 
    QwtWidgetOverlay* scaleOverlay;  // will be ScaleOverlay
 
    QPen _pen;
 

	
 
    bool pressed;
 
    bool started;
 
    double firstPos; // converted to plot coordinates
 
    double firstPosPx; // pixel coordinates
 
    double currentPosPx; // current position in pixel coordinates
 
    QList<double> snapPoints;
 
    QList<int> snapPoints;
 

	
 
    double position(double); // returns the axis mouse position relative to plot coordinates
 
    double positionPx(QMouseEvent*); // returns the axis mouse position in pixels
 
    int positionPx(QMouseEvent*); // returns the axis mouse position in pixels
 
    double posCanvasPx(double pos); // returns the given position in canvas coordinates
 

	
 
private slots:
 
    void updateSnapPoints();
 
};
 

	
 
#endif // SCALEPICKER_H
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