Qwt User's Guide 6.1.6

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- Cache : QwtSymbol
- CandleStick : QwtPlotTradingCurve
- CanvasFocusIndicator : QwtPlotCanvas
- Checkable : QwtLegendData
- Clickable : QwtLegendData
- ClipPoints : QwtPlotSpectroCurve
- ClipPolygons : QwtPlotCurve , QwtPlotIntervalCurve , QwtPlotShapeItem
- ClipSymbol : QwtPlotIntervalCurve
- ClipSymbols : QwtPlotTradingCurve
- Columns : QwtPlotHistogram
- ContourMode : QwtPlotSpectrogram
- CopyAlphaMask : QwtWidgetOverlay
- CopyBackingStore : QwtPlotDirectPainter
- Cross : QwtPlotMarker , QwtSymbol
- CrossRubberBand : QwtPicker