- Qt 5.5
- Qt Widgets
- Gradients
- gradients.h Example File
- Qt 5.5.1 Reference Documentation

# gradients.h Example File

painting/gradients/gradients.h

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the demonstration applications of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:LGPL21$
    ** Commercial License Usage
    ** Licensees holding valid commercial Qt licenses may use this file in
    ** accordance with the commercial license agreement provided with the
    ** Software or, alternatively, in accordance with the terms contained in
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    ** information use the contact form at http://www.qt.io/contact-us.
    **
    ** GNU Lesser General Public License Usage
    ** Alternatively, this file may be used under the terms of the GNU Lesser
    ** General Public License version 2.1 or version 3 as published by the Free
    ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
    ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
    ** following information to ensure the GNU Lesser General Public License
    ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
    ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
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    ** As a special exception, The Qt Company gives you certain additional
    ** rights. These rights are described in The Qt Company LGPL Exception
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    ** $QT_END_LICENSE$
    **
    ****************************************************************************/

    #ifndef GRADIENTS_H
    #define GRADIENTS_H

    #include "arthurwidgets.h"

    class QRadioButton;

    class HoverPoints;

    class ShadeWidget : public QWidget
    {
        Q_OBJECT

    public:
        enum ShadeType {
            RedShade,
            GreenShade,
            BlueShade,
            ARGBShade
        };

        ShadeWidget(ShadeType type, QWidget *parent);

        void setGradientStops(const QGradientStops &stops);

        void paintEvent(QPaintEvent *e) Q_DECL_OVERRIDE;

        QSize sizeHint() const Q_DECL_OVERRIDE { return QSize(150, 40); }
        QPolygonF points() const;

        HoverPoints *hoverPoints() const { return m_hoverPoints; }

        uint colorAt(int x);

    signals:
        void colorsChanged();

    private:
        void generateShade();

        ShadeType m_shade_type;
        QImage m_shade;
        HoverPoints *m_hoverPoints;
        QLinearGradient m_alpha_gradient;
    };

    class GradientEditor : public QWidget
    {
        Q_OBJECT

    public:
        GradientEditor(QWidget *parent);

        void setGradientStops(const QGradientStops &stops);

    public slots:
        void pointsUpdated();

    signals:
        void gradientStopsChanged(const QGradientStops &stops);

    private:
        ShadeWidget *m_red_shade;
        ShadeWidget *m_green_shade;
        ShadeWidget *m_blue_shade;
        ShadeWidget *m_alpha_shade;
    };

    class GradientRenderer : public ArthurFrame
    {
        Q_OBJECT

    public:
        GradientRenderer(QWidget *parent);
        void paint(QPainter *p) Q_DECL_OVERRIDE;

        QSize sizeHint() const Q_DECL_OVERRIDE { return QSize(400, 400); }

        HoverPoints *hoverPoints() const { return m_hoverPoints; }
        void mousePressEvent(QMouseEvent *e) Q_DECL_OVERRIDE;

    public slots:
        void setGradientStops(const QGradientStops &stops);

        void setPadSpread() { m_spread = QGradient::PadSpread; update(); }
        void setRepeatSpread() { m_spread = QGradient::RepeatSpread; update(); }
        void setReflectSpread() { m_spread = QGradient::ReflectSpread; update(); }

        void setLinearGradient() { m_gradientType = Qt::LinearGradientPattern; update(); }
        void setRadialGradient() { m_gradientType = Qt::RadialGradientPattern; update(); }
        void setConicalGradient() { m_gradientType = Qt::ConicalGradientPattern; update(); }

    private:
        QGradientStops m_stops;
        HoverPoints *m_hoverPoints;

        QGradient::Spread m_spread;
        Qt::BrushStyle m_gradientType;
    };

    class GradientWidget : public QWidget
    {
        Q_OBJECT

    public:
        GradientWidget(QWidget *parent);

    public slots:
        void setDefault1() { setDefault(1); }
        void setDefault2() { setDefault(2); }
        void setDefault3() { setDefault(3); }
        void setDefault4() { setDefault(4); }

    private:
        void setDefault(int i);

        GradientRenderer *m_renderer;
        GradientEditor *m_editor;

        QRadioButton *m_linearButton;
        QRadioButton *m_radialButton;
        QRadioButton *m_conicalButton;
        QRadioButton *m_padSpreadButton;
        QRadioButton *m_reflectSpreadButton;
        QRadioButton *m_repeatSpreadButton;

    };

    #endif // GRADIENTS_H