gradients.h Example File | Qt Widgets 5.12.11

- Qt 5.12
- Qt Widgets
- Gradients
- gradients.h Example File
- Qt 5.12.11 Reference Documentation

# gradients.h Example File

painting/gradients/gradients.h

     /****************************************************************************
     **
     ** Copyright (C) 2016 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
     **
     ** This file is part of the demonstration applications of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** 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
     ** a written agreement between you and The Qt Company. For licensing terms
     ** and conditions see https://www.qt.io/terms-conditions. For further
     ** information use the contact form at https://www.qt.io/contact-us.
     **
     ** BSD License Usage
     ** Alternatively, you may use this file under the terms of the BSD license
     ** as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of The Qt Company Ltd nor the names of its
     **     contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
     **
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #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) override;

         QSize sizeHint() const 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) override;

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

         HoverPoints *hoverPoints() const { return m_hoverPoints; }
         void mousePressEvent(QMouseEvent *e) 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); }
         void setPreset()     { changePresetBy(0); }
         void setPrevPreset() { changePresetBy(-1); }
         void setNextPreset() { changePresetBy(1); }

     private:
         void setDefault(int i);
         void updatePresetName();
         void changePresetBy(int indexOffset);

         GradientRenderer *m_renderer;
         GradientEditor *m_editor;

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

         int m_presetIndex = 0;
     };

     #endif // GRADIENTS_H