gradients.h Example File

  /****************************************************************************
  **
  ** 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); }

  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