Styles Example

/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtWidgets>

#include "norwegianwoodstyle.h"

NorwegianWoodStyle::NorwegianWoodStyle() :
    QProxyStyle(QStyleFactory::create("windows"))
{
}

void NorwegianWoodStyle::polish(QPalette &palette)
{
    QColor brown(212, 140, 95);
    QColor beige(236, 182, 120);
    QColor slightlyOpaqueBlack(0, 0, 0, 63);

    QImage backgroundImage(":/images/woodbackground.png");
    QImage buttonImage(":/images/woodbutton.png");
    QImage midImage = buttonImage.convertToFormat(QImage::Format_RGB32);

    QPainter painter;
    painter.begin(&midImage);
    painter.setPen(Qt::NoPen);
    painter.fillRect(midImage.rect(), slightlyOpaqueBlack);
    painter.end();

    palette = QPalette(brown);

    palette.setBrush(QPalette::BrightText, Qt::white);
    palette.setBrush(QPalette::Base, beige);
    palette.setBrush(QPalette::Highlight, Qt::darkGreen);
    setTexture(palette, QPalette::Button, buttonImage);
    setTexture(palette, QPalette::Mid, midImage);
    setTexture(palette, QPalette::Window, backgroundImage);

    QBrush brush = palette.background();
    brush.setColor(brush.color().dark());

    palette.setBrush(QPalette::Disabled, QPalette::WindowText, brush);
    palette.setBrush(QPalette::Disabled, QPalette::Text, brush);
    palette.setBrush(QPalette::Disabled, QPalette::ButtonText, brush);
    palette.setBrush(QPalette::Disabled, QPalette::Base, brush);
    palette.setBrush(QPalette::Disabled, QPalette::Button, brush);
    palette.setBrush(QPalette::Disabled, QPalette::Mid, brush);
}

void NorwegianWoodStyle::polish(QWidget *widget)
{
    if (qobject_cast<QPushButton *>(widget)
            || qobject_cast<QComboBox *>(widget))
        widget->setAttribute(Qt::WA_Hover, true);
}

void NorwegianWoodStyle::unpolish(QWidget *widget)
{
    if (qobject_cast<QPushButton *>(widget)
            || qobject_cast<QComboBox *>(widget))
        widget->setAttribute(Qt::WA_Hover, false);
}

int NorwegianWoodStyle::pixelMetric(PixelMetric metric,
                                    const QStyleOption *option,
                                    const QWidget *widget) const
{
    switch (metric) {
    case PM_ComboBoxFrameWidth:
        return 8;
    case PM_ScrollBarExtent:
        return QProxyStyle::pixelMetric(metric, option, widget) + 4;
    default:
        return QProxyStyle::pixelMetric(metric, option, widget);
    }
}

int NorwegianWoodStyle::styleHint(StyleHint hint, const QStyleOption *option,
                                  const QWidget *widget,
                                  QStyleHintReturn *returnData) const
{
    switch (hint) {
    case SH_DitherDisabledText:
        return int(false);
    case SH_EtchDisabledText:
        return int(true);
    default:
        return QProxyStyle::styleHint(hint, option, widget, returnData);
    }
}

void NorwegianWoodStyle::drawPrimitive(PrimitiveElement element,
                                       const QStyleOption *option,
                                       QPainter *painter,
                                       const QWidget *widget) const
{
    switch (element) {
    case PE_PanelButtonCommand:
        {
            int delta = (option->state & State_MouseOver) ? 64 : 0;
            QColor slightlyOpaqueBlack(0, 0, 0, 63);
            QColor semiTransparentWhite(255, 255, 255, 127 + delta);
            QColor semiTransparentBlack(0, 0, 0, 127 - delta);

            int x, y, width, height;
            option->rect.getRect(&x, &y, &width, &height);

            QPainterPath roundRect = roundRectPath(option->rect);
            int radius = qMin(width, height) / 2;

            QBrush brush;
            bool darker;

            const QStyleOptionButton *buttonOption =
                    qstyleoption_cast<const QStyleOptionButton *>(option);
            if (buttonOption
                    && (buttonOption->features & QStyleOptionButton::Flat)) {
                brush = option->palette.background();
                darker = (option->state & (State_Sunken | State_On));
            } else {
                if (option->state & (State_Sunken | State_On)) {
                    brush = option->palette.mid();
                    darker = !(option->state & State_Sunken);
                } else {
                    brush = option->palette.button();
                    darker = false;
                }
            }

            painter->save();
            painter->setRenderHint(QPainter::Antialiasing, true);
            painter->fillPath(roundRect, brush);
            if (darker)
                painter->fillPath(roundRect, slightlyOpaqueBlack);

            int penWidth;
            if (radius < 10)
                penWidth = 3;
            else if (radius < 20)
                penWidth = 5;
            else
                penWidth = 7;

            QPen topPen(semiTransparentWhite, penWidth);
            QPen bottomPen(semiTransparentBlack, penWidth);

            if (option->state & (State_Sunken | State_On))
                qSwap(topPen, bottomPen);

            int x1 = x;
            int x2 = x + radius;
            int x3 = x + width - radius;
            int x4 = x + width;

            if (option->direction == Qt::RightToLeft) {
                qSwap(x1, x4);
                qSwap(x2, x3);
            }

            QPolygon topHalf;
            topHalf << QPoint(x1, y)
                    << QPoint(x4, y)
                    << QPoint(x3, y + radius)
                    << QPoint(x2, y + height - radius)
                    << QPoint(x1, y + height);

            painter->setClipPath(roundRect);
            painter->setClipRegion(topHalf, Qt::IntersectClip);
            painter->setPen(topPen);
            painter->drawPath(roundRect);

            QPolygon bottomHalf = topHalf;
            bottomHalf[0] = QPoint(x4, y + height);

            painter->setClipPath(roundRect);
            painter->setClipRegion(bottomHalf, Qt::IntersectClip);
            painter->setPen(bottomPen);
            painter->drawPath(roundRect);

            painter->setPen(option->palette.foreground().color());
            painter->setClipping(false);
            painter->drawPath(roundRect);

            painter->restore();
        }
        break;
    default:
        QProxyStyle::drawPrimitive(element, option, painter, widget);
    }
}

void NorwegianWoodStyle::drawControl(ControlElement element,
                                     const QStyleOption *option,
                                     QPainter *painter,
                                     const QWidget *widget) const
{
    switch (element) {
    case CE_PushButtonLabel:
        {
            QStyleOptionButton myButtonOption;
            const QStyleOptionButton *buttonOption =
                    qstyleoption_cast<const QStyleOptionButton *>(option);
            if (buttonOption) {
                myButtonOption = *buttonOption;
                if (myButtonOption.palette.currentColorGroup()
                        != QPalette::Disabled) {
                    if (myButtonOption.state & (State_Sunken | State_On)) {
                        myButtonOption.palette.setBrush(QPalette::ButtonText,
                                myButtonOption.palette.brightText());
                    }
                }
            }
            QProxyStyle::drawControl(element, &myButtonOption, painter, widget);
        }
        break;
    default:
        QProxyStyle::drawControl(element, option, painter, widget);
    }
}

void NorwegianWoodStyle::setTexture(QPalette &palette, QPalette::ColorRole role,
                                    const QImage &image)
{
    for (int i = 0; i < QPalette::NColorGroups; ++i) {
        QBrush brush(image);
        brush.setColor(palette.brush(QPalette::ColorGroup(i), role).color());
        palette.setBrush(QPalette::ColorGroup(i), role, brush);
    }
}

QPainterPath NorwegianWoodStyle::roundRectPath(const QRect &rect)
{
    int radius = qMin(rect.width(), rect.height()) / 2;
    int diam = 2 * radius;

    int x1, y1, x2, y2;
    rect.getCoords(&x1, &y1, &x2, &y2);

    QPainterPath path;
    path.moveTo(x2, y1 + radius);
    path.arcTo(QRect(x2 - diam, y1, diam, diam), 0.0, +90.0);
    path.lineTo(x1 + radius, y1);
    path.arcTo(QRect(x1, y1, diam, diam), 90.0, +90.0);
    path.lineTo(x1, y2 - radius);
    path.arcTo(QRect(x1, y2 - diam, diam, diam), 180.0, +90.0);
    path.lineTo(x1 + radius, y2);
    path.arcTo(QRect(x2 - diam, y2 - diam, diam, diam), 270.0, +90.0);
    path.closeSubpath();
    return path;
}