File indexing completed on 2024-04-28 04:18:53

 // vim: set tabstop=4 shiftwidth=4 expandtab:
 /*
 Gwenview: an image viewer
 Copyright 2011 Aurélien Gâteau <agateau@kde.org>
 
 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Cambridge, MA 02110-1301, USA.
 
 */
 // Self
 #include "shadowfilter.h"
 
 // Local
 
 // KF
 
 // Qt
 #include <QColor>
 #include <QCoreApplication>
 #include <QHash>
 #include <QPainter>
 #include <QWidget>
 
 namespace Gwenview
 {
 struct ShadowFilterPrivate {
     QWidget *mWidget = nullptr;
     QHash<ShadowFilter::WidgetEdge, QColor> mShadows;
 
     void paintShadow(QPainter *painter, const QColor &color, QPoint origin, int dx, int dy)
     {
         const int gradientSize = 12;
 
         if (color == Qt::transparent) {
             return;
         }
         QLinearGradient gradient;
         gradient.setColorAt(0, color);
         gradient.setColorAt(1, Qt::transparent);
         gradient.setStart(origin);
         gradient.setFinalStop(origin.x() + dx * gradientSize, origin.y() + dy * gradientSize);
         painter->fillRect(mWidget->rect(), gradient);
     }
 
     void paint()
     {
         QPainter painter(mWidget);
         const QRect rect = mWidget->rect();
         QColor color;
 
         color = mShadows.value(ShadowFilter::LeftEdge, Qt::transparent);
         paintShadow(&painter, color, rect.topLeft(), 1, 0);
 
         color = mShadows.value(ShadowFilter::TopEdge, Qt::transparent);
         paintShadow(&painter, color, rect.topLeft(), 0, 1);
 
         color = mShadows.value(ShadowFilter::RightEdge, Qt::transparent);
         paintShadow(&painter, color, rect.topRight(), -1, 0);
 
         color = mShadows.value(ShadowFilter::BottomEdge, Qt::transparent);
         paintShadow(&painter, color, rect.bottomLeft(), 0, -1);
     }
 };
 
 ShadowFilter::ShadowFilter(QWidget *widget)
     : QObject(widget)
     , d(new ShadowFilterPrivate)
 {
     d->mWidget = widget;
     widget->installEventFilter(this);
 }
 
 ShadowFilter::~ShadowFilter()
 {
     delete d;
 }
 
 void ShadowFilter::setShadow(ShadowFilter::WidgetEdge edge, const QColor &color)
 {
     d->mShadows[edge] = color;
 }
 
 void ShadowFilter::reset()
 {
     d->mShadows.clear();
 }
 
 bool ShadowFilter::eventFilter(QObject *obj, QEvent *event)
 {
     if (event->type() == QEvent::Paint) {
         obj->removeEventFilter(this);
         QCoreApplication::sendEvent(obj, event);
         d->paint();
         obj->installEventFilter(this);
         return true;
     }
     return false;
 }
 
 } // namespace
 
 #include "moc_shadowfilter.cpp"