VideoRenderWidget.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "VideoRenderWidget.h"
#include <QWidget>
#include <QImage>
#include <QPainter>
#include <QPaintEvent>
#include <QSizePolicy>
#include <QPalette>
 
 
VideoRenderWidget::VideoRenderWidget(QWidget *parent)
    : QWidget(parent), renderer(new VideoRenderer(this))
{
    QPalette p = palette();
    p.setColor(QPalette::Window, Qt::black);
    setPalette(p);
    setAttribute(Qt::WA_OpaquePaintEvent);
    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
 
    // init aspect ratio settings (default values)
    aspect_ratio.num = 16;
    aspect_ratio.den = 9;
    pixel_ratio.num = 1;
    pixel_ratio.den = 1;
 
    connect(renderer, SIGNAL(present(const QImage &)), this, SLOT(present(const QImage &)));
}
 
VideoRenderWidget::~VideoRenderWidget()
{
}
 
VideoRenderer *VideoRenderWidget::GetRenderer() const
{
    return renderer;
}
 
void VideoRenderWidget::SetAspectRatio(openshot::Fraction new_aspect_ratio, openshot::Fraction new_pixel_ratio)
{
    aspect_ratio = new_aspect_ratio;
    pixel_ratio = new_pixel_ratio;
}
 
QRect VideoRenderWidget::centeredViewport(int width, int height)
{
    // calculate aspect ratio
    float aspectRatio = aspect_ratio.ToFloat() * pixel_ratio.ToFloat();
    int heightFromWidth = (int) (width / aspectRatio);
    int widthFromHeight = (int) (height * aspectRatio);
 
    if (heightFromWidth <= height) {
        return QRect(0,(height - heightFromWidth) / 2, width, heightFromWidth);
    } else {
        return QRect((width - widthFromHeight) / 2.0, 0, widthFromHeight, height);
  }
}
 
void VideoRenderWidget::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
 
    // maintain aspect ratio
    painter.fillRect(event->rect(), palette().window());
    painter.setViewport(centeredViewport(width(), height()));
    painter.drawImage(QRect(0, 0, width(), height()), image);
 
}
 
void VideoRenderWidget::present(const QImage &m)
{
    image = m;
    repaint();
}