Duckstation/src/duckstation-qt/collapsiblewidget.cpp

// https://stackoverflow.com/questions/32476006/how-to-make-an-expandable-collapsable-section-widget-in-qt
#include <QtCore/QPropertyAnimation>

#include "collapsiblewidget.h"

CollapsibleWidget::CollapsibleWidget(const QString& title, const int animationDuration, QWidget* parent)
  : QWidget(parent), animationDuration(animationDuration)
{
  toggleButton.setStyleSheet("QToolButton { border: none; }");
  toggleButton.setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
  toggleButton.setArrowType(Qt::ArrowType::RightArrow);
  toggleButton.setText(title);
  toggleButton.setCheckable(true);
  toggleButton.setChecked(false);

  contentArea.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

  // start out collapsed
  contentArea.setMaximumHeight(0);
  contentArea.setMinimumHeight(0);

  // let the entire widget grow and shrink with its content
  toggleAnimation.addAnimation(new QPropertyAnimation(this, "minimumHeight"));
  toggleAnimation.addAnimation(new QPropertyAnimation(this, "maximumHeight"));
  toggleAnimation.addAnimation(new QPropertyAnimation(&contentArea, "maximumHeight"));

  // don't waste space
  mainLayout.setContentsMargins(0, 0, 0, 0);
  mainLayout.addWidget(&toggleButton);
  mainLayout.addWidget(&contentArea);
  setLayout(&mainLayout);
  QObject::connect(&toggleButton, &QToolButton::clicked, [this](const bool checked) {
    toggleButton.setArrowType(checked ? Qt::ArrowType::DownArrow : Qt::ArrowType::RightArrow);
    toggleAnimation.setDirection(checked ? QAbstractAnimation::Forward : QAbstractAnimation::Backward);
    toggleAnimation.start();
  });
}

void CollapsibleWidget::setContentLayout(QLayout* contentLayout)
{
  delete contentArea.layout();
  contentArea.setLayout(contentLayout);
  const auto collapsedHeight = sizeHint().height() - contentArea.maximumHeight();
  auto contentHeight = contentLayout->sizeHint().height();
  for (int i = 0; i < toggleAnimation.animationCount() - 1; ++i)
  {
    QPropertyAnimation* spoilerAnimation = static_cast<QPropertyAnimation*>(toggleAnimation.animationAt(i));
    spoilerAnimation->setDuration(animationDuration);
    spoilerAnimation->setStartValue(collapsedHeight);
    spoilerAnimation->setEndValue(collapsedHeight + contentHeight);
  }
  QPropertyAnimation* contentAnimation =
    static_cast<QPropertyAnimation*>(toggleAnimation.animationAt(toggleAnimation.animationCount() - 1));
  contentAnimation->setDuration(animationDuration);
  contentAnimation->setStartValue(0);
  contentAnimation->setEndValue(contentHeight);
}