[dolphin] Animate gifs on preview

Summary:
Adds the capability to view animated images on the preview in the information panel.
This was a request from a user back in 2009 (https://bugs.kde.org/show_bug.cgi?id=182257), but I think nowadays with stickers/memes and what not, it's even more useful.
It keeps the size default transition of the preview viewer before starting the animation, so that the visual integration is smoother.

{F7289110}

FEATURE: 182257
FIXED-IN: 19.11.80

Test Plan: Open the information panel and hover over some animated images (gif/webp/mng)

Reviewers: #dolphin, #vdg, ngraham, elvisangelaccio

Reviewed By: #vdg, ngraham

Subscribers: pino, fuksitter, meven, broulik, kfm-devel

Tags: #dolphin

Differential Revision: https://phabricator.kde.org/D23538

1 files changed, 14 insertions, 0 deletions

diff --git a/src/panels/information/pixmapviewer.h b/src/panels/information/pixmapviewer.h
index 46e5cf5fc..37071045f 100644
--- a/src/panels/information/pixmapviewer.h
+++ b/src/panels/information/pixmapviewer.h
@@ -26,6 +26,7 @@
 #include <QWidget>
 
 class QPaintEvent;
+class QMovie;
 
 /**
  * @brief Widget which shows a pixmap centered inside the boundaries.
@@ -73,20 +74,33 @@ public:
     void setSizeHint(const QSize& size);
     QSize sizeHint() const override;
 
+    void setAnimatedImageFileName(const QString& fileName);
+    QString animatedImageFileName() const;
+
+    void stopAnimatedImage();
+
+    /**
+     * Checks if \a fileName contains an animated image supported by QMovie.
+     */
+    static bool isAnimatedImage(const QString &fileName);
+
 protected:
     void paintEvent(QPaintEvent* event) override;
 
 private Q_SLOTS:
     void checkPendingPixmaps();
+    void updateAnimatedImageFrame();
 
 private:
     QPixmap m_pixmap;
     QPixmap m_oldPixmap;
+    QMovie* m_animatedImage;
     QQueue<QPixmap> m_pendingPixmaps;
     QTimeLine m_animation;
     Transition m_transition;
     int m_animationStep;
     QSize m_sizeHint;
+    bool m_hasAnimatedImage;
 };
 
 inline QPixmap PixmapViewer::pixmap() const