Implement preview

Show 4 frames of the selected movie in PictureViewer2.

1 files changed, 40 insertions, 0 deletions

diff --git a/helper.cpp b/helper.cpp
index 3856bfc..348c066 100644
--- a/helper.cpp
+++ b/helper.cpp
@@ -24,6 +24,8 @@
 #include <QApplication>
 #include <QJsonDocument>
 #include <QJsonObject>
+#include <QPainter>
+#include <QDir>
 
 #include <stdio.h>
 
@@ -250,6 +252,44 @@ namespace Helper {
         return QJsonDocument::fromJson(ffData);
     }
 
+    QPixmap preview(const QString &path){
+        QVariantMap m = ffmpegData(path);
+        int secs = m.value("duration").toDouble();
+        int interval = secs / 4;
+        QImage retval(640 * 2 + 40, 480 * 2 + 40, QImage::Format_ARGB32);
+        retval.fill(Qt::transparent);
+        QPainter p(&retval);
+        QImage img1 = snapshot(path, 20);
+        p.drawImage(0, 0, img1);
+        QImage img2 = snapshot(path, interval * 2);
+        p.drawImage(680, 0, img2);
+        QImage img3 = snapshot(path, interval * 3);
+        p.drawImage(0, 520, img3);
+        QImage img4 = snapshot(path, secs - 60);
+        p.drawImage(680, 520, img4);
+        QPixmap pmretval = QPixmap::fromImage(retval);
+        return pmretval;
+    }
+
+    QImage snapshot(const QString &path, int where){
+        QSettings s;
+        QString ffmpeg = s.value("paths/ffmpeg").toString();
+        QStringList args;
+        QTemporaryFile tf;
+        tf.open();
+        args << "-y" << "-ss" << QString::number(where) << "-i" << path << "-f" << "image2" << "-vframes" << "1" << tf.fileName();
+        QProcess ffproc;
+        ffproc.start(ffmpeg, args);
+        if(!ffproc.waitForStarted()){
+            return QImage();
+        }
+        if(ffproc.state() == QProcess::Running){
+            ffproc.waitForFinished();
+        }
+        QImage retval(tf.fileName());
+        return retval.scaledToWidth(640);
+    }
+
     Duration::Duration() : mHours(0), mMinutes(0), mSeconds(0) {}
 
     Duration::Duration(qint64 seconds){