Respect exif rotation of images

Sometimes thumbnails still have the wrong dimensions, as they are scaled
to fit inside a rectange of the reported size in the image. Not sure,
who is wrong there, the media repo or we.

src/AvatarProvider.cpp

@@ -24,6 +24,7 @@
 #include "Cache.h"
 #include "Logging.h"
 #include "MatrixClient.h"
+#include "Utils.h"
 
 static QPixmapCache avatar_cache;
 
@@ -44,7 +45,7 @@ resolve(const QString &avatarUrl, int size, QObject *receiver, AvatarCallback ca
 
         auto data = cache::image(cacheKey);
         if (!data.isNull()) {
-                pixmap.loadFromData(data);
+                pixmap = QPixmap::fromImage(utils::readImage(&data));
                 avatar_cache.insert(cacheKey, pixmap);
                 callback(pixmap);
                 return;
@@ -54,9 +55,8 @@ resolve(const QString &avatarUrl, int size, QObject *receiver, AvatarCallback ca
         QObject::connect(proxy.get(),
                          &AvatarProxy::avatarDownloaded,
                          receiver,
-                         [callback, cacheKey](const QByteArray &data) {
-                                 QPixmap pm;
-                                 pm.loadFromData(data);
+                         [callback, cacheKey](QByteArray data) {
+                                 QPixmap pm = QPixmap::fromImage(utils::readImage(&data));
                                  avatar_cache.insert(cacheKey, pm);
                                  callback(pm);
                          });

src/MxcImageProvider.cpp

@@ -3,6 +3,7 @@
 #include "Cache.h"
 #include "Logging.h"
 #include "MatrixClient.h"
+#include "Utils.h"
 
 void
 MxcImageResponse::run()
@@ -14,11 +15,15 @@ MxcImageResponse::run()
                                      .arg(m_requestedSize.height());
 
                 auto data = cache::image(fileName);
-                if (!data.isNull() && m_image.loadFromData(data)) {
+                if (!data.isNull()) {
+                        m_image = utils::readImage(&data);
                         m_image = m_image.scaled(m_requestedSize, Qt::KeepAspectRatio);
                         m_image.setText("mxc url", "mxc://" + m_id);
-                        emit finished();
-                        return;
+
+                        if (!m_image.isNull()) {
+                                emit finished();
+                                return;
+                        }
                 }
 
                 mtx::http::ThumbOpts opts;
@@ -39,17 +44,22 @@ MxcImageResponse::run()
 
                           auto data = QByteArray(res.data(), res.size());
                           cache::saveImage(fileName, data);
-                          m_image.loadFromData(data);
+                          m_image = utils::readImage(&data);
                           m_image.setText("mxc url", "mxc://" + m_id);
 
                           emit finished();
                   });
         } else {
                 auto data = cache::image(m_id);
-                if (!data.isNull() && m_image.loadFromData(data)) {
+
+                if (!data.isNull()) {
+                        m_image = utils::readImage(&data);
                         m_image.setText("mxc url", "mxc://" + m_id);
-                        emit finished();
-                        return;
+
+                        if (!m_image.isNull()) {
+                                emit finished();
+                                return;
+                        }
                 }
 
                 http::client()->download(
@@ -73,11 +83,11 @@ MxcImageResponse::run()
                                     mtx::crypto::decrypt_file(temp, m_encryptionInfo.value()));
 
                           auto data = QByteArray(temp.data(), temp.size());
-                          m_image.loadFromData(data);
+                          cache::saveImage(m_id, data);
+                          m_image = utils::readImage(&data);
                           m_image.setText("original filename",
                                           QString::fromStdString(originalFilename));
                           m_image.setText("mxc url", "mxc://" + m_id);
-                          cache::saveImage(m_id, data);
 
                           emit finished();
                   });

src/Utils.cpp

@@ -1,9 +1,11 @@
 #include "Utils.h"
 
 #include <QApplication>
+#include <QBuffer>
 #include <QComboBox>
 #include <QDesktopWidget>
 #include <QGuiApplication>
+#include <QImageReader>
 #include <QProcessEnvironment>
 #include <QScreen>
 #include <QSettings>
@@ -657,3 +659,12 @@ utils::restoreCombobox(QComboBox *combo, const QString &value)
                 }
         }
 }
+
+QImage
+utils::readImage(QByteArray *data)
+{
+        QBuffer buf(data);
+        QImageReader reader(&buf);
+        reader.setAutoTransform(true);
+        return reader.read();
+}

src/Utils.h

@@ -306,4 +306,8 @@ centerWidget(QWidget *widget, QWidget *parent);
 
 void
 restoreCombobox(QComboBox *combo, const QString &value);
+
+//! Read image respecting exif orientation
+QImage
+readImage(QByteArray *data);
 }