5 files changed, 62 insertions, 0 deletions
diff --git a/desktop-widgets/divepicturewidget.cpp b/desktop-widgets/divepicturewidget.cpp
index a6864a5d9..46de16d09 100644
--- a/desktop-widgets/divepicturewidget.cpp
+++ b/desktop-widgets/divepicturewidget.cpp
@@ -59,3 +59,17 @@ void DivePictureWidget::mousePressEvent(QMouseEvent *event)
 		QListView::mousePressEvent(event);
 	}
 }
+
+void DivePictureWidget::wheelEvent(QWheelEvent *event)
+{
+	if (event->modifiers() == Qt::ControlModifier) {
+		// Angle delta is given in eighth parts of a degree. A classical mouse
+		// wheel click is 15 degrees. Each click should correspond to one zoom step.
+		// Therefore, divide by 15*8=120. To also support touch pads and finer-grained
+		// mouse wheels, take care to always round away from zero.
+		int delta = event->angleDelta().y();
+		int carry = delta > 0 ? 119 : -119;
+		emit zoomLevelChanged((delta + carry) / 120);
+	} else
+		QListView::wheelEvent(event);
+}
diff --git a/desktop-widgets/divepicturewidget.h b/desktop-widgets/divepicturewidget.h
index 09d4608c4..bf48a9d1b 100644
--- a/desktop-widgets/divepicturewidget.h
+++ b/desktop-widgets/divepicturewidget.h
@@ -14,9 +14,11 @@ public:
 protected:
 	void mouseDoubleClickEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
 	void mousePressEvent(QMouseEvent *event) Q_DECL_OVERRIDE;
+	void wheelEvent(QWheelEvent *event) Q_DECL_OVERRIDE;
 
 signals:
 	void photoDoubleClicked(const QString filePath);
+	void zoomLevelChanged(int delta);
 };
 
 class DivePictureThumbnailThread : public QThread {
diff --git a/desktop-widgets/tab-widgets/TabDivePhotos.cpp b/desktop-widgets/tab-widgets/TabDivePhotos.cpp
index 86749e770..571e0a3ac 100644
--- a/desktop-widgets/tab-widgets/TabDivePhotos.cpp
+++ b/desktop-widgets/tab-widgets/TabDivePhotos.cpp
@@ -29,6 +29,10 @@ TabDivePhotos::TabDivePhotos(QWidget *parent)
 			QDesktopServices::openUrl(QUrl::fromLocalFile(path));
 		}
 	);
+	connect(ui->photosView, &DivePictureWidget::zoomLevelChanged,
+		this, &TabDivePhotos::changeZoomLevel);
+	connect(ui->zoomSlider, &QAbstractSlider::valueChanged,
+		DivePictureModel::instance(), &DivePictureModel::setZoomLevel);
 }
 
 TabDivePhotos::~TabDivePhotos()
@@ -98,3 +102,8 @@ void TabDivePhotos::updateData()
 	divePictureModel->updateDivePictures();
 }
 
+void TabDivePhotos::changeZoomLevel(int delta)
+{
+	// We count on QSlider doing bound checks
+	ui->zoomSlider->setValue(ui->zoomSlider->value() + delta);
+}
diff --git a/desktop-widgets/tab-widgets/TabDivePhotos.h b/desktop-widgets/tab-widgets/TabDivePhotos.h
index 9b711595c..e2e7aa05c 100644
--- a/desktop-widgets/tab-widgets/TabDivePhotos.h
+++ b/desktop-widgets/tab-widgets/TabDivePhotos.h
@@ -26,6 +26,7 @@ private slots:
 	void addPhotosFromURL();
 	void removeAllPhotos();
 	void removeSelectedPhotos();
+	void changeZoomLevel(int delta);
 
 private:
 	Ui::TabDivePhotos *ui;
diff --git a/desktop-widgets/tab-widgets/TabDivePhotos.ui b/desktop-widgets/tab-widgets/TabDivePhotos.ui
index 35cfd375a..21e4544e6 100644
--- a/desktop-widgets/tab-widgets/TabDivePhotos.ui
+++ b/desktop-widgets/tab-widgets/TabDivePhotos.ui
@@ -21,6 +21,42 @@
      </property>
     </widget>
    </item>
+   <item>
+    <layout class="QHBoxLayout" name="zoomLayout">
+     <item>
+      <widget class="QLabel" name="zoomLabel">
+       <property name="text">
+        <string>Zoom level</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QSlider" name="zoomSlider">
+       <property name="minimum">
+        <number>-10</number>
+       </property>
+       <property name="maximum">
+        <number>10</number>
+       </property>
+       <property name="singleStep">
+        <number>1</number>
+       </property>
+       <property name="pageStep">
+        <number>1</number>
+       </property>
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+       <property name="tickPosition">
+        <enum>QSlider::TicksBelow</enum>
+       </property>
+       <property name="tickInterval">
+        <number>1</number>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
   </layout>
  </widget>
  <customwidgets>