added functions to override the resolution and matrix transform of the viewer widget

While in most circumstances these shouldn't be used, they're useful for
showing things like export previews

app/widget/viewer/viewer.cpp

@@ -185,6 +185,16 @@ void ViewerWidget::SetColorMenuEnabled(bool enabled)
   gl_widget_->SetColorMenuEnabled(enabled);
 }
 
+void ViewerWidget::SetOverrideSize(int width, int height)
+{
+  SizeChangedSlot(width, height);
+}
+
+void ViewerWidget::SetMatrix(const QMatrix4x4 &mat)
+{
+  gl_widget_->SetMatrix(mat);
+}
+
 void ViewerWidget::SetTexture(OpenGLTexturePtr tex)
 {
   if (tex == nullptr) {

app/widget/viewer/viewer.h

@@ -71,6 +71,10 @@ public:
 
   void SetColorMenuEnabled(bool enabled);
 
+  void SetOverrideSize(int width, int height);
+
+  void SetMatrix(const QMatrix4x4& mat);
+
 public slots:
   /**
    * @brief Set the texture to draw and draw it

app/widget/viewer/viewerglwidget.cpp

@@ -69,6 +69,12 @@ void ViewerGLWidget::DisconnectColorManager()
   ConnectColorManager(nullptr);
 }
 
+void ViewerGLWidget::SetMatrix(const QMatrix4x4 &mat)
+{
+  matrix_ = mat;
+  update();
+}
+
 void ViewerGLWidget::SetOCIODisplay(const QString &display)
 {
   ocio_display_ = display;
@@ -135,7 +141,7 @@ void ViewerGLWidget::paintGL()
     f->glBindTexture(GL_TEXTURE_2D, texture_);
 
     // Blit using the pipeline retrieved in initializeGL()
-    olive::gl::OCIOBlit(pipeline_, ocio_lut_, true);
+    olive::gl::OCIOBlit(pipeline_, ocio_lut_, true, matrix_);
 
     // Release retrieved texture
     f->glBindTexture(GL_TEXTURE_2D, 0);

app/widget/viewer/viewerglwidget.h

@@ -94,6 +94,13 @@ public:
    */
   void DisconnectColorManager();
 
+  /**
+   * @brief Set the transformation matrix to draw with
+   *
+   * Set this if you want the drawing to pass through some sort of transform (most of the time you won't want this).
+   */
+  void SetMatrix(const QMatrix4x4& mat);
+
 public slots:
   /**
    * @brief Set the texture to draw and draw it
@@ -195,6 +202,11 @@ private:
    */
   ColorProcessorPtr color_service_;
 
+  /**
+   * @brief Drawing matrix (defaults to identity)
+   */
+  QMatrix4x4 matrix_;
+
   bool color_menu_enabled_;
 
 private slots: