From 00438fffd2321e7d768ded9277c3143448112cdc Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Thu, 7 May 2015 23:07:20 +0200
Subject: [PATCH] + before trying to write out snapshot image check if it's
 null

---
 src/Gui/SoFCOffscreenRenderer.cpp | 12 ++++++++++--
 src/Gui/View3DInventorViewer.cpp  |  2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/Gui/SoFCOffscreenRenderer.cpp b/src/Gui/SoFCOffscreenRenderer.cpp
index 537500bdf..90a9ddd1e 100644
--- a/src/Gui/SoFCOffscreenRenderer.cpp
+++ b/src/Gui/SoFCOffscreenRenderer.cpp
@@ -94,6 +94,12 @@ void SoFCOffscreenRenderer::writeToImage (QImage& img) const
 
 void SoFCOffscreenRenderer::writeToImageFile(const char* filename, const char* comment, const SbMatrix& mat, const QImage& image)
 {
+    if (image.isNull()) {
+        std::stringstream str;
+        str << "Cannot save null image.";
+        throw Base::ValueError(str.str());
+    }
+
     Base::FileInfo file(filename);
     if (file.hasExtension("JPG") || file.hasExtension("JPEG")) {
         // writing comment in case of jpeg (Qt ignores setText() in case of jpeg)
@@ -163,13 +169,15 @@ void SoFCOffscreenRenderer::writeToImageFile(const char* filename, const char* c
                     f.close();
                     std::stringstream str;
                     str << "Cannot save image to file '" << filename << "'.";
-                    throw Base::Exception(str.str());
+                    throw Base::ValueError(str.str());
                 }
             }
             else {
                 std::stringstream str;
                 str << "Cannot open file '" << filename << "' for writing.";
-                throw Base::Exception(str.str());
+                Base::FileException e;
+                e.setMessage(str.str());
+                throw e;
             }
         }
         //
diff --git a/src/Gui/View3DInventorViewer.cpp b/src/Gui/View3DInventorViewer.cpp
index a61eae760..6660e1e14 100644
--- a/src/Gui/View3DInventorViewer.cpp
+++ b/src/Gui/View3DInventorViewer.cpp
@@ -899,7 +899,7 @@ void View3DInventorViewer::savePicture(int w, int h, const QColor& bg, QImage& i
 #if (COIN_MAJOR_VERSION >= 4)
     // The behaviour in Coin4 has changed so that when using the same instance of 'SoFCOffscreenRenderer'
     // multiple times internally the biggest viewport size is stored and set to the SoGLRenderAction.
-    // The trick is to add a callback node and override the viewport size with wath we want.
+    // The trick is to add a callback node and override the viewport size with what we want.
     //SoCallback* cbvp = new SoCallback;
     //cbvp->setCallback(setViewportCB);
     //root->addChild(cbvp);