Prevent LOK DocView crash if document too large.

There seems to be a maximum size that gdk's pixbuf
can handle, however I have been unable to find any
documentatation. Seeing as the current implementation
isn't realistically useable anyway, we might as well
set a hard limit here (in practice we'd have much smaller
tiles + compositing).

Specifically extras/source/shellnew/soffice.ods will fail
without this patch.

Change-Id: I6ac495adca8e15878989375ef8b2de472788279a

1 files changed, 18 insertions, 4 deletions

diff --git a/libreofficekit/source/gtk/lokdocview.c b/libreofficekit/source/gtk/lokdocview.c
index cdc23392f646..e8fe5264a418 100644
--- a/libreofficekit/source/gtk/lokdocview.c
+++ b/libreofficekit/source/gtk/lokdocview.c
@@ -108,12 +108,26 @@ void renderDocument( LOKDocView* pDocView )
 
     pDocView->pDocument->pClass->getDocumentSize( pDocView->pDocument, &nWidth, &nHeight );
 
-    // Draw the whole document at once (for now)
-
     // TODO: we really should scale by screen DPI here -- 10 seems to be a vaguely
     // correct factor for my screen at least.
-    nRenderWidth = nWidth * pDocView->fZoom / 10;
-    nRenderHeight = nHeight * pDocView->fZoom / 10;
+    const float fScaleFactor = 0.1;
+
+    // Various things blow up if we try to draw too large a tile,
+    // this size seems to be safe. (Very rare/unlikely that
+    const int nMaxWidth = 100000;
+    if ( nWidth * fScaleFactor > nMaxWidth )
+    {
+        nWidth = nMaxWidth;
+    }
+    if ( nHeight * fScaleFactor > nMaxWidth )
+    {
+        nHeight = nMaxWidth;
+    }
+
+    // Draw the whole document at once (for now)
+
+    nRenderWidth = nWidth * pDocView->fZoom * fScaleFactor;
+    nRenderHeight = nHeight * pDocView->fZoom * fScaleFactor;
 
     pDocView->pPixBuf = gdk_pixbuf_new( GDK_COLORSPACE_RGB,
                                         TRUE, 8,