ok non-zeroed empty extents is legitimate after all

Change-Id: Ida1e27322bad5d2d36ae4217bb84187a022ebadf

vcl/headless/svpgdi.cxx

@@ -1271,21 +1271,15 @@ cairo_user_data_key_t* SvpSalGraphics::getDamageKey()
 
 void SvpSalGraphics::releaseCairoContext(cairo_t* cr, bool bXorModeAllowed, const basegfx::B2DRange& rExtents) const
 {
-    sal_Int32 nExtentsLeft;
-    sal_Int32 nExtentsTop;
-    sal_Int32 nExtentsRight;
-    sal_Int32 nExtentsBottom;
-    if (rExtents.isEmpty()) {
-        nExtentsLeft = 0;
-        nExtentsTop = 0;
-        nExtentsRight = 0;
-        nExtentsBottom = 0;
-    } else {
-        nExtentsLeft = rExtents.getMinX();
-        nExtentsTop = rExtents.getMinY();
-        nExtentsRight = rExtents.getMaxX();
-        nExtentsBottom = rExtents.getMaxY();
+    if (rExtents.isEmpty())
+    {
+        //nothing changed, return early
+        cairo_destroy(cr);
+        return;
     }
+
+    sal_Int32 nExtentsLeft(rExtents.getMinX()), nExtentsTop(rExtents.getMinY());
+    sal_Int32 nExtentsRight(rExtents.getMaxX()), nExtentsBottom(rExtents.getMaxY());
     sal_Int32 nWidth = cairo_image_surface_get_width(m_pSurface);
     sal_Int32 nHeight = cairo_image_surface_get_height(m_pSurface);
     nExtentsLeft = std::max<sal_Int32>(nExtentsLeft, 0);