tdf#80282 swpagerelsize: corner case frame size max

Before the swpagerelsize commits,
(specifically 7c7fdf3e),
the max size was always Prt(). The regression comes if
the RelFrame is a pageFrame (like when the image is
anchored to the page). Then sometimes no maximum is set.

Change-Id: If1e93ce670bd0908eb2d1f89dabbe9861163d29e
Reviewed-on: https://gerrit.libreoffice.org/50034Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

sw/qa/extras/odfexport/odfexport.cxx

@@ -983,6 +983,13 @@ DECLARE_ODFEXPORT_TEST(testRelhPage, "relh-page.odt")
     CPPUNIT_ASSERT_EQUAL(sal_Int32(3168), parseDump("/root/page/body/txt/anchored/fly/infos/bounds", "height").toInt32());
 }
 
+DECLARE_ODFEXPORT_TEST(testRelhPageTdf80282, "relh-page-tdf80282.odt")
+{
+    uno::Reference<drawing::XShape> xTextFrame = getShape(1);
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Height", sal_Int32(8391), parseDump("//anchored/fly/infos/bounds", "height").toInt32());
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("Width",  sal_Int32(5953), parseDump("//anchored/fly/infos/bounds", "width").toInt32());
+}
+
 DECLARE_ODFEXPORT_TEST(testRelwPage, "relw-page.odt")
 {
     uno::Reference<drawing::XShape> xTextFrame = getShape(1);

sw/source/core/layout/fly.cxx

@@ -2357,8 +2357,14 @@ Size SwFlyFrame::CalcRel( const SwFormatFrameSize &rSz ) const
         // When size is a relative to page size, ignore size of SwBodyFrame.
         if (rSz.GetWidthPercentRelation() != text::RelOrientation::PAGE_FRAME)
             nRelWidth  = std::min( nRelWidth,  pRel->getFramePrintArea().Width() );
+        else if ( pRel->IsPageFrame() )
+            nRelWidth  = std::min( nRelWidth,  pRel->getFrameArea().Width() );
+
         if (rSz.GetHeightPercentRelation() != text::RelOrientation::PAGE_FRAME)
             nRelHeight = std::min( nRelHeight, pRel->getFramePrintArea().Height() );
+        else if ( pRel->IsPageFrame() )
+            nRelHeight = std::min( nRelHeight, pRel->getFrameArea().Height() );
+
         if( !pRel->IsPageFrame() )
         {
             const SwPageFrame* pPage = FindPageFrame();