tdf#96515 sw Hide Whitespace: avoid creating unneeded page frames

(cherry picked from commit 2c23d4ee)

Conflicts:
	sw/qa/extras/uiwriter/uiwriter.cxx
	sw/source/core/layout/calcmove.cxx

Change-Id: I9b273543ccf2eaa87116c6e1475860e9e872c445

sw/qa/extras/uiwriter/uiwriter.cxx

@@ -11,6 +11,7 @@
 #include <com/sun/star/drawing/GraphicExportFilter.hpp>
 #include <com/sun/star/i18n/TextConversionOption.hpp>
 #include <com/sun/star/frame/DispatchHelper.hpp>
+#include <com/sun/star/text/XParagraphAppend.hpp>
 #include <swmodeltestbase.hxx>
 #include <ndtxt.hxx>
 #include <wrtsh.hxx>
@@ -104,6 +105,7 @@ public:
     void testDde();
     void testTdf89954();
     void testTdf89720();
+    void testTdf96515();
 
     CPPUNIT_TEST_SUITE(SwUiWriterTest);
     CPPUNIT_TEST(testReplaceForward);
@@ -146,6 +148,7 @@ public:
     CPPUNIT_TEST(testDde);
     CPPUNIT_TEST(testTdf89954);
     CPPUNIT_TEST(testTdf89720);
+    CPPUNIT_TEST(testTdf96515);
 
     CPPUNIT_TEST_SUITE_END();
 
@@ -1150,6 +1153,25 @@ void SwUiWriterTest::testTdf89720()
 #endif
 }
 
+void SwUiWriterTest::testTdf96515()
+{
+    // Enable hide whitespace mode.
+    SwDoc* pDoc = createDoc();
+    SwWrtShell* pWrtShell = pDoc->GetDocShell()->GetWrtShell();
+    SwViewOption aViewOptions(*pWrtShell->GetViewOptions());
+    aViewOptions.SetHideWhitespaceMode(true);
+    pWrtShell->ApplyViewOptions(aViewOptions);
+
+    // Insert a new paragraph at the end of the document.
+    uno::Reference<text::XTextDocument> xTextDocument(mxComponent, uno::UNO_QUERY);
+    uno::Reference<text::XParagraphAppend> xParagraphAppend(xTextDocument->getText(), uno::UNO_QUERY);
+    xParagraphAppend->finishParagraph(uno::Sequence<beans::PropertyValue>());
+    calcLayout();
+
+    // This was 2, a new page was created for the new paragraph.
+    CPPUNIT_ASSERT_EQUAL(1, getPages());
+}
+
 CPPUNIT_TEST_SUITE_REGISTRATION(SwUiWriterTest);
 CPPUNIT_PLUGIN_IMPLEMENT();
 

sw/source/core/layout/calcmove.cxx

@@ -1519,7 +1519,34 @@ void SwContentFrm::MakeAll(vcl::RenderContext* /*pRenderContext*/)
         // Bottom(). This might happen with undersized TextFrms on the lower edge of a
         // multi-column section
         const long nPrtBottom = (GetUpper()->*fnRect->fnGetPrtBottom)();
-        const long nBottomDist =  (Frm().*fnRect->fnBottomDist)( nPrtBottom );
+        long nBottomDist =  (Frm().*fnRect->fnBottomDist)( nPrtBottom );
+
+        if (getRootFrm()->GetCurrShell()->GetViewOptions()->IsWhitespaceHidden())
+        {
+            // When whitespace is hidden, the page frame has two heights: the
+            // nominal (defined by the frame format), and the actual (which is
+            // at most the nominal height, but can be smaller in case there is
+            // no content for the whole page).
+            // The layout size is the actual one, but we want to move the
+            // content frame to a new page only in case it doesn't fit the
+            // nominal size.
+            if (nBottomDist < 0)
+            {
+                // Content frame doesn't fit the actual size, check if it fits the nominal one.
+                SwPageFrm* pPageFrame = FindPageFrm();
+                const SwFrameFormat* pPageFormat = static_cast<const SwFrameFormat*>(pPageFrame->GetRegisteredIn());
+                const Size& rPageSize = pPageFormat->GetFrmSize().GetSize();
+                long nWhitespace = rPageSize.getHeight() - pPageFrame->Frm().Height();
+                if (nWhitespace > -nBottomDist)
+                {
+                    // It does: don't move it and invalidate our page frame so
+                    // that it gets a larger height.
+                    nBottomDist = 0;
+                    pPageFrame->InvalidateSize();
+                }
+            }
+        }
+
         if( nBottomDist >= 0 )
         {
             if ( bKeep && bMoveable )