improve empty tools::Rectangle (width)

This is the width part, the height part will come next.

Instead of storing "empty" as a special value (which is easy to get
wrong, eg. some image filters pass in that special value, expecting it
to be a valid width), just use separate boolean values for width and
height empty.

Also lots of code was calling GetBottom() or GetRight() on an
empty rectangle, getting back that magic value and doing calculations
on it, resulting in completely bogus data.

So
(1) make the various Rectangle methods do something reasonable
    when the empty flags are set
(2) fix various other code to handle empty better
(3) assert when code accesses Bottom or Right and the empty flag
    is set.

Change-Id: I1163378cd2773dd8b386210f83400bb6b4701069
Reviewed-on: https://gerrit.libreoffice.org/73564
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 26 insertions, 6 deletions

diff --git a/tools/source/generic/gen.cxx b/tools/source/generic/gen.cxx
index 3593801579ac..6438405c99e2 100644
--- a/tools/source/generic/gen.cxx
+++ b/tools/source/generic/gen.cxx
@@ -55,11 +55,20 @@ OString Pair::toString() const
 void tools::Rectangle::SetSize( const Size& rSize )
 {
     if ( rSize.Width() < 0 )
+    {
         nRight  = nLeft + rSize.Width() +1;
+        mbWidthEmpty = false;
+    }
     else if ( rSize.Width() > 0 )
+    {
         nRight  = nLeft + rSize.Width() -1;
+        mbWidthEmpty = false;
+    }
     else
-        nRight = RECT_EMPTY;
+    {
+        nRight = 0;
+        mbWidthEmpty = true;
+    }
 
     if ( rSize.Height() < 0 )
         nBottom  = nTop + rSize.Height() +1;
@@ -72,11 +81,20 @@ void tools::Rectangle::SetSize( const Size& rSize )
 void tools::Rectangle::SaturatingSetSize(const Size& rSize)
 {
     if (rSize.Width() < 0)
+    {
         nRight = o3tl::saturating_add(nLeft, (rSize.Width() + 1));
+        mbWidthEmpty = false;
+    }
     else if ( rSize.Width() > 0 )
+    {
         nRight = o3tl::saturating_add(nLeft, (rSize.Width() - 1));
+        mbWidthEmpty = false;
+    }
     else
-        nRight = RECT_EMPTY;
+    {
+        nRight = 0;
+        mbWidthEmpty = true;
+    }
 
     if ( rSize.Height() < 0 )
         nBottom = o3tl::saturating_add(nTop, (rSize.Height() + 1));
@@ -88,7 +106,8 @@ void tools::Rectangle::SaturatingSetSize(const Size& rSize)
 
 void tools::Rectangle::SaturatingSetX(long x)
 {
-    nRight = o3tl::saturating_add(nRight, x - nLeft);
+    if (!mbWidthEmpty)
+        nRight = o3tl::saturating_add(nRight, x - nLeft);
     nLeft = x;
 }
 
@@ -146,7 +165,7 @@ tools::Rectangle& tools::Rectangle::Intersection( const tools::Rectangle& rRect
 
 void tools::Rectangle::Justify()
 {
-    if ( (nRight < nLeft) && (nRight != RECT_EMPTY) )
+    if ( (nRight < nLeft) && !mbWidthEmpty )
     {
         std::swap(nLeft, nRight);
     }
@@ -206,8 +225,9 @@ SvStream& ReadRectangle( SvStream& rIStream, tools::Rectangle& rRect )
 
     rRect.nLeft = nTmpL;
     rRect.nTop = nTmpT;
-    rRect.nRight = nTmpR;
+    rRect.nRight = nTmpR == Rectangle::RECT_EMPTY ? 0 : nTmpR;
     rRect.nBottom = nTmpB;
+    rRect.mbWidthEmpty = nTmpR == Rectangle::RECT_EMPTY;
 
     return rIStream;
 }
@@ -216,7 +236,7 @@ SvStream& WriteRectangle( SvStream& rOStream, const tools::Rectangle& rRect )
 {
     rOStream.WriteInt32( rRect.nLeft )
             .WriteInt32( rRect.nTop )
-            .WriteInt32( rRect.nRight )
+            .WriteInt32( rRect.mbWidthEmpty ? Rectangle::RECT_EMPTY : rRect.nRight )
             .WriteInt32( rRect.nBottom );
 
     return rOStream;