tdf#116931 Fix scale when calc cells move indirectly

For the anchor mode 'To Cell (resize with cell)' there
were errors e.g. when the cell the object is in does
not scale but move. If that move went further than the
object is, wrong offsets emerged.
Also added full linear per-cell scale instead of only
scale (no translation through scale). Overhauled to
use liner transfomations, too.

Change-Id: Icff0fad168476c68ea10fd5830bf53bd7294b89f
Reviewed-on: https://gerrit.libreoffice.org/63803
Tested-by: Jenkins
Reviewed-by: Armin Le Grand <Armin.Le.Grand@cib.de>
(cherry picked from commit 10a58ec15438d34a594437815882862c4576e2c0)
Reviewed-on: https://gerrit.libreoffice.org/63852
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

1 files changed, 76 insertions, 28 deletions

diff --git a/sc/source/core/data/drwlayer.cxx b/sc/source/core/data/drwlayer.cxx
index 5fd0945e6713..4f7f1978919f 100644
--- a/sc/source/core/data/drwlayer.cxx
+++ b/sc/source/core/data/drwlayer.cxx
@@ -651,11 +651,15 @@ void ScDrawLayer::ResizeLastRectFromAnchor(const SdrObject* pObj, ScDrawObjData&
     aPos.setX(TwipsToHmm(aPos.X()));
     aPos.setY(TwipsToHmm(aPos.Y()));
     aPos += lcl_calcAvailableDiff(*pDoc, nCol1, nRow1, nTab1, rData.maStartOffset);
+
+    // this sets the needed changed position (translation)
     aRect.SetPos(aPos);
 
     if (bCanResize)
     {
-        tools::Rectangle aLastCellRect = rData.getLastCellRect();
+        // all this stuff is additional stuff to evtl. not only translate the
+        // range (Rectangle), but also check for and evtl. do corrections for it's size
+        const tools::Rectangle aLastCellRect(rData.getLastCellRect());
 
         // If the row was hidden before, or we don't have a valid cell rect, calculate the
         // new rect based on the end point.
@@ -675,61 +679,105 @@ void ScDrawLayer::ResizeLastRectFromAnchor(const SdrObject* pObj, ScDrawObjData&
             // We calculate based on the last cell rect to be able to scale the image
             // as much as the cell was scaled.
             // Still, we keep the image in its current cell (to keep start anchor == end anchor)
-            tools::Rectangle aCurrentCellRect = GetCellRect(*GetDocument(), rData.maStart, true);
-            double fWidthFactor = static_cast<double>(aCurrentCellRect.GetWidth())
-                                  / static_cast<double>(aLastCellRect.GetWidth());
-            double fHeightFactor = static_cast<double>(aCurrentCellRect.GetHeight())
-                                   / static_cast<double>(aLastCellRect.GetHeight());
+            const tools::Rectangle aCurrentCellRect(GetCellRect(*GetDocument(), rData.maStart, true));
+            long nCurrentWidth(aCurrentCellRect.GetWidth());
+            long nCurrentHeight(aCurrentCellRect.GetHeight());
+            const long nLastWidth(aLastCellRect.GetWidth());
+            const long nLastHeight(aLastCellRect.GetHeight());
+
+            // tdf#116931 Avoid and correct nifty numerical problems with the integer
+            // based and converted values (GetCellRect uses multiplies with HMM_PER_TWIPS)
+            if(nCurrentWidth + 1 == nLastWidth || nCurrentWidth == nLastWidth + 1)
+            {
+                nCurrentWidth = nLastWidth;
+            }
 
-            bool bIsGrowingLarger = aLastCellRect.GetWidth() * aLastCellRect.GetHeight()
-                                    < aCurrentCellRect.GetWidth() * aCurrentCellRect.GetHeight();
+            if(nCurrentHeight + 1 == nLastHeight || nCurrentHeight == nLastHeight + 1)
+            {
+                nCurrentHeight = nLastHeight;
+            }
 
-            if (pObj->shouldKeepAspectRatio())
+            // get intial ScalingFactors
+            double fWidthFactor(nCurrentWidth == nLastWidth || 0 == nLastWidth
+                ? 1.0
+                : static_cast<double>(nCurrentWidth) / static_cast<double>(nLastWidth));
+            double fHeightFactor(nCurrentHeight == nLastHeight || 0 == nLastHeight
+                ? 1.0
+                : static_cast<double>(nCurrentHeight) / static_cast<double>(nLastHeight));
+
+            // check if we grow or shrink - and at all
+            const bool bIsGrowing(nCurrentWidth > nLastWidth || nCurrentHeight > nLastHeight);
+            const bool bIsShrinking(nCurrentWidth < nLastWidth || nCurrentHeight < nLastHeight);
+            const bool bIsSizeChanged(bIsGrowing || bIsShrinking);
+
+            // handle AspectRatio, only needed if size does change
+            if(bIsSizeChanged && pObj->shouldKeepAspectRatio())
             {
                 tools::Rectangle aRectIncludingOffset = aRect;
                 aRectIncludingOffset.setWidth(aRect.GetWidth() + rData.maStartOffset.X());
                 aRectIncludingOffset.setHeight(aRect.GetHeight() + rData.maStartOffset.Y());
                 long nWidth = aRectIncludingOffset.GetWidth();
                 assert(nWidth && "div-by-zero");
-                double fMaxWidthFactor = static_cast<double>(aCurrentCellRect.GetWidth())
+                double fMaxWidthFactor = static_cast<double>(nCurrentWidth)
                                          / static_cast<double>(nWidth);
                 long nHeight = aRectIncludingOffset.GetHeight();
                 assert(nHeight && "div-by-zero");
-                double fMaxHeightFactor = static_cast<double>(aCurrentCellRect.GetHeight())
+                double fMaxHeightFactor = static_cast<double>(nCurrentHeight)
                                           / static_cast<double>(nHeight);
                 double fMaxFactor = std::min(fMaxHeightFactor, fMaxWidthFactor);
 
-                if (bIsGrowingLarger) // cell is growing larger
+                if(bIsGrowing) // cell is growing larger
                 {
                     // To actually grow the image, we need to take the max
                     fWidthFactor = fHeightFactor = std::max(fWidthFactor, fHeightFactor);
                 }
-                else // cell is growing smaller, take the min
+                else if(bIsShrinking) // cell is growing smaller, take the min
                 {
                     fWidthFactor = fHeightFactor = std::min(fWidthFactor, fHeightFactor);
                 }
+
                 // We don't want the image to become larger than the current cell
                 fWidthFactor = fHeightFactor = std::min(fWidthFactor, fMaxFactor);
             }
 
-            // When shrinking the cell, and the image still fits in the smaller cell, don't resize it at all
-            if (bIsGrowingLarger
-                || rData.getShapeRect().GetUnion(aCurrentCellRect) != aCurrentCellRect)
+            if(bIsSizeChanged)
             {
-                aRect.setWidth(
-                    rtl::math::round(static_cast<double>(aRect.GetWidth()) * fWidthFactor));
-                aRect.setHeight(
-                    rtl::math::round(static_cast<double>(aRect.GetHeight()) * fHeightFactor));
+                // tdf#116931 re-organized scaling (if needed)
+                // Check if we need to scale at all. Always scale on growing.
+                bool bNeedToScale(bIsGrowing);
+
+                if(!bNeedToScale && bIsShrinking)
+                {
+                    // Check if original still fits into space. Do *not* forget to
+                    // compare with evtl. numerically corrected aCurrentCellRect
+                    const bool bFitsInX(aRect.Right() <= aCurrentCellRect.Left() + nCurrentWidth);
+                    const bool bFitsInY(aRect.Bottom() <= aCurrentCellRect.Top() + nCurrentHeight);
+
+                    // If the image still fits in the smaller cell, don't resize it at all
+                    bNeedToScale = (!bFitsInX || !bFitsInY);
+                }
 
-                // Reduce offset also when shrinking
-                if (!bIsGrowingLarger)
+                if(bNeedToScale)
                 {
-                    Point aAvailableSpaceInCell = Point(aRect.getX() - aLastCellRect.TopLeft().X(),
-                                                        aRect.getY() - aLastCellRect.TopLeft().Y());
-                    aRect.setX(rtl::math::round(static_cast<double>(aRect.getX())
-                                                + aAvailableSpaceInCell.X() * fWidthFactor));
-                    aRect.setY(rtl::math::round(static_cast<double>(aRect.getY())
-                                                + aAvailableSpaceInCell.Y() * fHeightFactor));
+                    // tdf#116931 use transformations now. Translation is already applied
+                    // (see aRect.SetPos above), so only scale needs to be applied - relative
+                    // to *new* CellRect (which is aCurrentCellRect).
+                    // Prepare scale relative to top-left of aCurrentCellRect
+                    basegfx::B2DHomMatrix aChange;
+
+                    aChange.translate(-aCurrentCellRect.getX(), -aCurrentCellRect.getY());
+                    aChange.scale(fWidthFactor, fHeightFactor);
+                    aChange.translate(aCurrentCellRect.getX(), aCurrentCellRect.getY());
+
+                    // create B2DRange and transform by prepared scale
+                    basegfx::B2DRange aNewRange(aRect.Left(), aRect.Top(), aRect.Right(), aRect.Bottom());
+
+                    aNewRange.transform(aChange);
+
+                    // apply to aRect
+                    aRect = tools::Rectangle(
+                        basegfx::fround(aNewRange.getMinX()), basegfx::fround(aNewRange.getMinY()),
+                        basegfx::fround(aNewRange.getMaxX()), basegfx::fround(aNewRange.getMaxY()));
                 }
             }
         }