Watermark: fix rotation calculation

* when angle > 180 was used calculated value was 0
* values are rounded

Change-Id: I0cade407883a60d8d802b487668882e95f42ddce
Reviewed-on: https://gerrit.libreoffice.org/38597
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

1 files changed, 25 insertions, 11 deletions

diff --git a/sw/source/core/edit/edfcol.cxx b/sw/source/core/edit/edfcol.cxx
index 8d6965c151bb..94c066e98c2f 100644
--- a/sw/source/core/edit/edfcol.cxx
+++ b/sw/source/core/edit/edfcol.cxx
@@ -266,6 +266,29 @@ void SwEditShell::SetClassification(const OUString& rName, SfxClassificationPoli
     }
 }
 
+sal_Int16 lcl_GetAngle(const drawing::HomogenMatrix3& rMatrix)
+{
+    basegfx::B2DHomMatrix aTransformation;
+    basegfx::B2DTuple aScale;
+    basegfx::B2DTuple aTranslate;
+    double fRotate = 0;
+    double fShear = 0;
+
+    aTransformation.set(0, 0, rMatrix.Line1.Column1);
+    aTransformation.set(0, 1, rMatrix.Line1.Column2);
+    aTransformation.set(0, 2, rMatrix.Line1.Column3);
+    aTransformation.set(1, 0, rMatrix.Line2.Column1);
+    aTransformation.set(1, 1, rMatrix.Line2.Column2);
+    aTransformation.set(1, 2, rMatrix.Line2.Column3);
+    aTransformation.set(2, 0, rMatrix.Line3.Column1);
+    aTransformation.set(2, 1, rMatrix.Line3.Column2);
+    aTransformation.set(2, 2, rMatrix.Line3.Column3);
+
+    aTransformation.decompose(aScale, aTranslate, fRotate, fShear);
+    sal_Int16 nDeg = round(basegfx::rad2deg(fRotate));
+    return nDeg < 0 ? round(nDeg) * -1 : round(360.0 - nDeg);
+}
+
 SfxWatermarkItem SwEditShell::GetWatermark()
 {
     SwDocShell* pDocShell = GetDoc()->GetDocShell();
@@ -311,13 +334,7 @@ SfxWatermarkItem SwEditShell::GetWatermark()
             if (xPropertySet->getPropertyValue(UNO_NAME_FILLCOLOR) >>= nColor)
                 aItem.SetColor(nColor);
             if (xPropertySet->getPropertyValue("Transformation") >>= aMatrix)
-            {
-                double y = aMatrix.Line2.Column1;
-                double x = aMatrix.Line1.Column1;
-                double nRad = atan2(y, x) * -1;
-                double nDeg = nRad * 180.0 / F_PI;
-                aItem.SetAngle(nDeg);
-            }
+                aItem.SetAngle(lcl_GetAngle(aMatrix));
             if (xPropertySet->getPropertyValue(UNO_NAME_FILL_TRANSPARENCE) >>= nTransparency)
                 aItem.SetTransparency(nTransparency);
 
@@ -374,10 +391,7 @@ void SwEditShell::SetWatermark(const SfxWatermarkItem& rWatermark)
             xPropertySet->getPropertyValue(UNO_NAME_FILLCOLOR) >>= nColor;
             xPropertySet->getPropertyValue(UNO_NAME_FILL_TRANSPARENCE) >>= nTransparency;
             xPropertySet->getPropertyValue("Transformation") >>= aMatrix;
-            double y = aMatrix.Line2.Column1;
-            double x = aMatrix.Line1.Column1;
-            double nRad = atan2(y, x) * -1;
-            nAngle = nRad * 180.0 / F_PI;
+            nAngle = lcl_GetAngle(aMatrix);
 
             // If the header already contains a watermark, see if it its text is up to date.
             uno::Reference<text::XTextRange> xTextRange(xWatermark, uno::UNO_QUERY);