tdf#101686 Writer textbox direction changes depending on zoom

Previously, DrawingLayer would apply RTL flags in the case of RTL text,
but it would not clear them in the case of LTR text.

In certain situations, it is possible for Writer to draw the contents of
a text box while the VCL output device is configured for RTL output. As
a result, whether DrawingLayer correctly drew LTR text as LTR would
depend on the order that text was rendered. This issue would manifest as
text boxes appearing to spontaneously mirror themselves while zooming
and scrolling through Writer documents containing RTL text.

This change updates the relevant portion of DrawingLayer to also clear
the RTL flags in the case of LTR text.

Change-Id: I3a75561d08cdf3ee6c74b8f6e62f75a1dfcf165e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/169942
Tested-by: Jenkins
Reviewed-by: Jonathan Clark <jonathan@libreoffice.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/drawinglayer/source/processor2d/vclprocessor2d.cxx b/drawinglayer/source/processor2d/vclprocessor2d.cxx
index 7c21e4ea1f1c..b21348cf6635 100644
--- a/drawinglayer/source/processor2d/vclprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclprocessor2d.cxx
@@ -315,6 +315,8 @@ void VclProcessor2D::RenderTextSimpleOrDecoratedPortionPrimitive2D(
             // set parameters and paint text snippet
             const basegfx::BColor aRGBFontColor(
                 maBColorModifierStack.getModifiedColor(rTextCandidate.getFontColor()));
+
+            // Store previous complex text layout state, to be restored after drawing
             const vcl::text::ComplexTextLayoutFlags nOldLayoutMode(mpOutputDevice->GetLayoutMode());
 
             if (rTextCandidate.getFontAttribute().getRTL())
@@ -325,6 +327,14 @@ void VclProcessor2D::RenderTextSimpleOrDecoratedPortionPrimitive2D(
                                   | vcl::text::ComplexTextLayoutFlags::TextOriginLeft;
                 mpOutputDevice->SetLayoutMode(nRTLLayoutMode);
             }
+            else
+            {
+                // tdf#101686: This is LTR text, but the output device may have RTL state.
+                vcl::text::ComplexTextLayoutFlags nLTRLayoutMode(nOldLayoutMode);
+                nLTRLayoutMode = nLTRLayoutMode & ~vcl::text::ComplexTextLayoutFlags::BiDiRtl;
+                nLTRLayoutMode = nLTRLayoutMode & ~vcl::text::ComplexTextLayoutFlags::BiDiStrong;
+                mpOutputDevice->SetLayoutMode(nLTRLayoutMode);
+            }
 
             OUString aText(rTextCandidate.getText());
             sal_Int32 nPos = rTextCandidate.getTextPosition();
@@ -460,10 +470,8 @@ void VclProcessor2D::RenderTextSimpleOrDecoratedPortionPrimitive2D(
                 }
             }
 
-            if (rTextCandidate.getFontAttribute().getRTL())
-            {
-                mpOutputDevice->SetLayoutMode(nOldLayoutMode);
-            }
+            // Restore previous layout mode
+            mpOutputDevice->SetLayoutMode(nOldLayoutMode);
 
             if (bChangeMapMode)
                 mpOutputDevice->Pop();