[LyX/master] Fix display of gather in lefteqn mode

[Jean-Marc Lasgouttes]

commit 7cb0284a3ffa469c4c99184725f5a3e0b4056508
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Thu Oct 4 16:05:46 2018 +0200

    Fix display of gather in lefteqn mode
    
    The column is flushed when the display of equations is flushed.
    
    Not sure what to do with RtL languages.
    
    Fixes bug 11324.
---
 src/mathed/InsetMathGrid.cpp  |    8 ++++++--
 src/mathed/InsetMathGrid.h    |    7 +++++--
 src/mathed/InsetMathHull.cpp  |    4 ++--
 src/mathed/InsetMathSplit.cpp |    5 +++--
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/mathed/InsetMathGrid.cpp b/src/mathed/InsetMathGrid.cpp
index c696c22..5a4830c 100644
--- a/src/mathed/InsetMathGrid.cpp
+++ b/src/mathed/InsetMathGrid.cpp
@@ -1843,15 +1843,19 @@ bool InsetMathGrid::getStatus(Cursor & cur, FuncRequest 
const & cmd,
 
 
 // static
-char InsetMathGrid::colAlign(HullType type, col_type col)
+char InsetMathGrid::colAlign(HullType type, col_type col, BufferParams const & 
bp)
 {
        switch (type) {
        case hullEqnArray:
                return "rcl"[col % 3];
 
        case hullMultline:
-       case hullGather:
                return 'c';
+       case hullGather:
+               if (!bp.is_math_indent)
+                       return 'c';
+               else
+                       return 'l';
 
        case hullAlign:
        case hullAlignAt:
diff --git a/src/mathed/InsetMathGrid.h b/src/mathed/InsetMathGrid.h
index af3f4c1..f93dc82 100644
--- a/src/mathed/InsetMathGrid.h
+++ b/src/mathed/InsetMathGrid.h
@@ -18,6 +18,8 @@
 
 namespace lyx {
 
+class BufferParams;
+
 
 /** Gridded math inset base class.
  *  This is the base to all grid-like editable math objects
@@ -267,8 +269,9 @@ protected:
 
        // The following two functions are used in InsetMathHull and
        // InsetMathSplit.
-       /// The value of a fixed col align for a certain hull type
-       static char colAlign(HullType type, col_type col);
+       /// The value of a fixed col align for a certain hull type (can
+       /// depend on the "indent math" setting).
+       static char colAlign(HullType type, col_type col,  BufferParams const 
&);
        /// The value of a fixed col spacing for a certain hull type
        static int colSpace(HullType type, col_type col);
 
diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 61d078a..582685e 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -430,7 +430,7 @@ InsetMath::mode_type InsetMathHull::currentMode() const
 // alignment is not implemented in the LyXHTML output.
 char InsetMathHull::defaultColAlign(col_type col)
 {
-       return colAlign(type_, col);
+       return colAlign(type_, col, buffer().params());
 }
 
 
@@ -452,7 +452,7 @@ char InsetMathHull::displayColAlign(idx_type idx) const
        case hullXAlignAt:
        case hullXXAlignAt:
        case hullFlAlign:
-               return colAlign(type_, col(idx));
+               return colAlign(type_, col(idx), buffer().params());
        default:
                break;
        }
diff --git a/src/mathed/InsetMathSplit.cpp b/src/mathed/InsetMathSplit.cpp
index c260e2e..200a0bc 100644
--- a/src/mathed/InsetMathSplit.cpp
+++ b/src/mathed/InsetMathSplit.cpp
@@ -16,6 +16,7 @@
 #include "MathStream.h"
 #include "MathSupport.h"
 
+#include "Buffer.h"
 #include "FuncRequest.h"
 #include "FuncStatus.h"
 #include "support/gettext.h"
@@ -61,7 +62,7 @@ char InsetMathSplit::defaultColAlign(col_type col)
            || name_ == "aligned"
            || name_ == "align"
            || name_ == "alignedat")
-               return colAlign(hullAlign, col);
+               return colAlign(hullAlign, col, buffer().params());
        return 'l';
 }
 
@@ -78,7 +79,7 @@ char InsetMathSplit::displayColAlign(idx_type idx) const
            || name_ == "aligned"
            || name_ == "align"
            || name_ == "alignedat")
-               return colAlign(hullAlign, col(idx));
+               return colAlign(hullAlign, col(idx), buffer().params());
        return InsetMathGrid::displayColAlign(idx);
 }