Re-work line trimming to fix issues with column highighters

Instead of triming only buffer ranges, add a trim_from method to
display line to keep the initial N columns, we know how many columns
are used by non-trimable widgets in DisplaySetup::widget_columns so
we can just pass this.

Also restore the previous logic for face merging

Fixes #4670

5 files changed, 39 insertions, 35 deletions

diff --git a/src/display_buffer.cc b/src/display_buffer.cc
index 2b377310..335fb5de 100644
--- a/src/display_buffer.cc
+++ b/src/display_buffer.cc
@@ -193,29 +193,45 @@ ColumnCount DisplayLine::length() const
     return len;
 }
 
-bool DisplayLine::trim(ColumnCount first_col, ColumnCount col_count, bool only_buffer)
+bool DisplayLine::trim(ColumnCount front, ColumnCount col_count)
 {
-    for (auto it = begin(); first_col > 0 and it != end(); )
+    return trim_from(0_col, front, col_count);
+}
+
+bool DisplayLine::trim_from(ColumnCount first_col, ColumnCount front, ColumnCount col_count)
+{
+    auto it = begin();
+    while (first_col > 0 and it != end())
     {
-        if (only_buffer and !it->has_buffer_range())
+        auto len = it->length();
+        if (len <= first_col)
         {
             ++it;
-            continue;
+            first_col -= len;
         }
+        else
+        {
+            it = ++split(it, front);
+            first_col = 0;
+        }
+    }
 
+    while (front > 0 and it != end())
+    {
         auto len = it->length();
-        if (len <= first_col)
+        if (len <= front)
         {
             m_atoms.erase(it);
-            first_col -= len;
+            front -= len;
         }
         else
         {
-            it->trim_begin(first_col);
-            first_col = 0;
+            it->trim_begin(front);
+            front = 0;
         }
     }
-    auto it = begin();
+
+    it = begin();
     for (; it != end() and col_count > 0; ++it)
         col_count -= it->length();
 
diff --git a/src/display_buffer.hh b/src/display_buffer.hh
index af37b18f..8008f86a 100644
--- a/src/display_buffer.hh
+++ b/src/display_buffer.hh
@@ -144,9 +144,13 @@ public:
     iterator erase(iterator beg, iterator end);
     DisplayAtom& push_back(DisplayAtom atom);
 
-    // remove first_col from the begining of the line, and make sure
+    // remove front from the begining of the line, and make sure
     // the line is less that col_count character
-    bool trim(ColumnCount first_col, ColumnCount col_count, bool only_buffer = false);
+    bool trim(ColumnCount front, ColumnCount col_count);
+
+    // remove front from the begining of the line + first_col, and make sure
+    // the line is less that col_count character
+    bool trim_from(ColumnCount first_col, ColumnCount front, ColumnCount col_count);
 
     // Merge together consecutive atoms sharing the same display attributes
     void optimize();
diff --git a/src/face.hh b/src/face.hh
index e1047bcd..ce544116 100644
--- a/src/face.hh
+++ b/src/face.hh
@@ -65,10 +65,10 @@ inline Face merge_faces(const Face& base, const Face& face)
     };
 
     auto choose = [&](Color Face::*color, Attribute final_attr) {
-        if (base.attributes & final_attr)
-            return base.*color;
         if (face.attributes & final_attr)
             return face.*color;
+        if (base.attributes & final_attr)
+            return base.*color;
         if (face.*color == Color::Default)
             return base.*color;
         if ((base.*color).isRGB() and (face.*color).isRGB() and (face.*color).a != 255)
diff --git a/src/highlighters.cc b/src/highlighters.cc
index 5245b3c6..4b9540b6 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -558,17 +558,6 @@ std::unique_ptr<Highlighter> create_dynamic_regex_highlighter(HighlighterParamet
     return make_hl(get_regex, get_face);
 }
 
-namespace
-{
-
-Face make_final(Face face)
-{
-    face.attributes |= Attribute::Final;
-    return face;
-}
-
-}
-
 const HighlighterDesc line_desc = {
     "Parameters: <value string> <face>\n"
     "Highlight the line given by evaluating <value string> with <face>",
@@ -615,7 +604,7 @@ std::unique_ptr<Highlighter> create_line_highlighter(HighlighterParameters param
         }
         const ColumnCount remaining = context.context.window().dimensions().column - column;
         if (remaining > 0)
-            it->push_back({ String{' ', remaining}, make_final(face) });
+            it->push_back({String{' ', remaining}, face});
     };
 
     return make_highlighter(std::move(func));
@@ -652,18 +641,13 @@ std::unique_ptr<Highlighter> create_column_highlighter(HighlighterParameters par
         if (column < context.setup.first_column or column >= context.setup.first_column + context.context.window().dimensions().column)
             return;
 
-        const Buffer& buffer = context.context.buffer();
+        column += context.setup.widget_columns;
         for (auto& line : display_buffer.lines())
         {
             auto remaining_col = column;
             bool found = false;
-            auto first_buf = find_if(line, [](auto& atom) { return atom.has_buffer_range(); });
-            BufferCoord last_pos{};
-            for (auto atom_it = first_buf; atom_it != line.end(); ++atom_it)
+            for (auto atom_it = line.begin(); atom_it != line.end(); ++atom_it)
             {
-                if (atom_it->has_buffer_range())
-                    last_pos = atom_it->end();
-
                 const auto atom_len = atom_it->length();
                 if (remaining_col < atom_len)
                 {
@@ -681,8 +665,8 @@ std::unique_ptr<Highlighter> create_column_highlighter(HighlighterParameters par
                 continue;
 
             if (remaining_col > 0)
-                line.push_back({buffer, last_pos, last_pos, String{' ', remaining_col}, make_final(Face{})});
-            line.push_back({buffer, last_pos, last_pos, " ", make_final(face)});
+                line.push_back({String{' ', remaining_col}, Face{}});
+            line.push_back({" ", face});
         }
     };
 
diff --git a/src/window.cc b/src/window.cc
index 47bf65bd..455e6a2d 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -159,7 +159,7 @@ const DisplayBuffer& Window::update_display_buffer(const Context& context)
         m_builtin_highlighters.highlight({context, setup, pass, {}}, m_display_buffer, range);
 
     for (auto& line : m_display_buffer.lines())
-        line.trim(setup.first_column, m_dimensions.column, true);
+        line.trim_from(setup.widget_columns, setup.first_column, m_dimensions.column);
 
     m_display_buffer.optimize();