Trim display lines before the colorize pass

Colorizing long lines can be costly, remove all the invisible atoms
earlier. Also optimize ForwardHighlighterApplier further by trimming
empty lines.

src/display_buffer.cc

@@ -264,18 +264,22 @@ bool DisplayLine::trim_from(ColumnCount first_col, ColumnCount front, ColumnCoun
     }
 
     auto front_it = it;
-    Face last_face{};
+    Optional<DisplayAtom> padding;
     while (front > 0 and it != end())
     {
         front -= it->trim_begin(front);
         kak_assert(it->empty() or front <= 0);
-        last_face = it->face;
+        if (front < 0)
+            padding.emplace(it->has_buffer_range()
+                ? DisplayAtom{it->buffer(), {it->begin(), it->begin()}, String{' ', -front}, it->face}
+                : DisplayAtom{String{' ', -front}, it->face});
+
         if (it->empty())
             ++it;
     }
     it = m_atoms.erase(front_it, it);
-    if (front < 0)
+    if (padding)
-        it = m_atoms.insert(it, DisplayAtom{String{' ', -front}, last_face});
+        it = m_atoms.insert(it, std::move(*padding));
 
     it = begin();
     for (; it != end() and col_count > 0; ++it)

src/display_buffer.hh

@@ -54,7 +54,7 @@ public:
 
     void replace(String text)
     {
-        kak_assert(m_type == Range);
+        if (m_type == Range)
             m_type = ReplacedRange;
         m_text = std::move(text);
     }

src/highlighters.cc

@@ -530,7 +530,7 @@ std::unique_ptr<Highlighter> create_column_highlighter(HighlighterParameters par
     if (params.size() != 2)
         throw runtime_error("wrong parameter count");
 
-    auto func = [col_expr=params[0], facespec=params[1]]
+    auto func = [col_expr=params[0], facespec=parse_face(params[1])]
                 (HighlightContext context, DisplayBuffer& display_buffer, BufferRange)
     {
         ColumnCount column = -1;
@@ -551,7 +551,7 @@ 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;
 
-        column += context.setup.widget_columns;
+        column += context.setup.widget_columns - context.setup.first_column;
         for (auto& line : display_buffer.lines())
         {
             auto remaining_col = column;
@@ -1801,26 +1801,29 @@ struct ForwardHighlighterApplier
         if (first_line != cur_line and first_line != end_line)
             cur_atom = first_line->begin();
         cur_line = first_line;
-        if (cur_line == end_line)
+        if (cur_line == end_line or cur_line->range().begin >= end)
             return;
 
         auto& region_lines = region_display.lines();
         region_lines.clear();
-        Vector<size_t> insert_idx;
+        Vector<std::pair<DisplayLineList::iterator, size_t>> insert_pos;
         while (cur_line != end_line and cur_line->range().begin < end)
         {
             auto& line = *cur_line;
             auto first = std::find_if(cur_atom, line.end(), [&](auto&& atom) { return atom.has_buffer_range() and atom.end() > begin; });
-            if (first->type() != DisplayAtom::ReplacedRange and first->begin() < begin)
+            if (first->type() == DisplayAtom::Range and first->begin() < begin)
                 first = ++line.split(first, begin);
             auto idx = first - line.begin();
 
             auto last = std::find_if(first, line.end(), [&](auto&& atom) { return atom.has_buffer_range() and atom.end() > end; });
-            if (last != line.end() and last->type() != DisplayAtom::ReplacedRange and last->begin() < end and last->end() > end)
+            if (last != line.end() and last->type() == DisplayAtom::Range and last->begin() < end)
                 last = ++line.split(last, end);
 
-            insert_idx.push_back(idx);
+            if (line.begin() + idx != last)
+            {
+                insert_pos.emplace_back(cur_line, idx);
                 region_lines.push_back(line.extract(line.begin() + idx, last));
+            }
 
             if (idx != line.atoms().size())
                 break;
@@ -1828,21 +1831,20 @@ struct ForwardHighlighterApplier
                 cur_atom = cur_line->begin();
         }
 
-        if (region_lines.empty())
-            return;
-
         region_display.compute_range();
         highlighter.highlight(context, region_display, {begin, end});
 
-        for (size_t i = 0; i < region_lines.size(); ++i, ++first_line)
+        for (size_t i = 0; i < insert_pos.size(); ++i)
         {
-            auto it = first_line->insert(
+            auto& [line_it, idx] = insert_pos[i];
-                first_line->begin() + insert_idx[i],
+            auto& atoms = region_lines[i].atoms();
-                std::move_iterator(region_lines[i].begin()),
+            auto it = line_it->insert(
-                std::move_iterator(region_lines[i].end()));
+                line_it->begin() + idx,
+                std::move_iterator(atoms.begin()),
+                std::move_iterator(atoms.end()));
 
-            if (first_line == cur_line)
+            if (line_it == cur_line)
-                cur_atom = it + region_lines[i].atoms().size();
+                cur_atom = it + atoms.size();
         }
     }
 };

src/window.cc

@@ -155,12 +155,14 @@ const DisplayBuffer& Window::update_display_buffer(const Context& context)
 
     m_display_buffer.compute_range();
     const BufferRange range{{0,0}, buffer().end_coord()};
-    for (auto pass : { HighlightPass::Wrap, HighlightPass::Move, HighlightPass::Colorize })
+    m_builtin_highlighters.highlight({context, setup, HighlightPass::Wrap, {}}, m_display_buffer, range);
-        m_builtin_highlighters.highlight({context, setup, pass, {}}, m_display_buffer, range);
+    m_builtin_highlighters.highlight({context, setup, HighlightPass::Move, {}}, m_display_buffer, range);
 
     for (auto& line : m_display_buffer.lines())
         line.trim_from(setup.widget_columns, setup.first_column, m_dimensions.column);
 
+    m_builtin_highlighters.highlight({context, setup, HighlightPass::Colorize, {}}, m_display_buffer, range);
+
     m_display_buffer.optimize();
 
     set_position({setup.first_line, setup.first_column});