Do not make cursor visible after mouse scrolling and view commands

ensure cursor is visible after user input except if the command
implementation opted-out. Hooks and timers should not enforce
visible cursor.

PageUp/PageDown and `<c-f>` / `<c-b>` commands still move the cursor
as this seemed a desired behaviour.

9 files changed, 55 insertions, 30 deletions

diff --git a/src/client.cc b/src/client.cc
index 6996ee13..5d6cee62 100644
--- a/src/client.cc
+++ b/src/client.cc
@@ -109,7 +109,10 @@ bool Client::process_pending_inputs()
             else if (key == Key::FocusOut)
                 context().hooks().run_hook(Hook::FocusOut, context().name(), context());
             else
+            {
+                context().ensure_cursor_visible = true;
                 m_input_handler.handle_key(key);
+            }
 
             context().hooks().run_hook(Hook::RawKey, to_string(key), context());
         }
diff --git a/src/context.hh b/src/context.hh
index 69377148..f6f00b80 100644
--- a/src/context.hh
+++ b/src/context.hh
@@ -144,6 +144,8 @@ public:
     void repeat_last_select() { if (m_last_select) m_last_select(*this); }
 
     Buffer* last_buffer() const;
+
+    bool ensure_cursor_visible = true;
 private:
     void begin_edition();
     void end_edition();
diff --git a/src/highlighter.hh b/src/highlighter.hh
index ad94f44d..925dcaa7 100644
--- a/src/highlighter.hh
+++ b/src/highlighter.hh
@@ -46,6 +46,7 @@ struct DisplaySetup
     DisplayCoord cursor_pos;
     // Offset of line and columns that must remain visible around cursor
     DisplayCoord scroll_offset;
+    bool ensure_cursor_visible;
 };
 
 using HighlighterIdList = ConstArrayView<StringView>;
diff --git a/src/highlighters.cc b/src/highlighters.cc
index 6f6d6e30..954f1417 100644
--- a/src/highlighters.cc
+++ b/src/highlighters.cc
@@ -752,7 +752,8 @@ struct WrapHighlighter : Highlighter
             win_line += wrap_count + 1;
 
             // scroll window to keep cursor visible, and update range as lines gets removed
-            while (buf_line >= cursor.line and setup.first_line < cursor.line and
+            while (setup.ensure_cursor_visible and
+                   buf_line >= cursor.line and setup.first_line < cursor.line and
                    setup.cursor_pos.line + setup.scroll_offset.line >= win_height)
             {
                 auto remove_count = 1 + line_wrap_count(setup.first_line, indent);
@@ -1660,7 +1661,8 @@ private:
                 setup.cursor_pos.column += cursor_move;
             }
 
-            if (last.line >= setup.first_line and
+            if (setup.ensure_cursor_visible and
+                last.line >= setup.first_line and
                 range.first.line <= setup.first_line + setup.line_count and
                 range.first.line != last.line)
             {
diff --git a/src/input_handler.cc b/src/input_handler.cc
index 66d30391..a5c88a21 100644
--- a/src/input_handler.cc
+++ b/src/input_handler.cc
@@ -180,7 +180,7 @@ struct MouseHandler
         }
 
         case Key::Modifiers::Scroll:
-            scroll_window(context, static_cast<int32_t>(key.key), (bool)m_dragging);
+            scroll_window(context, static_cast<int32_t>(key.key), m_dragging ? OnHiddenCursor::MoveCursor : OnHiddenCursor::PreserveSelections);
             return true;
 
         default: return false;
@@ -1852,7 +1852,7 @@ void hide_auto_info_ifn(const Context& context, bool hide)
         context.client().info_hide();
 }
 
-void scroll_window(Context& context, LineCount offset, bool mouse_dragging)
+void scroll_window(Context& context, LineCount offset, OnHiddenCursor on_hidden_cursor)
 {
     Window& window = context.window();
     Buffer& buffer = context.buffer();
@@ -1861,6 +1861,9 @@ void scroll_window(Context& context, LineCount offset, bool mouse_dragging)
     DisplayCoord win_pos = window.position();
     DisplayCoord win_dim = window.dimensions();
 
+    if (on_hidden_cursor == OnHiddenCursor::PreserveSelections)
+        context.ensure_cursor_visible = false;
+
     if ((offset < 0 and win_pos.line == 0) or (offset > 0 and win_pos.line == line_count - 1))
         return;
 
@@ -1870,25 +1873,27 @@ void scroll_window(Context& context, LineCount offset, bool mouse_dragging)
 
     win_pos.line = clamp(win_pos.line + offset, 0_line, line_count-1);
 
-    ScopedSelectionEdition selection_edition{context};
-    SelectionList& selections = context.selections();
-    Selection& main_selection = selections.main();
-    const BufferCoord anchor = main_selection.anchor();
-    const BufferCoordAndTarget cursor = main_selection.cursor();
+    window.set_position(win_pos);
+    if (on_hidden_cursor != OnHiddenCursor::PreserveSelections)
+    {
+        ScopedSelectionEdition selection_edition{context};
+        SelectionList& selections = context.selections();
+        Selection& main_selection = selections.main();
+        const BufferCoord anchor = main_selection.anchor();
+        const BufferCoordAndTarget cursor = main_selection.cursor();
 
-    auto cursor_off = mouse_dragging ? win_pos.line - window.position().line : 0;
+        auto cursor_off = win_pos.line - window.position().line;
 
-    auto line = clamp(cursor.line + cursor_off, win_pos.line + scrolloff.line,
-                      win_pos.line + win_dim.line - 1 - scrolloff.line);
+        auto line = clamp(cursor.line + cursor_off, win_pos.line + scrolloff.line,
+                          win_pos.line + win_dim.line - 1 - scrolloff.line);
 
-    const ColumnCount tabstop = context.options()["tabstop"].get<int>();
-    auto new_cursor = buffer.offset_coord(cursor, line - cursor.line, tabstop);
-    BufferCoord new_anchor = (mouse_dragging or new_cursor == cursor) ? anchor : new_cursor;
+        const ColumnCount tabstop = context.options()["tabstop"].get<int>();
+        auto new_cursor = buffer.offset_coord(cursor, line - cursor.line, tabstop);
 
-    window.set_position(win_pos);
-    main_selection = { new_anchor, new_cursor };
+        main_selection = {on_hidden_cursor == OnHiddenCursor::MoveCursor ? anchor : new_cursor, new_cursor};
 
-    selections.sort_and_merge_overlapping();
+        selections.sort_and_merge_overlapping();
+    }
 }
 
 }
diff --git a/src/input_handler.hh b/src/input_handler.hh
index 00d2d53a..afcc24d4 100644
--- a/src/input_handler.hh
+++ b/src/input_handler.hh
@@ -204,7 +204,13 @@ void on_next_key_with_autoinfo(const Context& context, StringView mode_name,
         });
 }
 
-void scroll_window(Context& context, LineCount offset, bool mouse_dragging = false);
+enum class OnHiddenCursor {
+    PreserveSelections,
+    MoveCursor,
+    MoveCursorAndAnchor,
+};
+
+void scroll_window(Context& context, LineCount offset, OnHiddenCursor on_hidden_cursor);
 
 }
 
diff --git a/src/normal.cc b/src/normal.cc
index 79a434ac..81caeb2d 100644
--- a/src/normal.cc
+++ b/src/normal.cc
@@ -368,6 +368,7 @@ void view_commands(Context& context, NormalParams params)
     const int count = params.count;
     on_next_key_with_autoinfo(context, "view", KeymapMode::View,
                              [count](Key key, Context& context) {
+        context.ensure_cursor_visible = false;
         if (key == Key::Escape)
             return;
 
@@ -400,10 +401,10 @@ void view_commands(Context& context, NormalParams params)
             window.scroll(-std::max<ColumnCount>(1, count));
             break;
         case 'j':
-            scroll_window(context,  std::max<LineCount>(1, count));
+            scroll_window(context,  std::max<LineCount>(1, count), OnHiddenCursor::PreserveSelections);
             break;
         case 'k':
-            scroll_window(context, -std::max<LineCount>(1, count));
+            scroll_window(context, -std::max<LineCount>(1, count), OnHiddenCursor::PreserveSelections);
             break;
         case 'l':
             window.scroll( std::max<ColumnCount>(1, count));
@@ -1408,7 +1409,7 @@ void scroll(Context& context, NormalParams params)
     const int count = params.count ? params.count : 1;
     const LineCount offset = (window.dimensions().line - 2) / (half ? 2 : 1) * count;
 
-    scroll_window(context, offset * direction);
+    scroll_window(context, offset * direction, OnHiddenCursor::MoveCursorAndAnchor);
 }
 
 template<Direction direction>
diff --git a/src/window.cc b/src/window.cc
index 757723d2..b660bbdb 100644
--- a/src/window.cc
+++ b/src/window.cc
@@ -202,11 +202,14 @@ DisplaySetup Window::compute_display_setup(const Context& context) const
     const int tabstop = context.options()["tabstop"].get<int>();
     const auto& cursor = context.selections().main().cursor();
 
-    // Ensure cursor line is visible
-    if (cursor.line - offset.line < win_pos.line)
-        win_pos.line = std::max(0_line, cursor.line - offset.line);
-    if (cursor.line + offset.line >= win_pos.line + m_dimensions.line)
-        win_pos.line = std::min(buffer().line_count()-1, cursor.line + offset.line - m_dimensions.line + 1);
+    bool ensure_cursor_visible = context.ensure_cursor_visible;
+    if (ensure_cursor_visible)
+    {
+        if (cursor.line - offset.line < win_pos.line)
+            win_pos.line = std::max(0_line, cursor.line - offset.line);
+        if (cursor.line + offset.line >= win_pos.line + m_dimensions.line)
+            win_pos.line = std::min(buffer().line_count()-1, cursor.line + offset.line - m_dimensions.line + 1);
+    }
 
     DisplaySetup setup{
         win_pos.line,
@@ -215,13 +218,15 @@ DisplaySetup Window::compute_display_setup(const Context& context) const
         0_col,
         {cursor.line - win_pos.line,
          get_column(buffer(), tabstop, cursor) - win_pos.column},
-        offset
+        offset,
+        ensure_cursor_visible
     };
     for (auto pass : { HighlightPass::Move, HighlightPass::Wrap })
         m_builtin_highlighters.compute_display_setup({context, setup, pass, {}}, setup);
     check_display_setup(setup, *this);
 
     // now ensure the cursor column is visible
+    if (ensure_cursor_visible)
     {
         auto underflow = std::max(-setup.first_column,
                                   setup.cursor_pos.column - setup.scroll_offset.column);
diff --git a/test/regression/3219-scroll-json-ui/script b/test/regression/3219-scroll-json-ui/script
index 0cfd5b58..2ba5f829 100644
--- a/test/regression/3219-scroll-json-ui/script
+++ b/test/regression/3219-scroll-json-ui/script
@@ -6,8 +6,8 @@ ui_out '{ "jsonrpc": "2.0", "method": "draw_status", "params": [[], [{ "face": {
 ui_out '{ "jsonrpc": "2.0", "method": "set_cursor", "params": ["buffer", { "line": 0, "column": 0 }] }'
 ui_out '{ "jsonrpc": "2.0", "method": "refresh", "params": [true] }'
 ui_in '{ "jsonrpc": "2.0", "method": "scroll", "params": [ 2 ] }'
-ui_out '{ "jsonrpc": "2.0", "method": "draw", "params": [[[{ "face": { "fg": "black", "bg": "white", "underline": "default", "attributes": [] }, "contents": "0" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "3\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "04\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "05\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "06\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "07\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "08\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "09\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "10\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "11\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "12\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "13\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "14\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "15\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "16\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "17\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "18\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "19\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "20\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "21\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "22\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "23\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "24\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "25\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "26\u000a" }]], { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }] }'
+ui_out '{ "jsonrpc": "2.0", "method": "draw", "params": [[[{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "03\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "04\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "05\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "06\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "07\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "08\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "09\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "10\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "11\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "12\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "13\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "14\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "15\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "16\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "17\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "18\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "19\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "20\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "21\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "22\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "23\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "24\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "25\u000a" }], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "26\u000a" }]], { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }] }'
 ui_out '{ "jsonrpc": "2.0", "method": "info_hide", "params": [] }'
-ui_out '{ "jsonrpc": "2.0", "method": "draw_status", "params": [[], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "out 3:1 " }, { "face": { "fg": "black", "bg": "yellow", "underline": "default", "attributes": [] }, "contents": "" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": " " }, { "face": { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }, "contents": "1 sel" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": " - client0@[kak-tests]" }], { "fg": "cyan", "bg": "default", "underline": "default", "attributes": [] }] }'
+ui_out '{ "jsonrpc": "2.0", "method": "draw_status", "params": [[], [{ "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": "out 1:1 " }, { "face": { "fg": "black", "bg": "yellow", "underline": "default", "attributes": [] }, "contents": "" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": " " }, { "face": { "fg": "blue", "bg": "default", "underline": "default", "attributes": [] }, "contents": "1 sel" }, { "face": { "fg": "default", "bg": "default", "underline": "default", "attributes": [] }, "contents": " - client0@[kak-tests]" }], { "fg": "cyan", "bg": "default", "underline": "default", "attributes": [] }] }'
 ui_out '{ "jsonrpc": "2.0", "method": "set_cursor", "params": ["buffer", { "line": 0, "column": 0 }] }'
 ui_out '{ "jsonrpc": "2.0", "method": "refresh", "params": [false] }'