console.lua: implement horizontal scroll

Bind Shift+LEFT, Shift+RIGHT, Shift+WHEEL_DOWN, Shift+WHEEL_UP,
WHEEL_LEFT, WHEEL_RIGHT to scroll the menu horizontally.

This lets you see long items that get clipped, like long history entries
and key bindings.

With proportional fonts items scroll in different amounts, but it's
still usable.

Author: guidocella

DOCS/man/select.rst

@@ -28,6 +28,12 @@ PGUP and Ctrl+b
 PGDN and Ctrl+f
     Scroll down one page.
 
+Shift+LEFT
+    Scroll left.
+
+Shift+RIGHT
+    Scroll right.
+
 Ctrl+y
     Copy the focused item to the clipboard.
 
@@ -41,6 +47,12 @@ WHEEL_UP
 WHEEL_DOWN
     Scroll down.
 
+WHEEL_LEFT and Shift+WHEEL_DOWN
+    Scroll left.
+
+WHEEL_RIGHT and Shift+WHEEL_UP
+    Scroll right.
+
 Typing printable characters does a fuzzy search of the presented items.
 
 If the query starts with ``'``, only exact matches are filtered. You can also

player/lua/console.lua

@@ -114,6 +114,7 @@ local first_match_to_print = 1
 local default_item
 local item_positions = {}
 local max_item_width = 0
+local horizontal_offset = 0
 
 local complete
 local cycle_through_completions
@@ -197,7 +198,7 @@ local function utf8_positions(str)
         positions[pos] = true
     end
 
-    return positions
+    return positions, pos
 end
 
 
@@ -564,42 +565,55 @@ local function get_matches_to_print(terminal)
             end
         end
 
-        local char_positions = utf8_positions(matches[i].text)
-        local start_of_last_match = matches[i].positions[1]
+        local char_positions, last_char_pos = utf8_positions(matches[i].text)
+        local start = horizontal_offset
+        repeat
+            start = start + 1
+        until char_positions[start] or start > last_char_pos
+        local text = matches[i].text:sub(start)
+        char_positions = utf8_positions(text)
+
+        local positions = {}
+        for _, position in ipairs(matches[i].positions) do
+            if position >= start then
+                positions[#positions + 1] = position - start + 1
+            end
+        end
+        local start_of_last_match = positions[1]
 
         if not start_of_last_match then
-            item = item .. escape(matches[i].text)
+            item = item .. escape(text)
         elseif start_of_last_match > 1 then
-            item = item .. escape(matches[i].text:sub(1, start_of_last_match - 1))
+            item = item .. escape(text:sub(1, start_of_last_match - 1))
         end
 
-        for j, pos in ipairs(matches[i].positions) do
-            local last_pos = matches[i].positions[j - 1]
+        for j, pos in ipairs(positions) do
+            local last_pos = positions[j - 1]
 
             if last_pos and pos > last_pos + 1 then
                 if char_positions[start_of_last_match] and char_positions[last_pos + 1] then
                     item = item .. highlight ..
-                           escape(matches[i].text:sub(start_of_last_match, last_pos)) ..
+                           escape(text:sub(start_of_last_match, last_pos)) ..
                            end_highlight ..
-                           escape(matches[i].text:sub(last_pos + 1, pos - 1))
+                           escape(text:sub(last_pos + 1, pos - 1))
                 else
-                    item = item .. escape(matches[i].text:sub(start_of_last_match, pos - 1))
+                    item = item .. escape(text:sub(start_of_last_match, pos - 1))
                 end
 
                 start_of_last_match = pos
             end
         end
 
         if start_of_last_match then
-            local last_pos = matches[i].positions[#matches[i].positions]
+            local last_pos = positions[#positions]
 
             if char_positions[start_of_last_match] and char_positions[last_pos + 1] then
                 item = item .. highlight ..
-                       escape(matches[i].text:sub(start_of_last_match, last_pos)) ..
+                       escape(text:sub(start_of_last_match, last_pos)) ..
                        end_highlight ..
-                       escape(matches[i].text:sub(last_pos + 1))
+                       escape(text:sub(last_pos + 1))
             else
-                item = item .. escape(matches[i].text:sub(start_of_last_match))
+                item = item .. escape(text:sub(start_of_last_match))
             end
         end
 
@@ -1202,6 +1216,15 @@ local function move_history(amount, is_wheel)
     render()
 end
 
+local function horizontal_scroll(amount)
+    if not selectable_items then
+        return
+    end
+
+    horizontal_offset = math.max(horizontal_offset + amount, 0)
+    render()
+end
+
 -- Go to the first command in the command history (PgUp)
 local function handle_pgup()
     if selectable_items then
@@ -1231,6 +1254,7 @@ local function search_history()
 
     searching_history = true
     selectable_items = {}
+    horizontal_offset = 0
 
     for i = 1, #history do
         selectable_items[i] = history[#history + 1 - i]
@@ -1497,6 +1521,12 @@ local function get_bindings()
         { "wheel_down",  function() move_history(1, true) end   },
         { "wheel_left",  function() end                         },
         { "wheel_right", function() end                         },
+        { "shift+left",  function() horizontal_scroll(-5) end   },
+        { "shift+right", function() horizontal_scroll(5)  end   },
+        { "wheel_left",  function() horizontal_scroll(-5) end   },
+        { "wheel_right", function() horizontal_scroll(5)  end   },
+        { "shift+wheel_up",   function() horizontal_scroll(-5) end },
+        { "shift+wheel_down", function() horizontal_scroll(5)  end },
         { "ctrl+left",   prev_word                              },
         { "alt+b",       prev_word                              },
         { "ctrl+right",  next_word                              },
@@ -1653,6 +1683,7 @@ mp.register_script_message("get-input", function (script_name, args)
 
     if args.items then
         selectable_items = {}
+        horizontal_offset = 0
 
         -- Limit the number of characters to prevent libass from freezing mpv.
         -- Not important for terminal output.