Merge pull request #4995 from wiktor-obrebski/widgets/text-area

Widgets/text area

Author: myk002

docs/dev/Lua API.rst

@@ -5513,6 +5513,155 @@ The ``EditField`` class also provides the following functions:
 
   Inserts the given text at the current cursor position.
 
+TextArea class
+--------------
+
+Subclass of Panel; implements a multi-line text field with features such as
+text wrapping, mouse control, text selection, clipboard support, history,
+and typical text editor shortcuts.
+
+Cursor Behavior
+~~~~~~~~~~~~~~~
+
+The cursor in the ``TextArea`` class is index-based, starting from 1,
+consistent with Lua's text indexing conventions.
+
+Each character, including newlines (``string.char(10)``),
+occupies a single index in the text content.
+
+Cursor movement and position are fully aware of line breaks,
+meaning they count as one unit in the offset.
+
+The cursor always points to the position between characters,
+with 1 being the position before the first character and
+``#text + 1`` representing the position after the last character.
+
+Cursor positions are preserved during text operations like insertion,
+deletion, or replacement. If changes affect the cursor's position,
+it will be adjusted to the nearest valid index.
+
+TextArea Attributes:
+
+* ``init_text``: The initial text content for the text area.
+
+* ``init_cursor``: The initial cursor position within the text content.
+  If not specified, defaults to end of the text (length of ``init_text`` + 1).
+
+* ``text_pen``: Optional pen used to draw the text. Default is ``COLOR_LIGHTCYAN``.
+
+* ``select_pen``: Optional pen used for text selection. Default is ``COLOR_CYAN``.
+
+* ``ignore_keys``: List of input keys to ignore.
+  Functions similarly to the ``ignore_keys`` attribute in the ``EditField`` class.
+
+* ``on_text_change``: Callback function called whenever the text changes.
+  The function signature should be ``on_text_change(new_text, old_text)``.
+
+* ``on_cursor_change``: Callback function called whenever the cursor position changes.
+  Expected function signature is ``on_cursor_change(new_cursor, old_cursor)``.
+
+* ``one_line_mode``: If set to ``true``, disables multi-line text features.
+  In this mode the :kbd:`Enter` key is not handled by the widget
+  as if it were included in ``ignore_keys``.
+  If multiline text (including ``\n`` chars) is pasted into the widget, newlines are removed.
+
+TextArea Functions:
+
+* ``textarea:getText()``
+
+    Returns the current text content of the ``TextArea`` widget as a string.
+    "\n" characters (``string.char(10)``) should be interpreted as new lines
+
+* ``textarea:setText(text)``
+
+    Sets the content of the ``TextArea`` to the specified string ``text``.
+    The cursor position will not be adjusted, so should be set separately.
+
+* ``textarea:getCursor()``
+
+    Returns the current cursor position within the text content.
+    The position is represented as a single integer, starting from 1.
+
+* ``textarea:setCursor(cursor)``
+
+    Sets the cursor position within the text content.
+
+* ``textarea:scrollToCursor()``
+
+    Scrolls the text area view to ensure that the current cursor position is visible.
+    This happens automatically when the user interactively moves the cursor or
+    pastes text into the widget, but may need to be called when ``setCursor`` is
+    called programmatically.
+
+* ``textarea:clearHistory()``
+
+    Clears undo/redo history of the widget.
+
+Functionality
+~~~~~~~~~~~~~
+
+The TextArea widget provides a familiar and intuitive text editing experience with baseline features such as:
+
+- Text Wrapping: Automatically fits text within the display area.
+- Mouse and Keyboard Support: Standard keys like :kbd:`Home`, :kbd:`End`, :kbd:`Backspace`, and :kbd:`Delete` are supported,
+  along with gestures like double-click to select a word or triple-click to select a line.
+- Clipboard Operations: copy, cut, and paste,
+  with intuitive defaults when no text is selected.
+- Undo/Redo: :kbd:`Ctrl` + :kbd:`Z` and :kbd:`Ctrl` + :kbd:`Y` for quick changes.
+- Additional features include advanced navigation, line management,
+  and smooth scrolling for handling long text efficiently.
+
+Detailed list:
+
+- Cursor Control: Navigate through text using arrow keys (Left, Right, Up,
+  and Down) for precise cursor placement.
+- Mouse Control: Use the mouse to position the cursor within the text,
+  providing an alternative to keyboard navigation.
+- Text Selection: Select text with the mouse, with support for replacing or
+  removing selected text.
+- Select Word/Line: Use double click to select current word, or triple click to
+  select current line.
+- Move By Word: Use :kbd:`Ctrl` + :kbd:`Left` and :kbd:`Ctrl` + :kbd:`Right` to
+  move the cursor one word back or forward.
+- Line Navigation: :kbd:`Home` moves the cursor to the beginning of the current
+  line, and :kbd:`End` moves it to the end.
+- Jump to Beginning/End: Quickly move the cursor to the beginning or end of the
+  text using :kbd:`Ctrl` + :kbd:`Home` and :kbd:`Ctrl` + :kbd:`End`.
+- Longest X Position Memory: The cursor remembers the longest x position when
+  moving up or down, making vertical navigation more intuitive.
+- New Lines: Easily insert new lines using the :kbd:`Enter` key, supporting
+  multiline text input.
+- Text Wrapping: Text automatically wraps within the editor, ensuring lines fit
+  within the display without manual adjustments.
+- Scrolling for long text entries.
+- Backspace Support: Use the backspace key to delete characters to the left of
+  the cursor.
+- Delete Character: :kbd:`Delete` deletes the character under the cursor.
+- Delete Current Line: :kbd:`Ctrl` + :kbd:`U` deletes the entire current line
+  where the cursor is located.
+- Delete Rest of Line: :kbd:`Ctrl` + :kbd:`K` deletes text from the cursor to
+  the end of the line.
+- Delete Last Word: :kbd:`Ctrl` + :kbd:`W` removes the word immediately before
+  the cursor.
+- Select All: Select entire text by :kbd:`Ctrl` + :kbd:`A`.
+- Undo/Redo: Undo/Redo changes by :kbd:`Ctrl` + :kbd:`Z` / :kbd:`Ctrl` +
+  :kbd:`Y`.
+- Clipboard Operations: Perform OS clipboard cut, copy, and paste operations on
+  selected text, allowing you to paste the copied content into other
+  applications.
+- Copy Text: Use :kbd:`Ctrl` + :kbd:`C` to copy selected text.
+  - copy selected text, if available
+  - if no text is selected it copy the entire current line, including the
+  terminating newline if present
+- Cut Text: Use :kbd:`Ctrl` + :kbd:`X` to cut selected text.
+  - cut selected text, if available
+  - if no text is selected it will cut the entire current line, including the
+  terminating newline if present
+- Paste Text: Use :kbd:`Ctrl` + :kbd:`V` to paste text from the clipboard into
+  the editor.
+  - replace selected text, if available
+  - If no text is selected, paste text in the cursor position
+
 Scrollbar class
 ---------------
 

library/lua/gui/widgets.lua

@@ -28,6 +28,7 @@ FilteredList = require('gui.widgets.filtered_list')
 TabBar = require('gui.widgets.tab_bar')
 RangeSlider = require('gui.widgets.range_slider')
 DimensionsTooltip = require('gui.widgets.dimensions_tooltip')
+TextArea = require('gui.widgets.text_area')
 
 Tab = TabBar.Tab
 makeButtonLabelText = Label.makeButtonLabelText

library/lua/gui/widgets/text_area.lua

@@ -0,0 +1,183 @@
+-- Multiline text area control
+
+local Panel = require('gui.widgets.containers.panel')
+local Scrollbar = require('gui.widgets.scrollbar')
+local TextAreaContent = require('gui.widgets.text_area.text_area_content')
+local HistoryStore = require('gui.widgets.text_area.history_store')
+
+local HISTORY_ENTRY = HistoryStore.HISTORY_ENTRY
+
+TextArea = defclass(TextArea, Panel)
+
+TextArea.ATTRS{
+    init_text = '',
+    init_cursor = DEFAULT_NIL,
+    text_pen = COLOR_LIGHTCYAN,
+    ignore_keys = {},
+    select_pen = COLOR_CYAN,
+    on_text_change = DEFAULT_NIL,
+    on_cursor_change = DEFAULT_NIL,
+    one_line_mode = false,
+    debug = false
+}
+
+function TextArea:init()
+    self.render_start_line_y = 1
+
+    self.text_area = TextAreaContent{
+        frame={l=0,r=3,t=0},
+        text=self.init_text,
+
+        text_pen=self.text_pen,
+        ignore_keys=self.ignore_keys,
+        select_pen=self.select_pen,
+        debug=self.debug,
+        one_line_mode=self.one_line_mode,
+
+        on_text_change=function (text, old_text)
+            self:updateLayout()
+            if self.on_text_change then
+                self.on_text_change(text, old_text)
+            end
+        end,
+        on_cursor_change=self:callback('onCursorChange')
+    }
+    self.scrollbar = Scrollbar{
+        frame={r=0,t=1},
+        on_scroll=self:callback('onScrollbar'),
+        visible=not self.one_line_mode
+    }
+
+    self:addviews{
+        self.text_area,
+        self.scrollbar,
+    }
+end
+
+function TextArea:getText()
+    return self.text_area.text
+end
+
+function TextArea:setText(text)
+    self.text_area.history:store(
+        HISTORY_ENTRY.OTHER,
+        self:getText(),
+        self:getCursor()
+    )
+
+    return self.text_area:setText(text)
+end
+
+function TextArea:getCursor()
+    return self.text_area.cursor
+end
+
+function TextArea:setCursor(cursor_offset)
+    return self.text_area:setCursor(cursor_offset)
+end
+
+function TextArea:clearHistory()
+    return self.text_area.history:clear()
+end
+
+function TextArea:onCursorChange(cursor, old_cursor)
+    local x, y = self.text_area.wrapped_text:indexToCoords(
+        self.text_area.cursor
+    )
+
+    if y >= self.render_start_line_y + self.text_area.frame_body.height then
+        self:updateScrollbar(
+            y - self.text_area.frame_body.height + 1
+        )
+    elseif  (y < self.render_start_line_y) then
+        self:updateScrollbar(y)
+    end
+
+    if self.on_cursor_change then
+        self.on_cursor_change(cursor, old_cursor)
+    end
+end
+
+function TextArea:scrollToCursor(cursor_offset)
+    if self.scrollbar.visible then
+        local _, cursor_line_y = self.text_area.wrapped_text:indexToCoords(
+            cursor_offset
+        )
+        self:updateScrollbar(cursor_line_y)
+    end
+end
+
+function TextArea:getPreferredFocusState()
+    return true
+end
+
+function TextArea:postUpdateLayout()
+    self:updateScrollbar(self.render_start_line_y)
+
+    if self.text_area.cursor == nil then
+        local cursor = self.init_cursor or #self.init_text + 1
+        self.text_area:setCursor(cursor)
+        self:scrollToCursor(cursor)
+    end
+end
+
+function TextArea:onScrollbar(scroll_spec)
+    local height = self.text_area.frame_body.height
+
+    local render_start_line = self.render_start_line_y
+    if scroll_spec == 'down_large' then
+        render_start_line = render_start_line + math.ceil(height / 2)
+    elseif scroll_spec == 'up_large' then
+        render_start_line = render_start_line - math.ceil(height / 2)
+    elseif scroll_spec == 'down_small' then
+        render_start_line = render_start_line + 1
+    elseif scroll_spec == 'up_small' then
+        render_start_line = render_start_line - 1
+    else
+        render_start_line = tonumber(scroll_spec)
+    end
+
+    self:updateScrollbar(render_start_line)
+end
+
+function TextArea:updateScrollbar(scrollbar_current_y)
+    local lines_count = #self.text_area.wrapped_text.lines
+
+    local render_start_line_y = math.min(
+        #self.text_area.wrapped_text.lines - self.text_area.frame_body.height + 1,
+        math.max(1, scrollbar_current_y)
+    )
+
+    self.scrollbar:update(
+        render_start_line_y,
+        self.frame_body.height,
+        lines_count
+    )
+
+    if (self.frame_body.height >= lines_count) then
+        render_start_line_y = 1
+    end
+
+    self.render_start_line_y = render_start_line_y
+    self.text_area:setRenderStartLineY(self.render_start_line_y)
+end
+
+function TextArea:renderSubviews(dc)
+    self.text_area.frame_body.y1 = self.frame_body.y1-(self.render_start_line_y - 1)
+    -- only visible lines of text_area will be rendered
+    TextArea.super.renderSubviews(self, dc)
+end
+
+function TextArea:onInput(keys)
+    if (self.scrollbar.is_dragging) then
+        return self.scrollbar:onInput(keys)
+    end
+
+    if keys._MOUSE_L and self:getMousePos() then
+        self:setFocus(true)
+    end
+
+    return TextArea.super.onInput(self, keys)
+end
+
+return TextArea