[ Widgets ]

Fill and Clear

koto::Fill fills a rectangular area with a repeated codepoint, foreground/background colors, and an optional id tag, while koto::Clear resets an area to spaces (U' ') with COLOR_DEFAULT colors (Header: koto/fill.hpp).

Quick example

Fill(Color::DarkGray)
    .fg(Color::Cyan)
    .char_code(U'.')
    .id(Id("backdrop"))
    .draw(frame, fill_area);

........................
........................
........................
........................

Behavior

Fill::draw(frame, area): Calls frame.fill(area, m_ch, m_fg, m_bg, m_tag_id) (src/fill.cpp:35-38), which writes Cell{m_ch, m_fg, m_bg, 1, false} to every coordinate in area and, if m_tag_id is not Id::none(), stamps m_hit_buffer and updates m_tag_bounds.
Clear::draw(frame, area): Calls frame.fill(area, U' ', COLOR_DEFAULT, COLOR_DEFAULT, m_tag_id) (src/fill.cpp:46-49), resetting every cell in area to a default blank space and optionally tagging the region with m_tag_id.

Methods

`Fill` methods

Method	Description	Default
`Fill()`	Default-constructs a `Fill` widget with `U' '` and `COLOR_DEFAULT` colors.	`m_ch = U' '`, `m_fg = COLOR_DEFAULT`, `m_bg = COLOR_DEFAULT`
`Fill(Color bg)`	Explicit constructor setting `m_bg = bg.value`.	`m_ch = U' '`, `m_fg = COLOR_DEFAULT`
`bg(Color color)`	Sets the fill background color.	`COLOR_DEFAULT`
`fg(Color color)`	Sets the fill character foreground color.	`COLOR_DEFAULT`
`char_code(char32_t ch)`	Sets the codepoint written to each cell.	`U' '`
`id(Id id)`	Sets the `id` token stamped into the `hit buffer` across `area`.	`Id::none()`
`draw(Frame& frame, Area area)`	Fills `area` in `frame`.	None

`Clear` methods

Method	Description	Default
`Clear()`	Default-constructs a `Clear` widget.	`m_tag_id = Id::none()`
`id(Id id)`	Sets the `id` token stamped into the `hit buffer` across `area`.	`Id::none()`
`draw(Frame& frame, Area area)`	Resets `area` in `frame` to `U' '` with `COLOR_DEFAULT` foreground and background.	None

Gotchas

Fill::char_code uses width 1 in Frame::fill: Frame::fill(area, m_ch, m_fg, m_bg, m_tag_id) constructs Cell{ch, fg, bg, 1, false} (src/frame.cpp:167-170), which Frame::set_cell promotes to width 2 if codepoint_width(ch) == 2. Avoid passing a 2-column CJK or emoji codepoint to Fill::char_code, because Frame::fill steps col by 1 across every column and each column will overwrite the continuation cell of the previous column.