CanvasBuffer class Core Rendering

A terminal canvas buffer managing character cells and their styles.

CanvasBuffer maintains an internal 2D grid of BufferCells representing the terminal screen content, including characters, foreground and background colors, and font styles.

It supports drawing characters and strings at arbitrary positions, clearing areas or the entire buffer, and flushing changes to the terminal with proper ANSI escape codes.

The buffer tracks an original terminal cursor offset, supports fullscreen mode, and manages cursor visibility for clean rendering.

Typical usage:

  1. Construct with terminal width and height.
  2. Use drawChar or drawAt to update cells.
  3. Call render to flush changes to the terminal.
  4. Use clear or clearBufferArea to reset contents.

Constructors

CanvasBuffer.new({required int width, required int height, bool isFullscreen = false})
Creates a CanvasBuffer with the specified width and height.

Properties

cursorOriginalColumn ↔ int
The original horizontal cursor column in the terminal (1-based). Columns increase from left to right.
getter/setter pair
cursorOriginalLine ↔ int
The original vertical cursor line in the terminal (1-based). Lines increase from top to bottom.
getter/setter pair
hashCode → int
The hash code for this object.
no setterinherited
height ↔ int
The height of the canvas in characters.
getter/setter pair
isFullscreen ↔ bool
Whether the buffer is in fullscreen mode.
getter/setter pair
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
width ↔ int
The width of the canvas in characters.
getter/setter pair

Methods

clear() → void
Clears the entire canvas buffer, resetting all cells to spaces with no style.
clearBufferArea(Rect area) → void
Clears a rectangular area within the buffer.
drawAt(int column, int line, String data, TextComponentStyle style) → void
Draws a string data starting at position (column, line) with a given style.
drawChar(int column, int line, String char, {AnsiColorType? fg, AnsiColorType? bg, Set<FontStyle>? styles}) → void
Draws a single character at position (column, line) with optional style.
flushArea(Rect area) → void
Flushes the contents of a rectangular area to the terminal.
getDrawnCanvas() → List<List<BufferCell>>
Returns the internal buffer grid for test inspection.
getRenderedString() → List<String>
Returns a list of strings representing the ANSI-encoded rendered output, one string per row.
getTerminalOffset() → (int, int)
Returns the original terminal cursor position as (column, line).
hideCursor() → void
Hides the terminal cursor using ANSI escape codes.
moveCursorTo(int column, int line) → void
Moves the terminal cursor to position (column, line) relative to the original offset.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
render() → void
Renders the entire buffer content to the terminal.
setTerminalOffset(int column, int line) → dynamic
Sets the original terminal cursor offset for relative rendering.
showCursor() → void
Shows the terminal cursor using ANSI escape codes.
toString() → String
A string representation of this object.
inherited
updateDimensions(int width, int height) → void
Updates the screen buffer dimensions to accommodate the new size.

Operators

operator ==(Object other) → bool
The equality operator.
inherited