class TermBuf::Buffer

• TermBuf::Buffer
• Reference
• Object

Overview

The in-memory terminal screen.

Two grids: back is what the application has drawn, front is what the terminal is believed to be showing. Every write lands in the back grid and marks damage; a paint diffs the two, and #commit_paint brings the front grid up to date once the bytes have gone out.

A single dirty-flag scheme would be smaller, but it leaves nothing to diff against after a forced repaint or a resize, and nothing for the scroll detector to verify a shift against.

Not fibre-safe, and deliberately so: one fibre owns the buffer and every mutation reaches it as a command.

Defined in:

termbuf/core/buffer.cr

Constructors

• .new(width : Int32, height : Int32)

Instance Method Summary

• #back : Grid

  What the application has drawn.

• #bounds : Rect

  The rectangle covering every cell.

• #clear(style : Style = Style::DEFAULT) : Nil

  Blanks every cell.

• #clusters : ClusterPool

  The interned multi code point clusters, for cells a Char cannot hold.

• #commit_paint : Nil

  Brings the front grid up to date after a paint has been written out, and clears the damage and scroll hints it was built from.

• #damage : Damage

  What has changed since the last paint.

• #dirty? : Bool

  Whether anything has changed since the last paint.

• #fill(rect : Rect, char : Char = ' ', style : Style = Style::DEFAULT) : Nil

  Sets every cell of rect to char.

• #front : Grid

  What the terminal is believed to be showing.

• #height : Int32

  Rows down.

• #invalidate : Nil

  Marks the whole screen dirty and forgets what the terminal was showing, so the next paint rewrites every cell.

• #painted? : Bool

  Whether the two grids agree, which is to say a paint would emit nothing.

• #policy : Unicode::WidthPolicy

  How clusters are measured.

• #policy=(policy : Unicode::WidthPolicy)

  How clusters are measured.

• #region(x : Int32, y : Int32, width : Int32, height : Int32, scrollback : Int32 = 0) : Region

  Registers a region.

• #region(bounds : Rect, scrollback : Int32 = 0) : Region

  Declares a region over bounds, keeping up to scrollback rows of what scrolls off the top.

• #regions : Array(Region)

  Regions declared with #region, in the order they were made.

• #resize(width : Int32, height : Int32, style : Style = Style::DEFAULT) : Nil

  Resizes both grids, keeping whatever content still fits anchored at the top left.

• #scroll(rect : Rect, lines : Int32, style : Style = Style::DEFAULT) : Nil

  Scrolls rect by lines rows, positive moving content up.

• #scroll_hints : Array(ScrollHint)

  Scrolls performed since the last paint, oldest first.

• #scroll_region(region : Region, lines : Int32, style : Style = Style::DEFAULT) : Nil

  Scrolls a region, keeping the rows that leave the top if the region has scrollback capacity.

• #styles : StyleTable

  The interned styles both grids refer to by id.

• #take_scroll_hints : Array(ScrollHint)

  Takes the scroll hints recorded since the last paint, leaving none behind.

• #to_text : String

  The back grid as text, one line per row, for specs and debugging.

• #width : Int32

  Columns across.

• #write(x : Int32, y : Int32, text : String, style : Style = Style::DEFAULT) : Int32

  Writes text starting at (x, y), one grapheme cluster per cell, stopping at the right edge of the row.

• #write_char(x : Int32, y : Int32, char : Char, style : Style = Style::DEFAULT) : Int32

  Writes a single character at (x, y).

Constructor Detail

Instance Method Detail