buffer

package
v0.0.0-...-4a23534 Latest Latest
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 Go to latest Published: Dec 12, 2025 License: MIT Imports: 6 Imported by: 0

Documentation

Overview

Package buffer provides a 2D cell-based buffer for terminal rendering. Similar to Ratatui's buffer system, it allows precise character positioning and supports overlapping content with proper style handling.

Index

Constants

View Source 
const (
	// Reset is the ANSI reset code.
	Reset   = "\033[0m"
	FgReset = "\033[39m"
	BgReset = "\033[49m"

	// BoldOn enables bold text.
	BoldOn           = "\033[1m"
	BoldOff          = "\033[22m"
	ItalicOn         = "\033[3m"
	ItalicOff        = "\033[23m"
	UnderlineOn      = "\033[4m"
	UnderlineOff     = "\033[24m"
	StrikethroughOn  = "\033[9m"
	StrikethroughOff = "\033[29m"

	// FgRGB is the ANSI foreground RGB format string.
	FgRGB = "\033[38;2;%d;%d;%dm"
	BgRGB = "\033[48;2;%d;%d;%dm"
)

ANSI escape code constants.

Variables

View Source 
var TailwindColors = map[string]Color{}/* 244 elements not displayed */

TailwindColors maps Tailwind color names to hex values.

Functions

func RuneCount 

func RuneCount(s string) int

RuneCount returns the number of runes in a string.

func RuneWidth 

func RuneWidth(r rune) int

RuneWidth returns the visual width of a rune (1 for normal, 2 for wide chars).

func StringWidth 

func StringWidth(s string) int

StringWidth returns the visual width of a string (handles wide chars).

Types

type BorderStyle 

type BorderStyle int

BorderStyle specifies the visual appearance of box borders. 

const (
	BorderNone    BorderStyle = iota // No border
	BorderNormal                     // Single-line border ┌─┐
	BorderRounded                    // Rounded corners ╭─╮
	BorderDouble                     // Double-line border ╔═╗
	BorderThick                      // Thick border ┏━┓
	BorderBlock                      // Block border ███
	BorderDotted                     // Dotted lines ┈┊
)

Border style constants.

func (BorderStyle) BorderChars 

func (b BorderStyle) BorderChars() (tl, tr, bl, br, h, v rune)

BorderChars returns the six Unicode glyphs for drawing this border style.

type Buffer 

type Buffer struct {
	// contains filtered or unexported fields
}

Buffer is a 2D grid of cells representing terminal content.

func NewBuffer 

func NewBuffer(width, height int) *Buffer

NewBuffer creates a new buffer filled with empty cells.

func (*Buffer) Clear 

func (b *Buffer) Clear()

Clear resets all cells to default (space, no style).

func (*Buffer) Debug 

func (b *Buffer) Debug() string

Debug returns a debug representation showing cell boundaries.

func (*Buffer) DrawBorder 

func (b *Buffer) DrawBorder(area Rect, border BorderStyle, fg, bg Color)

DrawBorder draws a border around an area.

func (*Buffer) Fill 

func (b *Buffer) Fill(area Rect, cell Cell)

Fill fills a rectangular area with a cell.

func (*Buffer) FillStyle 

func (b *Buffer) FillStyle(area Rect, style Style)

FillStyle applies a style to all cells in an area without changing characters.

func (*Buffer) Get 

func (b *Buffer) Get(x, y int) Cell

Get returns the cell at (x, y). Returns empty cell if out of bounds.

func (*Buffer) Height 

func (b *Buffer) Height() int

Height returns the buffer height.

func (*Buffer) Merge 

func (b *Buffer) Merge(x, y int, src *Buffer)

Merge overlays another buffer onto this one at position (x, y). Only non-space characters from src are copied (transparent overlay).

func (*Buffer) Rect 

func (b *Buffer) Rect() Rect

Rect returns a Rect covering the entire buffer.

func (*Buffer) Render 

func (b *Buffer) Render() string

Render converts the buffer to an ANSI-escaped string. Optimizes output by only emitting escape codes when style changes.

func (*Buffer) RenderArea 

func (b *Buffer) RenderArea(area Rect) string

RenderArea renders only a specific rectangular area of the buffer.

func (*Buffer) RenderCompact 

func (b *Buffer) RenderCompact() string

RenderCompact renders the buffer, trimming trailing spaces and empty lines.

func (*Buffer) Resize 

func (b *Buffer) Resize(width, height int) *Buffer

Resize creates a new buffer with the given dimensions. Content from the old buffer is preserved where it fits.

func (*Buffer) Set 

func (b *Buffer) Set(x, y int, cell Cell)

Set sets the cell at (x, y). Does nothing if out of bounds.

func (*Buffer) SetChar 

func (b *Buffer) SetChar(x, y int, ch rune)

SetChar sets only the character at (x, y), preserving style.

func (*Buffer) SetString 

func (b *Buffer) SetString(x, y int, s string, style Style) int

SetString writes a string starting at (x, y) with the given style. Handles wide characters (CJK) by using placeholder cells. Returns the number of columns consumed.

func (*Buffer) SetStringSimple 

func (b *Buffer) SetStringSimple(x, y int, s string) int

SetStringSimple writes a string with no styling.

func (*Buffer) SetStyle 

func (b *Buffer) SetStyle(x, y int, fg, bg Color, bold, italic, underline, strike bool)

SetStyle applies style attributes to the cell at (x, y).

func (*Buffer) String 

func (b *Buffer) String() string

String implements fmt.Stringer for easy printing.

func (*Buffer) Width 

func (b *Buffer) Width() int

Width returns the buffer width.

type Cell 

type Cell struct {
	Char          rune
	Fg            Color
	Bg            Color
	Bold          bool
	Italic        bool
	Underline     bool
	Strikethrough bool
}

Cell represents a single character cell in the terminal.

func DefaultCell 

func DefaultCell() Cell

DefaultCell returns a cell with a space character and no styling.

func (*Cell) Reset 

func (c *Cell) Reset()

Reset clears the cell to default state (space, no colors, no decorations).

type Color 

type Color struct {
	R, G, B uint8 // Red, Green, Blue components (0-255)
	Set     bool  // true if color was explicitly set
}

Color represents an RGB color with explicit set tracking. The Set field distinguishes between "not specified" and "set to black (0,0,0)".

A zero-value Color has Set=false, indicating no color was specified. Use NewColor to create a Color with Set=true.

func Hex 

func Hex(hex string) Color

Hex creates a Color from a 6-digit hex string without validation.

func NewColor 

func NewColor(r, g, b uint8) Color

NewColor creates a new Color with the given RGB values and Set=true.

func ParseBgColor 

func ParseBgColor(class string) (Color, bool)

ParseBgColor parses bg-{color} classes for background color.

func ParseBorderColor 

func ParseBorderColor(class string) (Color, bool)

ParseBorderColor parses border-{color} classes for border color.

func ParseColorValue 

func ParseColorValue(value string) (Color, bool)

ParseColorValue parses a color value from Tailwind name or arbitrary hex.

func ParseHex 

func ParseHex(hex string) (Color, bool)

ParseHex parses a 6-digit hex color string into RGB components.

func ParseTextColor 

func ParseTextColor(class string) (Color, bool)

ParseTextColor parses text-{color} classes for foreground color.

type Direction 

type Direction int

Direction specifies the axis for splitting. 

const (
	Horizontal Direction = iota // Split into columns (side by side)
	Vertical                    // Split into rows (stacked)
)

Direction constants for splitting rects.

type Rect 

type Rect struct {
	X, Y          int
	Width, Height int
}

Rect defines a rectangular area in the terminal.

func NewRect 

func NewRect(x, y, width, height int) Rect

NewRect creates a new Rect.

func (Rect) Area 

func (r Rect) Area() int

Area returns the total number of cells.

func (Rect) Bottom 

func (r Rect) Bottom() int

Bottom returns the bottom edge Y coordinate (exclusive).

func (Rect) Clamp 

func (r Rect) Clamp(bounds Rect) Rect

Clamp ensures the rect fits within another rect.

func (Rect) Contains 

func (r Rect) Contains(x, y int) bool

Contains returns true if the point (x, y) is inside the rect.

func (Rect) Inner 

func (r Rect) Inner(margin int) Rect

Inner returns a rect reduced by the given margin on all sides.

func (Rect) InnerMargins 

func (r Rect) InnerMargins(top, right, bottom, left int) Rect

InnerMargins returns a rect reduced by different margins on each side. Order: top, right, bottom, left (CSS style).

func (Rect) Intersection 

func (r Rect) Intersection(other Rect) Rect

Intersection returns the overlapping region of two rects. Returns an empty rect if they don't intersect.

func (Rect) Intersects 

func (r Rect) Intersects(other Rect) bool

Intersects returns true if this rect overlaps with another.

func (Rect) IsEmpty 

func (r Rect) IsEmpty() bool

IsEmpty returns true if the rect has zero area.

func (Rect) Left 

func (r Rect) Left() int

Left returns the left edge X coordinate.

func (Rect) Offset 

func (r Rect) Offset(dx, dy int) Rect

Offset moves the rect by (dx, dy).

func (Rect) Right 

func (r Rect) Right() int

Right returns the right edge X coordinate (exclusive).

func (Rect) Split 

func (r Rect) Split(dir Direction, sizes []int) []Rect

Split divides the rect into multiple parts based on sizes. For Horizontal: sizes are widths. For Vertical: sizes are heights. Negative sizes mean "remaining space" (like flex-grow).

func (Rect) SplitEqual 

func (r Rect) SplitEqual(dir Direction, n int) []Rect

SplitEqual divides the rect into n equal parts.

func (Rect) Top 

func (r Rect) Top() int

Top returns the top edge Y coordinate.

type Style 

type Style struct {
	Fg            Color
	Bg            Color
	Bold          bool
	Italic        bool
	Underline     bool
	Strikethrough bool
}

Style holds styling attributes for text rendering.

func (Style) WithBg 

func (s Style) WithBg(r, g, b uint8) Style

WithBg returns a new Style with background color set.

func (Style) WithBold 

func (s Style) WithBold() Style

WithBold returns a new Style with bold enabled.

func (Style) WithFg 

func (s Style) WithFg(r, g, b uint8) Style

WithFg returns a new Style with foreground color set.

func (Style) WithItalic 

func (s Style) WithItalic() Style

WithItalic returns a new Style with italic enabled.

func (Style) WithStrikethrough 

func (s Style) WithStrikethrough() Style

WithStrikethrough returns a new Style with strikethrough enabled.

func (Style) WithUnderline 

func (s Style) WithUnderline() Style

WithUnderline returns a new Style with underline enabled.

Source Files

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