termui/buffer.go
2016-11-10 23:25:53 -05:00

107 lines
2.3 KiB
Go

// Copyright 2016 Zack Guo <zack.y.guo@gmail.com>. All rights reserved.
// Use of this source code is governed by a MIT license that can
// be found in the LICENSE file.
package termui
import "image"
// Cell is a rune with assigned Fg and Bg
type Cell struct {
Ch rune
Fg Attribute
Bg Attribute
}
// Buffer is a renderable rectangle cell data container.
type Buffer struct {
Area image.Rectangle // selected drawing area
CellMap map[image.Point]Cell
}
// At returns the cell at (x,y).
func (b Buffer) At(x, y int) Cell {
return b.CellMap[image.Pt(x, y)]
}
// Set assigns a char to (x,y)
func (b Buffer) Set(x, y int, c Cell) {
b.CellMap[image.Pt(x, y)] = c
}
// Bounds returns the domain for which At can return non-zero color.
func (b Buffer) Bounds() image.Rectangle {
x0, y0, x1, y1 := 0, 0, 0, 0
for p := range b.CellMap {
if p.X > x1 {
x1 = p.X
}
if p.X < x0 {
x0 = p.X
}
if p.Y > y1 {
y1 = p.Y
}
if p.Y < y0 {
y0 = p.Y
}
}
return image.Rect(x0, y0, x1+1, y1+1)
}
// SetArea assigns a new rect area to Buffer b.
func (b *Buffer) SetArea(r image.Rectangle) {
b.Area.Max = r.Max
b.Area.Min = r.Min
}
// Sync sets drawing area to the buffer's bound
func (b *Buffer) Sync() {
b.SetArea(b.Bounds())
}
// NewCell returns a new cell
func NewCell(ch rune, fg, bg Attribute) Cell {
return Cell{ch, fg, bg}
}
// Merge merges bs Buffers onto b
func (b *Buffer) Merge(bs ...Buffer) {
for _, buf := range bs {
for p, v := range buf.CellMap {
b.Set(p.X, p.Y, v)
}
b.SetArea(b.Area.Union(buf.Area))
}
}
// NewBuffer returns a new Buffer
func NewBuffer() Buffer {
return Buffer{
CellMap: make(map[image.Point]Cell),
Area: image.Rectangle{}}
}
// Fill fills the Buffer b with ch,fg and bg.
func (b Buffer) Fill(ch rune, fg, bg Attribute) {
for x := b.Area.Min.X; x < b.Area.Max.X; x++ {
for y := b.Area.Min.Y; y < b.Area.Max.Y; y++ {
b.Set(x, y, Cell{ch, fg, bg})
}
}
}
// NewFilledBuffer returns a new Buffer filled with ch, fb and bg.
func NewFilledBuffer(x0, y0, x1, y1 int, ch rune, fg, bg Attribute) Buffer {
buf := NewBuffer()
buf.Area.Min = image.Pt(x0, y0)
buf.Area.Max = image.Pt(x1, y1)
for x := buf.Area.Min.X; x < buf.Area.Max.X; x++ {
for y := buf.Area.Min.Y; y < buf.Area.Max.Y; y++ {
buf.Set(x, y, Cell{ch, fg, bg})
}
}
return buf
}