package ui
import (
"fmt"
"github.com/gdamore/tcell"
"github.com/gdamore/tcell/views"
"github.com/mattn/go-runewidth"
)
// A context allows you to draw in a sub-region of the terminal
type Context struct {
screen tcell.Screen
viewport *views.ViewPort
x, y int
}
func (ctx *Context) X() int {
x, _, _, _ := ctx.viewport.GetPhysical()
return x
}
func (ctx *Context) Y() int {
_, y, _, _ := ctx.viewport.GetPhysical()
return y
}
func (ctx *Context) Width() int {
width, _ := ctx.viewport.Size()
return width
}
func (ctx *Context) Height() int {
_, height := ctx.viewport.Size()
return height
}
func NewContext(width, height int, screen tcell.Screen) *Context {
vp := views.NewViewPort(screen, 0, 0, width, height)
return &Context{screen, vp, 0, 0}
}
func (ctx *Context) Subcontext(x, y, width, height int) *Context {
vp_width, vp_height := ctx.viewport.Size()
if x < 0 || y < 0 {
panic(fmt.Errorf("Attempted to create context with negative offset"))
}
if x+width > vp_width || y+height > vp_height {
panic(fmt.Errorf("Attempted to create context larger than parent"))
}
vp := views.NewViewPort(ctx.viewport, x, y, width, height)
return &Context{ctx.screen, vp, ctx.x + x, ctx.y + y}
}
func (ctx *Context) SetCell(x, y int, ch rune, style tcell.Style) {
width, height := ctx.viewport.Size()
if x >= width || y >= height {
panic(fmt.Errorf("Attempted to draw outside of context"))
}
crunes := []rune{}
ctx.viewport.SetContent(x, y, ch, crunes, style)
}
func (ctx *Context) Printf(x, y int, style tcell.Style,
format string, a ...interface{}) int {
width, height := ctx.viewport.Size()
if x >= width || y >= height {
panic(fmt.Errorf("Attempted to draw outside of context"))
}
str := fmt.Sprintf(format, a...)
old_x := x
newline := func() bool {
x = old_x
y++
return y < height
}
for _, ch := range str {
switch ch {
case '\n':
if !newline() {
return runewidth.StringWidth(str)
}
case '\r':
x = old_x
default:
crunes := []rune{}
ctx.viewport.SetContent(x, y, ch, crunes, style)
x += runewidth.RuneWidth(ch)
if x == old_x+width {
if !newline() {
return runewidth.StringWidth(str)
}
}
}
}
return runewidth.StringWidth(str)
}
func (ctx *Context) Fill(x, y, width, height int, rune rune, style tcell.Style) {
vp := views.NewViewPort(ctx.viewport, x, y, width, height)
vp.Fill(rune, style)
}
func (ctx *Context) SetCursor(x, y int) {
ctx.screen.ShowCursor(ctx.x+x, ctx.y+y)
}
func (ctx *Context) HideCursor() {
ctx.screen.HideCursor()
}