subsonic-tui/vendor/github.com/rivo/tview/util.go
Sagi Dayan 48661005be
initial commit
Signed-off-by: Sagi Dayan <sagidayan@gmail.com>
2024-09-01 16:30:56 +03:00

162 lines
4.7 KiB
Go

package tview
import (
"math"
"os"
"regexp"
"github.com/gdamore/tcell/v2"
)
// Text alignment within a box. Also used to align images.
const (
AlignLeft = iota
AlignCenter
AlignRight
AlignTop = 0
AlignBottom = 2
)
var (
// Regular expression used to escape style/region tags.
nonEscapePattern = regexp.MustCompile(`(\[[a-zA-Z0-9_,;: \-\."#]+\[*)\]`)
// The number of colors available in the terminal.
availableColors = 256
)
// Package initialization.
func init() {
// Determine the number of colors available in the terminal.
info, err := tcell.LookupTerminfo(os.Getenv("TERM"))
if err == nil {
availableColors = info.Colors
}
}
// Print prints text onto the screen into the given box at (x,y,maxWidth,1),
// not exceeding that box. "align" is one of AlignLeft, AlignCenter, or
// AlignRight. The screen's background color will not be changed.
//
// You can change the colors and text styles mid-text by inserting a style tag.
// See the package description for details.
//
// Returns the number of actual bytes of the text printed (including style tags)
// and the actual width used for the printed runes.
func Print(screen tcell.Screen, text string, x, y, maxWidth, align int, color tcell.Color) (int, int) {
start, end, width := printWithStyle(screen, text, x, y, 0, maxWidth, align, tcell.StyleDefault.Foreground(color), true)
return end - start, width
}
// printWithStyle works like Print() but it takes a style instead of just a
// foreground color. The skipWidth parameter specifies the number of cells
// skipped at the beginning of the text. It returns the start index, end index
// (exclusively), and screen width of the text actually printed. If
// maintainBackground is "true", the existing screen background is not changed
// (i.e. the style's background color is ignored).
func printWithStyle(screen tcell.Screen, text string, x, y, skipWidth, maxWidth, align int, style tcell.Style, maintainBackground bool) (start, end, printedWidth int) {
totalWidth, totalHeight := screen.Size()
if maxWidth <= 0 || len(text) == 0 || y < 0 || y >= totalHeight {
return 0, 0, 0
}
// If we don't overwrite the background, we use the default color.
if maintainBackground {
style = style.Background(tcell.ColorDefault)
}
// Skip beginning and measure width.
var (
state *stepState
textWidth int
)
str := text
for len(str) > 0 {
_, str, state = step(str, state, stepOptionsStyle)
if skipWidth > 0 {
skipWidth -= state.Width()
if skipWidth <= 0 {
text = str
style = state.Style()
}
start += state.GrossLength()
} else {
textWidth += state.Width()
}
}
// Reduce all alignments to AlignLeft.
if align == AlignRight {
// Chop off characters on the left until it fits.
state = nil
for len(text) > 0 && textWidth > maxWidth {
_, text, state = step(text, state, stepOptionsStyle)
textWidth -= state.Width()
start += state.GrossLength()
style = state.Style()
}
x, maxWidth = x+maxWidth-textWidth, textWidth
} else if align == AlignCenter {
// Chop off characters on the left until it fits.
state = nil
subtracted := (textWidth - maxWidth) / 2
for len(text) > 0 && subtracted > 0 {
_, text, state = step(text, state, stepOptionsStyle)
subtracted -= state.Width()
textWidth -= state.Width()
start += state.GrossLength()
style = state.Style()
}
if textWidth < maxWidth {
x, maxWidth = x+maxWidth/2-textWidth/2, textWidth
}
}
// Draw left-aligned text.
end = start
rightBorder := x + maxWidth
state = &stepState{
unisegState: -1,
style: style,
}
for len(text) > 0 && x < rightBorder && x < totalWidth {
var c string
c, text, state = step(text, state, stepOptionsStyle)
if c == "" {
break // We don't care about the style at the end.
}
width := state.Width()
if width > 0 {
finalStyle := state.Style()
if maintainBackground {
_, backgroundColor, _ := finalStyle.Decompose()
if backgroundColor == tcell.ColorDefault {
_, _, existingStyle, _ := screen.GetContent(x, y)
_, background, _ := existingStyle.Decompose()
finalStyle = finalStyle.Background(background)
}
}
for offset := width - 1; offset >= 0; offset-- {
// To avoid undesired effects, we populate all cells.
runes := []rune(c)
if offset == 0 {
screen.SetContent(x+offset, y, runes[0], runes[1:], finalStyle)
} else {
screen.SetContent(x+offset, y, ' ', nil, finalStyle)
}
}
}
x += width
end += state.GrossLength()
printedWidth += width
}
return
}
// PrintSimple prints white text to the screen at the given position.
func PrintSimple(screen tcell.Screen, text string, x, y int) {
Print(screen, text, x, y, math.MaxInt32, AlignLeft, Styles.PrimaryTextColor)
}