cview/util.go

237 lines
6.2 KiB
Go

package tview
import (
"math"
"regexp"
"strconv"
"strings"
"github.com/gdamore/tcell"
runewidth "github.com/mattn/go-runewidth"
)
// Text alignment within a box.
const (
AlignLeft = iota
AlignCenter
AlignRight
)
// Semigraphical runes.
const (
GraphicsHoriBar = '\u2500'
GraphicsVertBar = '\u2502'
GraphicsTopLeftCorner = '\u250c'
GraphicsTopRightCorner = '\u2510'
GraphicsBottomRightCorner = '\u2518'
GraphicsBottomLeftCorner = '\u2514'
GraphicsDbVertBar = '\u2550'
GraphicsDbHorBar = '\u2551'
GraphicsDbTopLeftCorner = '\u2554'
GraphicsDbTopRightCorner = '\u2557'
GraphicsDbBottomRightCorner = '\u255d'
GraphicsDbBottomLeftCorner = '\u255a'
GraphicsRightT = '\u2524'
GraphicsLeftT = '\u251c'
GraphicsTopT = '\u252c'
GraphicsBottomT = '\u2534'
GraphicsCross = '\u253c'
GraphicsEllipsis = '\u2026'
)
var (
// InputFieldInteger accepts integers.
InputFieldInteger func(text string, ch rune) bool
// InputFieldFloat accepts floating-point numbers.
InputFieldFloat func(text string, ch rune) bool
// InputFieldMaxLength returns an input field accept handler which accepts
// input strings up to a given length. Use it like this:
//
// inputField.SetAcceptanceFunc(InputFieldMaxLength(10)) // Accept up to 10 characters.
InputFieldMaxLength func(maxLength int) func(text string, ch rune) bool
)
// Package initialization.
func init() {
// Initialize the predefined input field handlers.
InputFieldInteger = func(text string, ch rune) bool {
if text == "-" {
return true
}
_, err := strconv.Atoi(text)
return err == nil
}
InputFieldFloat = func(text string, ch rune) bool {
if text == "-" || text == "." {
return true
}
_, err := strconv.ParseFloat(text, 64)
return err == nil
}
InputFieldMaxLength = func(maxLength int) func(text string, ch rune) bool {
return func(text string, ch rune) bool {
return len([]rune(text)) <= maxLength
}
}
// Regular expressions.
var colors string
for color := range textColors {
if len(colors) > 0 {
colors += "|"
}
colors += color
}
colorPattern = regexp.MustCompile(`\[(` + colors + `)\]`)
}
// 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.
//
// Returns the number of actual runes printed 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) {
// We deal with runes, not with bytes.
runes := []rune(text)
if maxWidth < 0 {
return 0, 0
}
// AlignCenter is a special case.
if align == AlignCenter {
width := runewidth.StringWidth(text)
if width == maxWidth {
// Use the exact space.
return Print(screen, text, x, y, maxWidth, AlignLeft, color)
} else if width < maxWidth {
// We have more space than we need.
half := (maxWidth - width) / 2
return Print(screen, text, x+half, y, maxWidth-half, AlignLeft, color)
} else {
// Chop off runes until we have a perfect fit.
var start, choppedLeft, choppedRight int
ru := runes
for len(ru) > 0 && width-choppedLeft-choppedRight > maxWidth {
leftWidth := runewidth.RuneWidth(ru[0])
rightWidth := runewidth.RuneWidth(ru[len(ru)-1])
if choppedLeft < choppedRight {
start++
choppedLeft += leftWidth
ru = ru[1:]
} else {
choppedRight += rightWidth
ru = ru[:len(ru)-1]
}
}
return Print(screen, string(ru), x, y, maxWidth, AlignLeft, color)
}
}
// Draw text.
drawn := 0
drawnWidth := 0
for pos, ch := range runes {
chWidth := runewidth.RuneWidth(ch)
if drawnWidth+chWidth > maxWidth {
break
}
finalX := x + drawnWidth
if align == AlignRight {
ch = runes[len(runes)-1-pos]
finalX = x + maxWidth - chWidth - drawnWidth
}
_, _, style, _ := screen.GetContent(finalX, y)
style = style.Foreground(color)
for offset := 0; offset < chWidth; offset++ {
// To avoid undesired effects, we place the same character in all cells.
screen.SetContent(finalX+offset, y, ch, nil, style)
}
drawn++
drawnWidth += chWidth
}
return drawn, drawnWidth
}
// 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)
}
// WordWrap splits a text such that each resulting line does not exceed the
// given screen width. Possible split points are after commas, dots, dashes,
// and any whitespace. Whitespace at split points will be dropped.
//
// Text is always split at newline characters ('\n').
func WordWrap(text string, width int) (lines []string) {
x := 0
start := 0
candidate := -1 // -1 = no candidate yet.
startAfterCandidate := 0
countAfterCandidate := 0
var evaluatingCandidate bool
text = strings.TrimSpace(text)
for pos, ch := range text {
chWidth := runewidth.RuneWidth(ch)
if !evaluatingCandidate && x >= width {
// We've exceeded the width, we must split.
if candidate >= 0 {
lines = append(lines, text[start:candidate])
start = startAfterCandidate
x = countAfterCandidate
} else {
lines = append(lines, text[start:pos])
start = pos
x = 0
}
candidate = -1
evaluatingCandidate = false
}
switch ch {
// We have a candidate.
case ',', '.', '-':
if x > 0 {
candidate = pos + 1
evaluatingCandidate = true
}
// If we've had a candidate, skip whitespace. If not, we have a candidate.
case ' ', '\t':
if x > 0 && !evaluatingCandidate {
candidate = pos
evaluatingCandidate = true
}
// Split in any case.
case '\n':
lines = append(lines, text[start:pos])
start = pos + 1
evaluatingCandidate = false
countAfterCandidate = 0
x = 0
continue
// If we've had a candidate, we have a new start.
default:
if evaluatingCandidate {
startAfterCandidate = pos
evaluatingCandidate = false
countAfterCandidate = 0
}
}
x += chWidth
countAfterCandidate += chWidth
}
// Process remaining text.
text = strings.TrimSpace(text[start:])
if len(text) > 0 {
lines = append(lines, text)
}
return
}