switch to go-term-text to fix bad underflow for label rendering

1 files changed, 95 insertions, 0 deletions

diff --git a/vendor/github.com/MichaelMure/go-term-text/escapes.go b/vendor/github.com/MichaelMure/go-term-text/escapes.go
new file mode 100644
index 00000000..19f78c92
--- /dev/null
+++ b/vendor/github.com/MichaelMure/go-term-text/escapes.go
@@ -0,0 +1,95 @@
+package text
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+// EscapeItem hold the description of terminal escapes in a line.
+// 'item' is the actual escape command
+// 'pos' is the index in the rune array where the 'item' shall be inserted back.
+// For example, the escape item in "F\x1b33mox" is {"\x1b33m", 1}.
+type EscapeItem struct {
+	Item string
+	Pos  int
+}
+
+// ExtractTermEscapes extract terminal escapes out of a line and returns a new
+// line without terminal escapes and a slice of escape items. The terminal escapes
+// can be inserted back into the new line at rune index 'item.pos' to recover the
+// original line.
+//
+// Required: The line shall not contain "\n"
+func ExtractTermEscapes(line string) (string, []EscapeItem) {
+	var termEscapes []EscapeItem
+	var line1 strings.Builder
+
+	pos := 0
+	item := ""
+	occupiedRuneCount := 0
+	inEscape := false
+	for i, r := range []rune(line) {
+		if r == '\x1b' {
+			pos = i
+			item = string(r)
+			inEscape = true
+			continue
+		}
+		if inEscape {
+			item += string(r)
+			if r == 'm' {
+				termEscapes = append(termEscapes, EscapeItem{item, pos - occupiedRuneCount})
+				occupiedRuneCount += utf8.RuneCountInString(item)
+				inEscape = false
+			}
+			continue
+		}
+		line1.WriteRune(r)
+	}
+
+	return line1.String(), termEscapes
+}
+
+// ApplyTermEscapes apply the extracted terminal escapes to the edited line.
+// Escape sequences need to be ordered by their position.
+// If the position is < 0, the escape is applied at the beginning of the line.
+// If the position is > len(line), the escape is applied at the end of the line.
+func ApplyTermEscapes(line string, escapes []EscapeItem) string {
+	if len(escapes) == 0 {
+		return line
+	}
+
+	var out strings.Builder
+
+	currPos := 0
+	currItem := 0
+	for _, r := range line {
+		for currItem < len(escapes) && currPos >= escapes[currItem].Pos {
+			out.WriteString(escapes[currItem].Item)
+			currItem++
+		}
+		out.WriteRune(r)
+		currPos++
+	}
+
+	// Don't forget the trailing escapes, if any.
+	for currItem < len(escapes) {
+		out.WriteString(escapes[currItem].Item)
+		currItem++
+	}
+
+	return out.String()
+}
+
+// OffsetEscapes is a utility function to offset the position of a
+// collection of EscapeItem.
+func OffsetEscapes(escapes []EscapeItem, offset int) []EscapeItem {
+	result := make([]EscapeItem, len(escapes))
+	for i, e := range escapes {
+		result[i] = EscapeItem{
+			Item: e.Item,
+			Pos:  e.Pos + offset,
+		}
+	}
+	return result
+}