Function applyBackground

src/native-ts/color-diff/index.ts:768–817

(h: Highlight, theme: Theme, ranges: Range[])

}

function applyBackground(h: Highlight, theme: Theme, ranges: Range[]): void {
  if (!h.marker) return
  const lineBg = lineBackground(h.marker, theme)
  const wordBg = wordBackground(h.marker, theme)

  let rangeIdx = 0
  let byteOff = 0
  for (let li = 0; li < h.lines.length; li++) {
    const newLine: Block[] = []
    for (const [style, text] of h.lines[li]!) {
      const textStart = byteOff
      const textEnd = byteOff + text.length

      while (rangeIdx < ranges.length && ranges[rangeIdx]!.end <= textStart) {
        rangeIdx++
      }
      if (rangeIdx >= ranges.length) {
        newLine.push([{ ...style, background: lineBg }, text])
        byteOff = textEnd
        continue
      }

      let remaining = text
      let pos = textStart
      while (remaining.length > 0 && rangeIdx < ranges.length) {
        const r = ranges[rangeIdx]!
        const inRange = pos >= r.start && pos < r.end
        let next: number
        if (inRange) {
          next = Math.min(r.end, textEnd)
        } else if (r.start > pos && r.start < textEnd) {
          next = r.start
        } else {
          next = textEnd
        }
        const segLen = next - pos
        const seg = remaining.slice(0, segLen)
        newLine.push([{ ...style, background: inRange ? wordBg : lineBg }, seg])
        remaining = remaining.slice(segLen)
        pos = next
        if (pos >= r.end) rangeIdx++
      }
      if (remaining.length > 0) {
        newLine.push([{ ...style, background: lineBg }, remaining])
      }
      byteOff = textEnd
    }
    h.lines[li] = newLine
  }
}

function intoLines(
  h: Highlight,