MarkLite/renderer/editor.js

// MarkLite — Editor Module: line numbers, cursor, file size, scroll sync
(function () {
  'use strict';
  var ML = window.MarkLite;

  // ===== Line Numbers =====
  function countNewlines(text) {
    var count = 1;
    for (var i = 0, len = text.length; i < len; i++) {
      if (text.charCodeAt(i) === 10) count++;
    }
    return count;
  }

  ML.updateLineNumbers = function () {
    var count = countNewlines(ML.editor.value);
    if (count === ML.lineCountCache) return;
    ML.lineCountCache = count;
    if (count > 2000) {
      ML.renderVirtualLineNumbers(count);
    } else {
      var arr = new Array(count);
      for (var i = 0; i < count; i++) arr[i] = '<div class="line-num">' + (i + 1) + '</div>';
      ML.lineNumbers.innerHTML = arr.join('');
    }
  };

  ML.renderVirtualLineNumbers = function (totalLines) {
    var lineHeight = 20.8;
    var scrollTop = ML.editor.scrollTop;
    var viewportHeight = ML.editor.clientHeight;
    var buffer = 20;
    var startLine = Math.max(0, Math.floor(scrollTop / lineHeight) - buffer);
    var endLine = Math.min(totalLines, Math.ceil((scrollTop + viewportHeight) / lineHeight) + buffer);
    var visibleCount = endLine - startLine;
    var topPadding = startLine * lineHeight;
    var bottomPadding = (totalLines - endLine) * lineHeight;
    var arr = new Array(visibleCount + 2);
    arr[0] = '<div style="height:' + topPadding + 'px"></div>';
    for (var i = 0; i < visibleCount; i++) arr[i + 1] = '<div class="line-num">' + (startLine + i + 1) + '</div>';
    arr[visibleCount + 1] = '<div style="height:' + bottomPadding + 'px"></div>';
    ML.lineNumbers.innerHTML = arr.join('');
  };

  // ===== Cursor Position =====
  ML.updateCursorPosition = function () {
    var text = ML.editor.value;
    var pos = ML.editor.selectionStart;
    var textBefore = text.substring(0, pos);
    var lines = textBefore.split('\n');
    ML.statusCursor.textContent = '行 ' + lines.length + ', 列 ' + (lines[lines.length - 1].length + 1);
  };

  // ===== File Size =====
  ML.updateFileSize = function () {
    var bytes = new Blob([ML.editor.value]).size;
    ML.statusSize.textContent = ML.formatBytes(bytes);
    ML.statusSizeDivider.classList.add('visible');
  };

  // ===== Scroll Sync =====
  var previewPositions = null;
  var lineToPreviewMap = null;

  ML.cachePreviewPositions = function () {
    previewPositions = [];
    for (var i = 0; i < ML.preview.children.length; i++) previewPositions.push(ML.preview.children[i].offsetTop);
    buildLineToPreviewMap();
  };

  function buildLineToPreviewMap() {
    if (!previewPositions || previewPositions.length === 0) { lineToPreviewMap = null; return; }
    var text = ML.editor.value;
    var lines = text.split('\n');
    var totalLines = lines.length;
    var blockStartLines = [];
    var inCodeBlock = false;
    for (var i = 0; i < totalLines; i++) {
      var trimmed = lines[i].trimStart();
      if (trimmed.startsWith('```')) {
        if (!inCodeBlock) { blockStartLines.push(i); inCodeBlock = true; }
        else inCodeBlock = false;
        continue;
      }
      if (inCodeBlock) continue;
      if (trimmed.startsWith('#') || trimmed.startsWith('- ') || trimmed.startsWith('* ') || trimmed.startsWith('+ ') ||
          /^\d+\.\s/.test(trimmed) || trimmed.startsWith('> ') || trimmed.startsWith('|') ||
          trimmed.startsWith('---') || trimmed.startsWith('***') || trimmed.startsWith('___') ||
          (trimmed === '' && i > 0 && lines[i - 1].trim() === '')) {
        blockStartLines.push(i);
      }
    }
    var uniqueStartsArr = [].concat(_toConsumableArray(new Set(blockStartLines))).sort(function (a, b) { return a - b; });
    var uniqueStartsSet = new Set(uniqueStartsArr);
    lineToPreviewMap = new Float32Array(totalLines);
    if (uniqueStartsArr.length === 0) {
      for (var _i = 0; _i < totalLines; _i++) lineToPreviewMap[_i] = (_i / Math.max(1, totalLines - 1)) * previewPositions[previewPositions.length - 1];
      return;
    }
    var domCount = previewPositions.length;
    for (var _i2 = 0; _i2 < uniqueStartsArr.length; _i2++) {
      var lineIdx = uniqueStartsArr[_i2];
      var domIdx = Math.min(Math.floor((_i2 / uniqueStartsArr.length) * domCount), domCount - 1);
      lineToPreviewMap[lineIdx] = previewPositions[domIdx];
    }
    for (var _i3 = 0; _i3 < totalLines; _i3++) {
      if (lineToPreviewMap[_i3] !== 0 && uniqueStartsSet.has(_i3)) continue;
      var prevLine = -1, nextLine = -1;
      for (var j = _i3 - 1; j >= 0; j--) { if (lineToPreviewMap[j] !== 0 || uniqueStartsSet.has(j)) { prevLine = j; break; } }
      for (var _j = _i3 + 1; _j < totalLines; _j++) { if (lineToPreviewMap[_j] !== 0 || uniqueStartsSet.has(_j)) { nextLine = _j; break; } }
      if (prevLine === -1 && nextLine === -1) lineToPreviewMap[_i3] = 0;
      else if (prevLine === -1) lineToPreviewMap[_i3] = lineToPreviewMap[nextLine];
      else if (nextLine === -1) lineToPreviewMap[_i3] = lineToPreviewMap[prevLine];
      else { var ratio = (_i3 - prevLine) / (nextLine - prevLine); lineToPreviewMap[_i3] = lineToPreviewMap[prevLine] + ratio * (lineToPreviewMap[nextLine] - lineToPreviewMap[prevLine]); }
    }
  }

  function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } return Array.from(arr); }

  ML.syncScroll = function () {
    if (ML.viewMode !== 'split') return;
    var lineHeight = parseFloat(getComputedStyle(ML.editor).lineHeight) || 20.8;
    var scrollTop = ML.editor.scrollTop;
    var topLine = Math.floor(scrollTop / lineHeight);
    if (!previewPositions || previewPositions.length === 0) ML.cachePreviewPositions();
    if (!previewPositions || previewPositions.length === 0) return;
    if (lineToPreviewMap && topLine >= 0 && topLine < lineToPreviewMap.length) {
      ML.previewPanel.scrollTop = lineToPreviewMap[topLine];
    } else {
      var totalLines = ML.editor.value.split('\n').length;
      var ratio = totalLines > 1 ? topLine / (totalLines - 1) : 0;
      var targetIndex = Math.min(Math.floor(ratio * previewPositions.length), previewPositions.length - 1);
      if (targetIndex >= 0 && previewPositions[targetIndex] !== undefined) ML.previewPanel.scrollTop = previewPositions[targetIndex];
    }
  };

  // ===== Schedule Update =====
  ML.scheduleUpdate = function () {
    if (ML.updateTimer) clearTimeout(ML.updateTimer);
    ML.updateTimer = setTimeout(function () {
      ML.renderMarkdown(ML.editor.value);
      ML.updateLineNumbers();
      ML.updateFileSize();
      ML.cachePreviewPositions();
    }, 150);
  };
})();