HackMD/public/js/syncscroll.js
2017-01-04 23:01:44 +08:00

365 lines
12 KiB
JavaScript

// Inject line numbers for sync scroll.
import markdownitContainer from 'markdown-it-container';
import { md } from './extra';
function addPart(tokens, idx) {
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1;
const endline = tokens[idx].map[1];
tokens[idx].attrJoin('class', 'part');
tokens[idx].attrJoin('data-startline', startline);
tokens[idx].attrJoin('data-endline', endline);
}
}
md.renderer.rules.blockquote_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw');
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.table_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.bullet_list_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.list_item_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw');
if (tokens[idx].map) {
const startline = tokens[idx].map[0] + 1;
const endline = tokens[idx].map[1];
tokens[idx].attrJoin('data-startline', startline);
tokens[idx].attrJoin('data-endline', endline);
}
return self.renderToken(...arguments);
};
md.renderer.rules.ordered_list_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.link_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.paragraph_open = function (tokens, idx, options, env, self) {
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.heading_open = function (tokens, idx, options, env, self) {
tokens[idx].attrJoin('class', 'raw');
addPart(tokens, idx);
return self.renderToken(...arguments);
};
md.renderer.rules.fence = (tokens, idx, options, env, self) => {
const token = tokens[idx];
const info = token.info ? md.utils.unescapeAll(token.info).trim() : '';
let langName = '';
let highlighted;
if (info) {
langName = info.split(/\s+/g)[0];
if (/\!$/.test(info)) token.attrJoin('class', 'wrap');
token.attrJoin('class', options.langPrefix + langName.replace(/\=$|\=\d+$|\=\+$|\!$|\=\!/, ''));
token.attrJoin('class', 'hljs');
token.attrJoin('class', 'raw');
}
if (options.highlight) {
highlighted = options.highlight(token.content, langName) || md.utils.escapeHtml(token.content);
} else {
highlighted = md.utils.escapeHtml(token.content);
}
if (highlighted.indexOf('<pre') === 0) {
return `${highlighted}\n`;
}
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1;
const endline = tokens[idx].map[1];
return `<pre class="part" data-startline="${startline}" data-endline="${endline}"><code${self.renderAttrs(token)}>${highlighted}</code></pre>\n`;
}
return `<pre><code${self.renderAttrs(token)}>${highlighted}</code></pre>\n`;
};
md.renderer.rules.code_block = (tokens, idx, options, env, self) => {
if (tokens[idx].map && tokens[idx].level === 0) {
const startline = tokens[idx].map[0] + 1;
const endline = tokens[idx].map[1];
return `<pre class="part" data-startline="${startline}" data-endline="${endline}"><code>${md.utils.escapeHtml(tokens[idx].content)}</code></pre>\n`;
}
return `<pre><code>${md.utils.escapeHtml(tokens[idx].content)}</code></pre>\n`;
};
function renderContainer(tokens, idx, options, env, self) {
tokens[idx].attrJoin('role', 'alert');
tokens[idx].attrJoin('class', 'alert');
tokens[idx].attrJoin('class', `alert-${tokens[idx].info.trim()}`);
addPart(tokens, idx);
return self.renderToken(...arguments);
}
md.use(markdownitContainer, 'success', { render: renderContainer });
md.use(markdownitContainer, 'info', { render: renderContainer });
md.use(markdownitContainer, 'warning', { render: renderContainer });
md.use(markdownitContainer, 'danger', { render: renderContainer });
// FIXME: expose syncscroll to window
window.syncscroll = true;
window.preventSyncScrollToEdit = false;
window.preventSyncScrollToView = false;
const editScrollThrottle = 5;
const viewScrollThrottle = 5;
const buildMapThrottle = 100;
let viewScrolling = false;
let editScrolling = false;
let editArea = null;
let viewArea = null;
let markdownArea = null;
export function setupSyncAreas(edit, view, markdown) {
editArea = edit;
viewArea = view;
markdownArea = markdown;
editArea.on('scroll', _.throttle(syncScrollToView, editScrollThrottle));
viewArea.on('scroll', _.throttle(syncScrollToEdit, viewScrollThrottle));
}
let scrollMap, lineHeightMap, viewTop, viewBottom;
export function clearMap() {
scrollMap = null;
lineHeightMap = null;
viewTop = null;
viewBottom = null;
}
window.viewAjaxCallback = clearMap;
const buildMap = _.throttle(buildMapInner, buildMapThrottle);
// Build offsets for each line (lines can be wrapped)
// That's a bit dirty to process each line everytime, but ok for demo.
// Optimizations are required only for big texts.
function buildMapInner(callback) {
if (!viewArea || !markdownArea) return;
let i, offset, nonEmptyList, pos, a, b, _lineHeightMap, linesCount, acc, _scrollMap;
offset = viewArea.scrollTop() - viewArea.offset().top;
_scrollMap = [];
nonEmptyList = [];
_lineHeightMap = [];
viewTop = 0;
viewBottom = viewArea[0].scrollHeight - viewArea.height();
acc = 0;
const lines = editor.getValue().split('\n');
const lineHeight = editor.defaultTextHeight();
for (i = 0; i < lines.length; i++) {
const str = lines[i];
_lineHeightMap.push(acc);
if (str.length === 0) {
acc++;
continue;
}
const h = editor.heightAtLine(i + 1) - editor.heightAtLine(i);
acc += Math.round(h / lineHeight);
}
_lineHeightMap.push(acc);
linesCount = acc;
for (i = 0; i < linesCount; i++) {
_scrollMap.push(-1);
}
nonEmptyList.push(0);
// make the first line go top
_scrollMap[0] = viewTop;
const parts = markdownArea.find('.part').toArray();
for (i = 0; i < parts.length; i++) {
const $el = $(parts[i]);
let t = $el.attr('data-startline') - 1;
if (t === '') {
return;
}
t = _lineHeightMap[t];
if (t !== 0 && t !== nonEmptyList[nonEmptyList.length - 1]) {
nonEmptyList.push(t);
}
_scrollMap[t] = Math.round($el.offset().top + offset - 10);
}
nonEmptyList.push(linesCount);
_scrollMap[linesCount] = viewArea[0].scrollHeight;
pos = 0;
for (i = 1; i < linesCount; i++) {
if (_scrollMap[i] !== -1) {
pos++;
continue;
}
a = nonEmptyList[pos];
b = nonEmptyList[pos + 1];
_scrollMap[i] = Math.round((_scrollMap[b] * (i - a) + _scrollMap[a] * (b - i)) / (b - a));
}
_scrollMap[0] = 0;
scrollMap = _scrollMap;
lineHeightMap = _lineHeightMap;
if (loaded && callback) callback();
}
// sync view scroll progress to edit
let viewScrollingTimer = null;
export function syncScrollToEdit(event, preventAnimate) {
if (currentMode != modeType.both || !syncscroll || !editArea) return;
if (preventSyncScrollToEdit) {
if (typeof preventSyncScrollToEdit === 'number') {
preventSyncScrollToEdit--;
} else {
preventSyncScrollToEdit = false;
}
return;
}
if (!scrollMap || !lineHeightMap) {
buildMap(() => {
syncScrollToEdit(event, preventAnimate);
});
return;
}
if (editScrolling) return;
const scrollTop = viewArea[0].scrollTop;
let lineIndex = 0;
for (var i = 0, l = scrollMap.length; i < l; i++) {
if (scrollMap[i] > scrollTop) {
break;
} else {
lineIndex = i;
}
}
let lineNo = 0;
let lineDiff = 0;
for (var i = 0, l = lineHeightMap.length; i < l; i++) {
if (lineHeightMap[i] > lineIndex) {
break;
} else {
lineNo = lineHeightMap[i];
lineDiff = lineHeightMap[i + 1] - lineNo;
}
}
let posTo = 0;
let topDiffPercent = 0;
let posToNextDiff = 0;
const scrollInfo = editor.getScrollInfo();
const textHeight = editor.defaultTextHeight();
const preLastLineHeight = scrollInfo.height - scrollInfo.clientHeight - textHeight;
const preLastLineNo = Math.round(preLastLineHeight / textHeight);
const preLastLinePos = scrollMap[preLastLineNo];
if (scrollInfo.height > scrollInfo.clientHeight && scrollTop >= preLastLinePos) {
posTo = preLastLineHeight;
topDiffPercent = (scrollTop - preLastLinePos) / (viewBottom - preLastLinePos);
posToNextDiff = textHeight * topDiffPercent;
posTo += Math.ceil(posToNextDiff);
} else {
posTo = lineNo * textHeight;
topDiffPercent = (scrollTop - scrollMap[lineNo]) / (scrollMap[lineNo + lineDiff] - scrollMap[lineNo]);
posToNextDiff = textHeight * lineDiff * topDiffPercent;
posTo += Math.ceil(posToNextDiff);
}
if (preventAnimate) {
editArea.scrollTop(posTo);
} else {
const posDiff = Math.abs(scrollInfo.top - posTo);
var duration = posDiff / 50;
duration = duration >= 100 ? duration : 100;
editArea.stop(true, true).animate({
scrollTop: posTo
}, duration, "linear");
}
viewScrolling = true;
clearTimeout(viewScrollingTimer);
viewScrollingTimer = setTimeout(viewScrollingTimeoutInner, duration * 1.5);
}
function viewScrollingTimeoutInner() {
viewScrolling = false;
}
// sync edit scroll progress to view
let editScrollingTimer = null;
export function syncScrollToView(event, preventAnimate) {
if (currentMode != modeType.both || !syncscroll || !viewArea) return;
if (preventSyncScrollToView) {
if (typeof preventSyncScrollToView === 'number') {
preventSyncScrollToView--;
} else {
preventSyncScrollToView = false;
}
return;
}
if (!scrollMap || !lineHeightMap) {
buildMap(() => {
syncScrollToView(event, preventAnimate);
});
return;
}
if (viewScrolling) return;
let lineNo, posTo;
let topDiffPercent, posToNextDiff;
const scrollInfo = editor.getScrollInfo();
const textHeight = editor.defaultTextHeight();
lineNo = Math.floor(scrollInfo.top / textHeight);
// if reach the last line, will start lerp to the bottom
const diffToBottom = (scrollInfo.top + scrollInfo.clientHeight) - (scrollInfo.height - textHeight);
if (scrollInfo.height > scrollInfo.clientHeight && diffToBottom > 0) {
topDiffPercent = diffToBottom / textHeight;
posTo = scrollMap[lineNo + 1];
posToNextDiff = (viewBottom - posTo) * topDiffPercent;
posTo += Math.floor(posToNextDiff);
} else {
topDiffPercent = (scrollInfo.top % textHeight) / textHeight;
posTo = scrollMap[lineNo];
posToNextDiff = (scrollMap[lineNo + 1] - posTo) * topDiffPercent;
posTo += Math.floor(posToNextDiff);
}
if (preventAnimate) {
viewArea.scrollTop(posTo);
} else {
const posDiff = Math.abs(viewArea.scrollTop() - posTo);
var duration = posDiff / 50;
duration = duration >= 100 ? duration : 100;
viewArea.stop(true, true).animate({
scrollTop: posTo
}, duration, "linear");
}
editScrolling = true;
clearTimeout(editScrollingTimer);
editScrollingTimer = setTimeout(editScrollingTimeoutInner, duration * 1.5);
}
function editScrollingTimeoutInner() {
editScrolling = false;
}