115 lines
4.1 KiB
JavaScript
115 lines
4.1 KiB
JavaScript
/**
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* xterm.js: xterm, in the browser
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* Copyright (c) 2016, SourceLair Limited <www.sourcelair.com> (MIT License)
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*/
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/**
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* Represents the viewport of a terminal, the visible area within the larger buffer of output.
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* Logic for the virtual scroll bar is included in this object.
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* @param {Terminal} terminal The Terminal object.
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* @param {HTMLElement} viewportElement The DOM element acting as the viewport
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* @param {HTMLElement} charMeasureElement A DOM element used to measure the character size of
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* the terminal.
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*/
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function Viewport(terminal, viewportElement, scrollArea, charMeasureElement) {
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this.terminal = terminal;
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this.viewportElement = viewportElement;
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this.scrollArea = scrollArea;
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this.charMeasureElement = charMeasureElement;
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this.currentRowHeight = 0;
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this.lastRecordedBufferLength = 0;
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this.lastRecordedViewportHeight = 0;
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this.terminal.on('scroll', this.syncScrollArea.bind(this));
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this.terminal.on('resize', this.syncScrollArea.bind(this));
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this.viewportElement.addEventListener('scroll', this.onScroll.bind(this));
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this.syncScrollArea();
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}
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/**
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* Refreshes row height, setting line-height, viewport height and scroll area height if
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* necessary.
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* @param {number|undefined} charSize A character size measurement bounding rect object, if it
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* doesn't exist it will be created.
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*/
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Viewport.prototype.refresh = function(charSize) {
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var size = charSize || this.charMeasureElement.getBoundingClientRect();
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if (size.height > 0) {
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var rowHeightChanged = size.height !== this.currentRowHeight;
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if (rowHeightChanged) {
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this.currentRowHeight = size.height;
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this.viewportElement.style.lineHeight = size.height + 'px';
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this.terminal.rowContainer.style.lineHeight = size.height + 'px';
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}
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var viewportHeightChanged = this.lastRecordedViewportHeight !== this.terminal.rows;
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if (rowHeightChanged || viewportHeightChanged) {
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this.lastRecordedViewportHeight = this.terminal.rows;
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this.viewportElement.style.height = size.height * this.terminal.rows + 'px';
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}
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this.scrollArea.style.height = (size.height * this.lastRecordedBufferLength) + 'px';
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}
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};
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/**
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* Updates dimensions and synchronizes the scroll area if necessary.
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*/
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Viewport.prototype.syncScrollArea = function() {
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if (this.lastRecordedBufferLength !== this.terminal.lines.length) {
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// If buffer height changed
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this.lastRecordedBufferLength = this.terminal.lines.length;
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this.refresh();
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} else if (this.lastRecordedViewportHeight !== this.terminal.rows) {
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// If viewport height changed
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this.refresh();
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} else {
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// If size has changed, refresh viewport
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var size = this.charMeasureElement.getBoundingClientRect();
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if (size.height !== this.currentRowHeight) {
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this.refresh(size);
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}
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}
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// Sync scrollTop
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var scrollTop = this.terminal.ydisp * this.currentRowHeight;
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if (this.viewportElement.scrollTop !== scrollTop) {
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this.viewportElement.scrollTop = scrollTop;
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}
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};
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/**
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* Handles scroll events on the viewport, calculating the new viewport and requesting the
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* terminal to scroll to it.
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* @param {Event} ev The scroll event.
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*/
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Viewport.prototype.onScroll = function(ev) {
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var newRow = Math.round(this.viewportElement.scrollTop / this.currentRowHeight);
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var diff = newRow - this.terminal.ydisp;
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this.terminal.scrollDisp(diff, true);
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};
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/**
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* Handles mouse wheel events by adjusting the viewport's scrollTop and delegating the actual
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* scrolling to `onScroll`, this event needs to be attached manually by the consumer of
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* `Viewport`.
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* @param {WheelEvent} ev The mouse wheel event.
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*/
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Viewport.prototype.onWheel = function(ev) {
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if (ev.deltaY === 0) {
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// Do nothing if it's not a vertical scroll event
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return;
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}
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// Fallback to WheelEvent.DOM_DELTA_PIXEL
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var multiplier = 1;
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if (ev.deltaMode === WheelEvent.DOM_DELTA_LINE) {
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multiplier = this.currentRowHeight;
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} else if (ev.deltaMode === WheelEvent.DOM_DELTA_PAGE) {
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multiplier = this.currentRowHeight * this.terminal.rows;
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}
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this.viewportElement.scrollTop += ev.deltaY * multiplier;
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// Prevent the page from scrolling when the terminal scrolls
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ev.preventDefault();
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};
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export { Viewport };
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