127 lines
4 KiB
TypeScript
127 lines
4 KiB
TypeScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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import { getSettings } from './settings';
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function clamp(min: number, max: number, value: number) {
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return Math.min(max, Math.max(min, value));
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}
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function clampLine(line: number) {
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return clamp(0, getSettings().lineCount - 1, line);
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}
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export interface CodeLineElement {
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element: HTMLElement;
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line: number;
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}
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const getCodeLineElements = (() => {
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let elements: CodeLineElement[];
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return () => {
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if (!elements) {
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elements = Array.prototype.map.call(
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document.getElementsByClassName('code-line'),
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(element: any) => {
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const line = +element.getAttribute('data-line');
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return { element, line };
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})
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.filter((x: any) => !isNaN(x.line));
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}
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return elements;
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};
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})();
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/**
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* Find the html elements that map to a specific target line in the editor.
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*
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* If an exact match, returns a single element. If the line is between elements,
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* returns the element prior to and the element after the given line.
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*/
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export function getElementsForSourceLine(targetLine: number): { previous: CodeLineElement; next?: CodeLineElement; } {
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const lineNumber = Math.floor(targetLine);
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const lines = getCodeLineElements();
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let previous = lines[0] || null;
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for (const entry of lines) {
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if (entry.line === lineNumber) {
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return { previous: entry, next: undefined };
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}
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else if (entry.line > lineNumber) {
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return { previous, next: entry };
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}
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previous = entry;
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}
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return { previous };
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}
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/**
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* Find the html elements that are at a specific pixel offset on the page.
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*/
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export function getLineElementsAtPageOffset(offset: number): { previous: CodeLineElement; next?: CodeLineElement; } {
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const lines = getCodeLineElements();
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const position = offset - window.scrollY;
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let lo = -1;
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let hi = lines.length - 1;
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while (lo + 1 < hi) {
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const mid = Math.floor((lo + hi) / 2);
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const bounds = lines[mid].element.getBoundingClientRect();
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if (bounds.top + bounds.height >= position) {
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hi = mid;
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}
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else {
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lo = mid;
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}
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}
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const hiElement = lines[hi];
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const hiBounds = hiElement.element.getBoundingClientRect();
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if (hi >= 1 && hiBounds.top > position) {
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const loElement = lines[lo];
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return { previous: loElement, next: hiElement };
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}
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return { previous: hiElement };
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}
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/**
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* Attempt to reveal the element for a source line in the editor.
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*/
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export function scrollToRevealSourceLine(line: number) {
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const { previous, next } = getElementsForSourceLine(line);
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if (previous && getSettings().scrollPreviewWithEditor) {
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let scrollTo = 0;
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const rect = previous.element.getBoundingClientRect();
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const previousTop = rect.top;
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if (next && next.line !== previous.line) {
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// Between two elements. Go to percentage offset between them.
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const betweenProgress = (line - previous.line) / (next.line - previous.line);
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const elementOffset = next.element.getBoundingClientRect().top - previousTop;
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scrollTo = previousTop + betweenProgress * elementOffset;
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}
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else {
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scrollTo = previousTop;
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}
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window.scroll(0, Math.max(1, window.scrollY + scrollTo));
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}
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}
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export function getEditorLineNumberForPageOffset(offset: number) {
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const { previous, next } = getLineElementsAtPageOffset(offset);
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if (previous) {
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const previousBounds = previous.element.getBoundingClientRect();
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const offsetFromPrevious = (offset - window.scrollY - previousBounds.top);
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if (next) {
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const progressBetweenElements = offsetFromPrevious / (next.element.getBoundingClientRect().top - previousBounds.top);
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const line = previous.line + progressBetweenElements * (next.line - previous.line);
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return clampLine(line);
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}
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else {
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const progressWithinElement = offsetFromPrevious / (previousBounds.height);
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const line = previous.line + progressWithinElement;
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return clampLine(line);
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}
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}
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return null;
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}
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