code-server/extensions/image-preview/media/main.js

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/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
// @ts-check
"use strict";
(function () {
/**
* @param {number} value
* @param {number} min
* @param {number} max
* @return {number}
*/
function clamp(value, min, max) {
return Math.min(Math.max(value, min), max);
}
function getSettings() {
const element = document.getElementById('image-preview-settings');
if (element) {
const data = element.getAttribute('data-settings');
if (data) {
return JSON.parse(data);
}
}
throw new Error(`Could not load settings`);
}
/**
* Enable image-rendering: pixelated for images scaled by more than this.
*/
const PIXELATION_THRESHOLD = 3;
const SCALE_PINCH_FACTOR = 0.075;
const MAX_SCALE = 20;
const MIN_SCALE = 0.1;
const zoomLevels = [
0.1,
0.2,
0.3,
0.4,
0.5,
0.6,
0.7,
0.8,
0.9,
1,
1.5,
2,
3,
5,
7,
10,
15,
20
];
const settings = getSettings();
const isMac = settings.isMac;
const vscode = acquireVsCodeApi();
const initialState = vscode.getState() || { scale: 'fit', offsetX: 0, offsetY: 0 };
// State
let scale = initialState.scale;
let ctrlPressed = false;
let altPressed = false;
let hasLoadedImage = false;
let consumeClick = true;
let isActive = false;
// Elements
const container = document.body;
const image = document.createElement('img');
function updateScale(newScale) {
if (!image || !hasLoadedImage || !image.parentElement) {
return;
}
if (newScale === 'fit') {
scale = 'fit';
image.classList.add('scale-to-fit');
image.classList.remove('pixelated');
image.style.minWidth = 'auto';
image.style.width = 'auto';
vscode.setState(undefined);
} else {
scale = clamp(newScale, MIN_SCALE, MAX_SCALE);
if (scale >= PIXELATION_THRESHOLD) {
image.classList.add('pixelated');
} else {
image.classList.remove('pixelated');
}
const dx = (window.scrollX + container.clientWidth / 2) / container.scrollWidth;
const dy = (window.scrollY + container.clientHeight / 2) / container.scrollHeight;
image.classList.remove('scale-to-fit');
image.style.minWidth = `${(image.naturalWidth * scale)}px`;
image.style.width = `${(image.naturalWidth * scale)}px`;
const newScrollX = container.scrollWidth * dx - container.clientWidth / 2;
const newScrollY = container.scrollHeight * dy - container.clientHeight / 2;
window.scrollTo(newScrollX, newScrollY);
vscode.setState({ scale: scale, offsetX: newScrollX, offsetY: newScrollY });
}
vscode.postMessage({
type: 'zoom',
value: scale
});
}
function setActive(value) {
isActive = value;
if (value) {
if (isMac ? altPressed : ctrlPressed) {
container.classList.remove('zoom-in');
container.classList.add('zoom-out');
} else {
container.classList.remove('zoom-out');
container.classList.add('zoom-in');
}
} else {
ctrlPressed = false;
altPressed = false;
container.classList.remove('zoom-out');
container.classList.remove('zoom-in');
}
}
function firstZoom() {
if (!image || !hasLoadedImage) {
return;
}
scale = image.clientWidth / image.naturalWidth;
updateScale(scale);
}
function zoomIn() {
if (scale === 'fit') {
firstZoom();
}
let i = 0;
for (; i < zoomLevels.length; ++i) {
if (zoomLevels[i] > scale) {
break;
}
}
updateScale(zoomLevels[i] || MAX_SCALE);
}
function zoomOut() {
if (scale === 'fit') {
firstZoom();
}
let i = zoomLevels.length - 1;
for (; i >= 0; --i) {
if (zoomLevels[i] < scale) {
break;
}
}
updateScale(zoomLevels[i] || MIN_SCALE);
}
window.addEventListener('keydown', (/** @type {KeyboardEvent} */ e) => {
if (!image || !hasLoadedImage) {
return;
}
ctrlPressed = e.ctrlKey;
altPressed = e.altKey;
if (isMac ? altPressed : ctrlPressed) {
container.classList.remove('zoom-in');
container.classList.add('zoom-out');
}
});
window.addEventListener('keyup', (/** @type {KeyboardEvent} */ e) => {
if (!image || !hasLoadedImage) {
return;
}
ctrlPressed = e.ctrlKey;
altPressed = e.altKey;
if (!(isMac ? altPressed : ctrlPressed)) {
container.classList.remove('zoom-out');
container.classList.add('zoom-in');
}
});
container.addEventListener('mousedown', (/** @type {MouseEvent} */ e) => {
if (!image || !hasLoadedImage) {
return;
}
if (e.button !== 0) {
return;
}
ctrlPressed = e.ctrlKey;
altPressed = e.altKey;
consumeClick = !isActive;
});
container.addEventListener('click', (/** @type {MouseEvent} */ e) => {
if (!image || !hasLoadedImage) {
return;
}
if (e.button !== 0) {
return;
}
if (consumeClick) {
consumeClick = false;
return;
}
// left click
if (scale === 'fit') {
firstZoom();
}
if (!(isMac ? altPressed : ctrlPressed)) { // zoom in
zoomIn();
} else {
zoomOut();
}
});
container.addEventListener('wheel', (/** @type {WheelEvent} */ e) => {
// Prevent pinch to zoom
if (e.ctrlKey) {
e.preventDefault();
}
if (!image || !hasLoadedImage) {
return;
}
const isScrollWheelKeyPressed = isMac ? altPressed : ctrlPressed;
if (!isScrollWheelKeyPressed && !e.ctrlKey) { // pinching is reported as scroll wheel + ctrl
return;
}
if (scale === 'fit') {
firstZoom();
}
let delta = e.deltaY > 0 ? 1 : -1;
updateScale(scale * (1 - delta * SCALE_PINCH_FACTOR));
}, { passive: false });
window.addEventListener('scroll', e => {
if (!image || !hasLoadedImage || !image.parentElement || scale === 'fit') {
return;
}
const entry = vscode.getState();
if (entry) {
vscode.setState({ scale: entry.scale, offsetX: window.scrollX, offsetY: window.scrollY });
}
}, { passive: true });
container.classList.add('image');
image.classList.add('scale-to-fit');
image.addEventListener('load', () => {
if (hasLoadedImage) {
return;
}
hasLoadedImage = true;
vscode.postMessage({
type: 'size',
value: `${image.naturalWidth}x${image.naturalHeight}`,
});
document.body.classList.remove('loading');
document.body.classList.add('ready');
document.body.append(image);
updateScale(scale);
if (initialState.scale !== 'fit') {
window.scrollTo(initialState.offsetX, initialState.offsetY);
}
});
image.addEventListener('error', e => {
if (hasLoadedImage) {
return;
}
hasLoadedImage = true;
document.body.classList.add('error');
document.body.classList.remove('loading');
});
image.src = settings.src;
document.querySelector('.open-file-link').addEventListener('click', () => {
vscode.postMessage({
type: 'reopen-as-text',
});
});
window.addEventListener('message', e => {
switch (e.data.type) {
case 'setScale':
updateScale(e.data.scale);
break;
case 'setActive':
setActive(e.data.value);
break;
case 'zoomIn':
zoomIn();
break;
case 'zoomOut':
zoomOut();
break;
}
});
}());