{"id":13630393,"url":"https://github.com/tungs/timesnap","last_synced_at":"2025-10-24T08:12:47.387Z","repository":{"id":49574322,"uuid":"122102998","full_name":"tungs/timesnap","owner":"tungs","description":"Node.js program that takes screenshots at smooth intervals of web pages with JavaScript animations","archived":false,"fork":false,"pushed_at":"2024-01-17T10:30:54.000Z","size":240,"stargazers_count":237,"open_issues_count":28,"forks_count":59,"subscribers_count":9,"default_branch":"main","last_synced_at":"2025-03-28T16:09:26.268Z","etag":null,"topics":["nodejs","puppeteer"],"latest_commit_sha":null,"homepage":"","language":"JavaScript","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"bsd-3-clause","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/tungs.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2018-02-19T18:25:44.000Z","updated_at":"2025-03-24T01:44:37.000Z","dependencies_parsed_at":"2024-01-06T01:09:46.929Z","dependency_job_id":"c751659c-9691-44fb-b409-8627bba8c36b","html_url":"https://github.com/tungs/timesnap","commit_stats":{"total_commits":206,"total_committers":11,"mean_commits":"18.727272727272727","dds":0.3106796116504854,"last_synced_commit":"6782c67e8eefa2cb3ee87414662fb17883cf894f"},"previous_names":[],"tags_count":24,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/tungs%2Ftimesnap","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/tungs%2Ftimesnap/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/tungs%2Ftimesnap/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/tungs%2Ftimesnap/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/tungs","download_url":"https://codeload.github.com/tungs/timesnap/tar.gz/refs/heads/main","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":247217183,"owners_count":20903009,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["nodejs","puppeteer"],"created_at":"2024-08-01T22:01:41.130Z","updated_at":"2025-10-24T08:12:47.265Z","avatar_url":"https://github.com/tungs.png","language":"JavaScript","funding_links":[],"categories":["JavaScript","Packages"],"sub_categories":[],"readme":"# timesnap\n\n**timesnap** is a Node.js program that records screenshots of web pages that use JavaScript animations. It uses **[timeweb](https://github.com/tungs/timeweb)** and [puppeteer](https://github.com/GoogleChrome/puppeteer) to open a web page, overwrite its time-handling functions, and record snapshots at virtual times. For some web pages, this allows frames to be recorded slower than real time, while appearing smooth and consistent when recreated into a video.\n\nYou can use **timesnap** from the command line or as a Node.js library. It requires Node v8.9.0 or higher and npm.\n\nTo record screenshots and compile them into a video using only one command, see **[timecut](https://github.com/tungs/timecut)**. For using virtual time in browser, see **[timeweb](https://github.com/tungs/timeweb)**.\n\n## \u003ca name=\"limitations\" href=\"#limitations\"\u003e#\u003c/a\u003e **timeweb** and **timesnap** Limitations\n**timeweb** (and **timesnap** by extension) only overwrites JavaScript functions and video playback, so pages where changes occur via other means (e.g. through transitions/animations from CSS rules) will likely not render as intended.\n\n## Read Me Contents\n\n* [From the Command Line](#from-cli)\n  * [Global Install and Use](#cli-global-install)\n  * [Local Install and Use](#cli-local-install)\n  * [Command Line *url*](#cli-url-use)\n  * [Command Line Examples](#cli-examples)\n  * [Command Line *options*](#cli-options)\n* [From Node.js](#from-node)\n  * [Node Install](#node-install)\n  * [Node Examples](#node-examples)\n  * [Node API](#node-api)\n* [timesnap Modes](#modes)\n* [How it works](#how-it-works)\n\n## \u003ca name=\"from-cli\" href=\"#from-cli\"\u003e#\u003c/a\u003e From the Command Line\n\n### \u003ca name=\"cli-global-install\" href=\"#cli-global-install\"\u003e#\u003c/a\u003e Global Install and Use\nTo install:\n\nDue to [an issue in puppeteer](https://github.com/GoogleChrome/puppeteer/issues/375) with permissions, timesnap is not supported for global installation for root. You can configure `npm` to install global packages for a specific user by following this guide: https://docs.npmjs.com/getting-started/fixing-npm-permissions#option-two-change-npms-default-directory\n\nAfter configuring, run:\n```\nnpm install -g timesnap\n```\n\nTo use:\n```\ntimesnap \"url\" [options]\n```\n\n### \u003ca name=\"cli-local-install\" href=\"#cli-local-install\"\u003e#\u003c/a\u003e Local Install and Use\nTo install:\n```\ncd /path/to/installation/directory\nnpm install timesnap\n```\n\nTo use:\n```\nnode /path/to/installation/directory/node_modules/timesnap/cli.js \"url\" [options]\n```\n\n*Alternatively*:\n\nTo install:\n```\ncd /path/to/installation/directory\ngit clone https://github.com/tungs/timesnap.git\ncd timesnap\nnpm install\n```\n\nTo use:\n```\nnode /path/to/installation/directory/timesnap/cli.js \"url\" [options]\n```\n\n### \u003ca name=\"cli-url-use\" href=\"#cli-url-use\"\u003e#\u003c/a\u003e Command Line *url*\nThe url can be a web url (e.g. `https://github.com`) or a file path, with relative paths resolving in the current working directory. If no url is specified, defaults to `index.html`. Remember to enclose urls that contain special characters (like `#` and `\u0026`) with quotes.\n\n### \u003ca name=\"cli-examples\" href=\"#cli-examples\"\u003e#\u003c/a\u003e Command Line Examples\n\n**\u003ca name=\"cli-example-default\" href=\"#cli-example-default\"\u003e#\u003c/a\u003e Default behavior**:\n```\ntimesnap\n```\nOpens `index.html` in the current working directory, sets the viewport to 800x600, captures at 60 frames per second for 5 virtual seconds, and saves the frames to `001.png` to `300.png` in the current working directory. The defaults may change in the future, so for long-term scripting, it's a good idea to explicitly pass these options, like in the following example.\n\n**\u003ca name=\"cli-example-viewport-fps-duration-output\" href=\"#cli-example-viewport-fps-duration-output\"\u003e#\u003c/a\u003e Setting viewport size, frames per second, duration, and output pattern**:\n```\ntimesnap index.html --viewport=\"800,600\" --fps=60 --duration=5 --output-pattern=\"%03d.png\"\n```\nEquivalent to the current default `timesnap` invocation, but with explicit options. Opens `index.html` in the current working directory, sets the viewport to 800x600, captures at 60 frames per second for 5 virtual seconds, and saves the frames to `001.png` to `300.png` in the current working directory.\n\n**\u003ca name=\"cli-example-selector\" href=\"#cli-example-selector\"\u003e#\u003c/a\u003e Using a selector**:\n```\ntimesnap drawing.html -S \"canvas,svg\" --output-pattern=\"frames/%03d.png\"\n```\nOpens `drawing.html` in the current working directory, crops each frame to the bounding box of the first canvas or svg element, and captures frames using default settings (5 seconds @ 60fps), saving to `frames/001.png`... `frames/300.png` in the current working directory, making the directory `frames` if needed.\n\n**\u003ca name=\"cli-example-offsets\" href=\"#cli-example-offsets\"\u003e#\u003c/a\u003e Using offsets**:\n```\ntimesnap \"https://tungs.github.io/amuse/truchet-tiles/#autoplay=true\u0026switchStyle=random\" \\\n  -S \"#container\" \\\n  --left=20 --top=40 --right=6 --bottom=30 \\\n  --duration=20 --output-directory=frames\n```\nOpens https://tungs.github.io/amuse/truchet-tiles/#autoplay=true\u0026switchStyle=random (note the quotes in the url are necessary because of the `#` and `\u0026`). Crops each frame to the `#container` element, with an additional crop of 20px, 40px, 6px, and 30px for the left, top, right, and bottom, respectively. Captures frames for 20 virtual seconds at 60fps to `frames/0001.png`... `frames/1200.png` in the current working directory, making the directory `frames` if needed.\n\n**\u003ca name=\"cli-example-piping\" href=\"#cli-example-piping\"\u003e#\u003c/a\u003e Piping**:\n```\ntimesnap https://breathejs.org/examples/Drawing-US-Counties.html \\\n  -V \"1920,1080\" -S \"#draw-canvas\" --fps=60 --duration=10 \\\n  --round-to-even-width --round-to-even-height \\\n  --output-stdout | ffmpeg -framerate 60 -i pipe:0 -y -pix_fmt yuv420p video.mp4\n```\nOpens https://breathejs.org/examples/Drawing-US-Counties.html, sets the viewport size to 1920x1080, crops each frame to the bounding box of `#draw-canvas`, records at 60 frames per second for ten virtual seconds, and pipes the output to `ffmpeg`, which reads in the data from stdin, encodes the frames using pixel format `yuv420p`, and saves the result as `video.mp4` in the current working directory. It does not save individual frames to disk. It uses the `--round-to-even-width` and `--round-to-even-height` options to ensure the dimensions of the frames are even numbers, which ffmpeg requires for certain encodings.\n\n### \u003ca name=\"cli-options\" href=\"#cli-options\"\u003e#\u003c/a\u003e Command Line *options*\n* \u003ca name=\"cli-options-output-directory\" href=\"#cli-options-output-directory\"\u003e#\u003c/a\u003e Output Directory: `-o`, `--output-directory` *directory*\n    * Saves images to a *directory* (default `./`).\n* \u003ca name=\"cli-options-output-pattern\" href=\"#cli-options-output-pattern\"\u003e#\u003c/a\u003e Output Pattern: `-O`, `--output-pattern` *pattern*\n    * Sets each file name according to a printf-style *pattern* (e.g. `image-%03d.png`).\n* \u003ca name=\"cli-options-fps\" href=\"#cli-options-fps\"\u003e#\u003c/a\u003e Frame Rate: `-R`, `--fps` *frame rate*\n    * Frame rate (in frames per virtual second) of capture (default: `60`).\n* \u003ca name=\"cli-options-duration\" href=\"#cli-options-duration\"\u003e#\u003c/a\u003e Duration: `-d`, `--duration` *seconds*\n    * Duration of capture, in *seconds* (default: `5`).\n* \u003ca name=\"cli-options-frames\" href=\"#cli-options-frames\"\u003e#\u003c/a\u003e Frames: `--frames` *count*\n    * Number of frames to capture.\n* \u003ca name=\"cli-options-selector\" href=\"#cli-options-selector\"\u003e#\u003c/a\u003e Selector: `-S`, `--selector` \"*selector*\"\n    * Crops each frame to the bounding box of the first item found by the [CSS *selector*][CSS selector].\n* \u003ca name=\"cli-options-viewport\" href=\"#cli-options-viewport\"\u003e#\u003c/a\u003e Viewport: `-V`, `--viewport` *dimensions,otherOptions*\n    * Viewport dimensions, in pixels, followed by optional keys. For example, `800` (for width), or `\"800,600\"` (for width and height), or `\"800,600,deviceScaleFactor=2\"` for (width, height, and deviceScaleFactor). When running in Windows, quotes may be necessary for parsing commas. For a list of optional keys, see [`config.viewport`](#js-config-viewport).\n* \u003ca name=\"cli-options-canvas-capture-mode\" href=\"#cli-options-canvas-capture-mode\"\u003e#\u003c/a\u003e Canvas Capture Mode: `--canvas-capture-mode` *\\[format\\]*\n    * Experimental. Captures images from canvas data instead of screenshots. See [canvas capture mode](#canvas-capture-mode). Can provide an optional image format (e.g. `png`), otherwise it uses the saved image's extension, or defaults to `png` if the format is not specified or supported. Can prefix the format with `immediate:` (e.g. `immediate:png`) to immediately capture pixel data after rendering, which is sometimes needed for some WebGL renderers. Specify the canvas [using the `--selector` option](#cli-options-selector), otherwise it defaults to the first canvas in the document.\n* \u003ca name=\"cli-options-start\" href=\"#cli-options-start\"\u003e#\u003c/a\u003e Start: `-s`, `--start` *n seconds*\n    * Runs code for n virtual seconds before saving any frames (default: `0`).\n* \u003ca name=\"cli-options-x-offset\" href=\"#cli-options-x-offset\"\u003e#\u003c/a\u003e X Offset: `-x`, `--x-offset` *pixels*\n    * X offset of capture, in pixels (default: `0`).\n* \u003ca name=\"cli-options-y-offset\" href=\"#cli-options-y-offset\"\u003e#\u003c/a\u003e Y Offset: `-y`, `--y-offset` *pixels*\n    * Y offset of capture, in pixels (default: `0`).\n* \u003ca name=\"cli-options-width\" href=\"#cli-options-width\"\u003e#\u003c/a\u003e Width: `-W`, `--width` *pixels*\n    * Width of capture, in pixels.\n* \u003ca name=\"cli-options-height\" href=\"#cli-options-height\"\u003e#\u003c/a\u003e Height: `-H`, `--height` *pixels*\n    * Height of capture, in pixels.\n* \u003ca name=\"cli-options-round-to-even-width\" href=\"#cli-options-round-to-even-width\"\u003e#\u003c/a\u003e Round to Even Width: `--round-to-even-width`\n    * Rounds width up to the nearest even number.\n* \u003ca name=\"cli-options-round-to-even-height\" href=\"#cli-options-round-to-even-height\"\u003e#\u003c/a\u003e Round to Even Height: `--round-to-even-height`\n    * Rounds height up to the nearest even number.\n* \u003ca name=\"cli-options-transparent-background\" href=\"#cli-options-transparent-background\"\u003e#\u003c/a\u003e Transparent Background: `--transparent-background`\n    * Allows background to be transparent if there is no background styling.\n* \u003ca name=\"cli-options-left\" href=\"#cli-options-left\"\u003e#\u003c/a\u003e Left: `-l`, `--left` *pixels*\n    * Left edge of capture, in pixels. Equivalent to `--x-offset`.\n* \u003ca name=\"cli-options-right\" href=\"#cli-options-right\"\u003e#\u003c/a\u003e Right: `-r`, `--right` *pixels*\n    * Right edge of capture, in pixels. Ignored if `width` is specified.\n* \u003ca name=\"cli-options-top\" href=\"#cli-options-top\"\u003e#\u003c/a\u003e Top: `-t`, `--top` *pixels*\n    * Top edge of capture, in pixels. Equivalent to `--y-offset`.\n* \u003ca name=\"cli-options-bottom\" href=\"#cli-options-bottom\"\u003e#\u003c/a\u003e Bottom: `-b`, `--bottom` *pixels*\n    * Bottom edge of capture, in pixels. Ignored if `height` is specified.\n* \u003ca name=\"cli-options-unrandomize\" href=\"#cli-options-unrandomize\"\u003e#\u003c/a\u003e Unrandomize: `-u`, `--unrandomize` *\\[seeds\\]*\n    * Overwrites `Math.random` with a seeded pseudorandom number generator. Can provide optional seeds as up to four comma separated integers (e.g. `--unrandomize 2,3,5,7` or `--unrandomize 42`). If `seeds` is `random-seed` (i.e. `--unrandomize random-seed`), a random seed will be generated, displayed (if not in quiet mode), and used. If `seeds` is not provided, it uses the seeds `10,0,20,0`.\n* \u003ca name=\"cli-options-executable-path\" href=\"#cli-options-executable-path\"\u003e#\u003c/a\u003e Executable Path: `--executable-path` *path*\n    * Uses the Chromium/Chrome instance at *path* for puppeteer.\n* \u003ca name=\"cli-options-remote-url\" href=\"#cli-options-remote-url\"\u003e#\u003c/a\u003e Remote URL: `--remote-url` *path*\n    * URL of remote Chromium/Chrome instance to connect using *puppeteer.connect()*.\n* \u003ca name=\"cli-options-launch-arguments\" href=\"#cli-options-launch-arguments\"\u003e#\u003c/a\u003e Puppeteer Launch Arguments: `-L`, `--launch-arguments` *arguments*\n    * Arguments to pass to Puppeteer/Chromium, enclosed in quotes. Example: `--launch-arguments=\"--single-process\"`. A list of arguments can be found [here](https://peter.sh/experiments/chromium-command-line-switches).\n* \u003ca name=\"cli-options-no-headless\" href=\"#cli-options-no-headless\"\u003e#\u003c/a\u003e No Headless: `--no-headless`\n    * Runs Chromium/Chrome in windowed mode.\n* \u003ca name=\"cli-options-screenshot-type\" href=\"#cli-options-screenshot-type\"\u003e#\u003c/a\u003e Screenshot Type: `--screenshot-type` *type*\n    * Output image format for the screenshots. By default, the file extension is used to infer type, and failing that, `png` is used. `jpeg` is also available.\n* \u003ca name=\"cli-options-screenshot-quality\" href=\"#cli-options-screenshot-quality\"\u003e#\u003c/a\u003e Screenshot Quality: `--screenshot-quality` *number*\n    * Quality level between 0 to 1 for lossy screenshots. Defaults to 0.92 when in [canvas capture mode](#cli-options-canvas-capture-mode) and 0.8 otherwise.\n* \u003ca name=\"cli-options-start-delay\" href=\"#cli-options-start-delay\"\u003e#\u003c/a\u003e Start Delay: `--start-delay` *n seconds*\n    * Waits *n real seconds* after loading the page before starting the virtual timeline.\n* \u003ca name=\"cli-options-quiet\" href=\"#cli-options-quiet\"\u003e#\u003c/a\u003e Quiet: `-q`, `--quiet`\n    * Suppresses console logging.\n* \u003ca name=\"cli-options-output-stdout\" href=\"#cli-options-output-stdout\"\u003e#\u003c/a\u003e Output stdout: `--output-stdout`\n    * Outputs images to stdout. Useful for piping.\n* \u003ca name=\"cli-options-stop-function-name\" href=\"#cli-options-stop-function-name\"\u003e#\u003c/a\u003e Stop Function Name: `--stop-function-name` *function name*\n    * Creates a function with *function name* that the client web page can call to stop capturing. For instance, `--stop-function-name=stopCapture` could be called in the client, via `stopCapture()`.\n* \u003ca name=\"cli-options-version\" href=\"#cli-options-version\"\u003e#\u003c/a\u003e Version: `-v`, `--version`\n    * Displays version information. Immediately exits.\n* \u003ca name=\"cli-options-help\" href=\"#cli-options-help\"\u003e#\u003c/a\u003e Help: `-h`, `--help`\n    * Displays command line options. Immediately exits.\n\n## \u003ca name=\"from-node\" href=\"#from-node\"\u003e#\u003c/a\u003e From Node.js\n**timesnap** can also be included as a library inside Node.js programs.\n\n### \u003ca name=\"node-install\" href=\"#node-install\"\u003e#\u003c/a\u003e Node Install\n```\nnpm install timesnap --save\n```\n\n### \u003ca name=\"node-examples\" href=\"#node-examples\"\u003e#\u003c/a\u003e Node Examples\n\n**\u003ca name=\"node-example-basic\" href=\"#node-example-basic\"\u003e#\u003c/a\u003e Basic Use:**\n```node\nconst timesnap = require('timesnap');\ntimesnap({\n  url: 'https://tungs.github.io/amuse/truchet-tiles/#autoplay=true\u0026switchStyle=random',\n  viewport: {\n    width: 800,               // sets the viewport (window size) to 800x600\n    height: 600\n  },\n  selector: '#container',     // crops each frame to the bounding box of '#container'\n  left: 20, top: 40,          // further crops the left by 20px, and the top by 40px\n  right: 6, bottom: 30,       // and the right by 6px, and the bottom by 30px\n  fps: 30,                    // saves 30 frames for each virtual second\n  duration: 20,               // for 20 virtual seconds\n  outputDirectory: 'frames'   // to frames/001.png... frames/600.png\n                              // of the current working directory\n}).then(function () {\n  console.log('Done!');\n});\n```\n\n**\u003ca name=\"node-example-multiple\" href=\"#node-example-multiple\"\u003e#\u003c/a\u003e Multiple pages:**\n```node\nconst timesnap = require('timesnap');\nvar pages = [\n  {\n    url: 'https://tungs.github.io/amuse/truchet-tiles/#autoplay=true',\n    outputDirectory: 'truchet-tiles'\n  }, {\n    url: 'https://breathejs.org/examples/Drawing-US-Counties.html',\n    outputDirectory: 'counties'\n  }\n];\n(async () =\u003e {\n  for (let page of pages) {\n    await timesnap({\n      url: page.url,\n      outputDirectory: page.outputDirectory,\n      viewport: {\n        width: 800,\n        height: 600\n      },\n      duration: 20\n    });\n  }\n})();\n```\n\n### \u003ca name=\"node-api\" href=\"#node-api\"\u003e#\u003c/a\u003e Node API\n\nThe Node API is structured similarly to the command line options, but there are a few options for the Node API that are not accessible through the command line interface: [`config.logToStdErr`](#js-config-log-to-std-err), [`config.frameProcessor`](#js-config-frame-processor), [`config.navigatePageToURL`](#js-config-navigate-page-to-url), [`config.preparePage`](#js-config-prepare-page), [`config.preparePageForScreenshot`](#js-config-prepare-page-for-screenshot), [`config.logger`](#js-config-logger), and [`config.shouldSkipFrame`](#js-config-should-skip-frame).\n\n**timesnap(config)**\n*  \u003ca name=\"js-api-config\" href=\"#js-api-config\"\u003e#\u003c/a\u003e `config` \u0026lt;[Object][]\u0026gt;\n    * \u003ca name=\"js-config-url\" href=\"#js-config-url\"\u003e#\u003c/a\u003e `url` \u0026lt;[string][]\u0026gt; The url to load. It can be a web url, like `https://github.com` or a file path, with relative paths resolving in the current working directory (default: `index.html`).\n    * \u003ca name=\"js-config-output-directory\" href=\"#js-config-output-directory\"\u003e#\u003c/a\u003e `outputDirectory` \u0026lt;[string][]\u0026gt; Saves images to a directory. Makes one if necessary.\n    * \u003ca name=\"js-config-output-pattern\" href=\"#js-config-output-pattern\"\u003e#\u003c/a\u003e `outputPattern` \u0026lt;[string][]\u0026gt; Sets each file name according to a printf-style pattern (e.g. `image-%03d.png`)\n    * \u003ca name=\"js-config-fps\" href=\"#js-config-fps\"\u003e#\u003c/a\u003e `fps` \u0026lt;[number][]\u0026gt; Frame rate, in frames per virtual second, of capture (default: `60`).\n    * \u003ca name=\"js-config-duration\" href=\"#js-config-duration\"\u003e#\u003c/a\u003e `duration` \u0026lt;[number][]\u0026gt; Duration of capture, in seconds (default: `5`).\n    * \u003ca name=\"js-config-frames\" href=\"#js-config-frames\"\u003e#\u003c/a\u003e `frames` \u0026lt;[number][]\u0026gt; Number of frames to capture. Overrides default fps or default duration.\n    * \u003ca name=\"js-config-selector\" href=\"#js-config-selector\"\u003e#\u003c/a\u003e `selector` \u0026lt;[string][]\u0026gt; Crops each frame to the bounding box of the first item found by the specified [CSS selector][].\n    * \u003ca name=\"js-config-viewport\" href=\"#js-config-viewport\"\u003e#\u003c/a\u003e `viewport` \u0026lt;[Object][]\u0026gt;\n        * \u003ca name=\"js-config-viewport-width\" href=\"#js-config-viewport-width\"\u003e#\u003c/a\u003e `width` \u0026lt;[number][]\u0026gt; Width of viewport, in pixels (default: `800`).\n        * \u003ca name=\"js-config-viewport-height\" href=\"#js-config-viewport-height\"\u003e#\u003c/a\u003e `height` \u0026lt;[number][]\u0026gt; Height of viewport, in pixels (default: `600`).\n        * \u003ca name=\"js-config-viewport-scale-factor\" href=\"#js-config-viewport-scale-factor\"\u003e#\u003c/a\u003e `deviceScaleFactor` \u0026lt;[number][]\u0026gt; Device scale factor (default: `1`). Note that the captured image resolution is multiplied by the device scale factor.\n        * \u003ca name=\"js-config-viewport-mobile\" href=\"#js-config-viewport-mobile\"\u003e#\u003c/a\u003e `isMobile` \u0026lt;[boolean][]\u0026gt; Specifies whether the `meta viewport` tag should be used (default: `false`).\n        * \u003ca name=\"js-config-viewport-touch\" href=\"#js-config-viewport-touch\"\u003e#\u003c/a\u003e `hasTouch` \u0026lt;[boolean][]\u0026gt; Specifies whether the viewport supports touch (default: `false`).\n        * \u003ca name=\"js-config-viewport-landscape\" href=\"#js-config-viewport-landscape\"\u003e#\u003c/a\u003e `isLandscape` \u0026lt;[boolean][]\u0026gt; Specifies whether the viewport is in landscape mode (default: `false`).\n    * \u003ca name=\"js-config-canvas-capture-mode\" href=\"#js-config-canvas-capture-mode\"\u003e#\u003c/a\u003e `canvasCaptureMode` \u0026lt;[boolean][] | [string][]\u0026gt;\n        * Experimental. Captures images from canvas data instead of screenshots. See [canvas capture mode](#canvas-capture-mode). Can provide an optional image format (e.g. `png`), otherwise it uses the saved image's extension, or defaults to `png` if the format is not specified or supported. Can prefix the format with `immediate:` (e.g. `immediate:png`) to immediately capture pixel data after rendering, which is sometimes needed for some WebGL renderers. Specify the canvas by [setting `config.selector`](#js-config-selector), otherwise it defaults to the first canvas in the document.\n    * \u003ca name=\"js-config-start\" href=\"#js-config-start\"\u003e#\u003c/a\u003e `start` \u0026lt;[number][]\u0026gt; Runs code for `config.start` virtual seconds before saving any frames (default: `0`).\n    * \u003ca name=\"js-config-x-offset\" href=\"#js-config-x-offset\"\u003e#\u003c/a\u003e `xOffset` \u0026lt;[number][]\u0026gt; X offset of capture, in pixels (default: `0`).\n    * \u003ca name=\"js-config-y-offset\" href=\"#js-config-y-offset\"\u003e#\u003c/a\u003e `yOffset` \u0026lt;[number][]\u0026gt; Y offset of capture, in pixels (default: `0`).\n    * \u003ca name=\"js-config-width\" href=\"#js-config-width\"\u003e#\u003c/a\u003e `width` \u0026lt;[number][]\u0026gt; Width of capture, in pixels.\n    * \u003ca name=\"js-config-height\" href=\"#js-config-height\"\u003e#\u003c/a\u003e `height` \u0026lt;[number][]\u0026gt; Height of capture, in pixels.\n    * \u003ca name=\"js-config-transparent-background\" href=\"#js-config-transparent-background\"\u003e#\u003c/a\u003e `transparentBackground` \u0026lt;[boolean][]\u0026gt; Allows background to be transparent if there is no background styling.\n    * \u003ca name=\"js-config-round-to-even-width\" href=\"#js-config-round-to-even-width\"\u003e#\u003c/a\u003e `roundToEvenWidth` \u0026lt;[boolean][]\u0026gt; Rounds capture width up to the nearest even number.\n    * \u003ca name=\"js-config-round-to-even-height\" href=\"#js-config-round-to-even-height\"\u003e#\u003c/a\u003e `roundToEvenHeight` \u0026lt;[boolean][]\u0026gt; Rounds capture height up to the nearest even number.\n    * \u003ca name=\"js-config-left\" href=\"#js-config-left\"\u003e#\u003c/a\u003e `left` \u0026lt;[number][]\u0026gt; Left edge of capture, in pixels. Equivalent to `config.xOffset`.\n    * \u003ca name=\"js-config-right\" href=\"#js-config-right\"\u003e#\u003c/a\u003e `right` \u0026lt;[number][]\u0026gt; Right edge of capture, in pixels. Ignored if `config.width` is specified.\n    * \u003ca name=\"js-config-top\" href=\"#js-config-top\"\u003e#\u003c/a\u003e `top` \u0026lt;[number][]\u0026gt; Top edge of capture, in pixels. Equivalent to `config.yOffset`.\n    * \u003ca name=\"js-config-bottom\" href=\"#js-config-bottom\"\u003e#\u003c/a\u003e `bottom` \u0026lt;[number][]\u0026gt; Bottom edge of capture, in pixels. Ignored if `config.height` is specified.\n    * \u003ca name=\"js-config-unrandomize\" href=\"#js-config-unrandomize\"\u003e#\u003c/a\u003e `unrandomize` \u0026lt;[boolean][] | [string][] | [number][] | [Array][]\u0026lt;[number][]\u0026gt;\u0026gt; Overwrites `Math.random` with a seeded pseudorandom number generator. If it is a number, an array of up to four numbers, or a string of up to four comma separated numbers, then those values are used as the initial seeds. If it is true, then the default seed is used. If it is the string 'random-seed', a random seed will be generated, displayed (if quiet mode is not enabled), and used.\n    * \u003ca name=\"js-config-executable-path\" href=\"#js-config-executable-path\"\u003e#\u003c/a\u003e `executablePath` \u0026lt;[string][]\u0026gt; Uses the Chromium/Chrome instance at `config.executablePath` for puppeteer.\n     * \u003ca name=\"js-config-remote-url\" href=\"#js-config-remote-url\"\u003e#\u003c/a\u003e `remoteUrl` \u0026lt;[string][]\u0026gt; URL of remote Chromium/Chrome instance to connect using `puppeteer.connect()`.\n    * \u003ca name=\"js-config-launch-arguments\" href=\"#js-config-launch-arguments\"\u003e#\u003c/a\u003e `launchArguments` \u0026lt;[Array][] \u0026lt;[string][]\u0026gt;\u0026gt; Extra arguments for Puppeteer/Chromium. Example: `['--single-process']`. A list of arguments can be found [here](https://peter.sh/experiments/chromium-command-line-switches).\n    * \u003ca name=\"js-config-headless\" href=\"#js-config-headless\"\u003e#\u003c/a\u003e `headless` \u0026lt;[boolean][]\u0026gt; Runs puppeteer in headless (nonwindowed) mode (default: `true`).\n    * \u003ca name=\"js-config-screenshot-type\" href=\"#js-config-screenshot-type\"\u003e#\u003c/a\u003e `screenshotType` \u0026lt;[string][]\u0026gt; Output image format for the screenshots. By default, the file extension is used to infer type, and failing that, `'png'` is used. `'jpeg'` is also available.\n    * \u003ca name=\"js-config-screenshot-quality\" href=\"#js-config-screenshot-quality\"\u003e#\u003c/a\u003e `screenshotQuality` \u0026lt;[number][]\u0026gt; Quality level between 0 to 1 for lossy screenshots. Defaults to 0.92 when in [canvas capture mode](#js-config-canvas-capture-mode) and 0.8 otherwise.\n    * \u003ca name=\"js-config-start-delay\" href=\"#js-config-start-delay\"\u003e#\u003c/a\u003e `startDelay` \u0026lt;[number][]\u0026gt; Waits `config.startDelay` real seconds after loading before starting (default: `0`).\n    * \u003ca name=\"js-config-quiet\" href=\"#js-config-quiet\"\u003e#\u003c/a\u003e `quiet` \u0026lt;[boolean][]\u0026gt; Suppresses console logging.\n    * \u003ca name=\"js-config-logger\" href=\"#js-config-logger\"\u003e#\u003c/a\u003e `logger` \u0026lt;[function][](...[Object][])\u0026gt; Replaces console logging with a particular function. The passed arguments are the same as those to `console.log` (in this case, usually one string).\n    * \u003ca name=\"js-config-log-to-std-err\" href=\"#js-config-log-to-std-err\"\u003e#\u003c/a\u003e `logToStdErr` \u0026lt;[boolean][]\u0026gt; Logs to stderr instead of stdout. Doesn't do anything if `config.quiet` is set to true.\n    * \u003ca name=\"js-config-should-skip-frame\" href=\"#js-config-should-skip-frame\"\u003e#\u003c/a\u003e `shouldSkipFrame` \u0026lt;[function][]([Object][])\u0026gt; A function that determines whether a current frame should be skipped for capturing. It should return `true` if the current frame should be skipped, `false` if not. It is passed the following object:\n        * \u003ca name=\"js-config-should-skip-frame-frame-count\" href=\"#js-config-should-skip-frame-frame-count\"\u003e#\u003c/a\u003e `frameCount` \u0026lt;[number][]\u0026gt; The current frame count, starting at 1.\n        * \u003ca name=\"js-config-should-skip-frame-frames-to-capture\" href=\"#js-config-should-skip-frame-frames-to-capture\"\u003e#\u003c/a\u003e `framesToCapture` \u0026lt;[number][]\u0026gt; The total number of frames to be captured.\n        * \u003ca name=\"js-config-should-skip-frame-page\" href=\"#js-config-should-skip-frame-page\"\u003e#\u003c/a\u003e `page` \u0026lt;[Page][]\u0026gt; the puppeteer page.\n    * \u003ca name=\"js-config-stop-function-name\" href=\"#js-config-stop-function-name\"\u003e#\u003c/a\u003e `stopFunctionName` \u0026lt;[string][]\u0026gt; *function name* that the client web page can call to stop capturing. For instance, `'stopCapture'` could be called in the client, via `stopCapture()`.\n    * \u003ca name=\"js-config-frame-processor\" href=\"#js-config-frame-processor\"\u003e#\u003c/a\u003e `frameProcessor` \u0026lt;[function][]([Buffer][], [number][], [number][])\u0026gt; A function that will be called after capturing each frame. If `config.outputDirectory` and `config.outputPattern` aren't specified, enabling this suppresses automatic file output. After capturing each frame, `config.frameProcessor` is called with three arguments, and if it returns a promise, capture will be paused until the promise resolves:\n        * `screenshotData` \u0026lt;[Buffer][]\u0026gt; A buffer of the screenshot data.\n        * `frameNumber` \u0026lt;[number][]\u0026gt; The current frame number (1 based).\n        * `totalFrames` \u0026lt;[number][]\u0026gt; The total number of frames.\n    * \u003ca name=\"js-config-navigate-page-to-url\" href=\"#js-config-navigate-page-to-url\"\u003e#\u003c/a\u003e `navigatePageToURL` \u0026lt;[function][]([Object][])\u0026gt; A function that navigates a puppeteer page to a URL, overriding the default navigation to a URL. The function should return a promise that resolves once the page is finished navigating. The function is passed the following object:\n        * \u003ca name=\"js-config-navigate-page-to-url-page\" href=\"#js-config-navigate-page-to-url-page\"\u003e#\u003c/a\u003e `page` \u0026lt;[Page][]\u0026gt; the puppeteer page\n        * \u003ca name=\"js-config-navigate-page-to-url-url\" href=\"#js-config-navigate-page-to-url-url\"\u003e#\u003c/a\u003e `url` \u0026lt;[string][]\u0026gt; the url to navigate to\n    * \u003ca name=\"js-config-prepare-page\" href=\"#js-config-prepare-page\"\u003e#\u003c/a\u003e `preparePage` \u0026lt;[function][]([Page][])\u0026gt; A setup function that will be called one time before taking screenshots. If it returns a promise, capture will be paused until the promise resolves.\n        * `page` \u0026lt;[Page][]\u0026gt; The puppeteer instance of the page being captured.\n    * \u003ca name=\"js-config-prepare-page-for-screenshot\" href=\"#js-config-prepare-page-for-screenshot\"\u003e#\u003c/a\u003e `preparePageForScreenshot` \u0026lt;[function][]([Page][], [number][], [number][])\u0026gt; A setup function that will be called before each screenshot. If it returns a promise, capture will be paused until the promise resolves.\n        * `page` \u0026lt;[Page][]\u0026gt; The puppeteer instance of the page being captured.\n        * `frameNumber` \u0026lt;[number][]\u0026gt; The current frame number (1 based).\n        * `totalFrames` \u0026lt;[number][]\u0026gt; The total number of frames.\n* \u003ca name=\"js-api-return\" href=\"#js-api-return\"\u003e#\u003c/a\u003e returns: \u0026lt;[Promise][]\u0026gt; resolves after all the frames have been captured.\n\n## \u003ca name=\"modes\" href=\"#modes\"\u003e#\u003c/a\u003e **timesnap** Modes\n**timesnap** can capture frames using one of two modes:\n  * \u003ca name=\"screenshot-capture-mode\" href=\"#screenshot-capture-mode\"\u003e#\u003c/a\u003e **Screenshot capture mode** (default) uses puppeteer's built-in API to take screenshots of Chromium/Chrome windows. It can capture most parts of a webpage (e.g. div, svg, canvas) as they are rendered on the webpage. It can crop images, round to even widths/heights, but it usually runs slower than canvas capture mode.\n  * \u003ca name=\"canvas-capture-mode\" href=\"#canvas-capture-mode\"\u003e#\u003c/a\u003e **Canvas capture mode** (experimental) directly copies data from a canvas element and is often faster than using screenshot capture mode. If the background of the canvas is transparent, it may show up as transparent or black depending on the captured image format. Configuration options that adjust the crop and round to an even width/height do not currently have an effect. To use this mode, [use the `--canvas-capture-mode` option from the command line](#cli-options-canvas-capture-mode) or [set `config.canvasCaptureMode` from Node.js](#js-config-canvas-capture-mode). Also specify the canvas using a css selector, [using the `--selector` option from the command line](#cli-options-selector) or [setting `config.selector` from Node.js](#js-config-selector), otherwise it uses the first canvas element.\n\n## \u003ca name=\"how-it-works\" href=\"#how-it-works\"\u003e#\u003c/a\u003e How it works\n**timesnap** uses puppeteer's `page.evaluateOnNewDocument` feature to automatically overwrite a page's native time-handling JavaScript functions and objects (`new Date()`, `Date.now`, `performance.now`, `requestAnimationFrame`, `setTimeout`, `setInterval`, `cancelAnimationFrame`, `cancelTimeout`, and `cancelInterval`) to custom ones that use a virtual timeline, allowing for JavaScript computation to complete before taking a screenshot.\n\nThis work was inspired by [a talk by Noah Veltman](https://github.com/veltman/d3-unconf), who described altering a document's `Date.now` and `performance.now` functions to refer to a virtual time and using `puppeteer` to change that virtual time and take snapshots.\n\n[Object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object\n[Array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array\n[Promise]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise\n[string]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type\n[number]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type\n[boolean]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type\n[function]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions\n[CSS selector]: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors\n[Buffer]: https://nodejs.org/api/buffer.html#buffer_class_buffer\n[Page]: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#class-page\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ftungs%2Ftimesnap","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Ftungs%2Ftimesnap","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Ftungs%2Ftimesnap/lists"}