Adds support for screenshots

.gitignore

@@ -2,3 +2,4 @@ node_modules
 examples
 run.sh
 screenshot*
+output

README.md

@@ -287,3 +287,8 @@ Ouput:
 ]
 ```
 
+It is also possible to make screenshots of each slide but removing the considered element.
+
+```sh
+locator --output output-directory example.html
+```

index.js

@@ -4,6 +4,7 @@ const fs = require('fs').promises;
 const process = require('process');
 const puppeteer = require('puppeteer');
 const quality = require('./quality.js');
+const uuid = require('uuid').v4;
 
 // Size of the rendering of the web page
 const size = { width: 1280, height: 720 };
@@ -42,21 +43,36 @@ async function eprintln(data) {
 
 async function main() {
 
-    if (process.argv[2] === undefined) {
-        console.error('This program expects an argument.');
-        console.error('USAGE: locator <path-to-HTML-file>');
+    let outputDir = null;
+    let filename = process.argv[2];
+
+    if (process.argv[2] === "-o" || process.argv[2] === "--output") {
+        outputDir = process.argv[3];
+        filename = process.argv[4];
+    }
+
+    try {
+        await fs.mkdir(outputDir);
+    } catch (e) {
+        eprintln("Couldn't create directory " + outputDir + ": " + e);
+        process.exit(1);
+    }
+
+    if (filename === undefined) {
+        eprintln('This program expects an argument.');
+        eprintln('USAGE: locator <path-to-HTML-file>');
         process.exit(1);
     }
 
     // Path to the HTML file to analyse (given as relative path from current directory)
     // We need the full path so that puppeteer is able to access it
-    const path = process.argv[2].startsWith('/') ? process.argv[2] : process.cwd() + '/' + process.argv[2];
+    const path = filename.startsWith('/') ? filename : process.cwd() + '/' + filename;
 
     // Check that the file exists
     try {
         await fs.access(path, fs.constants.F_OK);
     } catch (e) {
-        console.error('No such file: ' + path);
+        eprintln('No such file: ' + path);
         process.exit(1);
     }
 
@@ -72,18 +88,25 @@ async function main() {
 
     // If there is no slide, try to run on HTML body
     if (root === null) {
-        console.error('Not a marp HTML file.');
+        eprintln('Not a marp HTML file.');
         process.exit(1);
     }
 
+    // Hide slides controls
+    await page.evaluate(() => {
+        for (let elt of document.getElementsByClassName('bespoke-marp-osc')) {
+            elt.style.visibility = "hidden";
+        }
+    });
+
     // Take a first screenshot
-    await page.screenshot({path: __dirname + '/' + 'screenshot1.png'});
+    await page.screenshot({path: (outputDir === null ? __dirname : outputDir) + '/' + 'screenshot1.png'});
 
     // Edit the page to shrink elements in order to get better bounding boxes
     let withSpan = await addSpan(root);
 
     // Take another screenshot and check the modification we made didn't change the layout of the page
-    await page.screenshot({path: __dirname + '/' + 'screenshot2.png'});
+    await page.screenshot({path: (outputDir === null ? __dirname : outputDir) + '/' + 'screenshot2.png'});
 
     // Compare both screenshots
     let file1 = await fs.readFile(__dirname + '/' + 'screenshot1.png');
@@ -96,7 +119,7 @@ async function main() {
 
         // Crash if they're different
         if (psnr > 70) {
-            eprintln("\x1b[33mWarning: " + process.argv[2] + " produced slight diff: psnr = " + psnr + '\x1b[0m');
+            eprintln("\x1b[33mWarning: " + filename + " produced slight diff: psnr = " + psnr + '\x1b[0m');
         } else {
             await eprintln("\x1b[31mError: age edit changed the layout: psnr = " + psnr + '\x1b[0m');
             process.exit(1);
@@ -104,13 +127,18 @@ async function main() {
     }
 
     // Analyse the root and output the result
-    let analyse = await analyseElement(root);
+    let analyse = await analyseElement(root, page, outputDir);
 
     if (process.argv[3] === '--flatten') {
         analyse = flatten(analyse);
     }
 
-    console.log(JSON.stringify(analyse, undefined, 4));
+    let json = JSON.stringify(analyse, undefined, 4);
+    if (outputDir === null) {
+        console.log();
+    } else {
+        await fs.writeFile(outputDir + '/annotations.json', json);
+    }
 
     await browser.close();
 
@@ -143,7 +171,7 @@ async function addSpan(element) {
 
 // Recursive function to analyse an HTML element.
 // The output is written in hierarchy.
-async function analyseElement(element) {
+async function analyseElement(element, page, outputDir = null) {
     // Get some information on the element
     let tagAttr = await element.getProperty('tagName');
     let tagName = await tagAttr.jsonValue();
@@ -159,6 +187,7 @@ async function analyseElement(element) {
     let analyse = {};
     analyse.tag = tagName;
     analyse.class = className;
+    analyse.uuid = uuid();
     analyse.box = box;
     box.x /= size.width;
     box.width /= size.width;
@@ -166,6 +195,21 @@ async function analyseElement(element) {
     box.height /= size.height;
     analyse.children = [];
 
+    if (outputDir !== null) {
+        // Perform a screenshot where the element is hidden
+        let previousVisibility = await element.evaluate(el => {
+            let previousVisibility = el.style.visibility;
+            el.style.visibility = "hidden";
+            return previousVisibility;
+        });
+
+        await page.screenshot({path: outputDir + '/' + analyse.uuid + '.png'});
+
+        await element.evaluate((el, previousVisibility) => {
+            el.style.visibility = previousVisibility;
+        }, [ previousVisibility ]);
+    }
+
     // Extract the text content if it is a span (we made those spans by ourselves in the addSpan function)
     if (tagName === 'SPAN' && textContent !== "") {
         analyse.text = textContent;
@@ -178,7 +222,7 @@ async function analyseElement(element) {
 
     for (let child of children) {
         // Recursively analyse the children
-        analyse.children.push(await analyseElement(child));
+        analyse.children.push(await analyseElement(child, page, outputDir));
     }
 
     return analyse;

package-lock.json

@@ -10,7 +10,8 @@
       "license": "ISC",
       "dependencies": {
         "pngjs": "^7.0.0",
-        "puppeteer": "^19.7.1"
+        "puppeteer": "^19.7.1",
+        "uuid": "^9.0.0"
       },
       "bin": {
         "locator": "index.js"
@@ -742,6 +743,14 @@
       "resolved": "https://registry.npmjs.org/util-deprecate/-/util-deprecate-1.0.2.tgz",
       "integrity": "sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw=="
     },
+    "node_modules/uuid": {
+      "version": "9.0.0",
+      "resolved": "https://registry.npmjs.org/uuid/-/uuid-9.0.0.tgz",
+      "integrity": "sha512-MXcSTerfPa4uqyzStbRoTgt5XIe3x5+42+q1sDuy3R5MDk66URdLMOZe5aPX/SQd+kuYAh0FdP/pO28IkQyTeg==",
+      "bin": {
+        "uuid": "dist/bin/uuid"
+      }
+    },
     "node_modules/webidl-conversions": {
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/webidl-conversions/-/webidl-conversions-3.0.1.tgz",

package.json

@@ -11,6 +11,7 @@
   "license": "ISC",
   "dependencies": {
     "pngjs": "^7.0.0",
-    "puppeteer": "^19.7.1"
+    "puppeteer": "^19.7.1",
+    "uuid": "^9.0.0"
   }
 }