Add Option for Scanning Alt Text (#1169)

* Add Option for Scanning Alt Text

* Don't scan alt text if option disabled

* Add scanAltText to Options Schema

* Add `scanning.scanAltText` Update Function

* Bump Options Test Version

* Remove Param Annotation

4 files changed, 27 insertions, 1 deletions

diff --git a/ext/js/app/frontend.js b/ext/js/app/frontend.js
index 8ac27979..c3022908 100644
--- a/ext/js/app/frontend.js
+++ b/ext/js/app/frontend.js
@@ -513,6 +513,7 @@ export class Frontend {
             matchTypePrefix: scanningOptions.matchTypePrefix,
             preventMiddleMouse,
             sentenceParsingOptions,
+            scanAltText: scanningOptions.scanAltText,
         });
         this._updateTextScannerEnabled();
 
diff --git a/ext/js/data/options-util.js b/ext/js/data/options-util.js
index 8af299d8..850ac81d 100644
--- a/ext/js/data/options-util.js
+++ b/ext/js/data/options-util.js
@@ -349,6 +349,7 @@ export class OptionsUtil {
                 enableOnSearchPage: true,
                 enableSearchTags: false,
                 layoutAwareScan: false,
+                scanAltText: true,
             },
 
             translation: {
@@ -549,6 +550,7 @@ export class OptionsUtil {
             this._updateVersion39,
             this._updateVersion40,
             this._updateVersion41,
+            this._updateVersion42,
         ];
         /* eslint-enable @typescript-eslint/unbound-method */
         if (typeof targetVersion === 'number' && targetVersion < result.length) {
@@ -1349,6 +1351,16 @@ export class OptionsUtil {
     }
 
     /**
+     * - Added scanning.scanAltText
+     * @type {import('options-util').UpdateFunction}
+     */
+    async _updateVersion42(options) {
+        for (const profile of options.profiles) {
+            profile.options.scanning.scanAltText = true;
+        }
+    }
+
+    /**
      * @param {string} url
      * @returns {Promise<chrome.tabs.Tab>}
      */
diff --git a/ext/js/display/display.js b/ext/js/display/display.js
index 3d18e416..01406382 100644
--- a/ext/js/display/display.js
+++ b/ext/js/display/display.js
@@ -461,6 +461,7 @@ export class Display extends EventDispatcher {
                 preventMiddleMouse: scanningOptions.preventMiddleMouse.onSearchQuery,
                 matchTypePrefix: false,
                 sentenceParsingOptions,
+                scanAltText: scanningOptions.scanAltText,
             },
         });
 
@@ -1984,6 +1985,7 @@ export class Display extends EventDispatcher {
             layoutAwareScan: scanningOptions.layoutAwareScan,
             preventMiddleMouse: false,
             sentenceParsingOptions,
+            scanAltText: scanningOptions.scanAltText,
         });
 
         this._contentTextScanner.setEnabled(true);
diff --git a/ext/js/language/text-scanner.js b/ext/js/language/text-scanner.js
index 249a2eda..759adf20 100644
--- a/ext/js/language/text-scanner.js
+++ b/ext/js/language/text-scanner.js
@@ -124,6 +124,8 @@ export class TextScanner extends EventDispatcher {
         this._sentenceBackwardQuoteMap = new Map();
         /** @type {import('text-scanner').InputConfig[]} */
         this._inputs = [];
+        /** @type {boolean} */
+        this._scanAltText = true;
 
         /** @type {boolean} */
         this._enabled = false;
@@ -255,6 +257,7 @@ export class TextScanner extends EventDispatcher {
         preventMiddleMouse,
         sentenceParsingOptions,
         matchTypePrefix,
+        scanAltText,
     }) {
         if (Array.isArray(inputs)) {
             this._inputs = inputs.map((input) => this._convertInput(input));
@@ -289,6 +292,9 @@ export class TextScanner extends EventDispatcher {
         if (typeof matchTypePrefix === 'boolean') {
             this._matchTypePrefix = matchTypePrefix;
         }
+        if (typeof scanAltText === 'boolean') {
+            this._scanAltText = scanAltText;
+        }
         if (typeof sentenceParsingOptions === 'object' && sentenceParsingOptions !== null) {
             const {scanExtent, terminationCharacterMode, terminationCharacters} = sentenceParsingOptions;
             if (typeof scanExtent === 'number') {
@@ -443,6 +449,11 @@ export class TextScanner extends EventDispatcher {
      */
     async _search(textSource, searchTerms, searchKanji, inputInfo, showEmpty = false) {
         try {
+            const isAltText = textSource instanceof TextSourceElement;
+            if (isAltText && !this._scanAltText) {
+                return;
+            }
+
             const inputInfoDetail = inputInfo.detail;
             const selectionRestoreInfo = (
                 (typeof inputInfoDetail === 'object' && inputInfoDetail !== null && inputInfoDetail.restoreSelection) ?
@@ -468,7 +479,7 @@ export class TextScanner extends EventDispatcher {
             const result = await this._findDictionaryEntries(textSource, searchTerms, searchKanji, optionsContext);
             if (result !== null) {
                 ({dictionaryEntries, sentence, type} = result);
-            } else if (showEmpty || (textSource !== null && textSource instanceof TextSourceElement && await this._isTextLookupWorthy(textSource.fullContent))) {
+            } else if (showEmpty || (textSource !== null && isAltText && await this._isTextLookupWorthy(textSource.fullContent))) {
                 // Shows a "No results found" message
                 dictionaryEntries = [];
                 sentence = {text: '', offset: 0};