Add alt text to images

Sources/Generator/Generators/HTMLElementsGenerator.swift

@@ -39,17 +39,17 @@ struct HTMLElementsGenerator {
         "\(text)<span class=\"icon-next\"></span>"
     }
 
-    func image(file: String, width: Int, height: Int) -> String {
+    func image(file: String, width: Int, height: Int, altText: String) -> String {
         """
         <span class="image">
-            <img src="\(file)" loading="lazy" width="\(width)" height="\(height)"/>
+            <img src="\(file)" loading="lazy" width="\(width)" height="\(height)" alt="\(altText)"/>
         </span>
         """
     }
 
-    func svgImage(file: String, part: SVGSelection, width: Int, height: Int) -> String {
+    func svgImage(file: String, part: SVGSelection, width: Int, height: Int, altText: String) -> String {
         let path = "\(file)#svgView(viewBox(\(part.x),\(part.y),\(part.width),\(part.height))"
-        return image(file: path, width: width, height: height)
+        return image(file: path, width: width, height: height, altText: altText)
     }
 
     func downloadButtons(_ buttons: [(file: String, text: String, downloadName: String?)]) -> String {

Sources/Generator/Generators/OverviewSectionGenerator.swift

@@ -56,6 +56,7 @@ struct OverviewSectionGenerator {
         let metadata = item.localized(for: language)
         var content = [SlideshowImageTemplate.Key : String]()
         content[.number] = "\(number + 1)"
+        content[.altText] = metadata.linkPreviewDescription
 
         if item.state.hasThumbnailLink {
             let fullPageUrl = item.fullPageUrl(for: language)

Sources/Generator/Generators/PageContentGenerator.swift

@@ -107,7 +107,7 @@ struct PageContentGenerator {
         case "svg":
             return handleSvg(page: page, file: file, area: alt)
         case "gif":
-            return handleGif(page: page, file: file)
+            return handleGif(page: page, file: file, altText: alt ?? "gif image")
         default:
             return handleFile(page: page, file: file, fileExtension: fileExtension)
         }
@@ -144,14 +144,18 @@ struct PageContentGenerator {
             destination: imagePath,
             requiredBy: page.path)
 
+        let altText = left.nonEmpty ?? rightTitle ?? "image"
+
+        var content = [PageImageTemplateKey : String]()
+        content[.altText] = altText
+        content[.image] = file.dropAfterLast(".")
+        content[.imageExtension] = file.lastComponentAfter(".")
+        content[.width] = "\(Int(size.width))"
+        content[.height] = "\(Int(size.height))"
+        content[.leftText] = left
+        content[.rightText] = rightTitle ?? ""
+
         guard createFullScreenVersion else {
-            let content: [PageImageTemplate.Key : String] = [
-                .image: file.dropAfterLast("."),
-                .imageExtension: file.lastComponentAfter("."),
-                .width: "\(Int(size.width))",
-                .height: "\(Int(size.height))",
-                .leftText: left,
-                .rightText: rightTitle ?? ""]
             return factory.image.generate(content)
         }
 
@@ -161,14 +165,7 @@ struct PageContentGenerator {
             requiredBy: page.path)
 
         largeImageCount += 1
-        let content: [EnlargeableImageTemplate.Key : String] = [
+        content[.number] = "\(largeImageCount)"
-            .image: file.dropAfterLast("."),
-            .imageExtension: file.lastComponentAfter("."),
-            .width: "\(Int(size.width))",
-            .height: "\(Int(size.height))",
-            .leftText: left,
-            .rightText: rightTitle ?? "",
-            .number: "\(largeImageCount)"]
         return factory.largeImage.generate(content)
     }
 
@@ -193,7 +190,7 @@ struct PageContentGenerator {
         return factory.video.generate(sources: sources, options: options)
     }
 
-    private func handleGif(page: Element, file: String) -> String {
+    private func handleGif(page: Element, file: String, altText: String) -> String {
         let imagePath = page.pathRelativeToRootForContainedInputFile(file)
         results.require(file: imagePath, source: page.path)
 
@@ -202,7 +199,7 @@ struct PageContentGenerator {
         }
         let width = Int(size.width)
         let height = Int(size.height)
-        return factory.html.image(file: file, width: width, height: height)
+        return factory.html.image(file: file, width: width, height: height, altText: altText)
     }
 
     private func handleSvg(page: Element, file: String, area: String?) -> String {
@@ -210,25 +207,36 @@ struct PageContentGenerator {
         results.require(file: imagePath, source: page.path)
 
         guard let size = results.getImageSize(atPath: imagePath, source: page.path) else {
-            return ""
+            return "" // Missing image warning already produced
         }
         let width = Int(size.width)
         let height = Int(size.height)
 
+        var altText = "image " + file.lastComponentAfter("/")
         guard let area = area else {
-            return factory.html.image(file: file, width: width, height: height)
+            return factory.html.image(file: file, width: width, height: height, altText: altText)
         }
         let parts = area.components(separatedBy: ",").map { $0.trimmed }
-        guard parts.count == 4,
+        switch parts.count {
-              let x = Int(parts[0]),
+        case 1:
+            return factory.html.image(file: file, width: width, height: height, altText: parts[0])
+        case 4:
+            break
+        case 5:
+            altText = parts[4]
+        default:
+            results.warning("Invalid area string for svg image", source: page.path)
+            return factory.html.image(file: file, width: width, height: height, altText: altText)
+        }
+        guard let x = Int(parts[0]),
               let y = Int(parts[1]),
               let partWidth = Int(parts[2]),
               let partHeight = Int(parts[3]) else {
             results.warning("Invalid area string for svg image", source: page.path)
-            return factory.html.image(file: file, width: width, height: height)
+            return factory.html.image(file: file, width: width, height: height, altText: altText)
         }
         let part = SVGSelection(x, y, partWidth, partHeight)
-        return factory.html.svgImage(file: file, part: part, width: width, height: height)
+        return factory.html.svgImage(file: file, part: part, width: width, height: height, altText: altText)
     }
 
     private func handleFile(page: Element, file: String, fileExtension: String) -> String {
@@ -301,6 +309,7 @@ struct PageContentGenerator {
         var content = [PageLinkTemplate.Key: String]()
         
         content[.title] = linkedPage.title(for: language)
+        content[.altText] = ""
 
         let fullThumbnailPath = linkedPage.thumbnailFilePath(for: language).destination
         // Note: Here we assume that the thumbnail was already used elsewhere, so already generated

Sources/Generator/Generators/ThumbnailListGenerator.swift

@@ -30,6 +30,7 @@ struct ThumbnailListGenerator {
         let (thumbnailSourcePath, thumbnailDestPath) = item.thumbnailFilePath(for: language)
         let thumbnailDestNoExtension = thumbnailDestPath.dropAfterLast(".")
         content[.image] = parent.relativePathToFileWithPath(thumbnailDestNoExtension)
+        content[.altText] = metadata.linkPreviewDescription
 
         if style == .large, let suffix = metadata.thumbnailSuffix {
             content[.title] = factory.html.make(title: metadata.title, suffix: suffix)

Sources/Generator/Templates/Elements/EnlargeableImageTemplate.swift

@@ -1,21 +0,0 @@
-import Foundation
-
-struct EnlargeableImageTemplate: Template {
-
-    enum Key: String, CaseIterable {
-        case image = "IMAGE"
-        case imageExtension = "IMAGE_EXT"
-        case width = "WIDTH"
-        case height = "HEIGHT"
-        case leftText = "LEFT_TEXT"
-        case rightText = "RIGHT_TEXT"
-        case number = "NUMBER"
-    }
-
-    static let templateName = "image-enlargeable.html"
-
-    let raw: String
-
-    let results: GenerationResultsHandler
-
-}

Sources/Generator/Templates/Elements/PageImageTemplate.swift

@@ -1,15 +1,31 @@
 import Foundation
 
+enum PageImageTemplateKey: String, CaseIterable {
+    case altText = "ALT_TEXT"
+    case image = "IMAGE"
+    case imageExtension = "IMAGE_EXT"
+    case width = "WIDTH"
+    case height = "HEIGHT"
+    case leftText = "LEFT_TEXT"
+    case rightText = "RIGHT_TEXT"
+    case number = "NUMBER"
+}
+
+struct EnlargeableImageTemplate: Template {
+
+    typealias Key = PageImageTemplateKey
+
+    static let templateName = "image-enlargeable.html"
+
+    let raw: String
+
+    let results: GenerationResultsHandler
+
+}
+
 struct PageImageTemplate: Template {
 
-    enum Key: String, CaseIterable {
+    typealias Key = PageImageTemplateKey
-        case image = "IMAGE"
-        case imageExtension = "IMAGE_EXT"
-        case width = "WIDTH"
-        case height = "HEIGHT"
-        case leftText = "LEFT_TEXT"
-        case rightText = "RIGHT_TEXT"
-    }
 
     static let templateName = "image.html"
 

Sources/Generator/Templates/Elements/PageLinkTemplate.swift

@@ -3,6 +3,7 @@ import Foundation
 struct PageLinkTemplate: Template {
 
     enum Key: String, CaseIterable {
+        case altText = "ALT_TEXT"
         case url = "URL"
         case image = "IMAGE"
         case title = "TITLE"

Sources/Generator/Templates/Elements/SlideshowImageTemplate.swift

@@ -3,6 +3,7 @@ import Foundation
 struct SlideshowImageTemplate: Template {
 
     enum Key: String, CaseIterable {
+        case altText = "ALT_TEXT"
         case url = "URL"
         case image = "IMAGE"
         case title = "TITLE"

Sources/Generator/Templates/Elements/ThumbnailTemplate.swift

@@ -6,6 +6,7 @@ protocol ThumbnailTemplate {
 }
 
 enum ThumbnailKey: String, CaseIterable {
+    case altText = "ALT_TEXT"
     case url = "URL"
     case image = "IMAGE"
     case title = "TITLE"