squash to previous: relax conditions when <img alt="cover">

koreader · Mar 20, 2024 · a6a71cb · a6a71cb
1 parent c95381c
commit a6a71cb
Showing 1 changed file with 36 additions and 15 deletions.
diff --git a/crengine/src/epubfmt.cpp b/crengine/src/epubfmt.cpp
@@ -352,9 +352,10 @@ bool ExtractCoverFilenameFromCoverPageFragment( LVStreamRef stream, lString32 &
         return false;
     // We expect to find a single image, and no text, to consider the image as a possible cover.
     lString32 img_href;
-    int nb_images_found = 0;
-    bool has_text = 0;
+    bool has_more_images = false;
+    bool has_text = false;
     bool in_body = false;
+    bool img_has_alt_attribute_equal_cover = false;
     ldomNode * coverDocRoot = coverDoc->getRootNode();
     /* For debugging:
     lString32Collection cssFiles;
@@ -380,16 +381,27 @@ bool ExtractCoverFilenameFromCoverPageFragment( LVStreamRef stream, lString32 &
                         }
                     }
                     else if (id == el_img ) { // <img src=''>
-                        img_href = n->getAttributeValue(attr_src);
-                        nb_images_found++;
+                        if ( img_href.empty() ) {
+                            img_href = n->getAttributeValue(attr_src);
+                            lString32 img_alt = n->getAttributeValue(attr_alt);
+                            if ( img_alt == U"cover" ) {
+                                img_has_alt_attribute_equal_cover = true;
+                            }
+                        }
+                        else {
+                            // Too many images for a single cover: give up
+                            has_more_images = true;
+                            break;
+                        }
                     }
                     else if (id == el_image ) { // <svg>...<image href=''>
-                        img_href = n->getAttributeValue(attr_href);
-                        nb_images_found++;
-                    }
-                    if ( nb_images_found > 1 ) {
-                        // Too many images for a single cover: give up
-                        break;
+                        if ( img_href.empty() ) {
+                            img_href = n->getAttributeValue(attr_href);
+                        }
+                        else {
+                            has_more_images = true;
+                            break;
+                        }
                     }
                 }
                 else if ( in_body && n->isText() ) {
@@ -426,11 +438,20 @@ bool ExtractCoverFilenameFromCoverPageFragment( LVStreamRef stream, lString32 &
         }
     }
     delete coverDoc;
-    // printf("EPUB coverpage check: has_text:%d, nb_images:%d, img_href:%d (%s)\n",
-    //               has_text, nb_images_found, !img_href.empty(), LCSTR(img_href));
-    if ( !has_text && nb_images_found == 1 && !img_href.empty() ) {
-        cover_image_href = img_href;
-        return true;
+    // printf("EPUB coverpage check: has_text:%d, has_more_images:%d, has_alt=cover:%d img_href:%d (%s)\n",
+    //               has_text, has_more_images, img_has_alt_attribute_equal_cover, !img_href.empty(), LCSTR(img_href));
+    if ( !img_href.empty() ) {
+        if ( !has_text && !has_more_images ) {
+            // Single image with no text in this fragment: it must be a cover image.
+            cover_image_href = img_href;
+            return true;
+        }
+        if ( img_has_alt_attribute_equal_cover ) {
+            // If we have met an image with alt="cover" before any text or other images,
+            // consider it valid.
+            cover_image_href = img_href;
+            return true;
+        }
     }
     return false;
 }