From 6071c4720db307d688edc7c4b84b6bb30fd3b963 Mon Sep 17 00:00:00 2001
From: blankie <blankie@nixnetmail.com>
Date: Tue, 20 Feb 2024 23:05:44 +1100
Subject: [PATCH] Fix finding thumbnail size for /img-master/ images

https://pixwhile.zangetsu.kaizoku.cyou/artworks/115861083
https://pixwhile.zangetsu.kaizoku.cyou/artworks/116018582
https://pixwhile.zangetsu.kaizoku.cyou/artworks/84869687
---
 pixivmodels.cpp | 46 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 11 deletions(-)

diff --git a/pixivmodels.cpp b/pixivmodels.cpp
index c253160..9d45dfe 100644
--- a/pixivmodels.cpp
+++ b/pixivmodels.cpp
@@ -308,21 +308,45 @@ static std::optional<std::pair<uint64_t, uint64_t>> get_thumbnail_size(blankie::
         return std::nullopt;
     }
 
-    std::smatch sm;
-    if (!std::regex_match(thumbnail_url.path, sm, illust_size_regex)) {
-        return std::nullopt;
-    }
+    uint64_t thumbnail_width, thumbnail_height;
 
-    uint64_t thumbnail_width = to_ull(sm.str(1));
-    // uint64_t thumbnail_height = to_ull(sm.str(2));
+    if (thumbnail_url.path.starts_with("/img-master/")) {
+        if (original_size->first <= 1200 && original_size->second <= 1200) {
+            return original_size;
+        }
+
+        // one side is implicitly 1200
+        if (original_size->first >= original_size->second) {
+            // original width >= original height
+
+            thumbnail_width = 1200;
+            // derived from original_size->second / (original_size->first / thumbnail_width)
+            // to make it more accurate without using floats
+            thumbnail_height = original_size->second * thumbnail_width / original_size->first;
+        } else {
+            // original width < original height
+
+            thumbnail_height = 1200;
+            // derived from original_size->first / (original_size->second / thumbnail_height)
+            // to make it more accurate without using floats
+            thumbnail_width = original_size->first * thumbnail_height / original_size->second;
+        }
+    } else {
+        std::smatch sm;
+        if (!std::regex_match(thumbnail_url.path, sm, illust_size_regex)) {
+            return std::nullopt;
+        }
+
+        thumbnail_width = to_ull(sm.str(1));
+        // thumbnail_height = to_ull(sm.str(2));
 
-    std::pair<uint64_t, uint64_t> real_thumbnail_size = {
-        thumbnail_width,
         // derived from original_size->second / (original_size->first / thumbnail_width)
         // to make it more accurate without using floats
-        original_size->second * thumbnail_width / original_size->first
-    };
-    return real_thumbnail_size;
+        thumbnail_height = original_size->second * thumbnail_width / original_size->first;
+    }
+
+    std::pair<uint64_t, uint64_t> thumbnail_size = {thumbnail_width, thumbnail_height};
+    return thumbnail_size;
 }
 
 static Images get_illust_images(const nlohmann::json& image, std::optional<nlohmann::json> image_metadata) {