Windows sometimes provides upside down thumbnail

[sebastsg]

windows_platform.cpp:

• surface load_file_thumbnail(std::filesystem::path path, int scale)
• surface bitmap_as_surface(HBITMAP bitmap_handle)

The documentation states that the bitmap height or stride is negative when flipped, but they are always positive. I see no way to detect whether or not a bitmap from IShellItemImageFactory starts from the top or bottom.

This seems to happen mostly (or always?) when a thumbnail is not already in the cache. When the thumbnail is requested again after being cached, it is oriented correctly.