Libjpeg has some internal support for downscaling already (2x, 4x). Not sure about
Libpng and other libraries. In general probably it can be implemented by downscaling decoded row of the pixels on the fly using callback API provided. From: tomhud...@google.com [mailto:tomhud...@google.com] On Behalf Of Tom Hudson Sent: 13 August 2012 15:00 To: webkit-dev@lists.webkit.org; Anton Obzhirov Subject: Fwd: [webkit-dev] image downscaling during decoding On Mon, Aug 13, 2012 at 9:39 AM, Anton Obzhirov <a.obzhi...@samsung.com> wrote: We are looking for ways to improve page loading speed and reduce memory usage for WebKit in general and for GTK port of WebKit in particular. One of the ideas is to implement downscaling of the images during decoding for image elements with rectangle less then original image size. At the moment such images are full decoded to a full size buffer and get downscaled during rendering. It can be quite beneficial in term of memory usage and should speed up rendering of the pages like image galleries for example. So what are your thoughts about it? Interesting idea! I know Chrome sees memory pressure from the downsampling two-step on some pages, so I'd think this is could be useful for us, too. Isn't it going to require fairly large and intrusive changes to several different third-party libraries, though? Also, different ports use different image downscaling algorithms; I can think of ways to try to enable incremental downscaling callbacks so you don't have to implement N downscales in each of M decoders, but none that are both general and performant. I'd love to see a proposal on this. Tom (from the right account this time)
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