- From: Justin Novosad <junov@google.com>
- Date: Thu, 18 Jul 2013 13:22:10 -0400
- To: Mark Callow <callow.mark@artspark.co.jp>
- Cc: WHAT Working Group <whatwg@whatwg.org>, "K. Gadd" <kg@luminance.org>
On Thu, Jul 18, 2013 at 5:45 AM, Mark Callow <callow.mark@artspark.co.jp>wrote: > On 2013/07/18 16:34, K. Gadd wrote: > > > > I understand the rationale behind gregg's suggestion for flipY, but > > ultimately don't know if that one makes any sense in a HTML5 context. It > > basically only exists because of the annoying disagreement between APIs > > like OpenGL and other APIs like HTML5 Canvas or Direct3D, specifically > > about which direction the Y axis goes. > It exists because of the annoying disagreement between the orientation > of the data in most image file formats and the default orientation for > textures images in OpenGL. There are a some image file formats that have > a bottom left orientation and there is one, extremely common, format, > EXIF, that includes metadata giving the visual orientation of the image. > The flipY item in the proposed dictionary could be handily extended to > an enum. E.g., > > * "none" - leave orientation alone > * "flipY" - ignore the EXIF orientation, just flip in Y > * "topLeftEXIF" - identify visual orientation from EXIF data and > re-order data so top-down, left-to-right processing for display > results in correct visual orientation > * "bottomRightEXIF" - as above but ordered for bottom-up, > left-to-right processing > > Regards > > -Mark > EXIF, may be a defacto standard in some image formats we use today, but I think we should probably be more general and just refer to this as image media meta-data. What should the default be? I hesitate between 'topLeft' and 'none'.
Received on Thursday, 18 July 2013 17:22:37 UTC