[whatwg] Adding features needed for WebGL to ImageBitmap

Mark Callow callow.mark at artspark.co.jp
Thu Jul 18 02:45:49 PDT 2013

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



が有ります。正式なメール受信者では無い場合はメール複製、 再配信または情
たら削除を行い配信者にご連絡をお願いいたし ます.

NOTE: This electronic mail message may contain confidential and
privileged information from HI Corporation. If you are not the intended
recipient, any disclosure, photocopying, distribution or use of the
contents of the received information is prohibited. If you have received
this e-mail in error, please notify the sender immediately and
permanently delete this message and all related copies.

More information about the whatwg mailing list