Could this be solved in workers?
x) Create canvas, set to desired size
x) Create 2D context
x) Create imageData object
x) Create a WebGL framebuffer object
x) Attach texture as color target to framebuffer
x) read back pixels into canvas2d's imageData.data member
x) ctx.putImageData into the canvas
1) Set CanvasProxy (or whatever it's called) to the size you want
2) Draw Texture
3) call CanvasProxy's toDataURL('image/png')
4) Set the CanvasProxy back to the original size
5) snip off the mime/encoding header
6) implement base64 decode in JS and decode to Uint8Array
Less steps and it's now async as well.
On Wed, Jan 16, 2013 at 8:02 AM, Florian Bösch pya...@gmail.com wrote:
Whatever the eventual solution to this problem, it should be the user of
the API driving the decision how to get the data.
On Wed, Jan 16, 2013 at 4:56 PM, Kyle Huey m...@kylehuey.com wrote:
On Wed, Jan 16, 2013 at 7:50 AM, Glenn Maynard gl...@zewt.org wrote:
On Wed, Jan 16, 2013 at 9:40 AM, Florian Bösch pya...@gmail.com wrote:
Perhaps we should think of a better scheme to export data than toFoo().
Maybe toData('url'), toData('arraybuffer') toData('blob') or perhaps
toData(URL), toData(ArrayBuffer) or toData(Blob). I tend to think that if
you're starting to write toA, toB, toC, toX methods on an object, you've
not thought this really trough what's a parameter, and what's a method.
We should be avoiding the need to return data in a bunch of different
interfaces in the first place. If the data is large, or takes a long or
nondeterministic amount of time to create (eg. something that would be
async in the UI thread), return a Blob; otherwise return an ArrayBuffer.
The user can convert from there as needed.
Well, the problem is that we fundamentally screwed up when we specced
Blob. It has a synchronous size getter which negates many of the
advantages of FileReader extracing data asynchronously. For something like
image encoding (that involves compression), where you have to perform the
operation to know the size, Blob and ArrayBuffer are effectively
interchangeable from the implementation perspective, since both require you
to perform the operation up front.
- Kyle
