Make tf.browser.fromPixels / toPixels and route tf.fromPixels / tf.toPixels to it.

[nsthorat]

We will delete tf.fromPixels in the 1.0 branch.

Fixes tensorflow/tfjs#669

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This change is 

[pyu10055]

Thanks, A high level question, what is the mechanism for a different env (node, wechat) to provide its own custom op (i.e. wechat.fromPixels) op and be able to attach to the tf namespace.

Reviewed 7 of 7 files at r1.
Reviewable status: 0 of 1 approvals obtained (waiting on @nsthorat)

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src/ops/browser.ts, line 26 at r1 (raw file):

 *
 * ```js
 * const image = new ImageData(1, 1);

ImageData(2,2) ?

[nsthorat]

wechat will have it's own package entirely so can provide a separate API (outside browser.fromPixels)

node will have decodeJpeg (not use fromPixels)

Reviewable status: 0 of 1 approvals obtained (waiting on @pyu10055)

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src/ops/browser.ts, line 26 at r1 (raw file):

Previously, pyu10055 (Ping Yu) wrote…

ImageData(2,2) ?

This is a 1x1 image (single value, 4 values of rgba)

[pyu10055]

My question since the PR to create a browser namespace for set of ops, what is way to adding other platform specific ops. Should we allow registering custom ops in engine so the ops can get to routed to the custom backend who implements them?

Reviewable status: 0 of 1 approvals obtained (waiting on @pyu10055)

[pyu10055]

Reviewable status: 0 of 1 approvals obtained

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src/ops/browser.ts, line 26 at r1 (raw file):

Previously, nsthorat (Nikhil Thorat) wrote…

This is a 1x1 image (single value, 4 values of rgba)

ah, right.

[nsthorat]

For now we're not going to tackle platform registration since wechat can have its own library (it will add quite a bit of complexity). We can talk about that offline, but this PR should be unrelated.

Reviewable status: 0 of 1 approvals obtained

[dsmilkov]

Reviewed 2 of 7 files at r1, 2 of 3 files at r2.
Reviewable status: 0 of 1 approvals obtained (waiting on @dsmilkov and @nsthorat)

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src/ops/browser.ts, line 41 at r2 (raw file):

 * 3 (ignores alpha channel of input image).
 */
/** @doc {heading: 'Tensors', subheading: 'Creation', namespace: 'browser'} */

let's have this under the section 'Browser'.

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src/ops/browser.ts, line 42 at r2 (raw file):

 */
/** @doc {heading: 'Tensors', subheading: 'Creation', namespace: 'browser'} */
function fromPixels_(

move toPixels also to browser

[nsthorat]

Reviewable status: 0 of 1 approvals obtained

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src/ops/browser.ts, line 42 at r2 (raw file):

Previously, dsmilkov (Daniel Smilkov) wrote…

move toPixels also to browser

Done.

[dsmilkov]

Reviewed 1 of 3 files at r2, 3 of 3 files at r3.
Reviewable status: complete! 1 of 1 approvals obtained