Skip to content

[core]Fix fromPixelAsync. #4757

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Feb 26, 2021
Merged

[core]Fix fromPixelAsync. #4757

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
fa127ab
[core]Fix fromPixelAsync.
lina128 Feb 26, 2021
e69d576
Merge branch 'master' into master
lina128 Feb 26, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
55 changes: 31 additions & 24 deletions tfjs-core/src/ops/browser.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -90,8 +90,7 @@ function fromPixels_(
} else if ((pixels as any).getContext != null) {
isCanvasLike = true;
} else if (
typeof (ImageBitmap) !== 'undefined' &&
pixels instanceof ImageBitmap) {
typeof (ImageBitmap) !== 'undefined' && pixels instanceof ImageBitmap) {
isImageBitmap = true;
} else {
throw new Error(
Expand Down Expand Up @@ -165,26 +164,27 @@ function fromPixels_(
// Helper functions for |fromPixelsAsync| to check whether the input can
// be wrapped into imageBitmap.
function isPixelData(pixels: PixelData|ImageData|HTMLImageElement|
HTMLCanvasElement|HTMLVideoElement|ImageBitmap): pixels is PixelData {
HTMLCanvasElement|HTMLVideoElement|
ImageBitmap): pixels is PixelData {
return (pixels != null) && ((pixels as PixelData).data instanceof Uint8Array);
}

function isImageBitmapFullySupported() {
return typeof window !== 'undefined' &&
typeof (ImageBitmap) !== 'undefined' &&
window.hasOwnProperty('createImageBitmap');
typeof (ImageBitmap) !== 'undefined' &&
window.hasOwnProperty('createImageBitmap');
}

function isNonEmptyPixels(pixels: PixelData|ImageData|HTMLImageElement|
HTMLCanvasElement|HTMLVideoElement|ImageBitmap) {
HTMLCanvasElement|HTMLVideoElement|ImageBitmap) {
return pixels != null && pixels.width !== 0 && pixels.height !== 0;
}

function canWrapPixelsToImageBitmap(pixels: PixelData|ImageData|
HTMLImageElement|HTMLCanvasElement|HTMLVideoElement|ImageBitmap) {
return isImageBitmapFullySupported() &&
!(pixels instanceof ImageBitmap) &&
isNonEmptyPixels(pixels) && !isPixelData(pixels);
HTMLImageElement|HTMLCanvasElement|
HTMLVideoElement|ImageBitmap) {
return isImageBitmapFullySupported() && !(pixels instanceof ImageBitmap) &&
isNonEmptyPixels(pixels) && !isPixelData(pixels);
}

/**
Expand All @@ -202,7 +202,7 @@ function canWrapPixelsToImageBitmap(pixels: PixelData|ImageData|
* This API is the async version of fromPixels. The API will first
* check |WRAP_TO_IMAGEBITMAP| flag, and try to wrap the input to
* imageBitmap if the flag is set to true.
*
*
* @param pixels The input image to construct the tensor from. The
* supported image types are all 4-channel. You can also pass in an image
* object with following attributes:
Expand All @@ -214,41 +214,48 @@ function canWrapPixelsToImageBitmap(pixels: PixelData|ImageData|
* @doc {heading: 'Browser', namespace: 'browser', ignoreCI: true}
*/
export async function fromPixelsAsync(
pixels: PixelData|ImageData|HTMLImageElement|HTMLCanvasElement|
HTMLVideoElement|ImageBitmap,
numChannels = 3) {
pixels: PixelData|ImageData|HTMLImageElement|HTMLCanvasElement|
HTMLVideoElement|ImageBitmap,
numChannels = 3) {
let inputs: PixelData|ImageData|HTMLImageElement|HTMLCanvasElement|
HTMLVideoElement|ImageBitmap = null;
HTMLVideoElement|ImageBitmap = null;

// Check whether the backend needs to wrap |pixels| to imageBitmap and
// whether |pixels| can be wrapped to imageBitmap.
if (env().getBool('WRAP_TO_IMAGEBITMAP') &&
canWrapPixelsToImageBitmap(pixels)) {
// Force the imageBitmap creation to not do any premultiply alpha
// ops.
const imageBitmap =
// tslint:disable-next-line: no-any
await (createImageBitmap as any)(pixels as ImageBitmapSource,
{premultiplyAlpha: 'none'});
let imageBitmap;

try {
// wrap in try-catch block, because createImageBitmap may not work
// properly in some browsers, e.g.
// https://bugzilla.mozilla.org/show_bug.cgi?id=1335594
// tslint:disable-next-line: no-any
imageBitmap = await (createImageBitmap as any)(
pixels as ImageBitmapSource, {premultiplyAlpha: 'none'});
} catch (e) {
imageBitmap = null;
}

// createImageBitmap will clip the source size.
// In some cases, the input will have larger size than its content.
// E.g. new Image(10, 10) but with 1 x 1 content. Using
// createImageBitmap will clip the size from 10 x 10 to 1 x 1, which
// is not correct. We should avoid wrapping such resouce to
// imageBitmap.
if (imageBitmap != null &&
imageBitmap.width === pixels.width &&
if (imageBitmap != null && imageBitmap.width === pixels.width &&
imageBitmap.height === pixels.height) {
inputs = imageBitmap;
} else {
inputs = pixels;
inputs = pixels;
}
} else {
inputs = pixels;
}
}

return fromPixels_(inputs, numChannels);
return fromPixels_(inputs, numChannels);
}

/**
Expand Down