Chromium Blog: June 2016

Universal rendering with SwiftShader, now open source

Wednesday, June 29, 2016

SwiftShader is a software library for high-performance graphics rendering on the CPU. Google already uses this library in multiple products, including Chrome, Android development tools, and cloud services. Starting today, SwiftShader is fully open source, expanding its pool of potential applications.

Since 2009, Chrome has used SwiftShader to enable 3D rendering on systems that can’t fully support hardware-accelerated rendering. While 3D content like WebGL is written for a GPU, some users’ devices don’t have graphics hardware capable of executing this content. Others may have drivers with serious bugs which can make 3D rendering unreliable, or even impossible. Chrome uses SwiftShader on these systems in order to ensure 3D web content is available to all users.

Chrome running without SwiftShader on a machine with an inadequate GPU (left) cannot run the WebGL Globe experiment. The same machine with SwiftShader enabled (right) is able to fully render the content.

SwiftShader implements the same OpenGL ES graphics more. SwiftShader also has applications in the cloud, enabling rendering on GPU-less systems.

To provide users with the best performance, SwiftShader uses several techniques to efficiently perform graphics calculations on the CPU. Dynamic code generation enables app streaming roid.

Developers can access the SwiftShader source code from its mailing list to stay up to date on the latest developments and collaborate with other SwiftShader developers from the open-source community.
Posted by Nicolas Capens, Software Engineer and Pixel Pirate

Chrome 52 Beta: CSS containment, simpler performance measurement, streamable responses from service workers, and more options for web push

Friday, June 10, 2016

Unless otherwise noted, changes described below apply to the newest Chrome Beta channel release for Android, Chrome OS, Linux, Mac, and Windows. CSS Containment Rich, interactive experiences are a cornerstone of the web, but can sometimes take a long time to render due to their complexity. Currently, Chrome improves rendering performance by using heuristics to determine which parts of a page have changed. Only sections that have changed are updated instead of rendering the entire page 60 times per second. However, because elements can display outside the bounds of their parents, it is possible that changes to one element could affect elements anywhere else in the document. This dramatically increases the number of elements that Chrome must consider while rendering.
New in this release, the CSS prevent an element’s children from displaying outside of its bounds. When an element updates, this guarantee allows Chrome to ignore any element outside the parent node during rendering, leading to faster rendering times. Performance Observer Collecting accurate real-user measurement (RUM) data is critical to detecting performance problems and regressions that may hurt the user experience of a site. Chrome's DevTools allow local site testing, but measuring how a site performs for real users with varied devices can be challenging. The latest version of Chrome supports the sites can declare which metrics they’re interested in. The browser notifies the site when new data points for those metrics become available. Service Worker Responses Powered by ReadableStreams Streaming HTTP responses allow browsers to progressively render earlier portions of a large HTML document before the entire response is available. The latest version of Chrome ReadableStream to the Response constructor. Offline Wikipedia client demonstrates the speed benefits of readable streams. Web Push Protocol and VAPID Support web push protocol. Other features in this release

Chrome now pauses animations while showing modal dialog boxes.

HTTP alternative services allow sites to specify additional origins that can be used to reach a certain resource, enabling easier protocol upgrades and load balancing.

ImageBitmapOptions to specify configurations on construction.

Sites can now free the memory consumed by an ImageBitmap using ImageBitmap.close().

Chrome now supports font-variant-numeric properties.

Touch gestures inside a cross-origin iframe can no longer trigger popups unless they correspond to a tap gesture, preventing accidental pop-ups during scrolling.

Now only secure origins can create or delete secure cookies on Chrome for Android.

The latest version of Chrome supports meter elements and allows easier custom CSS styling.

The protect against cross-origin scripting attacks.

Sites can request.

filter attribute, allowing sites to apply effects to primitives drawn to the canvas.

Sites can now test whether or not a key exists within the bounds of an IDBKeyRange.includes().

The MediaStream with a media element.

min and max attributes to simplify introspection.

RTCCertificates can now be stored in IndexedDB.

AudioListener now support automation methods, allowing smooth audio transitions.

Stylesheets can now specify alpha values for colors using eight- and four-bit hexadecimal values instead of the longer rgba() syntax.

Sites origin trial, allowing a site to disable automatic storage clearing when bookmarked.

Multiple WebVTT tracks will now be presented as user options in the default media controls, enabling language selection for captions and subtitles.

postMessage overrides of the form postMessage(message,transferables,targetOrigin) have been deprecated.
The MediaStream ended event and the corresponding onended attribute have been deprecated.
The icons entry no longer supports the density property.
The DynamicsCompressorNode.reduction attribute is now a readonly float instead of an AudioParam.
positioned using justify and align if the element does not have a left:, right:, top:, or bottom: position specified.
deprecated and removed due to low usage numbers.
X-Frame-Option will no longer be supported in the meta tag to support a more secure implementation.
Invalid values for track-kind are now treated as metadata instead of subtitles to improve media behavior in older user agents.

Posted by Shubhie Panicker, Performance Powerhouse

Chromium Blog

Universal rendering with SwiftShader, now open source

Chrome 52 Beta: CSS containment, simpler performance measurement, streamable responses from service workers, and more options for web push

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