Welcome!

SOA & WOA Authors: Paul Speciale, Trevor Parsons, Esmeralda Swartz, Pat Romanski, Elizabeth White

Blog Feed Post

Windows 8 Notifications: Image Handling

In the last post, I discussed the structure of a notification template and the mechanics for providing the various bit of information in that template. As you know, many of the notification templates can include one or more images, and that brings up a host of configuration options that I didn’t have a chance to get into last time. This post will fill in the gaps and provide insight into three main topics:

What image sizes and formats do you need to provide?

Where can the images be hosted?

How do you accommodate different device resolutions and themes?

I’ll close with a quick list of not-so-obvious features and behaviors that will hopefully save you some time as you plan out your strategy for supporting images as part of notifications used within your application.

Images Sizes and Format

There are two overarching constraints for images used within notifications:

  1. Images used in notifications must be in one of three formats: .png, .jpg/.jpeg, or .gif, and the format must match the extension.
  2. Images for notifications must be no larger than 200 KB and 1024 x 1024 in dimension.

Beyond that and depending on the device size and characteristics, images within Windows 8 may be scaled to one of four proportions (80%, 100%, 140% and 180%). Since the notification image formats supported are all raster formats (versus vector-based) you cannot rely on the scaling to result in clear, crisp imagery, so it’s recommended that you provide artwork to accommodate all four scaling factors.

The table below (which is adapted from the App images topic on MSDN) shows most of the sizes [see note] needed for tile and toast notifications as well as the (optional) badge logo for the start screen. Only those images highlighted in red (100% size for logo and small logo) are required and must be supplied in the app manifest (as .jpg/jpeg or .png formats [see note]). Other sizes are optional and if not provided will be generated by scaling the default 100% image.

appxmanifest Image Name
(where used)
80% [see note] 100% 140% 180%
Logo
(default square tile)
120x120 150x150 210x210 270x270
Small logo
(tile under semantic zoom,
tile and toast branding)
[see note]
24x24 30x30 42x42 54x54
Wide logo
(default wide tile)
248x120 310x150 434x210 558x270
Badge Logo [see note]
(Lock screen)
  24x24 33x33 43x43
Tip: Use the Visual Studio 2012 simulator to check out the appearance of your images under various scaling factors (and contrast modes [see note]).

Image Locations

Images used for notifications can be stored in one of three places:

  • within the app package, using the ms-appx:/// prefix to a directory in your deployed application (this is the default).
  • within local storage, using the ms-appdata:///local prefix to a directory within local storage. Note that images in temporary and roaming application data storage cannot be used.
  • on the web, using an http or https URI that serves up image content (this requires that the application declare Internet client capability in its manifest).

Within the template XML you can specify the entire image URI or use paths relative to the baseUri value specified within the template.  The baseUri can be set for either the visual (tile | toast) tag or the binding tag (tile | toast), with the latter overriding the former when provided.

App Package Images

Here, for example, is a code snippet from the App tiles and badges sample showing the use of an image within the local application package:

var tileXml = Windows.UI.Notifications.TileUpdateManager.getTemplateContent(
        Windows.UI.Notifications.TileTemplateType.tileWideImageAndText01);

// get the text attributes for this template and fill them in
var tileTextAttributes = tileXml.getElementsByTagName("text");
tileTextAttributes[0].appendChild(tileXml.createTextNode(
      "This tile notification uses ms-appx images"));

// get the image attributes for this template and fill them in
var tileImageAttributes = tileXml.getElementsByTagName("image");
tileImageAttributes[0].setAttribute("src", "ms-appx:///images/redWide.png");

Local Storage Images

The code for accessing an image in local storage is very similar, differing only by the addressing scheme:

tileImageAttributes[0].setAttribute("src", "ms-appdata:///local/images/redWide.png");

Here the image is located in a subdirectory called images at the location returned by ApplicationData.localFolder; when I ran an excursion of the sample app using this access mechanism, the image was served from:

C:\Users\joneil\AppData\Local\Packages\Microsoft.SDKSamples.Tiles.JS_8wekyb3d8bbwe\
    
LocalState\images\redWide.png

Images in the Cloud

One option to consider when architecting your application is leveraging the cloud for external resources that your application uses. If you place images and other content on the web or in the cloud, you’ve decoupled those resources from your application, and by doing so you can freshen the look and feel of your application without publishing a new version of your application or requiring the end users to get an update.

Windows Azure, Microsoft’s public cloud offering, can be an incredibly convenient and cost effective way to manage the images you’re using for your notifications. The easiest way to serve image content from Windows Azure is via blob storage which provides highly scalable and highly available storage of unstructured data at one of eight Windows Azure data centers worldwide. A Content Delivery Network (currently comprising 24 nodes) is also available to improve performance and user experience for end-users who aren’t located near a data center.

Keep in mind there are some caveats when using cloud or web hosted images:
  1. The most obvious is that if the machine lacks network connectivity, the image won't be available and the notification will not be sent.
  2. Web images are cached, so an update to the image in the cloud may not be immediately reflected on the client. If the cache is full, images will be removed in a policy opaque to the developer. Additionally the system will clear the cache when
    1. The application is uninstalled, or
    2. The user clears personal information from all of her application tiles (via the Settings flyout on the Start screen).

    The system will comply with caching and expiration headers in the HTTP response. Those headers are not configurable in Windows Azure storage alone, but a web service can be configured and hosted on Windows Azure to support this.

  3. The cloud isn't free! While there are no-cost options (like the 90-day trial and MSDN subscriptions), you ultimately may end up paying for the storage and the transactions (HTTP GET requests) that are made by your application. The complete pricing details are available at the Azure pricing page, but it’s very likely you'll be able to support a popular Windows 8 application for dollars if not pennies a month.

Handling Scaling and Contrast Themes

The elephant in the room thus far in this post is that all the samples I’ve shown above refer to a single image of some unknown size, and I appear to have ignored the advice to provide four different image sizes (80%, 100%, 140% and 180%) scale to provide the best user experience!

It turns out that there’s a bit of magic happening behind the scenes to make managing the combination of image sizes and contrast mode (don’t forget there’s are high-contrast white and high-contrast black options too!). The amount of ‘magic’ depends on the image source, so I’ll cover them independently below.

App Package Images

When you provide images as part of your application package, a naming convention can be leveraged which enables you to specify one base image name (say in the notification template image src attribute) yet the system automatically selects a file with a modified name based on the current scale factor and contrast mode.

For instance, while the code sample above refers to redWide.png, the application can deliver a slew of versions that vary by scale factor, contrast mode, culture (e.g., en-US versus zh-CN), and several other resource qualifiers.

A file named redWide.scale-140.png, if available, would be used in the samples above – in lieu of scaling the default image – whenever there was a request for redWide.png and the current scale required was 140%. Your code doesn’t need to do a thing!

If you had a special version of the tile just for those in French locales, you could name that image, redWide.lang-FR-fr_scale-140.png. (Note the lang prefix to the BCP-47 language identifier)

Likewise, redWide.scale-180_contrast-black.png would be used when the contrast mode is black and an image scaled to 180% is needed. By the way, redWide.contrast-black_scale-180.png works too!

You can also arrange the images in subdirectories, to provide a myriad of customization options. Take, for example, the following directory structure.

   1:  /ProjectFolder
   2:      /images
   3:          welcome.scale-80.png
   4:          welcome.scale-100.png
   5:          welcome.scale-140.png
   6:          /contrast-black
   7:              welcome.scale-80.png
   8:              welcome.scale-100.png
   9:              welcome.scale-140.png
  10:          /contrast-white
  11:              welcome.scale-80.png
  12:              welcome.scale-100.png
  13:              welcome.scale-140.png
  14:          /ja-JP
  15:              welcome.scale-80.png
  16:              welcome.scale-100.png
  17:              welcome.scale-140.png
  18:              /contrast-black
  19:                  welcome.scale-80.png
  20:                  welcome.scale-100.png
  21:                  welcome.scale-140.png
  22:              /contrast-white
  23:                  welcome.scale-80.png
  24:                  welcome.scale-100.png
  25:                  welcome.scale-140.png

If the application were run on a US based system, but the user selected a black high contrast theme, a reference for welcome.png for a tile notification on a typical laptop would pick the variant on Line 8.  Someone running the applications with his locale set to Japan on a high-resolution device would see the image file associated with Line 17.

Local Images

Unfortunately, none of the conventions supported for app package images are supported when using local images (the ms-appdata:///local namespace), but you could implement similar semantics programmatically using the following Windows APIs:

Attribute Windows Class or Property Values
Resolution DisplayProperties.resolutionScale Scale100Percent
Scale140Percent
Scale180Percent
Language ApplicationLanguage.languages a list of BCP-47 codes corresponding to the applications supported languages (see ���How to manage language and region” for details)
Contrast Scheme [see note] AccessibilitySettings.highContrast

AccessibilitySettings.highContrastScheme
true | false

”High Contrast White”
”High Contrast Black”
”High Contrast #1”
”High Contrast #2”
Home Region GlobalizationPreferences.homeGeographicRegion BCP-47 subtag code corresponding to user’s Region preference in Control Panel

Images in the Cloud

Both the tile schema and the toast schema include an optional attribute called addImageQuery, on the visual, binding, and image elements (the value set on the deepest element overriding those above it). When addImageQuery is set to true, HTTP/HTTPS requests made for images will have a query string appended consisting of the following three name value pairs:

Attribute Query String Name Query String Value
Resolution ms-scale 80, 100, 140 or 180
Language ms-lang BCP-47 code
Contrast Scheme [see note] ms-contrast standard
black
white

Here for instance is an HTTP request made for the redWide.png tile:

GET http://win8apps.blob.core.windows.net/images/redWide.png?ms-scale=100
&ms-contrast=standard&ms-lang=en-US HTTP/1.1 Accept: */* Accept-Encoding: identity, peerdist Range: bytes=0-2419 User-Agent: Microsoft BITS/7.6 X-P2P-PeerDist: Version=1.1 X-P2P-PeerDistEx: MinContentInformation=1.0, MaxContentInformation=2.0 Connection: Keep-Alive Host: win8apps.blob.core.windows.net

The good news is that you don’t have to figure out which variant of an image is being requested – that information is available in the query parameters; the bad news is that you have to build your own web service to inspect those parameters and serve up the correct image in response. You can’t just use the blob storage mechanism shown above, because those query parameters aren't automatically interpreted by Windows Azure blob storage, but you can still use Windows Azure with a little bit of code (PHP, ASP.NET, Node.js, or essentially any implementation of a web service that will run on Windows).


A Recap of the Not-So-Obvious

  • 80% images are used on tiles for some combinations of screen size and resolution.
  • Size specifications haven’t been published for images that appear on toast or that do not fill the entire tile, such as the template samples below. In most cases, these will be photographic images which scale fairly well (using the Fant algorithm internally). You could measure the sizes empirically, but if you create images that work for 180% scale they should also scale down well for the other three factors.
ToastImageAndText02 example   TileWideImageCollection example
  • Default images (those declared in your app manifest) must be .png or .jpg/.jpeg format, but you can use .gif in your toast and tile notification templates.
  • If an image is of the wrong format or not available (such as a image hosted on the Web when the client is not connected), the notification will not be sent.
  • The branding element is taken from the small logo in your manifest. For tiles it appears in the bottom left and for toast in the bottom right. In the tile schema you can use text, logo, or no branding; in the toast schema, the branding attribute is not used and you will always see the logo.
  • The badge logo must be monochromatic.
  • if you don’t supply multiple images to accommodate scaling, try to create images with dimensions that are a multiple of 5 as they won’t experience pixel shifting during scaling.
  • The Visual Studio simulator is an awesome way to test out tile behavior under different resolutions and contrast modes, but be aware, you’ll have to restart your debug session in the simulator if your change in resolution results in loading a different version of the image.
  • PC Settings > Ease of Access (accessible via the Settings charm) includes a switch to toggle High Contrast mode; however, since there are four high contrast modes, you’ll need to use the desktop Control Panel option to pick one.  Once you’ve selected the contrast mode there, PC Settings > Ease of Access will use that High Contrast mode when you toggle the option.Ease of Access settings for High Contrast (click for larger view)
  • Windows supports four high contrast modes (White, Black, #1, and #2), and these map to four overlapping resource types: standard, high, black, and white as follows:
    Contrast Setting in Control Panel Applicable Resource Qualifiers ms-contrast Query Parameter Value
    High Contrast White contrast-high and contrast-white white
    High Contrast Black contrast-high and contrast-black black
    High Contrast #1 contrast-high and contrast-black black
    High Contrast #2 contrast-high and contrast-black black
    none contrast-standard standard

Read the original blog entry...

More Stories By Jim O'Neil

Jim is a Technology Evangelist for Microsoft who covers the Northeast District, namely, New England and upstate New York. He is focused on engaging with the development community in the area through user groups, code camps, BarCamps, Microsoft-sponsored events, etc., and just in general serve as ambassador for Microsoft. Since 2009, Jim has been focusing on software development scenarios using cloud computing and Windows Azure. You can follow Jim on Twitter at @jimoneil

@ThingsExpo Stories
Samsung VP Jacopo Lenzi, who headed the company's recent SmartThings acquisition under the auspices of Samsung's Open Innovaction Center (OIC), answered a few questions we had about the deal. This interview was in conjunction with our interview with SmartThings CEO Alex Hawkinson. IoT Journal: SmartThings was developed in an open, standards-agnostic platform, and will now be part of Samsung's Open Innovation Center. Can you elaborate on your commitment to keep the platform open? Jacopo Lenzi: Samsung recognizes that true, accelerated innovation cannot be driven from one source, but requires a...
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...
P2P RTC will impact the landscape of communications, shifting from traditional telephony style communications models to OTT (Over-The-Top) cloud assisted & PaaS (Platform as a Service) communication services. The P2P shift will impact many areas of our lives, from mobile communication, human interactive web services, RTC and telephony infrastructure, user federation, security and privacy implications, business costs, and scalability. In his session at Internet of @ThingsExpo, Robin Raymond, Chief Architect at Hookflash Inc., will walk through the shifting landscape of traditional telephone a...
SYS-CON Events announced today that Matrix.org has been named “Silver Sponsor” of Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Matrix is an ambitious new open standard for open, distributed, real-time communication over IP. It defines a new approach for interoperable Instant Messaging and VoIP based on pragmatic HTTP APIs and WebRTC, and provides open source reference implementations to showcase and bootstrap the new standard. Our focus is on simplicity, security, and supporting the fullest feature set.
BSQUARE is a global leader of embedded software solutions. We enable smart connected systems at the device level and beyond that millions use every day and provide actionable data solutions for the growing Internet of Things (IoT) market. We empower our world-class customers with our products, services and solutions to achieve innovation and success. For more information, visit www.bsquare.com.
How do APIs and IoT relate? The answer is not as simple as merely adding an API on top of a dumb device, but rather about understanding the architectural patterns for implementing an IoT fabric. There are typically two or three trends: Exposing the device to a management framework Exposing that management framework to a business centric logic • Exposing that business layer and data to end users. This last trend is the IoT stack, which involves a new shift in the separation of what stuff happens, where data lives and where the interface lies. For instance, it’s a mix of architectural style...
SYS-CON Events announced today that SOA Software, an API management leader, will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. SOA Software is a leading provider of API Management and SOA Governance products that equip business to deliver APIs and SOA together to drive their company to meet its business strategy quickly and effectively. SOA Software’s technology helps businesses to accelerate their digital channels with APIs, drive partner adoption, monetize their assets, and achieve a...
From a software development perspective IoT is about programming "things," about connecting them with each other or integrating them with existing applications. In his session at @ThingsExpo, Yakov Fain, co-founder of Farata Systems and SuranceBay, will show you how small IoT-enabled devices from multiple manufacturers can be integrated into the workflow of an enterprise application. This is a practical demo of building a framework and components in HTML/Java/Mobile technologies to serve as a platform that can integrate new devices as they become available on the market.
SYS-CON Events announced today that Utimaco will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Utimaco is a leading manufacturer of hardware based security solutions that provide the root of trust to keep cryptographic keys safe, secure critical digital infrastructures and protect high value data assets. Only Utimaco delivers a general-purpose hardware security module (HSM) as a customizable platform to easily integrate into existing software solutions, embed business logic and build s...
Connected devices are changing the way we go about our everyday life, from wearables to driverless cars, to smart grids and entire industries revolutionizing business opportunities through smart objects, capable of two-way communication. But what happens when objects are given an IP-address, and we rely on that connection, sometimes with our lives? How do we secure those vast data infrastructures and safe-keep the privacy of sensitive information? This session will outline how each and every connected device can uphold a core root of trust via a unique cryptographic signature – a “bir...
Internet of @ThingsExpo Silicon Valley announced on Thursday its first 12 all-star speakers and sessions for its upcoming event, which will take place November 4-6, 2014, at the Santa Clara Convention Center in California. @ThingsExpo, the first and largest IoT event in the world, debuted at the Javits Center in New York City in June 10-12, 2014 with over 6,000 delegates attending the conference. Among the first 12 announced world class speakers, IBM will present two highly popular IoT sessions, which will take place November 4-6, 2014 at the Santa Clara Convention Center in Santa Clara, Calif...
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity.
WebRTC defines no default signaling protocol, causing fragmentation between WebRTC silos. SIP and XMPP provide possibilities, but come with considerable complexity and are not designed for use in a web environment. In his session at Internet of @ThingsExpo, Matthew Hodgson, technical co-founder of the Matrix.org, will discuss how Matrix is a new non-profit Open Source Project that defines both a new HTTP-based standard for VoIP & IM signaling and provides reference implementations.

SUNNYVALE, Calif., Oct. 20, 2014 /PRNewswire/ -- Spansion Inc. (NYSE: CODE), a global leader in embedded systems, today added 96 new products to the Spansion® FM4 Family of flexible microcontrollers (MCUs). Based on the ARM® Cortex®-M4F core, the new MCUs boast a 200 MHz operating frequency and support a diverse set of on-chip peripherals for enhanced human machine interfaces (HMIs) and machine-to-machine (M2M) communications. The rich set of periphera...

SYS-CON Events announced today that Aria Systems, the recurring revenue expert, has been named "Bronze Sponsor" of SYS-CON's 15th International Cloud Expo®, which will take place on November 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Aria Systems helps leading businesses connect their customers with the products and services they love. Industry leaders like Pitney Bowes, Experian, AAA NCNU, VMware, HootSuite and many others choose Aria to power their recurring revenue business and deliver exceptional experiences to their customers.
The Internet of Things (IoT) is going to require a new way of thinking and of developing software for speed, security and innovation. This requires IT leaders to balance business as usual while anticipating for the next market and technology trends. Cloud provides the right IT asset portfolio to help today’s IT leaders manage the old and prepare for the new. Today the cloud conversation is evolving from private and public to hybrid. This session will provide use cases and insights to reinforce the value of the network in helping organizations to maximize their company’s cloud experience.
The Internet of Things (IoT) is making everything it touches smarter – smart devices, smart cars and smart cities. And lucky us, we’re just beginning to reap the benefits as we work toward a networked society. However, this technology-driven innovation is impacting more than just individuals. The IoT has an environmental impact as well, which brings us to the theme of this month’s #IoTuesday Twitter chat. The ability to remove inefficiencies through connected objects is driving change throughout every sector, including waste management. BigBelly Solar, located just outside of Boston, is trans...
SYS-CON Events announced today that Matrix.org has been named “Silver Sponsor” of Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Matrix is an ambitious new open standard for open, distributed, real-time communication over IP. It defines a new approach for interoperable Instant Messaging and VoIP based on pragmatic HTTP APIs and WebRTC, and provides open source reference implementations to showcase and bootstrap the new standard. Our focus is on simplicity, security, and supporting the fullest feature set.
Predicted by Gartner to add $1.9 trillion to the global economy by 2020, the Internet of Everything (IoE) is based on the idea that devices, systems and services will connect in simple, transparent ways, enabling seamless interactions among devices across brands and sectors. As this vision unfolds, it is clear that no single company can accomplish the level of interoperability required to support the horizontal aspects of the IoE. The AllSeen Alliance, announced in December 2013, was formed with the goal to advance IoE adoption and innovation in the connected home, healthcare, education, aut...
SYS-CON Events announced today that Red Hat, the world's leading provider of open source solutions, will exhibit at Internet of @ThingsExpo, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Red Hat is the world's leading provider of open source software solutions, using a community-powered approach to reliable and high-performing cloud, Linux, middleware, storage and virtualization technologies. Red Hat also offers award-winning support, training, and consulting services. As the connective hub in a global network of enterprises, partners, a...