Click here to close now.




















Welcome!

Microservices Expo Authors: Carmen Gonzalez, Elizabeth White, Liz McMillan, Jason Bloomberg, Pat Romanski

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

@MicroservicesExpo Stories
DevOps Summit, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development...
Whether you like it or not, DevOps is on track for a remarkable alliance with security. The SEC didn’t approve the merger. And your boss hasn’t heard anything about it. Yet, this unruly triumvirate will soon dominate and deliver DevSecOps faster, cheaper, better, and on an unprecedented scale. In his session at DevOps Summit, Frank Bunger, VP of Customer Success at ScriptRock, will discuss how this cathartic moment will propel the DevOps movement from such stuff as dreams are made on to a prac...
SYS-CON Events announced today that DataClear Inc. will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. The DataClear ‘BlackBox’ is the only solution that moves your PC, browsing and data out of the United States and away from prying (and spying) eyes. Its solution automatically builds you a clean, on-demand, virus free, new virtual cloud based PC outside of the United States, and wipes it clean...
The word quantum often portends New Age mumbo-jumbo, in spite of the fact that quantum mechanics underlies many of today’s most important technologies, including lasers and the semiconductors found in every computer chip. Nevertheless, today quantum computing is becoming a reality. And while it may look to the layperson like mere mumbo-jumbo, in reality of the technology has largely moved out of the theoretical stage, as recent news indicates. In fact, two important announcements over the la...
SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
Any Ops team trying to support a company in today’s cloud-connected world knows that a new way of thinking is required – one just as dramatic than the shift from Ops to DevOps. The diversity of modern operations requires teams to focus their impact on breadth vs. depth. In his session at DevOps Summit, Adam Serediuk, Director of Operations at xMatters, Inc., will discuss the strategic requirements of evolving from Ops to DevOps, and why modern Operations has begun leveraging the “NoOps” approa...
All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades. With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo, November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Learn what is going on, contribute to the discussions, and e...
In today's digital world, change is the one constant. Disruptive innovations like cloud, mobility, social media, and the Internet of Things have reshaped the market and set new standards in customer expectations. To remain competitive, businesses must tap the potential of emerging technologies and markets through the rapid release of new products and services. However, the rigid and siloed structures of traditional IT platforms and processes are slowing them down – resulting in lengthy delivery ...
Early in my DevOps Journey, I was introduced to a book of great significance circulating within the Web Operations industry titled The Phoenix Project. (You can read our review of Gene’s book, if interested.) Written as a novel and loosely based on many of the same principles explored in The Goal, this book has been read and referenced by many who have adopted DevOps into their continuous improvement and software delivery processes around the world. As I began planning my travel schedule last...
In his session at 17th Cloud Expo, Ernest Mueller, Product Manager at Idera, will explain the best practices and lessons learned for tracking and optimizing costs while delivering a cloud-hosted service. He will describe a DevOps approach where the applications and systems work together to track usage, model costs in a granular fashion, and make smart decisions at runtime to minimize costs. The trickier parts covered include triggering off the right metrics; balancing resilience and redundancy ...
17th Cloud Expo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises ar...
SYS-CON Events announced today the Containers & Microservices Bootcamp, being held November 3-4, 2015, in conjunction with 17th Cloud Expo, @ThingsExpo, and @DevOpsSummit at the Santa Clara Convention Center in Santa Clara, CA. This is your chance to get started with the latest technology in the industry. Combined with real-world scenarios and use cases, the Containers and Microservices Bootcamp, led by Janakiram MSV, a Microsoft Regional Director, will include presentations as well as hands-on...
SYS-CON Events announced today that the "Second Containers & Microservices Expo" will take place November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Containers and microservices have become topics of intense interest throughout the cloud developer and enterprise IT communities.
Akana has announced the availability of the new Akana Healthcare Solution. The API-driven solution helps healthcare organizations accelerate their transition to being secure, digitally interoperable businesses. It leverages the Health Level Seven International Fast Healthcare Interoperability Resources (HL7 FHIR) standard to enable broader business use of medical data. Akana developed the Healthcare Solution in response to healthcare businesses that want to increase electronic, multi-device acce...
The web app is agile. The REST API is agile. The testing and planning are agile. But alas, data infrastructures certainly are not. Once an application matures, changing the shape or indexing scheme of data often forces at best a top down planning exercise and at worst includes schema changes that force downtime. The time has come for a new approach that fundamentally advances the agility of distributed data infrastructures. Come learn about a new solution to the problems faced by software organ...
Containers are not new, but renewed commitments to performance, flexibility, and agility have propelled them to the top of the agenda today. By working without the need for virtualization and its overhead, containers are seen as the perfect way to deploy apps and services across multiple clouds. Containers can handle anything from file types to operating systems and services, including microservices. What are microservices? Unlike what the name implies, microservices are not necessarily small,...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading in...
Docker containerization is increasingly being used in production environments. How can these environments best be monitored? Monitoring Docker containers as if they are lightweight virtual machines (i.e., monitoring the host from within the container), with all the common metrics that can be captured from an operating system, is an insufficient approach. Docker containers can’t be treated as lightweight virtual machines; they must be treated as what they are: isolated processes running on hosts....
Puppet Labs is pleased to share the findings from our 2015 State of DevOps Survey. We have deepened our understanding of how DevOps enables IT performance and organizational performance, based on responses from more than 20,000 technical professionals we’ve surveyed over the past four years. The 2015 State of DevOps Report reveals high-performing IT organizations deploy 30x more frequently with 200x shorter lead times. They have 60x fewer failures and recover 168x faster
Microservice architecture is fast becoming a go-to solution for enterprise applications, but it's not always easy to make the transition from an established, monolithic infrastructure. Lightweight and loosely coupled, building a set of microservices is arguably more difficult than building a monolithic application. However, once established, microservices offer a series of advantages over traditional architectures as deployment times become shorter and iterating becomes easier.