Welcome!

Microservices Expo Authors: Pat Romanski, Elizabeth White, Jason Bloomberg, Liz McMillan, Derek Weeks

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
Digital means customer preferences and behavior are driving enterprise technology decisions to be sure, but let’s not forget our employees. After all, when we say customer, we mean customer writ large, including partners, supply chain participants, and yes, those salaried denizens whose daily labor forms the cornerstone of the enterprise. While your customers bask in the warm rays of your digital efforts, are your employees toiling away in the dark recesses of your enterprise, pecking data into...
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
You deployed your app with the Bluemix PaaS and it's gaining some serious traction, so it's time to make some tweaks. Did you design your application in a way that it can scale in the cloud? Were you even thinking about the cloud when you built the app? If not, chances are your app is going to break. Check out this webcast to learn various techniques for designing applications that will scale successfully in Bluemix, for the confidence you need to take your apps to the next level and beyond.
I had the opportunity to catch up with Chris Corriere - DevOps Engineer at AutoTrader - to talk about his experiences in the realm of Rugged DevOps. We discussed automation, culture and collaboration, and which thought leaders he is following. Chris Corriere: Hey, I'm Chris Corriere. I'm a DevOps Engineer AutoTrader. Derek Weeks: Today we're going to talk about Rugged DevOps. It's a subject that's gaining a lot of traction in the community but not a lot of people are really familiar with wh...
SYS-CON Events announced today that Peak 10, Inc., a national IT infrastructure and cloud services provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Peak 10 provides reliable, tailored data center and network services, cloud and managed services. Its solutions are designed to scale and adapt to customers’ changing business needs, enabling them to lower costs, improve performance and focus inter...
Wow, if you ever wanted to learn about Rugged DevOps (some call it DevSecOps), sit down for a spell with Shannon Lietz, Ian Allison and Scott Kennedy from Intuit. We discussed a number of important topics including internal war games, culture hacking, gamification of Rugged DevOps and starting as a small team. There are 100 gold nuggets in this conversation for novices and experts alike.
In 2006, Martin Fowler posted his now famous essay on Continuous Integration. Looking back, what seemed revolutionary, radical or just plain crazy is now common, pedestrian and "just what you do." I love it. Back then, building and releasing software was a real pain. Integration was something you did at the end, after code complete, and we didn't know how long it would take. Some people may recall how we, as an industry, spent a massive amount of time integrating code from one team with another...
SYS-CON Events announced today that DatacenterDynamics has been named “Media Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY. DatacenterDynamics is a brand of DCD Group, a global B2B media and publishing company that develops products to help senior professionals in the world's most ICT dependent organizations make risk-based infrastructure and capacity decisions.
With DevOps becoming more well-known and established practice in nearly every industry that delivers software, it is important to continually reassess its efficacy. This week’s top 10 includes a discussion on how the quick uptake of DevOps adoption in the enterprise has posed some serious challenges. Additionally, organizations who have taken the DevOps plunge must find ways to find, hire and keep their DevOps talent in order to keep the machine running smoothly.
Between the mockups and specs produced by analysts, and resulting applications built by developers, there exists a gulf where projects fail, costs spiral, and applications disappoint. Methodologies like Agile attempt to address this with intensified communication, with partial success but many limitations. In his session at 18th Cloud Expo, Charles Kendrick, CTO & Chief Architect at Isomorphic Software, will present a revolutionary model enabled by new technologies. Learn how business and devel...
Call it DevOps or not, if you are concerned about releasing more code faster and at a higher quality, the resulting software delivery chain and process will look and smell like DevOps. But for existing development teams, no matter what the velocity objective is, getting from here to there is not something that can be done without a plan. Moving your release cadence from months to weeks is not just about learning Agile practices and getting some automation tools. It involves people, tooling and ...
The notion of customer journeys, of course, are central to the digital marketer’s playbook. Clearly, enterprises should focus their digital efforts on such journeys, as they represent customer interactions over time. But making customer journeys the centerpiece of the enterprise architecture, however, leaves more questions than answers. The challenge arises when EAs consider the context of the customer journey in the overall architecture as well as the architectural elements that make up each...
Much of the discussion around cloud DevOps focuses on the speed with which companies need to get new code into production. This focus is important – because in an increasingly digital marketplace, new code enables new value propositions. New code is also often essential for maintaining competitive parity with market innovators. But new code doesn’t just have to deliver the functionality the business requires. It also has to behave well because the behavior of code in the cloud affects performan...
APIs have taken the world by storm in recent years. The use of APIs has gone beyond just traditional "software" companies, to companies and organizations across industries using APIs to share information and power their applications. For some organizations, APIs are the biggest revenue drivers. For example, Salesforce generates nearly 50% of annual revenue through APIs. In other cases, APIs can increase a business's footprint and initiate collaboration. Netflix, for example, reported over 5 bi...
As the software delivery industry continues to evolve and mature, the challenge of managing the growing list of the tools and processes becomes more daunting every day. Today, Application Lifecycle Management (ALM) platforms are proving most valuable by providing the governance, management and coordination for every stage of development, deployment and release. Recently, I spoke with Madison Moore at SD Times about the changing market and where ALM is headed.
If there is anything we have learned by now, is that every business paves their own unique path for releasing software- every pipeline, implementation and practices are a bit different, and DevOps comes in all shapes and sizes. Software delivery practices are often comprised of set of several complementing (or even competing) methodologies – such as leveraging Agile, DevOps and even a mix of ITIL, to create the combination that’s most suitable for your organization and that maximize your busines...
Struggling to keep up with increasing application demand? Learn how Platform as a Service (PaaS) can streamline application development processes and make resource management easy.
New Relic, Inc. has announced a set of new features across the New Relic Software Analytics Cloud that offer IT operations teams increased visibility, and the ability to diagnose and resolve performance problems quickly. The new features further IT operations teams’ ability to leverage data and analytics, as well as drive collaboration and a common, shared understanding between teams. Software teams are under pressure to resolve performance issues quickly and improve availability, as the comple...
The goal of any tech business worth its salt is to provide the best product or service to its clients in the most efficient and cost-effective way possible. This is just as true in the development of software products as it is in other product design services. Microservices, an app architecture style that leans mostly on independent, self-contained programs, are quickly becoming the new norm, so to speak. With this change comes a declining reliance on older SOAs like COBRA, a push toward more s...
The proper isolation of resources is essential for multi-tenant environments. The traditional approach to isolate resources is, however, rather heavyweight. In his session at 18th Cloud Expo, Igor Drobiazko, co-founder of elastic.io, will draw upon their own experience with operating a Docker container-based infrastructure on a large scale and present a lightweight solution for resource isolation using microservices. He will also discuss the implementation of microservices in data and applicat...