|By Jim O'Neil||
|August 6, 2012 08:07 AM EDT||
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:
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.
There are two overarching constraints for images used within notifications:
- Images used in notifications must be in one of three formats: .png, .jpg/.jpeg, or .gif, and the format must match the extension.
- 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
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]
24x24 33x33 43x43
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:///localprefix to a directory within local storage. Note that images in temporary and roaming application data storage cannot be used.
- on the web, using an
httpsURI 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.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.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:
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:
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:
- The most obvious is that if the machine lacks network connectivity, the image won't be available and the notification will not be sent.
- 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
- The application is uninstalled, or
- 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.
- 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.
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.pngand 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)
redWide.scale-180_contrast-black.pngwould be used when the contrast mode is black and an image scaled to 180% is needed. By the way,
You can also arrange the images in subdirectories, to provide a myriad of customization options. Take, for example, the following directory structure.
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.
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|
|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
”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|
|Contrast Scheme [see note]||
Here for instance is an HTTP request made for the
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).
- 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.
- 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.
- 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-contrastQuery Parameter Value
High Contrast White
white High Contrast Black
black High Contrast #1
black High Contrast #2
SYS-CON Events announced today that Enzu will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Enzu’s mission is to be the leading provider of enterprise cloud solutions worldwide. Enzu enables online businesses to use its IT infrastructure to their competitive advantage. By offering a suite of proven hosting and management services, Enzu wants companies to focus on the core of their online busine...
Oct. 22, 2016 09:00 PM EDT Reads: 1,235
@DevOpsSummit has been named the ‘Top DevOps Influencer' by iTrend. iTrend processes millions of conversations, tweets, interactions, news articles, press releases, blog posts - and extract meaning form them and analyzes mobile and desktop software platforms used to communicate, various metadata (such as geo location), and automation tools. In overall placement, @DevOpsSummit ranked as the number one ‘DevOps Influencer' followed by @CloudExpo at third, and @MicroservicesE at 24th.
Oct. 22, 2016 09:00 PM EDT Reads: 3,883
Enterprise IT has been in the era of Hybrid Cloud for some time now. But it seems most conversations about Hybrid are focused on integrating AWS, Microsoft Azure, or Google ECM into existing on-premises systems. Where is all the Private Cloud? What do technology providers need to do to make their offerings more compelling? How should enterprise IT executives and buyers define their focus, needs, and roadmap, and communicate that clearly to the providers?
Oct. 22, 2016 08:45 PM EDT Reads: 2,466
Analysis of 25,000 applications reveals 6.8% of packages/components used included known defects. Organizations standardizing on components between 2 - 3 years of age can decrease defect rates substantially. Open source and third-party packages/components live at the heart of high velocity software development organizations. Today, an average of 106 packages/components comprise 80 - 90% of a modern application, yet few organizations have visibility into what components are used where.
Oct. 22, 2016 08:45 PM EDT Reads: 1,490
SYS-CON Events announced today that Sheng Liang to Keynote at SYS-CON's 19th Cloud Expo, which will take place on November 1-3, 2016 at the Santa Clara Convention Center in Santa Clara, California.
Oct. 22, 2016 08:30 PM EDT Reads: 1,671
So you think you are a DevOps warrior, huh? Put your money (not really, it’s free) where your metrics are and prove it by taking The Ultimate DevOps Geek Quiz Challenge, sponsored by DevOps Summit. Battle through the set of tough questions created by industry thought leaders to earn your bragging rights and win some cool prizes.
Oct. 22, 2016 08:15 PM EDT Reads: 3,768
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
Oct. 22, 2016 07:45 PM EDT Reads: 1,816
Without lifecycle traceability and visibility across the tool chain, stakeholders from Planning-to-Ops have limited insight and answers to who, what, when, why and how across the DevOps lifecycle. This impacts the ability to deliver high quality software at the needed velocity to drive positive business outcomes. In his general session at @DevOpsSummit at 19th Cloud Expo, Eric Robertson, General Manager at CollabNet, will discuss how customers are able to achieve a level of transparency that e...
Oct. 22, 2016 07:00 PM EDT Reads: 768
SYS-CON Events announced today that SoftNet Solutions will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. SoftNet Solutions specializes in Enterprise Solutions for Hadoop and Big Data. It offers customers the most open, robust, and value-conscious portfolio of solutions, services, and tools for the shortest route to success with Big Data. The unique differentiator is the ability to architect and ...
Oct. 22, 2016 06:45 PM EDT Reads: 618
If you are within a stones throw of the DevOps marketplace you have undoubtably noticed the growing trend in Microservices. Whether you have been staying up to date with the latest articles and blogs or you just read the definition for the first time, these 5 Microservices Resources You Need In Your Life will guide you through the ins and outs of Microservices in today’s world.
Oct. 22, 2016 05:15 PM EDT Reads: 6,435
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Oct. 22, 2016 04:00 PM EDT Reads: 3,585
In his general session at 18th Cloud Expo, Lee Atchison, Principal Cloud Architect and Advocate at New Relic, discussed cloud as a ‘better data center’ and how it adds new capacity (faster) and improves application availability (redundancy). The cloud is a ‘Dynamic Tool for Dynamic Apps’ and resource allocation is an integral part of your application architecture, so use only the resources you need and allocate /de-allocate resources on the fly.
Oct. 22, 2016 04:00 PM EDT Reads: 3,661
For those unfamiliar, as a developer working in marketing for an infrastructure automation company, I have tried to clarify the different versions of DevOps by capitalizing the part that benefits in a given DevOps scenario. In this case we’re talking about operations improvements. While devs – particularly those involved in automation or DevOps will find it interesting, it really talks to growing issues Operations are finding. The problem is right in front of us, we’re confronting it every day,...
Oct. 22, 2016 04:00 PM EDT Reads: 3,083
In his keynote at 19th Cloud Expo, Sheng Liang, co-founder and CEO of Rancher Labs, will discuss the technological advances and new business opportunities created by the rapid adoption of containers. With the success of Amazon Web Services (AWS) and various open source technologies used to build private clouds, cloud computing has become an essential component of IT strategy. However, users continue to face challenges in implementing clouds, as older technologies evolve and newer ones like Docke...
Oct. 22, 2016 03:30 PM EDT Reads: 2,247
At its core DevOps is all about collaboration. The lines of communication must be opened and it takes some effort to ensure that they stay that way. It’s easy to pay lip service to trends and talk about implementing new methodologies, but without action, real benefits cannot be realized. Success requires planning, advocates empowered to effect change, and, of course, the right tooling. To bring about a cultural shift it’s important to share challenges. In simple terms, ensuring that everyone k...
Oct. 22, 2016 03:00 PM EDT Reads: 12,356
In his session at 19th Cloud Expo, Claude Remillard, Principal Program Manager in Developer Division at Microsoft, will contrast how his team used config as code and immutable patterns for continuous delivery of microservices and apps to the cloud. He will show the immutable patterns helps developers do away with most of the complexity of config as code-enabling scenarios such as rollback, zero downtime upgrades with far greater simplicity. He will also have live demos of building immutable pipe...
Oct. 22, 2016 02:45 PM EDT Reads: 1,506
Application transformation and DevOps practices are two sides of the same coin. Enterprises that want to capture value faster, need to deliver value faster – time value of money principle. To do that enterprises need to build cloud-native apps as microservices by empowering teams to build, ship, and run in production. In his session at @DevOpsSummit at 19th Cloud Expo, Neil Gehani, senior product manager at HPE, will discuss what every business should plan for how to structure their teams to d...
Oct. 22, 2016 01:15 PM EDT Reads: 1,284
SYS-CON Events announced today that Transparent Cloud Computing (T-Cloud) Consortium will exhibit at the 19th International Cloud Expo®, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. The Transparent Cloud Computing Consortium (T-Cloud Consortium) will conduct research activities into changes in the computing model as a result of collaboration between "device" and "cloud" and the creation of new value and markets through organic data proces...
Oct. 22, 2016 12:45 PM EDT Reads: 1,275
When we talk about the impact of BYOD and BYOA and the Internet of Things, we often focus on the impact on data center architectures. That's because there will be an increasing need for authentication, for access control, for security, for application delivery as the number of potential endpoints (clients, devices, things) increases. That means scale in the data center. What we gloss over, what we skip, is that before any of these "things" ever makes a request to access an application it had to...
Oct. 22, 2016 12:00 PM EDT Reads: 13,605
Virgil consists of an open-source encryption library, which implements Cryptographic Message Syntax (CMS) and Elliptic Curve Integrated Encryption Scheme (ECIES) (including RSA schema), a Key Management API, and a cloud-based Key Management Service (Virgil Keys). The Virgil Keys Service consists of a public key service and a private key escrow service.
Oct. 22, 2016 08:30 AM EDT Reads: 959