|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
One of the biggest challenges when developing connected devices is identifying user value and delivering it through successful user experiences. In his session at Internet of @ThingsExpo, Mike Kuniavsky, Principal Scientist, Innovation Services at PARC, described an IoT-specific approach to user experience design that combines approaches from interaction design, industrial design and service design to create experiences that go beyond simple connected gadgets to create lasting, multi-device exp...
Nov. 26, 2014 03:15 PM EST Reads: 817
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 26, 2014 03:15 PM EST Reads: 671
Connected devices and the Internet of Things are getting significant momentum in 2014. In his session at Internet of @ThingsExpo, Jim Hunter, Chief Scientist & Technology Evangelist at Greenwave Systems, examined three key elements that together will drive mass adoption of the IoT before the end of 2015. The first element is the recent advent of robust open source protocols (like AllJoyn and WebRTC) that facilitate M2M communication. The second is broad availability of flexible, cost-effective ...
Nov. 26, 2014 03:15 PM EST Reads: 557
The Internet of Things will greatly expand the opportunities for data collection and new business models driven off of that data. In her session at @ThingsExpo, Esmeralda Swartz, CMO of MetraTech, discussed how for this to be effective you not only need to have infrastructure and operational models capable of utilizing this new phenomenon, but increasingly service providers will need to convince a skeptical public to participate. Get ready to show them the money!
Nov. 26, 2014 03:00 PM EST Reads: 816
The Internet of Things will put IT to its ultimate test by creating infinite new opportunities to digitize products and services, generate and analyze new data to improve customer satisfaction, and discover new ways to gain a competitive advantage across nearly every industry. In order to help corporate business units to capitalize on the rapidly evolving IoT opportunities, IT must stand up to a new set of challenges. In his session at @ThingsExpo, Jeff Kaplan, Managing Director of THINKstrateg...
Nov. 26, 2014 03:00 PM EST Reads: 665
Cultural, regulatory, environmental, political and economic (CREPE) conditions over the past decade are creating cross-industry solution spaces that require processes and technologies from both the Internet of Things (IoT), and Data Management and Analytics (DMA). These solution spaces are evolving into Sensor Analytics Ecosystems (SAE) that represent significant new opportunities for organizations of all types. Public Utilities throughout the world, providing electricity, natural gas and water,...
Nov. 26, 2014 03:00 PM EST Reads: 714
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 @ThingsExpo, Robin Raymond, Chief Architect...
Nov. 26, 2014 02:00 PM EST Reads: 1,406
High-performing enterprise Software Quality Assurance (SQA) teams validate systems that are ready for use - getting most actively involved as components integrate and form complete systems. These teams catch and report on defects, making sure the customer gets the best software possible. SQA teams have leveraged automation and virtualization to execute more thorough testing in less time - bringing Dev and Ops together, ensuring production readiness. Does the emergence of DevOps mean the end of E...
Nov. 25, 2014 11:30 PM EST Reads: 1,055
Scott Jenson leads a project called The Physical Web within the Chrome team at Google. Project members are working to take the scalability and openness of the web and use it to talk to the exponentially exploding range of smart devices. Nearly every company today working on the IoT comes up with the same basic solution: use my server and you'll be fine. But if we really believe there will be trillions of these devices, that just can't scale. We need a system that is open a scalable and by using ...
Nov. 25, 2014 09:30 PM EST Reads: 1,161
The Internet of Things is tied together with a thin strand that is known as time. Coincidentally, at the core of nearly all data analytics is a timestamp. When working with time series data there are a few core principles that everyone should consider, especially across datasets where time is the common boundary. In his session at Internet of @ThingsExpo, Jim Scott, Director of Enterprise Strategy & Architecture at MapR Technologies, discussed single-value, geo-spatial, and log time series dat...
Nov. 25, 2014 09:30 PM EST Reads: 1,209
"Verizon offers public cloud, virtual private cloud as well as private cloud on-premises - many different alternatives. Verizon's deep knowledge in applications and the fact that we are responsible for applications that make call outs to other systems. Those systems and those resources may not be in Verizon Cloud, we understand at the end of the day it's going to be federated," explained Anne Plese, Senior Consultant, Cloud Product Marketing at Verizon Enterprise, in this SYS-CON.tv interview at...
Nov. 25, 2014 09:00 PM EST Reads: 1,307
"For the past 4 years we have been working mainly to export. For the last 3 or 4 years the main market was Russia. In the past year we have been working to expand our footprint in Europe and the United States," explained Andris Gailitis, CEO of DEAC, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 25, 2014 08:15 PM EST Reads: 1,087
The term culture has had a polarizing effect among DevOps supporters. Some propose that culture change is critical for success with DevOps, but are remiss to define culture. Some talk about a DevOps culture but then reference activities that could lead to culture change and there are those that talk about culture change as a set of behaviors that need to be adopted by those in IT. There is no question that businesses successful in adopting a DevOps mindset have seen departmental culture change, ...
Nov. 25, 2014 07:00 PM EST Reads: 973
The Domain Name Service (DNS) is one of the most important components in networking infrastructure, enabling users and services to access applications by translating URLs (names) into IP addresses (numbers). Because every icon and URL and all embedded content on a website requires a DNS lookup loading complex sites necessitates hundreds of DNS queries. In addition, as more internet-enabled ‘Things' get connected, people will rely on DNS to name and find their fridges, toasters and toilets. Acco...
Nov. 25, 2014 07:00 PM EST Reads: 1,256
"Cloud consumption is something we envision at Solgenia. That is trying to let the cloud spread to the user as a consumption, as utility computing. We want to allow the people to just pay for what they use, not a subscription model," explained Ermanno Bonifazi, CEO & Founder of Solgenia, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 25, 2014 06:15 PM EST Reads: 954
Enthusiasm for the Internet of Things has reached an all-time high. In 2013 alone, venture capitalists spent more than $1 billion dollars investing in the IoT space. With "smart" appliances and devices, IoT covers wearable smart devices, cloud services to hardware companies. Nest, a Google company, detects temperatures inside homes and automatically adjusts it by tracking its user's habit. These technologies are quickly developing and with it come challenges such as bridging infrastructure gaps,...
Nov. 25, 2014 04:30 PM EST Reads: 1,284
SYS-CON Media announced that Centrify, a provider of unified identity management across cloud, mobile and data center environments that delivers single sign-on (SSO) for users and a simplified identity infrastructure for IT, has launched an ad campaign on Cloud Computing Journal. The ads focus on security: how an organization can successfully control privilege for all of the organization’s identities to mitigate identity-related risk without slowing down the business, and how Centrify provides ...
Nov. 24, 2014 11:00 PM EST Reads: 1,171
SAP is delivering break-through innovation combined with fantastic user experience powered by the market-leading in-memory technology, SAP HANA. In his General Session at 15th Cloud Expo, Thorsten Leiduck, VP ISVs & Digital Commerce, SAP, discussed how SAP and partners provide cloud and hybrid cloud solutions as well as real-time Big Data offerings that help companies of all sizes and industries run better. SAP launched an application challenge to award the most innovative SAP HANA and SAP HANA...
Nov. 24, 2014 09:30 PM EST Reads: 1,141
"SAP had made a big transition into the cloud as we believe it has significant value for our customers, drives innovation and is easy to consume. When you look at the SAP portfolio, SAP HANA is the underlying platform and it powers all of our platforms and all of our analytics," explained Thorsten Leiduck, VP ISVs & Digital Commerce at SAP, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 24, 2014 09:15 PM EST Reads: 1,148
"We help companies that are using a lot of Software as a Service. We help companies manage and gain visibility into what people are using inside the company and decide to secure them or use standards to lock down or to embrace the adoption of SaaS inside the company," explained Scott Kriz, Co-founder and CEO of Bitium, in this SYS-CON.tv interview at 15th Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Nov. 24, 2014 07:15 PM EST Reads: 1,096