progress - Dave's Blog

Win10 PWA Terminology

Folks familiar with JavaScript UWP apps in Win10 have often been confused by what PWAs in Win10 actually are. TLDR: PWAs in Win10 are simply JavaScript UWP apps. The main difference between these JS UWP Apps and our non-PWA JS UWP apps are our target end developer audience, and how we get Win10 PWAs into the Microsoft Store. See this Win10 blog post on PWAs on Win10 for related info.

Web App

On the web a subset of web sites are web apps. These are web sites that have app like behavior - that is a user might call it an app like Outlook, Maps or Gmail. And they may also have a W3C app manifest.

A subset of web apps are progressive web apps. Progressive web apps are web apps that have a W3C app manifest and a service worker. Various OSes are beginning to support PWAs as first class apps on their platform. This is true for Win10 as well in which PWAs are run as a WWA.

Windows Web App

In Win10 a WWA (Windows Web App) is an unofficial term for a JavaScript UWP app. These are UWP apps so they have an AppxManifest.xml, they are packaged in an Appx package, they run in an App Container, they use WinRT APIs, and are installed via the Microsoft Store. Specific to WWAs though, is that the AppxManifest.xml specifies a StartPage attribute identifying some HTML content to be used as the app. When the app is activated the OS will create a WWAHost.exe process that hosts the HTML content using the EdgeHtml rendering engine.

Packaged vs Hosted Web App

Within that we have a notion of a packaged web app and an HWA (hosted web app). There's no real technical distinction for the end developer between these two. The only real difference is whether the StartPage identifies remote HTML content on the web (HWA), or packaged HTML content from the app's appx package (packaged web app). An end developer may create an app that is a mix of these as well, with HTML content in the package and HTML content from the web. These terms are more like ends on a continuum and identifying two different developer scenarios since the underlying technical aspect is pretty much identical.

Win10 PWA

Win10 PWAs are simply HWAs that specify a StartPage of a URI for a PWA on the web. These are still JavaScript UWP apps with all the same behavior and abilities as other UWP apps. We have two ways of getting PWAs into the Microsoft Store as Win10 PWAs. The first is PWA Builder which is a tool that helps PWA end developers create and submit to the Microsoft Store a Win10 PWA appx package. The second is a crawler that runs over the web looking for PWAs which we convert and submit to the Store using an automated PWA Builder-like tool to create a Win10 PWA from PWAs on the web (see Welcoming PWAs to Win10 for more info). In both cases the conversion involves examining the PWAs W3C app manifest and producing a corresponding AppxManifest.xml. Not all features supported by AppxManifest.xml are also available in the W3c app manifest. But the result of PWA Builder can be a working starting point for end developers who can then update the AppxManifest.xml as they like to support features like share targets or others not available in W3C app manifests.

Web Security Contest - Stripe CTF

PowerShell Scanning Script

I've hooked up the printer/scanner to the Media Center PC since I leave that on all the time anyway so we can have a networked printer. I wanted to hook up the scanner in a somewhat similar fashion but I didn't want to install HP's software (other than the drivers of course). So I've written my own script for scanning in PowerShell that does the following:

1. Scans using the Windows Image Acquisition APIs via COM
2. Runs OCR on the image using Microsoft Office Document Imaging via COM (which may already be on your PC if you have Office installed)
3. Converts the image to JPEG using .NET Image APIs
4. Stores the OCR text into the EXIF comment field using .NET Image APIs (which means Windows Search can index the image by the text in the image)
5. Moves the image to the public share

Here's the actual code from my scan.ps1 file:

param([Switch] $ShowProgress, [switch] $OpenCompletedResult)

$filePathTemplate = "C:\users\public\pictures\scanned\scan {0} {1}.{2}";
$time = get-date -uformat "%Y-%m-%d";

[void]([reflection.assembly]::loadfile( "C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.Drawing.dll"))

$deviceManager = new-object -ComObject WIA.DeviceManager
$device = $deviceManager.DeviceInfos.Item(1).Connect();

foreach ($item in $device.Items) {
        $fileIdx = 0;
        while (test-path ($filePathTemplate -f $time,$fileIdx,"*")) {
                [void](++$fileIdx);
        }

        if ($ShowProgress) { "Scanning..." }

        $image = $item.Transfer();
        $fileName = ($filePathTemplate -f $time,$fileIdx,$image.FileExtension);
        $image.SaveFile($fileName);
        clear-variable image

        if ($ShowProgress) { "Running OCR..." }

        $modiDocument = new-object -comobject modi.document;
        $modiDocument.Create($fileName);
        $modiDocument.OCR();
        if ($modiDocument.Images.Count -gt 0) {
                $ocrText = $modiDocument.Images.Item(0).Layout.Text.ToString().Trim();
                $modiDocument.Close();
                clear-variable modiDocument

                if (!($ocrText.Equals(""))) {
                        $fileAsImage = New-Object -TypeName system.drawing.bitmap -ArgumentList $fileName
                        if (!($fileName.EndsWith(".jpg") -or $fileName.EndsWith(".jpeg"))) {
                                if ($ShowProgress) { "Converting to JPEG..." }

                                $newFileName = ($filePathTemplate -f $time,$fileIdx,"jpg");
                                $fileAsImage.Save($newFileName, [System.Drawing.Imaging.ImageFormat]::Jpeg);
                                $fileAsImage.Dispose();
                                del $fileName;

                                $fileAsImage = New-Object -TypeName system.drawing.bitmap -ArgumentList $newFileName 
                                $fileName = $newFileName
                        }

                        if ($ShowProgress) { "Saving OCR Text..." }

                        $property = $fileAsImage.PropertyItems[0];
                        $property.Id = 40092;
                        $property.Type = 1;
                        $property.Value = [system.text.encoding]::Unicode.GetBytes($ocrText);
                        $property.Len = $property.Value.Count;
                        $fileAsImage.SetPropertyItem($property);
                        $fileAsImage.Save(($fileName + ".new"));
                        $fileAsImage.Dispose();
                        del $fileName;
                        ren ($fileName + ".new") $fileName
                }
        }
        else {
                $modiDocument.Close();
                clear-variable modiDocument
        }

        if ($ShowProgress) { "Done." }

        if ($OpenCompletedResult) {
                . $fileName;
        }
        else {
                $result = dir $fileName;
                $result | add-member -membertype noteproperty -name OCRText -value $ocrText
                $result
        }
}

I ran into a few issues:

• MODI doesn't seem to be in the Office 2010 Technical Preview I installed first. Installing Office 2007 fixed that.
• The MODI.Document class, at least via PowerShell, can't be instantiated in a 64bit environment. To run the script on my 64bit OS I had to start powershell from the 32bit cmd.exe (C:\windows\syswow64\cmd.exe).
• I was planning to hook up my script to the scanner's 'Scan' button, but HP didn't get the button working for their Vista driver. Their workaround is "don't do that!".
• You must call Image.Dispose() to get .NET to release its reference to the corresponding image file.
• In trying to figure out how to store the text in the files comment, I ran into a dead-end trying to find the corresponding setter for GetDetailsOf which folks like James O'Neil use in PowerShell for interesting ends.

The Wii Fit's Mind Games

Sarah received her Wii Fit a few weeks ago. The Wii Fit is a game for the Wii and a balance board accessory that can tell how you're standing on it: leaning forward, standing on one foot, leaning backward and mostly on your left foot, etc. The game puts you through various exercises grouped into the categories of aerobic, balance, strength, and yoga. It also lets you set goals and keeps track of how well you do, how long you play, and a graph of your weight.

The portion I didn't expect were the mind games. Sarah turned it on after not using it for a day and it said something to the effect of 'Oh, didn't have time to exercise yesterday? Huh. Interesting....' I'm paraphrasing of course but the Wii Fit was definitely trying to lay down some guilt. In another instance when starting up the Wii Fit Sarah was asked 'Did you know that Dave has been using Wii Fit?' She selected yes and it then asked her how she thought I was progressing giving her four options. She selected the worst one, that I was getting worse (jokingly I hope) and it told her to tell me that, but not to use those words. In conversation Sarah should mention to me that I've been "living large". Now I'm not paraphrasing. It reminded me a bit of this xkcd comic 'Zealous Autoconfig'. Hopefully this is the extent of the manipulation and mind games that the Wii Fit will perform.

Zeno's Progress Bar - Stolen Thoughts

More of my thoughts have been stolen: In my previous job the customer wanted a progress bar displayed while information was copied off of proprietary hardware, during which the software didn't get any indication of progress until the copy was finished. I joked (mostly) that we could display a progress bar that continuously slows down and never quite reaches the end until we know we're done getting info from the hardware. The amount of progress would be a function of time where as time approaches infinity, progress approaches a value of at most 100 percent.

This is similar to Zeno's Paradox which says you can't cross a room because to do so first you must cross half the room, then you must cross half the remaining distance, then half the remaining again, and so on which means you must take an infinite number of steps. There's also an old joke inspired by Zeno's Paradox. The joke is the prototypical engineering vs sciences joke and is moderately humorous, but I think the fact that Wolfram has an interactive applet demonstrating the joke is funnier than the joke itself.

I recently found Lou Franco's blog post "Using Zeno's Paradox For Progress Bars" which covers the same concept as Zeno's Progress Bar but with real code. Apparently Lou wasn't making a joke and actually used this progress bar in an application. A progress bar that doesn't accurately represent progress seems dishonest. In cases like the Vista Defrag where the software can't make a reasonable guess about how long a process will take the software shouldn't display a progress bar.

Similarly a paper by Chris Harrison "Rethinking the Progress Bar" suggests that if a progress bar speeds up towards the end the user will perceive the operation as taking less time. The paper is interesting, but as in the previous case, I'd rather have progress accurately represented even if it means the user doesn't perceive the operation as being as fast.

Update: I should be clearer about Lou's post. He was actually making a practical and implementable suggestion as to how to handle the case of displaying progress when you have some idea of how long it will take but no indications of progress, whereas my suggestion is impractical and more of a joke concerning displaying progress with no indication of progress nor a general idea of how long it will take.