Slider and IsDirectionReversed–Why doesn’t my app work on WP8 (part 6 of N)

Just when you thought all the bugs must have been ironed out by now, you stumble across a new one.

I’ve recently been updating all of my apps to Visual Studio 2013 so support will be simpler in future, and as a result started porting to WP8 from our old WP7 codebase.

Of course, everything is supposed to just work.  Today we’ll focus on the IsDirectionReversedProperty, which as will see should really be called IsDirectionReversedProperly!

Try sticking this in your WP app:

<Slider Orientation="Horizontal" Maximum="10" IsDirectionReversed="True" />

Can you see where this is going?

Now add Minimum="5" and be amazed that this slipped through testing.

It’s broken on the 720p emulator.  It’s broken on my Lumia 920 with GDR3.  It’s not broken in a WP7 app though.

So, I wonder how Microsoft can fix this out in the wild, (though it only seems to work in any kind of reasonable way if Minimum is set to 0).  Someone may be depending on this behavior.

Wow, that’s a tall image–Why doesn’t my app work on WP8 (part 5 of N)

I’m getting ready to port our app Where's my Tent to WP8, and as a start, I thought I’d rebuild it with the latest libraries, and incorporate some changes from our other apps.

After hooking in the new code, I ran it on my WP8 device, and had a big surprise.

On WP7, it appears that photos returned from the CameraCaptureTask are always in Landscape mode, though you can figure out what orientation they really are in using a technique described by Tim Heuer.

Unfortunately for me, my app was coded to assume Landscape, so when an image is actually delivered in portrait mode, my assumptions break due to this breaking change.

If you’ve made the same assumption, you’ll have the same problem.

I suspect Tim’s code might not work either

Because now his code that rotates the image may now fail because it returns portait, and then he rotates the pixels.

Update 17 June 2013

It turns out that on WP8, the Exif data doesn’t exist at all in the stream returned by the Photo Chooser, so Tim’s code will crash, as it doesn’t check for an exception or null.

Why doesn’t my app work on wp8 (part 1 of n)

We recently switched over to a Lumia 920 for testing our apps, and have found that some of our apps just don’t work correctly.

For instance, our popular Skied Demon ski logging app exhibits problems on Windows 8 on a Lumia 920.

It turns out that the problem is caused by setting up BitmapCache as the CacheMode on some of the controls to improve performance.  The ironic thing is that this fails on Windows Phone 8 and not on Windows Phone 7.

This may also be caused by the increased screen resolution on this particular phone though I haven’t yet been able to verify that.  I suspect that what’s happening is that a bitmap is being constructed for the size of the zoomed area.  As that size grows, eventually the entire thing falls apart.

However, I would have expected WP8 to behave at least as well as WP7.

So, that’s one (of presumably many to follow pitfalls, as we know at least one more of our apps is currently not working, probably caused by a store issue)

Windows 8 CP acmFormatChoose Bug

Yesterday, I decided to take the plunge and install W8 CP on a VHD, as described by Ed Bott here

It took a good few tries, but the step I hadn’t counted on was when I created the VHD, it takes a very long time to complete, and the UI doesn’t show you much in the Disk Manager.

Eventually, the 64 bit version was all up and running, so I decided to try our program RIP Vinyl, and was pleasingly surprised that our custom built installer wrapper we use for all of our projects installed without a hitch.

So, I launched the program, and recorded a test stream from YouTube.  It worked straight away on Windows 8!

Unfortunately, when I went to change the recording format to MP3, I started to hit problems.  Pressing the format change buttons did nothing.

The code allows the user to change the recording format by selecting a format via the acmFormatChoose dialog, but unfortunately, no matter what I tried, I keep getting a return code of 0x0000000B, or MMSYSERR_INVALPARAM

I’ve now built a very simple test using VS2010 and an MFC dialog based app, which runs fine on everything but W8.

I haven’t yet tried on the 32 bit version of W8.

Here’s the code I run on a button press in my MFC app:

MMRESULT Cacmformatchoosetest10Dlg::CheckFormat()
{
  ACMFORMATCHOOSE acmfmtch;
  int waveFormatExSizeMax;
  TCHAR waveformatName[_MAX_PATH];
  waveformatName[0] = 0;
  

  acmMetrics(NULL, ACM_METRIC_MAX_SIZE_FORMAT, &waveFormatExSizeMax);
  
  void *buffer = _alloca(2 * waveFormatExSizeMax);
  WAVEFORMATEX &wfx = *( (WAVEFORMATEX *) buffer);

  memset(&wfx, 0, sizeof(wfx));
  wfx.cbSize = 0;
  wfx.nChannels = 2;
  wfx.nBlockAlign=4;
  wfx.nSamplesPerSec=44100;
  wfx.wBitsPerSample=16;
  wfx.wFormatTag = WAVE_FORMAT_PCM;
  wfx.nAvgBytesPerSec=44100*4;

  ZeroMemory(&acmfmtch, sizeof(acmfmtch));

  acmfmtch.cbStruct = sizeof(acmfmtch);
  acmfmtch.fdwStyle = 0;
  acmfmtch.pfnHook = NULL; 
  acmfmtch.pszName = waveformatName;
  acmfmtch.cchName = _MAX_PATH;
  acmfmtch.pszTitle = _T("Title");
  acmfmtch.hwndOwner = NULL;
  acmfmtch.pwfx = &wfx;
  acmfmtch.cbwfx = waveFormatExSizeMax;

  acmfmtch.fdwEnum = ACM_FORMATENUMF_INPUT ; 
  acmfmtch.pwfxEnum = NULL; 

  return acmFormatChoose(&acmfmtch);
}

If anyone wants the entire project to try, please contact me via @WieserSoftware on twitter.

Silverlight Toolkit ListPicker changes

After my post about a week ago, about the Silverlight Toolkit November 2011 installer installing the wrong version I took some advice and started using NuGet.

So, as I’ve been updating my apps, I’ve begun adding the references to the latest toolkit.  Today, I came across a breaking change (I’ve switched from Version 1.0 to Version 7.0 of the toolkit in one jump) in the ListPicker.

My first clue should have been that ItemCountThreshold="3" raised an error, so I removed it, as the new threshold is consistent with my application.

Then I noticed that my picker page seemed to have a different font from the version of our Chromatic Tuner for Windows Phone: Tune Up that’s released on Marketplace.

It turns out, the ListPicker now navigates to a new page, which raised another bug in our software, because previously OnNavigatedTo was not called after the Picker was dismissed. 

As the program was so simple, we set the selected Item in the ListPicker irrespective of whether we were a new page, and therefore lost the new selection.