QRShow

Program to display QR codes

An app that can display one of 4 different QR codes. (No more fumbling for a piece of paper or trying to pull a phone out a pocket when entering a concert.) These QR codes are downloaded from the internet.

QRShow is licensed under the GPL V3.0. The latest source tree is available for browsing here and tarballs for the latest and older versions are located at the following links:

Latest version
Version 1.21 - Initial release

QR display

The initial display is a screen showing the first QR code stored on the device. If no code has been downloaded yet then the left hand image above will be displayed. Tapping on the screen (or pushing the select button on non-touch screens) will download the image from the URL specified in the settings for the app.

This is just the first of 4 different QR codes that can be shown. Swiping up/down (or pressing up/down buttons) will cycle through the 4 different QR codes.

Manage Photo

Pressing the Back button (or swiping right on a touch screen) brings up this screen. From here you can:

Delete photo
This will delete the QR image from the watch and go back to the QR display screen where you can download a new copy of that image.
Cancel
Cancel this screen and go back to the QR display screen.
Exit app
Terminate the QRShow app.

QR Image Management

The easiest way to manage the QR code images is to store them on a cloud service. When utilizing a cloud service there are a few issues that have to be addressed (look to the sections on specific cloud storage providers to see work arounds for thesee issues):

Direct link
Images are loaded onto the watch via Garmin proxy serers and these servers only accecpt direct links to a file image (most cloud services provide links that point to an HTML wrapper around the actual file).
Persistent names
Although not technically required (you can update the settings for QRShow every time you upload a new QR code) it is much more convenient if the contents of a cloud storage file can be changed without changing the direct link for that file.

One way to deal with cloud storage and QRShow is to create 4 different files on your cloud storage provider. Configure direct links to those files as the settings URLs for the QRShow app. Then all you need to do is upload a new QR image into one of the cloud storage files and then tell QRShow to load the new image.

Google drive

It is very easy to integrate Google Drive with QRShow:

Direct link
Right click on the file name and then select share->share. In the popup change the General access from Restricted to Anyone with the link. Clicking on the Copy link copies the html wrapper link to the clipboard. Now you have to convert that wrapper URL to a direct link.
The web site Google Drive Direct Link Generator tells you exactly how to generate a direct link (usable by QRShow) from a Google Drive html wrapper link¹.
Persistent names
Google Drive allows the user to easily update a file without changing it URL links (perfect for using with QRShow). Right click on the file name and then select File information -> Manage versions. In the popup select Upload new version and then you can upload a new QR image for that file, leaving all of it's access URLs unchanged.

Dropbox

It's also simple to integrate Dropbox with QRShow:

Direct link
Use the Dropbox page to copy the share link. This link will end with the string dl=0. Change that string to dl=1 and you now have a direct link that is usable with QRShow.
Persistent names
This is easy, all you have to do is upload a new version of the QR code, making sure that you use the same name for the file in the new upload. On Dropbox, an uploaded file with the same name as a current Dropbox file just replaces the contents without affecting the sharable link.

Microsoft One Drive

Haven't been able to get One Drive share with anyone links to work, Microsoft still requires some sort of authentication (any authentiation breaks the Garmin proxy servers). If anyone has a solution let me know and I'll incorporate it.

Apple iCloud

Haven't been able to get iCloud share links to work either. If anyone has a solution let me know and I'll incorporate it.

Configuration

QRShow is configurable through the Connect IQ app on your phone. These settings are:

Cache images
QRShow will save each QR code in the app storage space so that they can be display even if the connected phone is not available. Unfortunately, Garmin has decided to put severe restrictions on what can be stored on the phone. ² Because of this, devices like a Fenix5 does not have enough space to store a simple QR code. ³ Setting this control to false will have QRShow download the QR image from the internet every time and will not store the image in the watches memory. This severely degrades the utility of the app but at least it still works.
URL
These are the 4 different URLs that contain the QR codes that the app will show.

QR Codes vs. images

This app was mainly designed to show QR codes so that's all that this documentation talks about. As it turns out, a QR code is just an image. QRShow will happily display any image you link it to, it doesn't care. Also, much is I have issues with the way Garmin handles images (check out the footnotes for my rants on this subject) a side effect of the Garmin approach is that there doesn't seem to be any limits on the size of image that you can display on your watch. On my Venu3 I have successfully displayed a 5,000 by 5,000 pixel image that was stored in a 33MByte file with no problem. You lose a lot of detail as the Garmin proxy servers compress those 5000x5000 pixels down to the 354x354 pixels that are actually displayed on the watch but it all works.

^{1.
Unfortunately,
nothing on the internet is
permanent so it's possible
that the Google Drive Direct Link Generator
site could go away.
If that happens,
the instructions for manually
converting a Google Drive html wrapper
URL into a direct access URL are simple.
Given an HTML wrapper URL of:

https://drive.google.com/file/d/1LDRlyZaZTF-bxHjBDEiL2obMxYHtf3YT/view?usp=sharing

you create a direct access URL by
extracting the file UUID,
the part between /d/ and /view,
and put it into a new URL which looks like this:

https://drive.google.com/uc?export=download&id=1LDRlyZaZTF-bxHjBDEiL2obMxYHtf3YT

^{2.
Major Rant.
Explain to me again why,
on my Venu3 watch that
has 8G of memory,
QRShow only has 128K
of storage space available
for QR images.}

^{3.
Second Rant.
Even though there is 128K of
total storage space, older
devices,
like the Fenix5,
can only store individual
items that are less than 8K
in size.
This is too small for
even a simple QR code so
storing images on older
devices won't work
⁴.
Fortunaely,
newer devices,
like the Venu3,
have increased the individual
item limit to 32K which
is enough to store images
on those devices.}

^{4.
Third Rant.
The obvious workaround
for the restricted item
size is to just break
the internal image bitmap
that the uses into 8K
chunks and then store those
chunks.
Nope,
Garmin does not provide any
API that allows an app to
mainipulate bitmaps so there's
no way to do this.}}