Ability to zoom

[LarsBuur]

I have experimented with the plugin and everything seems to work great. Our QR codes are rather small and it would be a great help if we somehow could control the camera zoom. If we get to close to the QR code then it becomes blurry. For our purposes a setting of e.g. 1.5 zoom on .scan would be great.

[bitjson]

I haven't really thought about this use case, but I can see us supporting it. Have you thought about how the API should work?

I'd love to review a pull request for the feature!

[LarsBuur]

Thanks for the feedback! A simple suggestion would be:

let zoomFactor = 1.5;
QRScanner.setZoom(zoomFactor, function(err, status){
  err && console.error(err);
  console.log(status);
});

And this would not break backwards compatibility.

I have no clue how to set zoom in swift and android so I would not be the right person som create this feature. If you have an idea as to where to implement this I would like to give it a try. My testing efforts are also rather limited as I have only an iOS device.

[bitjson]

Trying to thing about the other details –

We would probably also need to add at least one status object property for the functionality – maybe something like canZoom to describe if any optical zoom is available on the current camera, and the setZoom method could take a number between 0 and 1 (minimum and maximum zoom level)? I think that would abstract it enough (not sure how the various OS APIs do zooming), and still provide flexibility implementations that need to show the user an indication of the current zoom level.

[LarsBuur]

If the design of canZoom is using values between 0 and 1 to set the zoom then 0 would mean not zoomed (default) and 1 meaning max zoomed.

canZoom makes sense for ui purposes - but I am not sure if there even are cameras out there that does not allow zooming. Besides that my use case does not require optical zoom. Our problem is that if you bring in the camera to close then it gets blurry and cant focus. - both on android and iOS

I have added an image to show our challenges. I accept that this might be an edge case. Out use case is that we want an app where our assembly line can scan our sensors before final assembly.

[bitjson]

Ah, I hadn't considered that digital zoom might be valuable. It would probably be good to test that assumption first (since digital zoom isn't actually improving image quality, I wonder if simply scaling the image will assist in decoding the QR code at all).

If it is valuable, I'd say a good option for modifying the API would be to define zoomFactor values between 0 and 1 as optical zoom, and values between 1 and 2 as digital zoom.

So implementations can choose if/how they want to provide each stage of zoom.

[princeandrewdiana]

same problem here. any updates?

[burtontanner]

I have woked around this by suggesting a smaller scan area. If the code is in the center of the screen and can focus, it works pretty well. My data matrix is 1/4 inch.

[princeandrewdiana]

I see. Were you able to solve it?

[liuyao552]

When can I zoom automatically