The tested qrcode scanner is ios13.0 and iphone11. and the png is show on a web page.
it is difficult(not possible?) to scan qrcode with 2048bytes with fix png size 256(default setting). I never success scan once with this setting. scale up the web is not working either.
workaround1:
if the pixelsPerModule is in range 1.0 and 2.0 , make it to 1.0 and compute offset to make it in the center of the png.(do not try to large scale with nearest with 1.5x, it will make one Module more like two Modules from the scanner)
This workaround will make it can be scaned, but a little difficult(Like the iphone must face the computer screen parallel)
workaround2:
if the length of content is large than 512 , make the png size to at least 512x512.
This workaround will make it very easy to scan.
ps, scan a qrcode with 2048 bytes content is slow on ios13.0, The machine may have too much work to do.
workaround1:
workaround2: