Barcode: PDF417 barcode output cannot be read when it is smaller in size
Posted on:22 Jan 2020 15:36
There are minimal required/guided sizes for a barcode to be readable/scannable. The general guideline is to have 3 pixels per module. Technically, with higher PPI/DPI (Pixels Per Inch/Dots Per Inch) devices, 2 pixels are enough. This goes for both modules across columns and across rows. If you need to generate small barcodes you should ensure these guidelines are respected for your barcode to be scannable.
Let's take the 2"x1" label mentioned in the comments as an example. Given monitors have a very accurate pixel grid (compared to some printers) modules can be 2x2 pixels as a minimum. The most common monitors have a PPI value of 72 so for optimal results the barcode can be at most 144x72 pixels. Subtract the start, end and row indicator clusters that are reserved and collectively are 69 pixels and you are left with 75 pixels. A single data cluster is 17 modules, multiplied by 2 pixels per module you get 34 pixels. 75 pixels can fit two 34 pixel columns, which is the maximum number of columns you can have in that space without having modules that are below the guided size.
There is still plenty of information that can be fit in two columns you can have up to 36 rows and that is a lot. Correctly setting up the control should allow you to have scannable barcodes.
We verified we see identical problems with the barcode output in the Telerik UI for WPF.
Posted on:21 Jul 2016 15:36
Our 7-year Silverlight project may get derailed due to this key feature. We're required to place PDF417 barcodes on 2" x 1" labels and we cannot get them to scan at that size using the Telerik barcode control. Generation via online sites works well for same values but those are not Silverlight. We may need to port from Silverlight a couple of years early...