From playing around with it it feels like the text layer is centred on page whereas the canvas layer is aligned to the left.
What is text layer in pdf. For the foreground you append it thereafter. The basic idea there is you. How to tell if the hidden text layer in a pdf file is from OCR or notHelpful.
By means of text showing operators. There is only one Layer 1 or Layer 2 and so on. They can be edited moved or deleted without affecting anything on the content layer.
PDF Layer is a feature which allows some content to be made visible or invisible in the PDF. Annotations are distinct from the main page content in the PDF file. Its uses include PDF overlays having alternate languages appear and adding details to diagrams.
A text layer is added to the image layer usually placed underneath. It makes the PDF Layer widely be used to deal with related contents within the same PDF. There are several text rendering modes.
Developers can use PDF layer to set some content to be visible and others to be invisible in the same PDF file. Comments and markup are superimposed on the annotation layer. Many PDF files contain the content layer only.
Such documents become similar to true PDFs though depending on the quality of the image or the recognizability of the writing may not be. At the same time it also supports us. If you add something to a PDF in the background you simply prepend it before the existing content.