2024‐01‐03 Code Walkthrough

Working from SHA d18bb7c9a29e8e48dac86c99f03a43370a71ab95

pre-notes:

• Backing PDF manipulation library : https://pdf-lib.js.org/

The Code

The page renders!

• main.js has a DOMContentLoaded listener. It hooks up the change listeners

The user does something!

• changeHandlers.js has some of the change handlers. They primarily call updateForm(book)
• formUtils.js calls the book's createpages() and then updates the UI, calling several render functions (which live in renderUtils.js)

The magic of book.js ✨

• createpages() is basically top of the funnel.
  • manipulates a lot of book member variables along the way and then references them all over as it works it's way through sub function calls.
  • handles converting things from the uploaded PDF (this.currentdoc) into the appropriately rotated/modified this.managedDoc (which should be the source of all downstream PDFs)
  • applies the Source Manipulation section
  • instantiates and sets the appropriate this.book object based on layout/imposition
  • calls updatePageLayoutInfo in the renderUtils.js for the preview spacing box

A user clicks the Generate button

• createoutputfiles() is called

  • things start diverging here between classic and wacky
  • calls calculate_dimensions and passes it down as dim for future use
  • passes down calculatelayout as well

• live notes

• gotta embed the page into the PDFDocument and then draw the page on the PDFPage

• transparent line on a page because you can't add a page w/o content -- the library errors!

• good intro ticket, remove 3rd BOOKLET_LAYOUTS param and just reverse the 2nd. see signatures.js (double check that)