If you’re using the Adobe Digital Publishing Suite to create apps for mobile devices such as the iPad and Kindle Fire, it’s important to structure your source files appropriately. There are two main reasons for structuring files appropriately:
- To import articles, re-create folios, or create folio renditions for multiple devices.
- To transfer files from one computer to another.
Structuring Files for Import
The Folio Builder panel offers two methods for creating articles: using the Add button to create an article or layout from the current document, or using the Import option to import one or more articles. When you use the Import method, the folder structure determines how the article is imported. This is all explained in the Structuring folders for imported articles help topic. Here is a quick summary of the article:
- If you’re importing multiple articles, create a parent folder with article subfolders.
- For articles based on InDesign source documents, create InDesign files with _h and _v suffixes such as kayaking_h.indd and kayaking_v.indd. Be consistent with your orientation: each article folder should have either one InDesign file (horizontal or vertical) or two InDesign files for dual-orientation files. Although we recommend that you include all your image files and overlay assets in the article folder, it isn’t required. Files you link to can be anywhere on your system.
- For articles based on HTML files, include only the HTML assets you’re using for the article. Unlike InDesign source files, all HTML assets in the folder are uploaded, sometimes resulting in folio bloat. For single-orientation folios, make sure that the HTML file includes a _h or _v suffix, such as index_h.html.
- If you want to use a special icon that appears when users tap the Table of Contents icon in the viewer, add a .png file to the article folder. Make sure that you use a small, 70×70 image for this TOC file — it doesn’t get resampled. Also, keep other image files inside a subfolder so that an image isn’t accidentally used as the TOC file. The above screen shot shows TOC images in each folder. These images appear when you open the Folio Basics issue in DPS Tips and tap the TOC icon, as shown here:
- When importing multiple articles, you can include a sidecar.xml file that brings in article metadata, such as the article author and description. Again, see the Structuring folders for imported articles help topic for tips on working with the sidecar.xml file.
Structuring Files for Overlays
Some DPS overlays require the source files to appear in their own folder. These overlays include Image Sequence, Panorama, Audio controller skins, and local Web Content files.
For Web Content overlays based on local HTML assets instead of URLs, make sure that the HTML file you specify appears in its own folder. All content in the HTML folder gets uploaded with the article, so this folder should include only the HTML assets used in the HTML file.
These overlay folders can appear anywhere on your computer, but we recommend that you keep your overlay files in the article folder to keep things tidy in case you need to transfer files.
Moving Folio Files to a Different Computer
If you need to transfer the source files for InDesign CS6, simply use the Package feature (in InDesign, choose File > Package) to package the InDesign file and transfer the packaged contents. InDesign CS6 includes all the assets, including overlay assets. Overlay assets are stored in an “Overlay Assets” subfolder. When you transfer the packaged contents to a different computer, the files maintain their links.
Transferring the source files for InDesign CS5 and CS5.5 is a different matter. When you package files, the overlay assets are not included. For best results, follow these steps:
- Open the InDesign CS5/CS5.5 source document and package it (for best results, do this early in the process to avoid having to relink overlays). You’ll end up with a folder that includes a Links subfolder, a Fonts subfolder, and instructions.txt. You can delete the instructions.txt file.
- If the article is part of a dual-orientation folio, add the alternate layout document to the packaged folder. Use the appropriate naming conventions for the document: article_h.indd and article_v.indd.
- Add all image and resource files — especially overlay assets — to the articles folder. I like to keep all assets, both interactive and non-interactive, in the Links subfolder.
When you transfer the files from one computer to another, you should be able to relink all the image files without a hitch. However, you (or the person receiving the files) will most likely need to select each overlay that links to local files — Image Sequence, Panorama, Audio skins, and local Web Content files, and use the Overlay Creator panel to point to the right location. You’ll likely see a yellow triangle above the assets icon. If you try to import an article before relinking the overlays, you’ll get an “Invalid assets” error message.
Which Files Are Uploaded?
Finally, let’s talk about which files get uploaded when you create an article. Understanding this will help you to determine which type of files to use in your layout and how to reduce folio size.
Non-interactive text and images – Each text frame, object, shape, or overlay poster that is not part of the actual overlay is resampled and included in part of the background image generated for each page of the article. This background file’s image format — PNG, JPG, or PDF — is determined by the Image Format setting when you create the article. For each page, a 72-ppi image is created using the same dimensions as the folio size (such as 1024×768).
The takeaway here is that you can use large PSD, AI, and TIFF files for non-interactive content in your InDesign layout. For best results, use images with at least 144 effective ppi.
Interactive source files that get resampled – Any image or source file that’s part of a slideshow (multi-state object), scrollable frame, button or hyperlink, is resampled as a 72-ppi PNG or JPG file.
Pass-through interactive source files – When you create an article, the source files for certain image formats are uploaded to the server without being compressed or resampled, even if the frames for these overlays are resized. These overlays include Image Sequence, Panorama, Pan & Zoom, Audio controller files, local Web Content files, and Audio and Video files.
The takeaway is that you should compress and resize certain overlay files to keep folio size to a minimum.
Let me know if I missed anything.