BS EN 62524:2011 pdf free download Multimedia systems and equipment — Multimedia e-publishing and e-books — Reader’s format for e-publishing
In the third step of the distribution chain,the publisher creates the final version of thedocument in the reader’s format,based on data obtained from the generic format in theprevious step,and finally distributes it to the reader. There can be several distinct reader’sformats,adapted to the various reading devices and distribution schemes.Because of readingdevices’ potential limitations,some reader’s format may lack support for certain features ofthe corresponding generic format. lt is the publisher’s role to determine how to convert an e-book to a less capable format.
4.2Requirements for reader’s format
The reader’s format can satisfy the following requirements of readers:a) non-revisable
As the reader’s format is the final form of the document,which will be used only forviewing, there is little point in it being revisable. What matters most is that the file shouldbe easy to process,even if this makes editing the data more difficult.Being revisable caneven be considered a problem, since it makes the format needlessly complex.
b) equipment-adaptive, application-adaptive
The reader’s format is directly processed while the reader browses the book.For thatreason,to maximize the reader’s comfort, the format should be specifically designed tomatch the capabilities of the device,in terms of CPU power,memory foot-print,displaysize,etc. For example, a format targeted at a device with weak processing abilities should,in order to keep the memory and CPU requirements low:(1) Use a light special purposebinary structure,rather than processing-intensive formats like XML.(2) store the pre-calculated position of the elements, rather than compute the layout on the fly ..On theother hand,if the target reading device is a high end processing system like a PC,aformat allowing for rich multimedia effects would be preferred,since it can easily behandled.
c) legibility
To achieve a sufficient level of reading comfort,it is important that the reader’s formatpays attention to legibility on the reading device. ln that regard, the followingimplementation methods can be considered.
. Fixed page layout
The format defines the document so that each page of the document may be renderedidentically on any reading device. In this type of layout, it is common to record directlyin the file the actual position of all displayable elements. Generally, as the publishercan specify precisely the final aspect, he will set the layout that is deemed to be themost comfortable for the reader.Consequently, complex designs can be achieved,aslong as the display is as large as, or maybe larger, than the designer expected,makingit possible to reach excellent levels of legibility. On the other hand, if the actual displayis smaller than the one the document was designed for,it must be zoomed out,possibly making some characters unreadable, or the reader has to scroll around the document, reducing the reading comfort.
• Flowing layout In this type of layout, the reading device dynamically determines, according to the screen size, where line breaks should be inserted, and compute the resulting position of the various elements. The final layout therefore depends on the screen size, font type, font size, etc. The reading device usually has a set of rules to handle word wrapping or hyphenation (ends of lines). Even though this layout model cannot achieve designs as sophisticated as fixed page layouts, it can guarantee that the text will remain clearly readable, whatever the screen size. It also usually gives more customization options to the reader, letting him set parameters as the font size or colour, making it more easily adaptable to individual readers’ preferences. On the other hand, the publisher somewhat loses control over the final appearance of the document.
• Others Intermediate solutions also exist. For example, a format could specify what is essentially a fixed layout when the screen is large enough to display the defined layout at the current zoom level, but also allow, when zooming in, to change the layout (by collapsing the margins or changing the paragraphs size, for example), so that the characters can indeed be zoomed in, without making the page larger than the screen.