Tagged PDF Funsies
nibblestew.blogspot.com
nibblestew.blogspot.com
> PSD is not even a bad format. Calling it such would be an insult to other bad formats, such as PCX or JPEG. No, PSD is an abysmal format.
> Having worked on this code for several weeks now, my hate for PSD has grown to a raging fire that burns with the fierce passion of a million suns.
> If there are two different ways of doing something, PSD will do both, in different places....
[1]: https://github.com/zepouet/Xee-xCode-4.5/blob/master/XeePhot...
> "In the long run every [technology] becomes rococo - then rubble." — AJP
Things like PSD were designed by committees within Adobe, taking account marketing's concerns and building consensus around a camel when a horse, or perhaps cheetah, would have been vastly superior.
What the author describes is a general data structure called a "number tree", which is a general mapping from integers to arbitrary objects, represented as a tree of PDF objects. It is used in the standard at many places; in some cases, the keys are not consecutive.
The advantage over a plain dictionary or array is that the whole structure need not fit it memory at once. It's questionable if this is ever needed, but in early days of the PDF standard machines were much smaller and the authors decided to plan for documents with millions of pages processed by small machines. This style of thinking permeates the whole standard: see for example the page tree.
Still, it's unnecessarily complex for all but a tiny fraction (possibly zero) of uses. I would really appreciate if it were possible to use dictionaries instead of number trees whenever the tree is small.