Re: Upcoming Zend_Pdf Enhancements

> Does anybody know what the status is? And especially the status of the
> enhancements to the memory usage and template system of zend pdf?
> Thanks!  
>
>
>
>
> Willie Alberty wrote:
> >
> > For the last few months I have been working with Kevin McArthur on a  
> > comprehensive PDF generation project for a client [Streamflow] who has  
> > some pretty advanced layout needs. The project is nearing completion  
> > and we have been discussing the possibility of contributing large  
> > portions of the code back to the Zend Framework as improvements to  
> > Zend_Pdf.
> >
> > In light of several recent postings to fw-general and fw-formats, as  
> > well as a few encouraging proposals recently submitted to the Wiki, we  
> > would like to formally announce our plans and describe the new  
> > functionality at a high level here.
> >
> > We will be submitting proposals in the coming weeks that describe  
> > these new components in more detail along with fully-functional  
> > reference implementations. Our hope is to join forces with other  
> > interested developers to help fast-track these proposals through the  
> > feedback and approval process, write tests, user documentation, and  
> > examples, and exercise the code as much as possible.
> >
> > We're really proud of this work and are excited to share it with the  
> > community. We believe that these enhancements will further establish  
> > Zend_Pdf's role as the gold standard for PDF generation using PHP.
> >
> >
> > Text Layout Engine
> > ------------------
> >
> > "How do I wrap long lines of text?" This is probably the most commonly-
> > asked question regarding Zend_Pdf. I'm pleased to report that not only  
> > have we solved the problem of text-wrapping, but a whole host of  
> > others as well. The new engine provides fully-automatic text layout,  
> > and has customization hooks in a variety of places.
> >
> > Line breaks are calculated using the Unicode Line Breaking Algorithm  
> > (UAX #14), providing linguistically-appropriate line breaks, not just  
> > at whitespace characters.
> >
> > Paragraph styles allow you to specify left-, center-, and right-
> > alignment, as well as full justification, line leading, line height,  
> > line multiple (double-space, triple-space, etc.), pre- and post-  
> > paragraph spacing, left- and right-side margins, and first-line  
> > indentation. Paragraph styles also support left-, center-, right-, and  
> > decimal-aligned tab stops, with or without leaders, for intra-line  
> > alignment needs.
> >
> > In addition to the left-to-right line sweep used by most Latin-based  
> > scripts, right-to-left line sweep is also supported, and is  
> > automatically detected by the layout engine; you never need to supply  
> > strings in reverse character order for right-to-left text layout.
> >
> > The layout engine is based around the concept of an attributed string.  
> > These are Unicode strings of unlimited length, and fully support the  
> > entire Unicode character set, including characters outside the Basic  
> > Multilingual Plane (BMP).
> >
> > Attributed strings allow you to assign stylistic attributes to  
> > arbitrary ranges of characters within the string. These attributes are  
> > used by typesetters to determine the specific look and location for  
> > every character. This means that you can make unlimited style changes  
> > within a block of text, even changing styles character-by-character if  
> > desired.
> >
> > The layout engine automatically manages all of these style changes,  
> > applying them as necessary when drawing the text on the page. The  
> > following style attributes are supported:
> >
> >   - Font
> >   - Font size
> >   - Fill color
> >   - Stroke width and color
> >   - Underline and strikethrough
> >   - Super- and sub-script
> >   - Background color
> >
> > You can add your own custom attributes as well, which you can use in  
> > your own subclasses to completely customize the layout engine's  
> > behavior.
> >
> > These attributed strings will eventually be shared with Zend_Rtf  
> > (recently proposed by Andries Seutens), as each attributed string is  
> > essentially a self-contained RTF document. This opens up the  
> > possibility for generating fully-styled PDF or RTF output from the  
> > same source with only a couple of lines of code. It will also  
> > eventually be possible to use existing styled RTF documents as the  
> > basis for PDF text drawing, eliminating the need to manually apply  
> > style attributes in your PHP code.
> >
> > A layout manager class is responsible for drawing these attributed  
> > strings. It lays out the text in a series of arbitrarily-shaped text  
> > containers, automatically moving from one to the next as each is  
> > filled. Rectangular and circular containers will be provided, but you  
> > can easily create your own custom containers for other shapes or to  
> > flow text around images.
> >
> > Multi-column output is as easy as creating two adjacent text  
> > containers on the same page. Text containers don't even need to be on  
> > the same PDF page: you can start your text in a small container on  
> > page 1, then continue it on page 17.
> >
> > Callback functions are provided to allow you to create text additional  
> > containers as needed, which can be located on new pages. This is  
> > useful if you do not know the length of the text you are drawing ahead  
> > of time, or if you want to adapt your layout on-the-fly.
> >
> > You can also use multiple layout managers on a single page, allowing  
> > you to create complex multi-page flows for a series of text runs.  
> > These can be useful for creating page headers and footers, or for  
> > running stories side-by-side in a newsletter.
> >
> >
> > Drawing Model
> > -------------
> >
> > Three new primitive geometry classes allow you to precisely define  
> > drawing locations, sizes, and regions. They also provide a host of  
> > convenience functions allowing for calculation, conversion,  
> > intersection testing, etc.:
> >
> >   - Point: x and y coordinate
> >   - Size: height and width
> >   - Rectangle: combination of a point and size
> >
> > PDF pages are drawn using a series of content streams, which contain  
> > all of the low-level drawing commands. Zend_Pdf_Page currently manages  
> > its own private content stream.
> >
> > We've separated content streams from Zend_Pdf_Page, promoting them to  
> > first-class objects. This allows us to use these content streams as  
> > templates that can be reused again and again, either on a single page  
> > or multiple pages. Templates can greatly reduce PDF file sizes and  
> > improve memory use and performance in PDF viewer applications.
> >
> > It is also possible to create a template from any page in an existing  
> > PDF document. You can then reuse the template in the same PDF, or even  
> > copy it to a new PDF document, where you can use it as a page  
> > background, draw it as a thumbnail, perform imposition, etc.
> >
> >
> > Performance and Memory
> > ----------------------
> >
> > We've also made numerous performance and memory-usage improvements  
> > throughout the code. Most data is now lazily-loaded, allowing you to  
> > manipulate very large documents, containing thousands or millions of  
> > individual objects or hundreds of megabytes or gigabytes in size, with  
> > a very low memory footprint.
> >
> >
> > Future Enhancements
> > -------------------
> >
> > All of this new functionality lays the groundwork for even more  
> > powerful enhancements down the road:
> >
> >   - Top-to-bottom line sweep for Asian scripts
> >   - Bi-directional text (for Hebrew, Arabic, and others)
> >   - Bulleted and numbered text lists
> >   - HTML-inspired inline text tables
> >   - Inline attachments (for example, images that flow with text)
> >   - Advanced typographic features such as tracking, pairwise kerning,  
> > ligatures, etc.
> >   - Hyphenation support
> >   - Glyph substitution using fallback fonts
> >   - and more...
> >
> >
> > Again, we're really excited to be sharing this code with the  
> > community. We'll be creating the proposals for the various components  
> > in the coming weeks and announcing them on the fw-formats list when  
> > they're ready for review. In the meantime, if you have any high-level  
> > questions, please don't hesitate to ask.
> >
> > --
> >
> > Willie Alberty, Owner
> > Spenlen Media
> > willie@...
> >
> > http://www.spenlen.com/
> >
> >
> >
>