Render handler introduction

Information for writing new render handlers.

The most important thing about drawing Flash shapes is to understand how their fill styles work. A single Flash character can contain any number shapes that use any number of different fill styles and line styles. The shapes of a character are defined by a number of "paths". Some important things about paths:

Simple examples to understand this concept:

            +--------------------------------+
            |XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX|
            |XXX+------------------------+XXX|
            |XXX|                        |XXX|
            |XXX+------------------------+XXX|
            |XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX|
            +--------------------------------+
            +-------A-------+-------B--------+
            |...............|################|
            A...............C################B
            |...............|################|
            +-------A-------+-------B--------+

Flash will probably produce three paths (A,B,C) and two fill styles. Paths "A" and "B" will have just one fill style (fillstyle1 will be zero) while path "C" (which contains only one straight line!!) will have two fill styles. To be exact the horizontal edges would not even be necessary to render this shape (for a scanline based renderer) but they are necessary then the character is about to be rotated.

Now, these are simple examples but complex graphics can be compressed very efficiently this way. Also, this method was most probably intended for a renderer engine that can produce the final character in just one pass (like the AGG backend does too).