CSCI 5733
XML Application Development
Summer 2009
Homework #4

Due date: August 3, 2009

Simplified fractal generator in SVG

Fractal contains recurring patterns. See http://www.mecxpert.de/svg/fractals.html for a simple introduction to IFS (Iterated Function Systems) fractal using the famous triangle fractal as an example.

Write a Java program, CreateFractal.java, and an XSLT program, generateFractal.xsl, for the generation of fractals in SVG format.

The Java program CreateFractal.java uses the service of generateFractal.xsl (but it is programmed in a way so it can also use other XSLT programs in the future.) It has exactly four command line arguments.

Java CreateFractal inputBaseFractal.svg fratcalTransform.xml generateFractal.xsl outputFractal.svg

inputBaseFractal.svg is the input base pattern of the fractal in SVG format that describes the basic pattern to recur. It uses a subset of SVG elements and additional elements and has the following requirements:

• The basic pattern is described in a <g> element of the <svg> element.
• The <g> element must have an id attribute with value "baseFractal".
• The <g> element may contain a <transform> attribute. This transform attribute will be applied to patterns of all depth.
• All descendant of the <g> element should not contain the transform attribute.
• Other fractal data is described in the element <fractal:data> using the namespace "http://dcm.uhcl.edu/yue/fractal".
• The element <fractal:data> has exactly four attributes (besides the namespace declaration of fractal):
  • width: width of the output SVG viewbox.
  • height: height of the output SVG viewbox.
  • maxDepthLevel: a positive number to indicate the maximum level of depth to be generated. If maxDepthLevel=1, no additional recurring pattern will be generated except of the base pattern.
  • viewOption: 'all' or 'last'.
    • last: only the last depth of patterns will be displayed.
    • all: all depths of patterns will be displayed (from depth 0 to maxDepthLevel). Furthermore, the opacity of each depth will increase uniformly. For example, if maxDepthLevel = 6, then the opacities of depth 0 and 1 will be 1/6 and 2/6 respectively.

Note that a better design is to separate <fractal:data> into a separate XML file to decouple the basic pattern and the view option. (There means your XSLT program will need to handle two input XML documents probably using extensions.) However, to simplify development, this is not required or allowed here.

generateFractal.xsl is the XSLT program you need to develop to merge the two input files and produce the output SVG file. You must use XSLT in this project.

fratcalTransform.xml describes the transformation used to generate the patterns in the next depth. The DTD is:

<!ELEMENT FractalTransformation (transform+) >
<!ELEMENT transform (EMPTY) >
<!ATTLIST transform transform CDATA #REQUIRED>

• Each <transform> element describes a pattern in the next depth generated by using a pattern in the previous depth. The transform attribute is the SVG transform attribute describing the transformation to create the new pattern.

outputFractal.svg is the output SVG file storing the generated fractal:

• The namespace fractal should not appear in the SVG file.

The following examples illustrate how the system works. Study the input and output files carefully.

(1) Triangle

Java CreateFractal triangle_1.svg triangle_base_1.xml generateFractal.xsl triangle_1_out.svg

Input files: triangle_1.svg, triangle_base_1.xml

Output SVG: triangle_1_out.svg

(2) Circle (Face)

Java CreateFractal circle4.svg FTBase_1.xml generateFractal.xsl circle4_out.svg

Input files: circle4.svg, FTBase_1.xml.

Output SVG: circle4_out.svg

(3) Ellipse

Java CreateFractal ellipse.svg FTBase_1.xml generateFractal.xsl ellipse_out.svg

Input files: ellipse.svg, FTBase_1.xml.

Output SVG: ellipse_out.svg

(4) Rectangle animation

Java CreateFractal animate.svg FTBase_1.xml generateFractal.xsl animate_out.svg

Input files: animate.svg, FTBase_1.xml.

Output SVG: animate_out.svg

Put all your files into the directory hw/h4 directly under your dcmweb account (not under the pages subdirectory.) Turn in program listing and output SVG listing of the four cases included. It is extremely important to use standard names. I will use a script to test run your program with various test files. If you do not use standard names, the script may not work and you will be penalized.

As usual, good documentation is expected.