MapServer Rendering Plugin Status

This page documents the rendering plugin implementation status for MapServer version 6.0.

What Works:

• create image function (into an imageObj)
  • notes...
• basic vector API is in place (e.g. draw line, fill polygon, etc...)
  • Cairo Graphics is implemented in trunk
  • AGG is minimally implemented in a sandbox
  • KML SoC work uses this API
  • ...
• basic text API is in place
  • performance concerns regarding font handling
  • per glyph or per string?
• symbols support works for the most part
  • exception in PIXMAP symbols

Remaining Tasks:

• implement lazy PIXMAP loading
• write our own image loaders (into an imageObj), this is part of the rendering API
  • using libpng, libjpeg and something for GIF
  • drivers could choose to implement their own (e.g. GD)
• write our own image writers (from an imageObj), again, this is part of the rendering API
  • using libpng, libjpeg and something for GIF
  • drivers could choose to implement their own (e.g. GD)
  • Thomas has implemented PNG and JPEG writers already, minus color pre-preocessing and some other output optionss
• raster API implementation
  • how to deal with potentially different image buffers (e.g. GD vs. everything else)?
• implement color pre-processing
  • quantization
  • is there still a need for a partial palette?
• existing renderer re-writes
  • GD
  • vector drivers (PDF/SVG/Flash), may, in some cases, be replaced by Cairo
• symbol API gaps
  • use an imageObj instead of a gdImagePtr
• vector API gaps
  • polygon fills using a tile
  • hatching support
    • possibility exists to create a hatch generator (e.g. all the lines) and we'd pass those to the renderer
    • GD driver has code to compute the lines, but they aren't clipped
• remove GD dependencies from certain functional areas, specifically scalebar, legend and reference map generation
  • embedding may be difficult, however, if the symbolObj changes to use imageObj's for PIXMAP symbols then the current process can probably be retained