todo.txt

- use libclutter for interactive use?

- draw to user-specified cairo surface (so the user has full choice of
  output)
- has to be *fast*
- must be easy to use on / port to win32 (primary target: *nix)
- initially in perl, later in C + perl bindings
- interactive support
  - fast redraw on resize
  - fast redraw on un-/zoom
  - fast redraw on move of viewport (when zoomed in)
  - fast redraw on dataset modification (i.e. update only one graph)
  - fast redraw on tuple modification (later)
  - "live" datasets (later)
  - translate cursor coordinats to data "coordinates"
  - hitareas for graphs + elements (labels, scales, legend) (later)

- charts:
  - pies (later)
  - polars (later)
    - points
    - line
    - linepoints
    - combined
  - cartesian 3D  (later)
    - surfaces
    - shade
  - cartesian 2D
    - plot types:
      - points
      - line (+point)
      - stacked lines
      - area
      - stacked area
      - bars
      - stacked bars
      - combined
      - scatter (later)
      - countour (later)
      - paths (later)
    - "unlimited" axises per chart
      - custom placement of axises (top/zero/bottom, left/zero/right)
      - 2 scales per axis (left/right, above/below)
        - bind scales to any axis (i.e. x to a vertical one)
        - choice of x and y scale per dataset
        - per tuple scales (bargraphs, ...)
        - numeric scales:
          - linear
          - logarithmic
        - draw major/minor tics:
          - at specified positions
          - from number of tics
          - from distance of tics
          - tick labels:
            - at specified tics
            - handle labels that would overlap (skip, indent, ...)
            - customizable formatting
	    - adjustable orientation


cache graphs:
- draw each graph to it's own surface / cache cairo path
  - get data-sources' min/max
  - prepare line type parameters (color, solid/dashed/..., brush)
  - for each data set:
    - calc surface coords
    - plot segment
    - remeber path for hitarea

after resize / zoom / movement of a graph:
- calculate number of required axis labels and ticks
- generate axis labels and get their size
- generate legend box and get it's size
- calculate (remaining) plot area size
- draw axises, add labels
- draw resized (part?) graph_surfaces into plot area