Gri: axis scaling

Chapters:
  1: Introduction
  2: Simple example
  3: Invocation
  4: Finer Control
  5: X-Y Plots
  6: Contour Plots
  7: Image Plots
  8: Examples
  9: Gri Commands
  10: Programming
  11: Environment
  12: Emacs Mode
  13: History
  14: Installation
  15: Gri Bugs
  16: Test Suite
  17: Gri in Press
  18: Acknowledgments
  19: License

Indices:
  Concepts
  Commands
  Variables

4.2: Axis scaling

Gri normally assumes that you are plotting scientific graphs, and therefore whenever it sees a command like `draw curve' or `draw symbol', it draws an appropriate axis first. You can turn this feature off, by using `draw axes none' before the other `draw' command.

Furthermore, Gri picks axis scales by itself, by scanning the (`x', `y') columns. If you don't like the scales Gri picks, you can override them (see Range).

Gri normally draws axes labelled at left and bottom, and with an axis frame with tics all around. If you don't like this default axis style you can specify other styles. For example, if the commands `draw x axis' and `draw y axis' are placed before the `draw curve' command, Gri will realize you've already specified axes, and just draw them on the left and bottom sides of the box, without completing the axis frame.

For your general use, Gri stores the minimum and maximum x and y values of the axes in the variables `..xleft..', `..xright..', `..ybottom..', and `..ytop..'. It also stores the increments used in labelling these axes in the `..xinc..' and `..yinc..' variables.

To determine the minimum and maximum values of column data, you may use the built-in RPN functions `min', `max', and `mean' (see Manipulation of Columns etc).

Gri stores the last (x,y) pair on a curve (whether data or axis) in the `..xlast..' and `..ylast..' variables

Gri stores the axis sizes in `..xsize..' and `..ysize..'. It stores the space to the left of the plot in `..xmargin..' and the space below the plot in `..ymargin..'.