TableOfReal: Draw rows as histogram...

A command to draw a histogram from the rows in the selected TableOfReal object.

The histogram will consist of groups of bars. The number of groups will be determined by the number of selected columns from the table, while the number of bars within each group will be determined from the number of selected rows.

## Settings

Row numbers and Column range
  determine the part of the table that you want to draw. The column range determines the number of bars that you want to draw for each row selected by the Row numbers argument.
Ymin and Ymax
  the drawing boundaries.

The following arguments are all relative to the width of a bar in the histogram.

Horizontal offset
  the offset from the left and right margin.
Distance between bar groups
  the distance between each group, i.e., the distance between the right side of the last bar in a group to the left side of the first bar in the next group.
Distance between bars
  the distance between the bars in a group.
Grey values
  the grey values of the bars in a group.

## Bar positioning

If you want to put the labels yourself you will need the following information.

The width of a bar is determined as follows:

width = 1 / (nc · nr + 2 · hoffset + (nc - 1)· intergroup +nc·(nr -1)· interbar),

where nc is the number of columns (groups) to draw, nr is the number of rows to draw (the number of bars within a group), hoffset is the horizontal offset, intergroup the distance between each group and interbar the distance between the bars within a group.

The spacing between the bars drawn from a row:

dx = (intergroup + nr + (nr -1) · interbar) * width

The first bar for the k-th row starts at:

x1 = hoffset · width + (k - 1) · (1 + interbar) · width