DBANDCOLOURS procedure

Plots a band of colours, for example, to provide a key for a heatmap (R.W. Payne).

No Options

Parameters

`START` = scalars or text	Initial colour for each band; must be set
`END` =scalars or text	Final colour for each band; must be set
`MINIMUM` = scalars	Start of the range of values represented in each band; must be set
`MAXIMUM` = scalars	Endpoint of the range of values represented in each band; must be set
`NBANDS` = scalar	Number of bands in each graph; default 100
`TITLE` = texts	Title for each graph; default * i.e. none
`WINDOW`= scalars	Window for each graph; default 1
`ORIENTATION`= string tokens	Orientation of each test graph (horizontal, upwards, downwards); default hori
`SCREEN`= string token	Whether to clear the screen before plotting each graph (clear, keep); default clear

Description

DBANDCOLOURSplots a band of colours corresponding to a range of values, which can be used, for example, to provide a key for a heatmap. The START and END parameters define the colours at the start and end of the band, as either a scalar containing an RGB value, or a text containing the name of one of the standard colours. (See the PEN directive for details.) The corresponding initial and final values of the variate in the heatmap are specified by the MINIMUM and MAXIMUM parameters.

The NBANDS parameter specifies the number of bands to appear in the graph. The default of 100 provides a fairly smooth gradation of colours through the plot.

The ORIENTATION parameter defines the direction of the plot, with one of the following settings:

horizontalhorizontally, left-to-right, across the wimdow (default);

upwardsvertically with the minimum at the origin; and

downwardsvertically with the maximum at the origin.

The WINDOW parameter specifies the window to be used for the plot (default 1), the TITLE parameter can provide a title, and the SCREEN parameter indicates whether existing plots on the screen are to be kept or cleared (default).

Options: None

Parameters: START, END, MINIMUM, MAXIMUM, NBANDS,TITLE,WINDOW, ORIENTATION, SCREEN

Method

DBANDCOLOURS uses the FHEATCOLOURS procedure to form a matrix containing RGB values of the band of colours, and then plots it using the DBITMAP directive.

Example

CAPTION  'DBANDCOLOURS example'; STYLE=meta
" define windows for a lower & a right-hand key "

FRAME    11,12; YLOWER=0,0.2; YUPPER=0.2,1;\
             YMLOWER=0.15,0.1; YMUPPER=0.02,0.07;\
             XLOWER=0,0.8; XUPPER=0.8,1;\
             XMLOWER=0.12,0.05; XMUPPER=0.05,0.1

DBANDCOLOURS START='blue'; END='yellow'; MINIMUM=0; MAXIMUM=200; WINDOW=11

DBANDCOLOURS START='blue'; END='yellow'; MINIMUM=0; MAXIMUM=200; WINDOW=12;\
             ORIENTATION=upwards; SCREEN=keep

Updated on April 15, 2024

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