plshade1(3) Shade individual region on the basis of value

## SYNOPSIS

plshade1(a, nx, ny, defined, xmin, xmax, ymin, ymax, shade_min, shade_max, sh_cmap, sh_color, sh_width, min_color, min_width, max_color, max_width, fill, rectangular, pltr, pltr_data)

## DESCRIPTION

Shade individual region on the basis of value. Use plshades(3plplot) if you want to shade a number of contiguous regions using continuous colors. In particular the edge contours are treated properly in plshades(3plplot). If you attempt to do contiguous regions with plshade1(3plplot) (or plshade(3plplot)) the contours at the edge of the shade are partially obliterated by subsequent plots of contiguous shaded regions. plshade1(3plplot) differs from plshade(3plplot) by the type of the first argument. Look at the argument list below, plcont(3plplot) and the PLplot documentation for more information about the transformation from grid to world coordinates. Shading NEEDS DOCUMENTATION, but as a stopgap look at how plshade(3plplot) is used in examples/c/x15c.c

Redacted form: General: plshade1(a, defined, xmin, xmax, ymin, ymax, shade_min, shade_max, sh_cmap, sh_color, sh_width, min_color, min_width, max_color, max_width, fill, rectangular, pltr, pltr_data) Perl/PDL: plshade1(a, xmin, xmax, ymin, ymax, shade_min, shade_max, sh_cmap, sh_color, sh_width, min_color, min_width, max_color, max_width, fill, rectangular, defined, pltr, pltr_data)

This function is used in example 15.

## ARGUMENTS

a (const PLFLT *, input)
Contains array to be plotted. The array must have been declared as PLFLT a[nx][ny].
nx (PLINT, input)
First dimension of array "a".
ny (PLINT, input)
Second dimension of array "a".
defined (PLINT (*) (PLFLT, PLFLT), input)
User function specifying regions excluded from the shading plot. This function accepts x and y coordinates as input arguments and must return 0 if the point is in the excluded region or 1 otherwise. This argument can be NULL if all the values are valid.
xmin (PLFLT, input)
Defines the "grid" coordinates. The data a[0][0] has a position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin) and so on.
xmax (PLFLT, input)
Defines the "grid" coordinates. The data a[0][0] has a position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin) and so on.
ymin (PLFLT, input)
Defines the "grid" coordinates. The data a[0][0] has a position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin) and so on.
ymax (PLFLT, input)
Defines the "grid" coordinates. The data a[0][0] has a position of (xmin,ymin), a[nx-1][0] has a position at (xmax,ymin) and so on.
shade_min (PLFLT, input)
Defines the lower end of the interval to be shaded. If shade_max <= shade_min, plshade1(3plplot) does nothing.
shade_max (PLFLT, input)
Defines the upper end of the interval to be shaded. If shade_max <= shade_min, plshade1(3plplot) does nothing.
sh_cmap (PLINT, input)
Defines color map. If sh_cmap=0, then sh_color is interpreted as a color map 0 (integer) index. If sh_cmap=1, then sh_color is interpreted as a color map 1 floating-point index which ranges from 0. to 1.
sh_color (PLFLT, input)
Defines color map index if cmap0 or color map input value (ranging from 0. to 1.) if cmap1.
sh_width (PLFLT, input)
Defines width used by the fill pattern.
min_color (PLINT, input)
Defines pen color, width used by the boundary of shaded region. The min values are used for the shade_min boundary, and the max values are used on the shade_max boundary. Set color and width to zero for no plotted boundaries.
min_width (PLFLT, input)
Defines pen color, width used by the boundary of shaded region. The min values are used for the shade_min boundary, and the max values are used on the shade_max boundary. Set color and width to zero for no plotted boundaries.
max_color (PLINT, input)
Defines pen color, width used by the boundary of shaded region. The min values are used for the shade_min boundary, and the max values are used on the shade_max boundary. Set color and width to zero for no plotted boundaries.
max_width (PLFLT, input)
Defines pen color, width used by the boundary of shaded region. The min values are used for the shade_min boundary, and the max values are used on the shade_max boundary. Set color and width to zero for no plotted boundaries.
fill (void (*) (PLINT, const PLFLT *, const PLFLT *), input)
Routine used to fill the region. Use plfill(3plplot). Future version of plplot may have other fill routines.
rectangular (PLBOOL, input)
Set rectangular to true if rectangles map to rectangles after coordinate transformation with pltrl. Otherwise, set rectangular to false. If rectangular is set to true, plshade tries to save time by filling large rectangles. This optimization fails if the coordinate transformation distorts the shape of rectangles. For example a plot in polar coordinates has to have rectangular set to false.
pltr (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer) , input)
Pointer to function that defines transformation between indices in array z and the world coordinates (C only). Transformation functions are provided in the PLplot library: pltr0(3plplot) for identity mapping, and pltr1(3plplot) and pltr2(3plplot) for arbitrary mappings respectively defined by one- and two-dimensional arrays. In addition, user-supplied routines for the transformation can be used as well. Examples of all of these approaches are given in the PLplot documentation. The transformation function should have the form given by any of pltr0(3plplot), pltr1(3plplot), or pltr2(3plplot).
pltr_data (PLPointer, input)
Extra parameter to help pass information to pltr0(3plplot), pltr1(3plplot), pltr2(3plplot), or whatever routine that is externally supplied.

## AUTHORS

Many developers (who are credited at http://plplot.sourceforge.net/credits.php) have contributed to PLplot over its long history.