Author image Ed J

NAME

PDL::Graphics::PLplot - Object-oriented interface from perl/PDL to the PLPLOT plotting library

SYNOPSIS

  use PDL;
  use PDL::Graphics::PLplot;

  my $pl = PDL::Graphics::PLplot->new (DEV => "png", FILE => "test.png");
  my $x  = sequence(10);
  my $y  = $x**2;
  $pl->xyplot($x, $y);
  $pl->close;

Only version 5.15.0+ of PLplot is fully supported, due to a C-level API change that is invisible at PDL-level. However, the library does support installation with PLplot 5.13.0+.

For more information on PLplot, see

 http://www.plplot.org/

Also see the test file, t/plplot.t in this distribution for some working examples.

LONG NAMES

If you are annoyed by the long constructor call, consider installing the aliased CPAN package. Using aliased, the above example becomes

  use PDL;
  use aliased 'PDL::Graphics::PLplot';

  my $pl = PLplot->new (DEV => "png", FILE => "test.png");
  my $x  = sequence(10);
  # etc, as above

DESCRIPTION

This is the PDL interface to the PLplot graphics library. It provides a familiar 'perlish' Object Oriented interface as well as access to the low-level PLplot commands from the C-API.

OPTIONS

The following options are supported. Most options can be used with any function. A few are only supported on the call to 'new'.

Options used upon creation of a PLplot object (with 'new'):

BACKGROUND

Set the color for index 0, the plot background

DEV

Set the output device type. To see a list of allowed types, try:

  PDL::Graphics::PLplot->new();
   PDL::Graphics::PLplot->new(DEV => 'png', FILE => 'test.png');

FILE

Set the output file or display. For file output devices, sets the output file name. For graphical displays (like 'xwin') sets the name of the display, eg ('hostname.foobar.com:0')

   PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png');
   PDL::Graphics::PLplot->new(DEV => 'xwin', FILE => ':0');

OPTS

Set plotting options. See the PLplot documentation for the complete listing of available options. The value of 'OPTS' must be a hash reference, whose keys are the names of the options. For instance, to obtain PostScript fonts with the ps output device, use:

   PDL::Graphics::PLplot->new(DEV => 'ps', OPTS => {drvopt => 'text=1'});

MEM

This option is used in conjunction with DEV => 'mem'. This option takes as input a PDL image and allows one to 'decorate' it using PLplot. The 'decorated' PDL image can then be written to an image file using, for example, PDL::IO::Pic. This option may not be available if plplot does not include the 'mem' driver.

  # read in Earth image and draw an equator.
  my $pl = PDL::Graphics::PLplot->new (MEM => $earth, DEV => 'mem');
  my $x  = pdl(-180, 180);
  my $y  = zeroes(2);
  $pl->xyplot($x, $y,
              BOX => [-180,180,-90,90],
              VIEWPORT => [0.0, 1.0, 0.0, 1.0],
              XBOX => '', YBOX => '',
              PLOTTYPE => 'LINE');
  $pl->close;

FRAMECOLOR

Set color index 1, the frame color

JUST

A flag used to specify equal scale on the axes. If this is not specified, the default is to scale the axes to fit best on the page.

  PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png', JUST => 1);

ORIENTATION

The orientation of the plot:

  0 --   0 degrees (landscape mode)
  1 --  90 degrees (portrait mode)
  2 -- 180 degrees (seascape mode)
  3 -- 270 degrees (upside-down mode)

Intermediate values (0.2) are acceptable if you are feeling daring.

  # portrait orientation
  PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png', ORIENTATION => 1);

PAGESIZE

Set the size in pixels of the output page.

  # PNG 500 by 600 pixels
  PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png', PAGESIZE => [500,600]);

SUBPAGES

Set the number of sub pages in the plot, [$nx, $ny]

  # PNG 300 by 600 pixels
  # Two subpages stacked on top of one another.
  PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png', PAGESIZE => [300,600],
                                              SUBPAGES => [1,2]);

Options used after initialization (after 'new')

BOX

Set the plotting box in world coordinates. Used to explicitly set the size of the plotting area.

 my $pl = PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png');
 $pl->xyplot ($x, $y, BOX => [0,100,0,200]);

CHARSIZE

Set the size of text in multiples of the default size. CHARSIZE => 1.5 gives characters 1.5 times the normal size.

COLOR

Set the current color for plotting and character drawing. Colors are specified not as color indices but as RGB triples. Some pre-defined triples are included:

  BLACK        GREEN        WHEAT        BLUE
  RED          AQUAMARINE   GREY         BLUEVIOLET
  YELLOW       PINK         BROWN        CYAN
  TURQUOISE    MAGENTA      SALMON       WHITE
  ROYALBLUE    DEEPSKYBLUE  VIOLET       STEELBLUE1
  DEEPPINK     MAGENTA      DARKORCHID1  PALEVIOLETRED2
  TURQUOISE1   LIGHTSEAGREEN SKYBLUE     FORESTGREEN
  CHARTREUSE3  GOLD2        SIENNA1      CORAL
  HOTPINK      LIGHTCORAL   LIGHTPINK1   LIGHTGOLDENROD
 # These two are equivalent:
 $pl->xyplot ($x, $y, COLOR => 'YELLOW');
 $pl->xyplot ($x, $y, COLOR => [0,255,0]);

CONTOURLABELS

Control of labels for contour plots.

Must either be 0 (turn off contour labels), 1 (turn on default contour labels) or a five element array:

 offset:  Offset of label from contour line (if set to 0.0, labels are printed on the lines). Default value is 0.006.
 size:    Font height for contour labels (normalized). Default value is 0.3.
 spacing: Spacing parameter for contour labels. Default value is 0.1.
 lexp:    If the contour numerical label is greater than 10^(lexp) or less than 10^(-lexp),
          then the exponential format is used. Default value of lexp is 4.
 sigdig:  Number of significant digits. Default value is 2";
 $pl->shadeplot ($z, $nsteps, BOX => [-1, 1, -1, 1], PLOTTYPE => 'CONTOUR', CONTOURLABELS => [0.004, 0.2, 0.2, 4, 2]);
 $pl->shadeplot ($z, $nsteps, BOX => [-1, 1, -1, 1], PLOTTYPE => 'CONTOUR', CONTOURLABELS => 0); # turn off labels
 $pl->shadeplot ($z, $nsteps, BOX => [-1, 1, -1, 1], PLOTTYPE => 'CONTOUR', CONTOURLABELS => 1); # use default labels

GRIDMAP

Set a user-defined grid map. This is an X and Y vector that tells what are the world coordinates for each pixel in $z It is used in 'shadeplot' for non-standard mappings between the input 2D surface to plot and the world coordinates. For example if your surface does not completely fill up the plotting window.

 my $z = $surface; # 2D PDL to plot (generated elsewhere)
 my $nlevels = 20;
 my ($nx, $ny) = $z->dims;
 my @zbounds = ($minx, $maxx, $miny, $maxy);

 # Map X coords linearly to X range, Y coords linearly to Y range
 my $xmap = ((sequence($nx)*(($zbounds[1] - $zbounds[0])/($nx - 1))) + $zbounds[0]);
 my $ymap = ((sequence($ny)*(($zbounds[3] - $zbounds[2])/($ny - 1))) + $zbounds[2]);
 $pl->shadeplot ($z, $nlevels, PALETTE => 'GREENRED', GRIDMAP => [$xmap, $ymap]);

GRIDMAP2

Set a user-defined two dimensional grid map. These are 2D X and Y matrices that tell what are the world coordinates for each pixel in $z It is used in 'shadeplot' for non-standard mappings between the input 2D surface to plot and the world coordinates, for example irregular grids like polar projections.

 my $r_pts     = 40;
 my $theta_pts = 40;
 my $pi        = 4*atan2(1,1);
 my $nlevels   = 20;

 my $r     = ((sequence ($r_pts)) / ($r_pts - 1))->dummy (1, $theta_pts);
 my $z     = $r;  # or any other 2D surface to plot...
 my $theta = ((2 * $pi / ($theta_pts - 2)) * sequence ($theta_pts))->dummy (0, $r_pts);
 my $xmap  = $r * cos ($theta);
 my $ymap  = $r * sin ($theta);

 $pl->shadeplot ($z, $nlevels, PLOTTYPE => 'CONTOUR',
                               JUST     => 1,
                               BOX      => [-1,1,-1,1],
                               PALETTE  => 'GREENRED',
                               GRIDMAP2 => [$xmap, $ymap]);

LINEWIDTH

Set the line width for plotting. Values range from 1 to a device dependent maximum.

LINESTYLE

Set the line style for plotting. Pre-defined line styles use values 1 to 8, one being a solid line, 2-8 being various dashed patterns.

MAJTICKSIZE

Set the length of major ticks as a fraction of the default setting. One (default) means leave these ticks the normal size.

MINTICKSIZE

Set the length of minor ticks (and error bar terminals) as a fraction of the default setting. One (default) means leave these ticks the normal size.

NXSUB

The number of minor tick marks between each major tick mark on the X axis. Specify zero (default) to let PLplot compute this automatically.

NYSUB

The number of minor tick marks between each major tick mark on the Y axis. Specify zero (default) to let PLplot compute this automatically.

PALETTE

Load pre-defined color map 1 color ranges. Currently, values include:

  RAINBOW   -- from Red to Violet through the spectrum
  REVERSERAINBOW   -- Violet through Red
  GREYSCALE -- from black to white via grey.
  REVERSEGREYSCALE -- from white to black via grey.
  GREENRED  -- from green to red
  REDGREEN  -- from red to green
 # Plot x/y points with the z axis in color
 $pl->xyplot ($x, $y, PALETTE => 'RAINBOW', PLOTTYPE => 'POINTS', COLORMAP => $z);

PLOTTYPE

Specify which type of XY or shade plot is desired:

  LINE       -- A line
  POINTS     -- A bunch of symbols
  LINEPOINTS -- both

  or, for 'shadeplot':
  CONTOUR    -- A contour plot of 2D data
  SHADE      -- A shade plot of 2D data

STACKED_BAR_COLORS

For 'bargraph', request a stacked bar chart. Must contain a reference to a perl list of color names or RGB triples.

 # $labels is a reference to a perl array with N x-axis labels
 # $values is an NxM PDL where M is the number of stacked bars (in this case 2,
 # since STACKED_BAR_COLORS contains two colors).
 $pl->bargraph($labels, $values, STACKED_BAR_COLORS => ['GREEN', [128,0,55]);

SUBPAGE

Set which subpage to plot on. Subpages are numbered 1 to N. A zero can be specified meaning 'advance to the next subpage' (just a call to pladv()).

  my $pl = PDL::Graphics::PLplot->new(DEV      => 'png',
                                        FILE     => 'test.png',
                                        SUBPAGES => [1,2]);
  $pl->xyplot ($x, $y, SUBPAGE => 1);
  $pl->xyplot ($a, $b, SUBPAGE => 2);

SYMBOL

Specify which symbol to use when plotting PLOTTYPE => 'POINTS'. A large variety of symbols are available, see: http://plplot.sourceforge.net/examples-data/demo07/x07.*.png, where * is 01 - 17. You are most likely to find good plotting symbols in the 800s: http://plplot.sourceforge.net/examples-data/demo07/x07.06.png

SYMBOLSIZE

Specify the size of symbols plotted in multiples of the default size (1). Value are real numbers from 0 to large.

TEXTPOSITION

Specify the placement of text. Either relative to border, specified as:

 [$side, $disp, $pos, $just]

Where

  side = 't', 'b', 'l', or 'r' for top, bottom, left and right
  disp is the number of character heights out from the edge
  pos  is the position along the edge of the viewport, from 0 to 1.
  just tells where the reference point of the string is: 0 = left, 1 = right, 0.5 = center.

or inside the plot window, specified as:

 [$x, $y, $dx, $dy, $just]

Where

  x  = x coordinate of reference point of string.
  y  = y coordinate of reference point of string.
  dx   Together with dy, this specifies the inclination of the string.
       The baseline of the string is parallel to a line joining (x, y) to (x+dx, y+dy).
  dy   Together with dx, this specifies the inclination of the string.
  just Specifies the position of the string relative to its reference point.
       If just=0, the reference point is at the left and if just=1,
       it is at the right of the string. Other values of just give
       intermediate justifications.
 # Plot text on top of plot
 $pl->text ("Top label",  TEXTPOSITION => ['t', 4.0, 0.5, 0.5]);

 # Plot text in plotting area
 $pl->text ("Line label", TEXTPOSITION => [50, 60, 5, 5, 0.5]);

TITLE

Add a title on top of a plot.

 # Plot text on top of plot
 $pl->xyplot ($x, $y, TITLE => 'X vs. Y');

UNFILLED_BARS

For 'bargraph', if set to true then plot the bars as outlines in the current color and not as filled boxes

 # Plot text on top of plot
 $pl->bargraph($labels, $values, UNFILLED_BARS => 1);

VIEWPORT

Set the location of the plotting window on the page. Takes a four element array ref specifying:

 xmin -- The coordinate of the left-hand edge of the viewport. (0 to 1)
 xmax -- The coordinate of the right-hand edge of the viewport. (0 to 1)
 ymin -- The coordinate of the bottom edge of the viewport. (0 to 1)
 ymax -- The coordinate of the top edge of the viewport. (0 to 1)

You will need to use this to make color keys or insets.

 # Make a small plotting window in the lower left of the page
 $pl->xyplot ($x, $y, VIEWPORT => [0.1, 0.5, 0.1, 0.5]);

 # Also useful in creating color keys:
 $pl->xyplot   ($x, $y, PALETTE => 'RAINBOW', PLOTTYPE => 'POINTS', COLORMAP => $z);
 $pl->colorkey ($z, 'v', VIEWPORT => [0.93, 0.96, 0.15, 0.85]);

 # Plot an inset; first the primary data and then the inset. In this
 # case, the inset contains a selection of the orignal data
 $pl->xyplot ($x, $y);
 $pl->xyplot (where($x, $y, $x < 1.2), VIEWPORT => [0.7, 0.9, 0.6, 0.8]);

XBOX

Specify how to label the X axis of the plot as a string of option letters:

  a: Draws axis, X-axis is horizontal line (y=0), and Y-axis is vertical line (x=0).
  b: Draws bottom (X) or left (Y) edge of frame.
  c: Draws top (X) or right (Y) edge of frame.
  d: Plot labels as date / time. Values are assumed to be seconds since the epoch (as used by gmtime).
  f: Always use fixed point numeric labels.
  g: Draws a grid at the major tick interval.
  h: Draws a grid at the minor tick interval.
  i: Inverts tick marks, so they are drawn outwards, rather than inwards.
  l: Labels axis logarithmically. This only affects the labels, not the data,
     and so it is necessary to compute the logarithms of data points before
     passing them to any of the drawing routines.
  m: Writes numeric labels at major tick intervals in the
     unconventional location (above box for X, right of box for Y).
  n: Writes numeric labels at major tick intervals in the conventional location
     (below box for X, left of box for Y).
  s: Enables subticks between major ticks, only valid if t is also specified.
  t: Draws major ticks.

The default is 'BCNST' which draws lines around the plot, draws major and minor ticks and labels major ticks.

 # plot two lines in a box with independent X axes labeled
 # differently on top and bottom
 $pl->xyplot($x1, $y, XBOX  => 'bnst',  # bottom line, bottom numbers, ticks, subticks
                      YBOX  => 'bnst'); # left line, left numbers, ticks, subticks
 $pl->xyplot($x2, $y, XBOX => 'cmst', # top line, top numbers, ticks, subticks
                      YBOX => 'cst',  # right line, ticks, subticks
                      BOX => [$x2->minmax, $y->minmax]);

XERRORBAR

Used only with "xyplot". Draws horizontal error bars at all points ($x, $y) in the plot. Specify a PDL containing the same number of points as $x and $y which specifies the width of the error bar, which will be centered at ($x, $y).

XLAB

Specify a label for the X axis.

XTICK

Interval (in graph units/world coordinates) between major x axis tick marks. Specify zero (default) to allow PLplot to compute this automatically.

YBOX

Specify how to label the Y axis of the plot as a string of option letters. See "XBOX".

YERRORBAR

Used only for xyplot. Draws vertical error bars at all points ($x, $y) in the plot. Specify a PDL containing the same number of points as $x and $y which specifies the width of the error bar, which will be centered at ($x, $y).

YLAB

Specify a label for the Y axis.

YTICK

Interval (in graph units/world coordinates) between major y axis tick marks. Specify zero (default) to allow PLplot to compute this automatically.

ZRANGE

For "xyplot" (when COLORMAP is specified), for "shadeplot" and for "colorkey". Normally, the range of the Z variable (color) is taken as $z->minmax. If a different range is desired, specify it in ZRANGE, like so:

  $pl->shadeplot ($z, $nlevels, PALETTE => 'GREENRED', ZRANGE => [0,100]);

or

  $pl->xyplot ($x, $y, PALETTE  => 'RAINBOW', PLOTTYPE => 'POINTS',
                       COLORMAP => $z,        ZRANGE => [-90,-20]);
  $pl->colorkey  ($z, 'v', VIEWPORT => [0.93, 0.96, 0.13, 0.85],
                       ZRANGE => [-90,-20]);

METHODS

These are the high-level, object oriented methods for PLplot.

new

Create an object representing a plot.

 Arguments:
 none.

 Supported options:
 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES
  my $pl = PDL::Graphics::PLplot->new(DEV => 'png',  FILE => 'test.png');

setparm

Set options for a plot object.

 Arguments:
 none.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $pl->setparm (TEXTSIZE => 2);

xyplot

Plot XY lines and/or points. Also supports color scales for points. This function works with bad values. If a bad value is specified for a points plot, it is omitted. If a bad value is specified for a line plot, the bad value makes a gap in the line. This is useful for drawing maps; for example $x and $y can be the continent boundary latitude and longitude.

 Arguments:
 $x, $y

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $pl->xyplot($x, $y, PLOTTYPE => 'POINTS', COLOR => 'BLUEVIOLET', SYMBOL => 1, SYMBOLSIZE => 4);
  $pl->xyplot($x, $y, PLOTTYPE => 'LINEPOINTS', COLOR => [50,230,30]);
  $pl->xyplot($x, $y, PALETTE => 'RAINBOW', PLOTTYPE => 'POINTS', COLORMAP => $z);

stripplots

Plot a set of strip plots with a common X axis, but with different Y axes. Looks like a stack of long, thin XY plots, all line up on the same X axis.

 Arguments:
 $xs -- 1D PDL with common X axis values, length = N
 $ys -- reference to a list of 1D PDLs with Y-axis values, length = N
        or 2D PDL with N x M elements
 -- OR --
 $xs -- reference to a list of 1D PDLs with X-axis values
 $ys -- reference to a list of 1D PDLs with Y-axis values
 %opts -- Options hash

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  my $x  = sequence(20);
  my $y1  = $x**2;
  my $y2  = sqrt($x);
  my $y3  = $x**3;
  my $y4  = sin(($x/20) * 2 * $pi);
  $ys  = cat($y1, $y2, $y3, $y4);
  $pl->stripplots($x, $ys, PLOTTYPE => 'LINE', TITLE => 'functions',
                           YLAB     => ['x**2', 'sqrt(x)', 'x**3', 'sin(x/20*2pi)'],
                           COLOR    => ['GREEN', 'DEEPSKYBLUE', 'DARKORCHID1', 'DEEPPINK'], XLAB => 'X label');
  # Equivalent to above:
  $pl->stripplots($x, [$y1, $y2, $y3, $y4],
                           PLOTTYPE => 'LINE', TITLE => 'functions',
                           YLAB     => ['x**2', 'sqrt(x)', 'x**3', 'sin(x/20*2pi)'],
                           COLOR    => ['GREEN', 'DEEPSKYBLUE', 'DARKORCHID1', 'DEEPPINK'], XLAB => 'X label');

  # Here's something a bit different. Notice that different xs have
  # different lengths.
  $x1  = sequence(20);
  $y1  = $x1**2;

  $x2  = sequence(18);
  $y2  = sqrt($x2);

  $x3  = sequence(24);
  $y3  = $x3**3;

  my $x4  = sequence(27);
  $a  = ($x4/20) * 2 * $pi;
  my $y4  = sin($a);

  $xs  = [$x1, $x2, $x3, $x4];
  $ys  = [$y1, $y2, $y3, $y4];
  $pl->stripplots($xs, $ys, PLOTTYPE => 'LINE', TITLE => 'functions',
                YLAB => ['x**2', 'sqrt(x)', 'x**3', 'sin(x/20*2pi)'],
                         COLOR => ['GREEN', 'DEEPSKYBLUE', 'DARKORCHID1', 'DEEPPINK'], XLAB => 'X label');

In addition, COLOR may be specified as a reference to a list of colors. If this is done, the colors are applied separately to each plot.

Also, the options Y_BASE and Y_GUTTER can be specified. Y_BASE gives the Y offset of the bottom of the lowest plot (0-1, specified like a VIEWPORT, defaults to 0.1) and Y_GUTTER gives the gap between the graphs (0-1, default = 0.02).

colorkey

Plot a color key showing which color represents which value

 Arguments:
 $range   : A PDL which tells the range of the color values
 $orientation : 'v' for vertical color key, 'h' for horizontal

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  # Plot X vs. Y with Z shown by the color.  Then plot
  # vertical key to the right of the original plot.
  $pl->xyplot ($x, $y, PALETTE => 'RAINBOW', PLOTTYPE => 'POINTS', COLORMAP => $z);
  $pl->colorkey ($z, 'v', VIEWPORT => [0.93, 0.96, 0.15, 0.85]);

shadeplot

Create a shaded contour plot of 2D PDL 'z' with 'nsteps' contour levels. Linear scaling is used to map the coordinates of Z(X, Y) to world coordinates via the "BOX" option.

 Arguments:
 $z : A 2D PDL which contains surface values at each XY coordinate.
 $nsteps : The number of contour levels requested for the plot.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  # vertical key to the right of the original plot.
  # The BOX must be specified to give real coordinate values to the $z array.
  $pl->shadeplot ($z, $nsteps, BOX => [-1, 1, -1, 1], PALETTE => 'RAINBOW', ZRANGE => [0,100]);
  $pl->colorkey  ($z, 'v', VIEWPORT => [0.93, 0.96, 0.15, 0.85], ZRANGE => [0,100]);

histogram

Create a histogram of a 1-D variable.

 Arguments:
 $x : A 1D PDL
 $nbins : The number of bins to use in the histogram.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $pl->histogram ($x, $nbins, BOX => [$min, $max, 0, 100]);

histogram1

Create a histogram of a 1-D variable. This alternative to 'histogram' creates filled boxes and also handles Y-axis scaling better.

 Arguments:
 $x : A 1D PDL
 $nbins : The number of bins to use in the histogram.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $pl->histogram1 ($x, $nbins, COLOR => 'GREEN');

bargraph

Simple utility to plot a bar chart with labels on the X axis. The usual options can be specified, plus one other: MAXBARLABELS specifies the maximum number of labels to allow on the X axis. The default is 20. If this value is exceeded, then every other label is plotted. If twice MAXBARLABELS is exceeded, then only every third label is printed, and so on.

if UNFILLED_BARS is set to true, then plot the bars as outlines and not as filled rectangles.

A stacked bar graph can be created if the STACKED_BAR_COLORS option is set. The option takes a reference to a perl list of color names or RGB triplets. If this option is set, then $x should not be a 1-D PDL of N bar heights, but a 2D PDL of NxM where N is the number of bars and M is the number of colors in STACKED_BAR_COLORS.

 Arguments:
 $labels -- A reference to a perl list of strings.
 $values -- A PDL of values to be plotted.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $labels = ['one', 'two', 'three'];
  $values = pdl(1, 2, 3);

  # Note if TEXTPOSITION is specified, it must be in 4 argument mode (border mode):
  # [$side, $disp, $pos, $just]
  #
  # Where side = 't', 'b', 'l', or 'r' for top, bottom, left and right
  #              'tv', 'bv', 'lv' or 'rv' for top, bottom, left or right perpendicular to the axis.
  #
  #     disp is the number of character heights out from the edge
  #     pos  is the position along the edge of the viewport, from 0 to 1.
  #     just tells where the reference point of the string is: 0 = left, 1 = right, 0.5 = center.
  #
  # The '$pos' entry will be ignored (computed by the bargraph routine)
  $pl->bargraph($labels, $values, MAXBARLABELS => 30, TEXTPOSITION => ['bv', 0.5, 1.0, 1.0]);

  # A stacked bar chart:
  $labels = ['label1', 'label2', 'label3'];
  $values = pdl([[50,40,60],   # green bars
                 [20,10,30]]); # purple ([128, 0, 56]) bars
  $pl->bargraph ($labels, $values, STACKED_BAR_COLORS => ['GREEN', [128, 0, 56]])

text

Write text on a plot. Text can either be written with respect to the borders or at an arbitrary location and angle (see the "TEXTPOSITION" entry).

 Arguments:
 $t : The text.

 Supported options:
 All options except:

 BACKGROUND
 DEV
 FILE
 FRAMECOLOR
 JUST
 PAGESIZE
 SUBPAGES

(These must be set in call to 'new'.)

  $pl->text("Count", COLOR => 'PINK',
            TEXTPOSITION => ['t', 3, 0.5, 0.5]); # top, 3 units out, string ref. pt in
                                                 # center of string, middle of axis

close

Close a PLplot object, writing out the file and cleaning up.

Arguments: None

Returns: Nothing

This closing of the PLplot object can be done explicitly though the 'close' method. Alternatively, a DESTROY block does an automatic close whenever the PLplot object passes out of scope.

  $pl->close;

FUNCTIONS

The PDL low-level interface to the PLplot library closely mimics the C API. Users are referred to the PLplot User's Manual, distributed with the source PLplot tarball. This manual is also available on-line at the PLplot web site (http://www.plplot.org/).

There are three differences in the way the functions are called. The first one is due to a limitation in the pp_def wrapper of PDL, which forces all the non-ndarray arguments to be at the end of the arguments list. It is the case of strings (char *) arguments in the C API. This affects the following functions:

  plaxes
  plbox
  plbox3
  plmtex
  plmtex3
  plstart
  plstripc
  plmap
  plmeridians
  plshades
  plshade1

This difference can be got around by a call to

  plplot_use_standard_argument_order(1);

This re-arranges the string arguments to their proper/intuitive position compared with the C plplot interface. This can be restored to its default by calling:

  plplot_use_standard_argument_order(0);

The second notable different between the C and the PDL APIs is that many of the PDL calls do not need arguments to specify the size of the the vectors and/or matrices being passed. These size parameters are deduced from the size of the ndarrays, when possible and are just omitted from the C call when translating it to perl.

The third difference has to do with output parameters. In C these are passed in with the input parameters. In the perl interface, they are omitted. For example:

C:

  pllegend(&p_legend_width, &p_legend_height,
           opt, position, x, y, plot_width, bg_color, bb_color, bb_style, nrow, ncolumn, nlegend,
           opt_array,
           text_offset, text_scale, text_spacing, text_justification,
           text_colors, (const char **)text, box_colors, box_patterns, box_scales, box_line_widths,
           line_colors, line_styles, line_widths, symbol_colors, symbol_scales, symbol_numbers, (const char **)symbols);

perl:

  my ($legend_width, $legend_height) =
    pllegend ($position, $opt, $x, $y, $plot_width, $bg_color, $nlegend,
    \@opt_array,
    $text_offset, $text_scale, $text_spacing, $test_justification,
    \@text_colors, \@text, \@box_colors, \@box_patterns, \@box_scales, \@line_colors,
    \@line_styles, \@line_widths, \@symbol_colors, \@symbol_scales, \@symbol_numbers, \@symbols);

Some of the API functions implemented in PDL have other specificities in comparison with the C API and will be discussed below.

pladv

  Signature: (int page())

info not available

pladv does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plaxes

  Signature: (double xzero();double yzero();double xtick();int nxsub();double ytick();int nysub(); char *xopt;char *yopt)

info not available

plaxes does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plbin

  Signature: (int nbin();double x(dima);double y(dima);int center())

info not available

plbin does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plbox

  Signature: (double xtick();int nxsub();double ytick();int nysub(); char *xopt;char *yopt)

info not available

plbox does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plbox3

  Signature: (double xtick();int nsubx();double ytick();int nsuby();double ztick();int nsubz(); char *xopt;char *xlabel;char *yopt;char *ylabel;char *zopt;char *zlabel)

info not available

plbox3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcol0

  Signature: (int icolzero())

info not available

plcol0 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcol1

  Signature: (double colone())

info not available

plcol1 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcpstrm

  Signature: (int iplsr();int flags())

info not available

plcpstrm does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pldid2pc

  Signature: (double xmin(dima);double ymin(dima);double xmax(dima);double ymax(dima))

info not available

pldid2pc does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pldip2dc

  Signature: (double xmin(dima);double ymin(dima);double xmax(dima);double ymax(dima))

info not available

pldip2dc does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plenv

  Signature: (double xmin();double xmax();double ymin();double ymax();int just();int axis())

info not available

plenv does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plenv0

  Signature: (double xmin();double xmax();double ymin();double ymax();int just();int axis())

info not available

plenv0 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plerrx

  Signature: (int n();double xmin(dima);double xmax(dima);double y(dima))

info not available

plerrx does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plerry

  Signature: (int n();double x(dima);double ymin(dima);double ymax(dima))

info not available

plerry does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfill3

  Signature: (int n();double x(dima);double y(dima);double z(dima))

info not available

plfill3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfont

  Signature: (int ifont())

info not available

plfont does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfontld

  Signature: (int fnt())

info not available

plfontld does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgchr

  Signature: (double [o]p_def();double [o]p_ht())

info not available

plgchr does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgcompression

  Signature: (int [o]compression())

info not available

plgcompression does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgdidev

  Signature: (double [o]p_mar();double [o]p_aspect();double [o]p_jx();double [o]p_jy())

info not available

plgdidev does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgdiori

  Signature: (double [o]p_rot())

info not available

plgdiori does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgdiplt

  Signature: (double [o]p_xmin();double [o]p_ymin();double [o]p_xmax();double [o]p_ymax())

info not available

plgdiplt does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgfam

  Signature: (int [o]p_fam();int [o]p_num();int [o]p_bmax())

info not available

plgfam does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plglevel

  Signature: (int [o]p_level())

info not available

plglevel does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgpage

  Signature: (double [o]p_xp();double [o]p_yp();int [o]p_xleng();int [o]p_yleng();int [o]p_xoff();int [o]p_yoff())

info not available

plgpage does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgspa

  Signature: (double [o]xmin();double [o]xmax();double [o]ymin();double [o]ymax())

info not available

plgspa does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgvpd

  Signature: (double [o]p_xmin();double [o]p_xmax();double [o]p_ymin();double [o]p_ymax())

info not available

plgvpd does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgvpw

  Signature: (double [o]p_xmin();double [o]p_xmax();double [o]p_ymin();double [o]p_ymax())

info not available

plgvpw does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgxax

  Signature: (int [o]p_digmax();int [o]p_digits())

info not available

plgxax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgyax

  Signature: (int [o]p_digmax();int [o]p_digits())

info not available

plgyax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgzax

  Signature: (int [o]p_digmax();int [o]p_digits())

info not available

plgzax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pljoin

  Signature: (double xone();double yone();double xtwo();double ytwo())

info not available

pljoin does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pllightsource

  Signature: (double x();double y();double z())

info not available

pllightsource does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pllsty

  Signature: (int lin())

info not available

pllsty does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmtex

  Signature: (double disp();double pos();double just(); char *side;char *text)

info not available

plmtex does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmtex3

  Signature: (double disp();double pos();double just(); char *side;char *text)

info not available

plmtex3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpat

  Signature: (int nlin();int inc(dima);int del(dima))

info not available

plpat does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plprec

  Signature: (int setp();int prec())

info not available

plprec does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpsty

  Signature: (int patt())

info not available

plpsty does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plptex

  Signature: (double x();double y();double dx();double dy();double just(); char *text)

info not available

plptex does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plptex3

  Signature: (double x();double y();double z();double dx();double dy();double dz();double sx();double sy();double sz();double just(); char *text)

info not available

plptex3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plschr

  Signature: (double def();double scale())

info not available

plschr does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap0n

  Signature: (int ncolzero())

info not available

plscmap0n does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap1n

  Signature: (int ncolone())

info not available

plscmap1n does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscol0

  Signature: (int icolzero();int r();int g();int b())

info not available

plscol0 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscolbg

  Signature: (int r();int g();int b())

info not available

plscolbg does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscolor

  Signature: (int color())

info not available

plscolor does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscompression

  Signature: (int compression())

info not available

plscompression does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsdidev

  Signature: (double mar();double aspect();double jx();double jy())

info not available

plsdidev does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsdimap

  Signature: (int dimxmin();int dimxmax();int dimymin();int dimymax();double dimxpmm();double dimypmm())

info not available

plsdimap does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsdiori

  Signature: (double rot())

info not available

plsdiori does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsdiplt

  Signature: (double xmin();double ymin();double xmax();double ymax())

info not available

plsdiplt does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsdiplz

  Signature: (double xmin();double ymin();double xmax();double ymax())

info not available

plsdiplz does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pl_setcontlabelparam

  Signature: (double offset();double size();double spacing();int active())

info not available

pl_setcontlabelparam does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pl_setcontlabelformat

  Signature: (int lexp();int sigdig())

info not available

pl_setcontlabelformat does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsfam

  Signature: (int fam();int num();int bmax())

info not available

plsfam does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsmaj

  Signature: (double def();double scale())

info not available

plsmaj does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsmin

  Signature: (double def();double scale())

info not available

plsmin does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsori

  Signature: (int ori())

info not available

plsori does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plspage

  Signature: (double xp();double yp();int xleng();int yleng();int xoff();int yoff())

info not available

plspage does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plspause

  Signature: (int pause())

info not available

plspause does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsstrm

  Signature: (int strm())

info not available

plsstrm does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plssub

  Signature: (int nx();int ny())

info not available

plssub does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plssym

  Signature: (double def();double scale())

info not available

plssym does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstar

  Signature: (int nx();int ny())

info not available

plstar does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstart

  Signature: (int nx();int ny(); char *devname)

info not available

plstart does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstripa

  Signature: (int id();int pen();double x();double y())

info not available

plstripa does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstripd

  Signature: (int id())

info not available

plstripd does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsvpa

  Signature: (double xmin();double xmax();double ymin();double ymax())

info not available

plsvpa does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsxax

  Signature: (int digmax();int digits())

info not available

plsxax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsxwin

  Signature: (int window_id())

info not available

plsxwin does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsyax

  Signature: (int digmax();int digits())

info not available

plsyax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plszax

  Signature: (int digmax();int digits())

info not available

plszax does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plvasp

  Signature: (double aspect())

info not available

plvasp does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plvpas

  Signature: (double xmin();double xmax();double ymin();double ymax();double aspect())

info not available

plvpas does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plvpor

  Signature: (double xmin();double xmax();double ymin();double ymax())

info not available

plvpor does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plw3d

  Signature: (double basex();double basey();double height();double xminzero();double xmaxzero();double yminzero();double ymaxzero();double zminzero();double zmaxzero();double alt();double az())

info not available

plw3d does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plwidth

  Signature: (int width())

info not available

plwidth does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plwind

  Signature: (double xmin();double xmax();double ymin();double ymax())

info not available

plwind does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plP_gpixmm

  Signature: (double p_x(dima);double p_y(dima))

info not available

plP_gpixmm does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscolbga

  Signature: (int r();int g();int b();double a())

info not available

plscolbga does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscol0a

  Signature: (int icolzero();int r();int g();int b();double a())

info not available

plscol0a does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plline

  Signature: (x(n); y(n))

Draws line segments along (x1,y1)->(x2,y2)->(x3,y3)->...

If the nth value of either x or y are bad, then it will be skipped, breaking the line. In this way, you can specify multiple line segments with a single pair of x and y ndarrays.

The usage is straight-forward:

 plline($x, $y);

For example:

 # Draw a sine wave
 $x = sequence(100)/10;
 $y = sin($x);

 # Draws the sine wave:
 plline($x, $y);

 # Set values above 3/4 to 'bad', effectively drawing a bunch of detached,
 # capped waves
 $y->setbadif($y > 3/4);
 plline($x, $y);

plline processes bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpath

  Signature: (int n(); x1(); x2(); y1(); y2())

info not available

plpath ignores the bad-value flag of the input ndarrays. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcolorpoints

  Signature: (x(n); y(n); z(n); int sym(); minz(); maxz())

PDL-specific: Implements what amounts to a threaded version of plsym.

Bad values for z are simply skipped; all other bad values are not processed.

In the following usage, all of the ndarrays must have the same dimensions:

 plcolorpoints($x, $y, $z, $symbol_index, $minz, $maxz)

For example:

 # Generate a parabola some points
 my $x = sequence(30) / 3;   # Regular sampling
 my $y = $x**2;              # Parabolic y
 my $z = 30 - $x**3;         # Cubic coloration
 my $symbols = floor($x);    # Use different symbols for each 1/3 of the plot
                             #  These should be integers.

 plcolorpoints($x, $y, $z, $symbols, -5, 20);  # Thread over everything
 plcolorpoints($x, $y, 1, 1, -1, 2);           # same color and symbol for all

plcolorpoints processes bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsmem

  Signature: (int maxx();int maxy();image(3,x,y))

info not available

plsmem does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfbox

  Signature: (xo(); yo())

Box drawing primitive, taken from PLPLOT bar graph example

plfbox does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfbox1

  Signature: (xo(); yo(); bh(); w())

Box drawing primitive that allows specifying base height and width in addition to offset and height

plfbox1 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plunfbox

  Signature: (xo(); yo())

Similar box drawing primitive, but without fill (just draw outline of box)

plunfbox does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plunfbox1

  Signature: (xo(); yo(); bh(); w())

Box drawing primitive that allows specifying base height and width in addition to offset and height

plunfbox1 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plParseOpts

  Signature: (int [o] retval(); SV* argv; int mode)

Parse PLplot options given in @ARGV-like arrays

plParseOpts does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpoin

  Signature: (x(n); y(n); int code())

Plots a character at the specified points

plpoin does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpoin3

  Signature: (x(n); y(n); z(n); int code())

Plots a character at the specified points in 3 space

plpoin3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plline3

  Signature: (x(n); y(n); z(n))

Draw a line in 3 space

plline3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plpoly3

  Signature: (x(n); y(n); z(n); int draw(m); int ifcc())

Draws a polygon in 3 space

plpoly3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plhist

  Signature: (data(n); datmin(); datmax(); int nbin(); int oldwin())

Plot a histogram from unbinned data

plhist does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plfill

  Signature: (x(n); y(n))

Area fill

plfill does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgradient

  Signature: (x(n); y(n); angle())

Area fill with color gradient

plgradient does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsym

  Signature: (x(n); y(n); int code())

Plots a symbol at the specified points

plsym does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsurf3d

  Signature: (x(nx); y(ny); z(nx,ny); int opt(); clevel(nlevel))

Plot shaded 3-d surface plot

plsurf3d does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsurf3dl

  Signature: (x(nx); y(ny); z(nx,ny); int opt(); clevel(nlevel); int indexxmin(); int indexxmax(); int indexymin(nx); int indexymax(nx))

Plot shaded 3-d surface plot with limits

plsurf3dl does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstyl

  Signature: (int mark(nms); int space(nms))

Set line style

plstyl does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plseed

  Signature: (int seed())

info not available

plseed does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plrandd

  Signature: (double [o]rand())

info not available

plrandd does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plAllocGrid

  Signature: (double xg(nx); double yg(ny); indx [o] grid())

Allocates a PLcGrid object for use in pltr1

plAllocGrid does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plAlloc2dGrid

  Signature: (double xg(nx,ny); double yg(nx,ny); indx [o] grid())

Allocates a PLcGrid2 object for use in pltr2

plAlloc2dGrid does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

init_pltr

  Signature: (P(); C(); SV* p0; SV* p1; SV* p2)

Used internally to set the variables pltr{0,1,2}_iv to the "pointers" of the Perl subroutines pltr{1,2,3}. These variables are later used by get_standard_pltrcb to provide the pointers to the C function pltr{0,1,2}. This accelerates functions like plcont and plshades when those standard transformation functions are used.

init_pltr does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmap

  Signature: (minlong(); maxlong(); minlat(); maxlat(); SV* mapform; char* type)

plot continental outline in world coordinates

plmap does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstring

  Signature: (x(na); y(na); char* string)

plot a string along a line

plstring does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plstring3

  Signature: (x(na); y(na); z(na); char* string)

plot a string along a 3D line

plstring3 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmeridians

  Signature: (dlong(); dlat(); minlong(); maxlong(); minlat(); maxlat(); SV* mapform)

Plot the latitudes and longitudes on the background

plmeridians does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plshades

  Signature: (z(x,y); xmin(); xmax(); ymin(); ymax();
                  clevel(l); int fill_width(); int cont_color();
                  int cont_width(); int rectangular(); SV* defined; SV* pltr; SV* pltr_data)

Shade regions on the basis of value

plshades does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcont

  Signature: (f(nx,ny); int kx(); int lx(); int ky(); int ly(); clevel(nlevel); SV* pltr; SV* pltr_data)

Plot contours

plcont does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmesh

  Signature: (x(nx); y(ny); z(nx,ny); int opt())

Surface mesh

plmesh does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plmeshc

  Signature: (x(nx); y(ny); z(nx,ny); int opt(); clevel(nlevel))

Magnitude colored plot surface mesh with contour

plmeshc does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plot3d

  Signature: (x(nx); y(ny); z(nx,ny); int opt(); int side())

3-d surface plot

plot3d does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plot3dc

  Signature: (x(nx); y(ny); z(nx,ny); int opt(); clevel(nlevel))

Plots a 3-d representation of the function z[x][y] with contour

plot3dc does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap1l

  Signature: (int itype(); isty(n); coord1(n); coord2(n); coord3(n); int rev(nrev))

Set color map1 colors using a piece-wise linear relationship

plscmap1l does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plshade1

  Signature: (a(nx,ny); left(); right(); bottom(); top(); shade_min();shade_max(); sh_cmap(); sh_color(); sh_width();min_color(); min_width(); max_color(); max_width();rectangular(); SV* defined; SV* pltr; SV* pltr_data)

Shade individual region on the basis of value

plshade1 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plimage

  Signature: (idata(nx,ny); xmin(); xmax(); ymin(); ymax();zmin(); zmax(); Dxmin(); Dxmax(); Dymin(); Dymax())

Plot gray-level image

plimage does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plimagefr

  Signature: (idata(nx,ny); xmin(); xmax(); ymin(); ymax();zmin(); zmax(); valuemin(); valuemax(); SV* pltr; SV* pltr_data)

Plot image with transformation

plimagefr does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plxormod

  $status = plxormod ($mode)

Set xor mode: mode = 1-enter, 0-leave, status = 0 if not interactive device

See the PLplot manual for reference.

plGetCursor

  %gin = plGetCursor ()

plGetCursor waits for graphics input event and translate to world coordinates and returns a hash with the following keys:

    type:      of event (CURRENTLY UNUSED)
    state:     key or button mask
    keysym:    key selected
    button:    mouse button selected
    subwindow: subwindow (alias subpage, alias subplot) number
    string:    translated string
    pX, pY:    absolute device coordinates of pointer
    dX, dY:    relative device coordinates of pointer
    wX, wY:    world coordinates of pointer

Returns an empty hash if no translation to world coordinates is possible.

plgstrm

  $strm = plgstrm ()

Returns the number of the current output stream.

plgsdev

  $driver = plgdev ()

Returns the current driver name.

plmkstrm

  $strm = plmkstrm ()

Creates a new stream and makes it the default. Returns the number of the created stream.

plgver

  $version = plgver ()

Get the current library version number

See the PLplot manual for reference.

plstripc

  Signature: (xmin(); xmax(); xjump(); ymin(); ymax();xlpos(); ylpos(); int y_ascl(); int acc();int colbox(); int collab();int colline(n); int styline(n);int [o] id(); char* xspec; char* yspec; SV* legline;char* labx; char* laby; char* labtop)

FIXME: documentation here!

plstripc does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgriddata

  Signature: (x(npts); y(npts); z(npts); xg(nptsx); yg(nptsy);int type(); data(); [o] zg(nptsx,nptsy))

FIXME: documentation here!

plgriddata does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plarc

  plarc ($x, $y, $a, $b, $angle1, $angle2, $rotate, $fill);

Draw a (possibly) filled arc centered at x, y with semimajor axis a and semiminor axis b, starting at angle1 and ending at angle2. See the PLplot manual for reference.

plstransform

  plstransform ($subroutine_reference, $data);

Sets the default transformation routine for plotting.

  sub mapform {
    my ($x, $y, $data) = @_;

    my $radius = 90.0 - $y;
    my $xp = $radius * cos ($x * pi / 180);
    my $yp = $radius * sin ($x * pi / 180);

    return ($xp, $yp);
  }
  plstransform (\&mapform, undef);

See the PLplot manual for more details.

plslabelfunc

  plslabelfunc ($subroutine_reference);
  # A custom axis labeling function for longitudes and latitudes.
  sub geolocation_labeler {
    my ($axis, $value, $length) = @_;
    my ($direction_label, $label_val);
    if (($axis == PL_Y_AXIS) && $value == 0) {
        return "Eq";
      } elsif ($axis == PL_Y_AXIS) {
      $label_val = $value;
      $direction_label = ($label_val > 0) ? " N" : " S";
    } elsif ($axis == PL_X_AXIS) {
      my $times  = floor((abs($value) + 180.0 ) / 360.0);
      $label_val = ($value < 0) ? $value + 360.0 * $times : $value - 360.0 * $times;
      $direction_label = ($label_val > 0) ? " E"
                       : ($label_val < 0) ? " W"
                       :                    "";
    }
    return substr (sprintf ("%.0f%s", abs($label_val), $direction_label), 0, $length);
  }
  plslabelfunc(\&geolocation_labeler);

The PDL version of plslabelfunc only has one argument--the perl subroutine to do the label translation:

  my $labeltext = perl_labelfunc($axis, $value, $length);

No 'data' argument is used, it is assumed that global data or a closure containing necessary data can be used in 'perl_labelfunc'.

See the PLplot manual for more details.

pllegend

  my ($legend_width, $legend_height) =
      pllegend ($position, $opt, $x, $y, $plot_width, $bg_color, $nlegend,
      \@opt_array,
      $text_offset, $text_scale, $text_spacing, $test_justification,
      \@text_colors, \@text, \@box_colors, \@box_patterns, \@box_scales, \@line_colors,
      \@line_styles, \@line_widths, \@symbol_colors, \@symbol_scales, \@symbol_numbers, \@symbols);

See the PLplot manual for more details.

plspal0

  plspal0($filename);

Set color palette 0 from the input .pal file. See the PLplot manual for more details.

plspal1

  plspal1($filename);

Set color palette 1 from the input .pal file. See the PLplot manual for more details.

plbtime

  my ($year, $month, $day, $hour, $min, $sec) = plbtime($ctime);

Calculate broken-down time from continuous time for current stream.

plconfigtime

  plconfigtime($scale, $offset1, $offset2, $ccontrol, $ifbtime_offset, $year, $month, $day, $hour, $min, $sec);

Configure transformation between continuous and broken-down time (and vice versa) for current stream.

plctime

  my $ctime = plctime($year, $month, $day, $hour, $min, $sec);

Calculate continuous time from broken-down time for current stream.

pltimefmt

  pltimefmt($fmt);

Set format for date / time labels. Labels must be configured to treat values as seconds since the epoch via the XBOX/YBOX flags. $fmt is generally consistent with the POSIX strpformat/strftime flags, but see the PLplot manual for details.

plsesc

  plsesc($esc);

Set the escape character for text strings. See the PLplot manual for more details.

plvect

  Signature: (u(nx,ny); v(nx,ny); scale(); SV* pltr; SV* pltr_data)

Vector field plots

plvect does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsvect

  Signature: (arrowx(npts); arrowy(npts); int fill())

Give zero-length PDLs for arrowx and arrowy to pass NULL to PLplot func.

plsvect does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plhlsrgb

  Signature: (double h();double l();double s();double [o]p_r();double [o]p_g();double [o]p_b())

info not available

plhlsrgb does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgcol0

  Signature: (int icolzero(); int [o]r(); int [o]g(); int [o]b())

info not available

plgcol0 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgcolbg

  Signature: (int [o]r(); int [o]g(); int [o]b())

info not available

plgcolbg does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap0

  Signature: (int r(n); int g(n); int b(n))

info not available

plscmap0 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap1

  Signature: (int r(n); int g(n); int b(n))

info not available

plscmap1 does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgcol0a

  Signature: (int icolzero(); int [o]r(); int [o]g(); int [o]b(); double [o]a())

info not available

plgcol0a does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgcolbga

  Signature: (int [o]r(); int [o]g(); int [o]b(); double [o]a())

info not available

plgcolbga does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap0a

  Signature: (int r(n); int g(n); int b(n); double a(n))

info not available

plscmap0a does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap1a

  Signature: (int r(n); int g(n); int b(n); double a(n))

info not available

plscmap1a does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plscmap1la

  Signature: (int itype(); isty(n); coord1(n); coord2(n); coord3(n); coord4(n); int rev(nrev))

Set color map1 colors using a piece-wise linear relationship, include alpha channel

plscmap1la does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plgfont

  Signature: (int [o]p_family(); int [o]p_style(); int [o]p_weight())

info not available

plgfont does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plsfont

  Signature: (int family(); int style(); int weight())

info not available

plsfont does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

plcalc_world

  Signature: (double rx(); double ry(); double [o]wx(); double [o]wy(); int [o]window())

info not available

plcalc_world does not process bad values. It will set the bad-value flag of all output ndarrays if the flag is set for any of the input ndarrays.

pl_cmd

   pl_cmd($CMD, $data);
   See the PLplot manual for reference.
   Gives access to low level driver. $CMD is an integer. $data opaque data.

pl_setCairoCtx

   pl_setCairoCtx($cairo_context);
   Used with cairo external drivers to set the cairo context.
   $cairo_context should be a Cairo::Context object.
   Uses pl_cmd underneath, but extracts the real C struct pointer from the Cairo::Context.

WARNINGS AND ERRORS

PLplot gives many errors and warnings. Some of these are given by the PDL interface while others are internal PLplot messages. Below are some of these messages, and what you need to do to address them:

  • Box must be a ref to a four element array

    When specifying a box, you must pass a reference to a four-element array, or use an anonymous four-element array.

     # Gives trouble:
     $pl->xyplot($x, $y, BOX => (0, 0, 100, 200) );
     # What you meant to say was:
     $pl->xyplot($x, $y, BOX => [0, 0, 100, 200] );
  • Too many colors used! (max 15)

AUTHORS

  Doug Hunt <dhunt@ucar.edu>
  Rafael Laboissiere <rlaboiss@users.sourceforge.net>
  David Mertens <mertens2@illinois.edu>

SEE ALSO

perl(1), PDL(1), http://www.plplot.org/

The other common graphics packages include PDL::PGPLOT and PDL::TriD.