PDL::Graphics::PGPLOT::Window - A OO interface to PGPLOT windows
perldl> use PDL::Graphics::PGPLOT::Window perldl> $win = PDL::Graphics::PGPLOT::Window->new(Device => '/xs'); perldl> $a = pdl [1..100] perldl> $b = sqrt($a) perldl> $win->line($b) perldl> $win->hold() perldl> $c = sin($a/10)*2 + 4 perldl> $win->line($c)
In the following documentation the commands are not shown in their OO versions. This is for historical reasons and should not cause too much trouble.
This package offers a OO interface to the PGPLOT plotting package. This is intended to replace the traditional interface in the PDL::Graphics::PGPLOT manpage and contains interfaces to a large number of PGPLOT routines. Below the usage examples for each function tend to be given in the non-OO version for historical reasons. This will slowly be changed, but in the meantime refer to the section on OO-interface below to see how to convert the usage information below to OO usage (it is totally trivial).
PDL::Graphics::PGPLOT::Window is an interface to the PGPLOT graphical libraries.
The list of currently availably methods:
imag - Display an image (uses pgimag()/pggray() as appropriate) ctab - Load an image colour table ctab_info - Get information about currently loaded colour table line - Plot vector as connected points points - Plot vector as points errb - Plot error bars cont - Display image as contour map bin - Plot vector as histogram (e.g. bin(hist($data)) ) hi2d - Plot image as 2d histogram (not very good IMHO...) poly - Draw a polygon vect - Display 2 images as a vector field text - Write text in the plot area label_axes - Print axis titles legend - Create a legend with different texts, linestyles etc. cursor - Interactively read cursor positions. circle - Draw a circle ellipse - Draw an ellipse.
Device manipulation commands:
new - Constructor for a new PGPLOT output device close - Close a PGPLOT output device focus - Set focus to the given device. This should normally be done behind the scenes. hold - Hold current plot window range - allows overlays etc. release - Release back to autoscaling of new plot window for each command held - Returns true if the graphics is held on the current device. env - Define a plot window, put on 'hold' panel - Move to a specified plot panel when several panels are defined. erase - Erase the current window (or panel)
options - Get the options set for the present output device id - The ID for the device device - The device type name - The window name
Notes: $transform
for image/cont etc. is used in the same way as the
TR()
array in the underlying PGPLOT FORTRAN routine but is, fortunately,
zero-offset. The transform()
routine can be used to create this piddle.
For completeness: The transformation array connect the pixel index to a world coordinate such that:
X = tr[0] + tr[1]*i + tr[2]*j Y = tr[3] + tr[4]*i + tr[5]*j
In general variables are passed to the pgplot routines by using
get_dataref
to get the reference to the values. Before passing to pgplot routines
however, the data are checked to see if they are in accordance with the
format (typically dimensionality) required by the PGPLOT routines.
This is done using the routine checkarg
(internal to PGPLOT). This routine
checks the dimensionality of the input data. If there are superfluous
dimensions of size 1 they will be trimmed away until the dimensionality
is correct. Example:
Assume a piddle with dimensions (1,100,1,1) is passed to line
, which
expects its inputs to be vectors. checkarg
will then return a piddle
with dimensions (100). If instead the same piddle was passed to imag
,
which requires 2D piddles as output, checkarg
would return a piddle
with dimensionality (100, 1) (Dimensions are removed from the start)
Thus, if you want to provide support for another PGPLOT function, the structure currently look like this (there are plans to use the Options package to simplify the options parsing):
# Extract the hash(es) on the commandline ($arg, $opt)=_extract_hash(@_); <Check the number of input parameters> <deal with $arg> checkarg($x, 3); # For a hypothetical 3D routine. ... pgcube($n, $x->get_dataref); 1;
All routines in this package take a hash with options as an optional input. This options hash can be used to set parameters for the subsequent plotting without going via the PGPLOT commands.
This is implemented such that the plotting settings (such as line width,
line style etc.) are affected only for that plot, any global changes made,
say, with pgslw()
are preserved. Some modifications apply when using
the OO interface, see below.
The following options are always parsed. Whether they have any importance
depend on the routine invoked - e.g. line style is irrelevant for imag
,
or the justify
option is irrelevant if the display is on 'hold'.
This is indicated in the help text for the commands below.
The options are not case sensitive and will match for unique substrings, but this is not encouraged as obscure options might invalidate what you thought was a unique substring.
In the listing below examples are given of each option. The actual option can then be used in a plot command by specifying it as an argument to the function wanted (it can be placed anywhere in the command list).
E.g:
$opt={COLOR=>2}; line $x, $y, $opt; # This will plot a line with red color
The following
$opt = {ARROW => {FS=>1, ANGLE=>60, VENT=>0.3, SIZE=>5}};
will make a broad arrow of five times the normal size.
Alternatively the arrow can be specified as a set of numbers corresponding to an extention to the syntax for pgsah. The equivalent to the above is
$opt = {ARROW => pdl([1, 60, 0.3, 5})};
For the latter the arguments must be in the given order, and if any are not given the default values of 1, 45, 0.3 and 1.0 respectively will be used.
$opt = {ARROWSIZE => 2.5};
EMPTY (-2) draw no box, axes or labels BOX (-1) draw box only NORMAL (0) draw box and label it with coordinates AXES (1) same as NORMAL, but also draw (X=0,Y=0) axes GRID (2) same as AXES, but also draw grid lines LOGX (10) draw box and label X-axis logarithmically LOGY (20) draw box and label Y-axis logarithmically LOGXY (30) draw box and label both axes logarithmically
TYPE
(set to
'relative' or 'absolute') and VALUE
(the amount to change the limits
by), or set to 1, which is equivalent to
BORDER => { TYPE => 'rel', VALUE => 0.05 }
$opt = {CHARSIZE => 1.5}
0 - WHITE 1 - BLACK 2 - RED 3 - GREEN 4 - BLUE 5 - CYAN 6 - MAGENTA 7 - YELLOW 8 - ORANGE 14 - DARKGRAY 16 - LIGHTGRAY
However there is a much more flexible mechanism to deal with colour. The colour can be set as a 3 or 4 element anonymous array (or piddle) which gives the RGB colours. If the array has four elements the first element is taken to be the colour index to change. For normal work you might want to simply use a 3 element array with R, G and B values and let the package deal with the details. The R,G and B values go from 0 to 1.
In addition the package will also try to interpret non-recognised
colour names using the default X11 lookup table, normally using the
rgb.txt
that came with PGPLOT.
For more details on the handling of colour it is best that the user consults the PGPLOT documentation. Further details on the handling of colour can be found in the documentation for the internal routine _set_colour.
1 - SOLID 2 - OUTLINE 3 - HATCHED 4 - CROSS_HATCHED
$opt = {FILLTYPE => 'SOLID'};
(see below for an example of hatched fill)
1 - NORMAL 2 - ROMAN 3 - ITALIC 4 - SCRIPT
(Note that in a string, the font can be changed using the escape sequences
\fn
, \fr
, \fi
and \fs
respectively)
$opt = {FONT => 'ROMAN'};
gives the same result as
$opt = {FONT => 2};
min(height, width)
of the view surface, and PHASE to
set the offset the hatching. Alternatively this can be specified as a
1x3 piddle $hatch=pdl[$angle, $sep, $phase]
.
$opt = {FILLTYPE => 'HATCHED', HATCHING => {ANGLE=>30, SEPARATION=>4}};
Can also be specified as
$opt = {FILL=> 'HATCHED', HATCH => pdl [30,4,0.0]};
For another example of hatching, see poly.
pgenv()
command for more information.
1 - SOLID line 2 - DASHED 3 - DOT-DASH-dot-dash 4 - DOTTED 5 - DASH-DOT-DOT-dot
or using name (as given in capitals above). Thus the following two specifications both specify the line to be dotted:
$opt = {LINESTYLE => 4}; $varopt = {LINESTYLE => 'DOTTED'};
The names are not case sensitive, but the full name is required.
$opt = {LINEWIDTH => 10}; # A rather fat line
Xrange
and Yrange
. If omitted
PGPLOT selects appropriate defaults (minimum and maximum of the data range
in general). These options are ignored if the window is on hold.
line $x, $y, {xr => [0,5]}; # y-range uses default line $x, $y, {Xrange => [0,5], Yrange => [-1,3]}; # fully specified range
This section will briefly describe how the PDL::Graphics::PGPLOT::Window package can be used in an object-oriented (OO) approach and what the advantages of this would be. We will start with the latter
my $win1 = Graphics::new('PGPLOT', {Device => '/xs'}); my $win2 = Graphics::new('gnuplot', {Background => 'Gray'};
From a more practical point of of view such abstraction also comes in handy when you write a large program package and you do not want to import routines nilly-willy in which case an OO approach with method calls is a lot cleaner.
Anyway, enough philosophizing, let us get down to Earth and give some examples of the use of OO PGPLOT. As an example we will take Odd (which happens to be a common Norwegian name) who is monitoring the birth of rabbits in O'Fib-o-nachy's farm (alternatively he can of course be monitoring processes or do something entirely different). Odd wants the user to be able to monitor both the birth rates and accumulated number of rabbits and the spatial distribution of the births. Since these are logically different he chooses to have two windows open:
$rate_win = PDL::Graphics::PGPLOT::Window->new(Device => '/xw', Aspect => 1, WindowWidth => 5, NXPanel => 2);
$area_win = PDL::Graphics::PGPLOT::Window->new(Device => '/xw', Aspect => 1, WindowWidth => 5);
See the documentation for the new manpage below for a full overview of the options you can pass to the constructor.
Next, Odd wants to create plotting areas for subsequent plots and maybe show the expected theoretical trends
$rate_win->env(0, 10, 0, 1000, {XTitle => 'Days', YTitle => '#Rabbits'}); $rate_win->env(0, 10, 0, 100, {Xtitle=>'Days', Ytitle => 'Rabbits/day'});
$area_win->env(0, 1, 0, 1, {XTitle => 'Km', Ytitle => 'Km'}); # And theoretical prediction. $rate_win->line(sequence(10), fibonacci(10), {Panel => [1, 1]});
That is basically it. The commands should automatically focus the relevant window. Due to the limitations of PGPLOT this might however lead you to plot in the wrong panel... The package tries to be smart and do this correctly, but might get it wrong at times.
A new addition to the graphics interface is the ability to record plot commands. This can be useful when you create a nice-looking plot on the screen that you want to re-create on paper for instance. Or if you want to redo it with slightly changed variables for instance. This is still under development and views on the interface are welcome.
The functionality is somewhat detached from the plotting functions described below so I will discuss them and their use here.
Recording is off by default. To turn it on when you create a new
device you can set the Recording
option to true, or you can set
the $PDL::Graphics::PGPLOT::RECORDING
variable to 1. I recommend doing the
latter in your .perldlrc
file at least since you will often have use
for recording in the perldl script.
The recording is meant to help you recreate a plot with new data or to a different device. The most typical situation is that you have created a beautiful plot on screen and want to have a Postscript file with it. In the dreary old world you needed to go back and execute all commands manually, but with this wonderful new contraption, the recorder, you can just replay your commands:
dev '/xs', {Recording => 1} $x = sequence(10) line $x, $x**2, {Linestyle => 'Dashed'} $s = retrieve_state() # Get the current tape out of the recorder. dev '/cps' replay $s
This should result in a pgplot.ps
file with a parabola drawn with a
dashed line. Note the command retrieve_state
which retrieves the current
state of the recorder and return an object (of type PDL::Graphics::State)
that is used to replay commands later.
Like any self-respecting recorder you can turn the recorder on and off
using the turn_on_recording
and turn_off_recording
respectively.
Likewise you can clear the state using the clear_state
command.
$w=PDL::Graphics::PGPLOT::Window->new(Device => '/xs'); $w->turn_on_recording; $x=sequence(10); $y=$x*$x; $w->line($x, $y); $w->turn_off_recording; $w->line($y, $x); $w->turn_on_recording; $w->line($x, $y*$x); $state = $w->retrieve_state();
We can then replay $state
and get a parabola and a cubic plot.
$w->replay($state);
The data are stored in the state object as references to the real data. This leads to one good and one potentially bad consequence:
$im = sequence(10,10) imag $im $s=retrieve_state
Now this was a rather dull plot, and in reality we wanted to show an
image using rvals
. Instead of re-creating the plot (which of course
here would be the simplest option) we just change $im
:
$im -= sequence(10,10) $im += rvals(10,10)
Now replay the commands
replay $s
And hey presto! A totally different plot. Note however the trickery
required to avoid losing reference to $im
$im = sequence(1000,1000) imag $im $s = retrieve_state $im = rvals(10,10)
Thus after the execution of these commands we still have a reference to a 1000x1000 array which takes up a lot of memory...
The solution is to call clear
on the state variable:
$s->clear()
(This is done automatically if the variable goes out of scope). I forsee
this problem to most acute when working on the perldl
command line,
but since this is exactly where the recording is most useful the best
advice is just to be careful and call clear on state variables.
If you are working with scripts and use large images for instance I would instead recommend that you do not turn on recording unless you need it.
A more detailed listing of the functions and their usage follows. For all functions we specify which options take effect and what other options exist for the given function. The function descriptions below are all given for the non-OO usage for historical reasons, but since the conversion to an OO method is trivial there is no major need for concern. Whenever you see a function example of the form
Usage: a_simple_function($x, $y, $z [, $opt]);
and you wish to use the OO version, just let your mind read the above line as:
Usage: $win->a_simple_function($x, $y, $z [, $opt]);
where $win
is a PDL::Graphics::PGPLOT::Window object. That is all.
Constructor for PGPLOT object/device/plot window.
Usage: PDL::Graphics::PGPLOT::Window->new($opt); Usage: PDL::Graphics::PGPLOT::Window->new($option=>$value,...);
Options to new()
can either be specified via a reference to a hash
$win = PDL::Graphics::PGPLOT::Window->new({Dev=>'/xserve',ny=>2});
or directly, as an array
# NOTE: no more {} ! $win = PDL::Graphics::PGPLOT::Window->new(Dev=>'/xserve',ny=>2);
The following lists the recognised options:
hold()
and release()
methods.
_setup_window
routine below.
An important point to note is that the default values of most options can be specified by passing these to the constructor. All general options (common to several functions) can be adjusted in such a way, but function specific options can not be set in this way (this is a design limitation which is unlikely to be changed).
Thus the following call will set up a window where the default axis colour will be yellow and where plot lines normally have red colour and dashed linestyle.
$win = PDL::Graphics::PGPLOT::Window->new(Device => '/xs', AxisColour => 'Yellow', Colour => 'Red', LineStyle => 'Dashed');
Close a plot window
Usage: $win->close()
Close the current window. This does not necessarily mean that the window is removed from your screen, but it does ensure that the device is closed.
A message will be printed to STDOUT giving the name of the
file created if the plot was made to a hardcopy device and
$PDL::verbose
is true.
Check if a window is on hold
$is_held = $win->held();
Function to check whether the window is held or not.
Hold the present window.
Usage: $win->hold()
Holds the present window so that subsequent plot commands overplots.
Switch to a different panel
$win->panel(<num>);
Move to a different panel on the plotting surface. Note that you will need to erase it manually if that is what you require.
Release a plot window.
$win->release()
Release a plot window so that subsequent plot commands move to the next panel or erase the plot and create a new plot.
Erase plot
$win->erase($opt);
Erase a plot area. This accepts the option Panel
or alternatively a number
or array reference which makes it possible to specify the panel to erase when
working with several panels.
Define a plot window, and put graphics on 'hold'
$win->env( $xmin, $xmax, $ymin, $ymax, [$justify, $axis] ); $win->env( $xmin, $xmax, $ymin, $ymax, [$options] );
$xmin
, $xmax
, $ymin
, $ymax
are the plot boundaries.
$justify
is a boolean value (default is 0);
if true the axes scales will be the same (see justify).
$axis
describes how the axes should be drawn (see
axis) and defaults to 0.
If the second form is used, $justify and $axis can be set in the options hash, for example:
$win->env( 0, 100, 0, 50, {JUSTIFY => 1, AXIS => 'GRID', CHARSIZE => 0.7} );
In addition the following options can also be set for env
:
$win->env(0, 1, 0, 1, {PlotPosition => [0.1, 0.5, 0.1, 0.5]}); $win->env(5, 9, 0, 8, {PlotPosition => [0.1, 0.5, 0.5, 0.9]});
Label plot axes
$win->label_axes(<xtitle>, <ytitle>, <plot title>, $options);
Draw labels for each axis on a plot.
Display an image (uses pgimag()
/pggray()
as appropriate)
$win->imag ( $image, [$min, $max, $transform], [$opt] )
Notes: $transform
for image/cont etc. is used in the same way as the
TR()
array in the underlying PGPLOT FORTRAN routine but is,
fortunately, zero-offset. The transform()
routine can be used to
create this piddle.
There are several options related to scaling. By default, the image is scaled to fit the PGPLOT default viewport on the screen. Scaling, aspect ratio preservation, and 1:1 pixel mapping are available. (1:1 pixel mapping GREATLY increases the speed of pgimag, and is useful for, eg, movie display; but it's not recommended for final output as it's not device-independent.)
To draw a colour bar (or wedge), either use the DrawWedge
option,
or the draw_wedge()
routine (once the image has been drawn).
Options recognised:
ITF - the image transfer function applied to the pixel values. It may be one of 'LINEAR', 'LOG', 'SQRT' (lower case is acceptable). It defaults to 'LINEAR'. MIN - Sets the minimum value to be used for calculation of the display stretch MAX - Sets the maximum value for the same TRANSFORM - The transform 'matrix' as a 6x1 vector for display PIX - Sets the image pixel aspect ratio. By default, imag stretches the image pixels so that the final image aspect ratio fits the viewport exactly. Setting PIX=>1 causes the image aspect ratio to be preserved. (the image is scaled to avoid cropping, unless you specify scaling manually). Larger numbers yield "landscape mode" pixels. PITCH - Sets the number of image pixels per screen unit, in the Y direction. The X direction is determined by PIX, which defaults to 1 if PITCH is specified and PIX is not. PITCH causes UNIT to default to "inches" so that it is easy to say 100dpi by specifying {PITCH=>100}. Larger numbers yield higher resolution (hence smaller appearing) images. UNIT - Sets the screen unit used for scaling. Must be one of the PGPLOT supported units (inch, mm, pixel, normalized). You can refer to them by name or by number. Defaults to pixels if not specified. SCALE - Syntactic sugar for the reciprocal of PITCH. Makes the UNIT default to "pixels" so you can say "{SCALE=>1}" to see your image in device pixels. Larger SCALEs lead to larger appearing images. DrawWedge - set to 1 to draw a colour bar (default is 0) Wedge - see the draw_wedge() routine
The following standard options influence this command:
AXIS, BORDER, JUSTIFY
To see an image with maximum size in the current window, but square pixels, say: $win->imag( $a, { PIX=>1 } ); An alternative approach is to try: $win->imag( $a, { JUSTIFY=>1 } ); To see the same image, scaled 1:1 with device pixels, say: $win->imag( $a, { SCALE=>1 } ); To see an image made on a device with 1:2 pixel aspect ratio, with X pixels the same as original image pixels, say $win->imag( $a, { PIX=>0.5, SCALE=>2 } ); To display an image at 100 dpi on any device, say: $win->imag( $a, { PITCH=>100 } ); To display an image with 100 micron pixels, say: $win->imag( $a, { PITCH=>10, UNIT=>'mm' } );
Display an image with correct aspect ratio
$win->imag1 ( $image, [$min, $max, $transform], [$opt] )
This is syntactic sugar for
$win->imag( { PIX=>1 } );
Add a wedge (colour bar) to an image.
$win->draw_wedge( [$opt] )
Adds a wedge - shows the mapping between colour and value for a pixel - to
the current image. This can also be achieved by setting DrawWedge
to 1
when calling the imag
routine.
The colour and font size are the same as used to draw the image axes
(although this will probably fail if you did it yourself). To control the size
and location of the wedge, use the Wedge
option, giving it a hash reference
containing any of the following:
Width
value by about 1 to keep the text readable.
Default is ''.
undef
, uses the
value used by imag
(recommended choice). Default is undef
.
undef
, uses the
value used by imag
(recommended choice). Default is undef
.
$a = rvals(50,50); $win = PDL::Graphics::PGPLOT::Window->new(); $win->imag( $a, { Justify => 1, ITF => 'sqrt' } ); $win->draw_wedge( { Wedge => { Width => 4, Label => 'foo' } } ); # although the following might be more sensible $win->imag( $a, { Justify => 1, ITF => 'sqrt', DrawWedge => 1, Wedge => { Width => 4, Label => 'foo'} } );
Load an image colour table.
Usage:
ctab ( $name, [$contrast, $brightness] ) # Builtin col table ctab ( $ctab, [$contrast, $brightness] ) # $ctab is Nx4 array ctab ( $levels, $red, $green, $blue, [$contrast, $brightness] ) ctab ( '', $contrast, $brightness ) # use last color table
Note: See PDL::Graphics::LUT for access to a large number of colour tables.
Plot vector as connected points
If the 'MISSING' option is specified, those points in the $y
vector
which are equal to the MISSING value are not plotted, but are skipped
over. This allows one to quickly draw multiple lines with one call to
line
, for example to draw coastlines for maps.
Usage: line ( [$x,] $y, [$opt] )
The following standard options influence this command:
AXIS, BORDER, COLO(U)R, JUSTIFY, LINESTYLE, LINEWIDTH, MISSING
$x = sequence(10)/10.; $y = sin($x)**2; # Draw a red dot-dashed line line $x, $y, {COLOR => 'RED', LINESTYLE=>3};
Plot vector as points
Usage: points ( [$x,] $y, [$symbol(s)], [$opt] )
Options recognised:
SYMBOL - Either a piddle with the same dimensions as $x, containing the symbol associated to each point or a number specifying the symbol to use for every point, or a name specifying the symbol to use according to the following (recognised name in capital letters): 0 - SQUARE 1 - DOT 2 - PLUS 3 - ASTERISK 4 - CIRCLE 5 - CROSS 7 - TRIANGLE 8 - EARTH 9 - SUN 11 - DIAMOND 12- STAR PLOTLINE - If this is >0 a line will be drawn through the points.
The following standard options influence this command:
AXIS, BORDER, CHARSIZE, COLOUR, JUSTIFY, LINESTYLE, LINEWIDTH
The ColorValues option allows one to plot XYZ data with the Z axis mapped to a color value. For example:
use PDL::Graphics::LUT; ctab(lut_data('idl5')); # set up color palette to 'idl5' points ($x, $y, {ColorValues => $z});
$y = sequence(10)**2+random(10); # Plot blue stars with a solid line through: points $y, {PLOTLINE => 1, COLOUR => BLUE, SYMBOL => STAR};
Plot error bars (using pgerrb()
)
Usage:
errb ( $y, $yerrors, [$opt] ) errb ( $x, $y, $yerrors, [$opt] ) errb ( $x, $y, $xerrors, $yerrors, [$opt] ) errb ( $x, $y, $xloerr, $xhierr, $yloerr, $yhierr, [$opt])
Options recognised:
TERM - Length of terminals in multiples of the default length SYMBOL - Plot the datapoints using the symbol value given, either as name or number - see documentation for 'points'
The following standard options influence this command:
AXIS, BORDER, CHARSIZE, COLOUR, JUSTIFY, LINESTYLE, LINEWIDTH
$y = sequence(10)**2+random(10); $sigma=0.5*sqrt($y); errb $y, $sigma, {COLOUR => RED, SYMBOL => 18};
Display image as contour map
Usage: cont ( $image, [$contours, $transform, $misval], [$opt] )
Notes: $transform
for image/cont etc. is used in the same way as the
TR()
array in the underlying PGPLOT FORTRAN routine but is,
fortunately, zero-offset. The transform()
routine can be used to
create this piddle.
Options recognised:
CONTOURS - A piddle with the contour levels FOLLOW - Follow the contour lines around (uses pgcont rather than pgcons) If this is set >0 the chosen linestyle will be ignored and solid line used for the positive contours and dashed line for the negative contours. LABELS - An array of strings with labels for each contour LABELCOLOUR - The colour of labels if different from the draw colour This will not interfere with the setting of draw colour using the colour keyword. MISSING - The value to ignore for contouring NCONTOURS - The number of contours wanted for automatical creation, overridden by CONTOURS TRANSFORM - The pixel-to-world coordinate transform vector
The following standard options influence this command:
AXIS, BORDER, COLOUR, JUSTIFY, LINESTYLE, LINEWIDTH
$x=sequence(10,10); $ncont = 4; $labels= ['COLD', 'COLDER', 'FREEZING', 'NORWAY'] # This will give four blue contour lines labelled in red. cont $x, {NCONT => $ncont, LABELS => $labels, LABELCOLOR => RED, COLOR => BLUE}
Plot vector as histogram (e.g. bin(hist($data))
)
Usage: bin ( [$x,] $data )
Options recognised:
CENTRE - if true, the x values denote the centre of the bin otherwise they give the lower-edge (in x) of the bin CENTER - as CENTRE
The following standard options influence this command:
AXIS, BORDER, COLOUR, JUSTIFY, LINESTYLE, LINEWIDTH
Plot image as 2d histogram (not very good IMHO...)
Usage: hi2d ( $image, [$x, $ioff, $bias], [$opt] )
Options recognised:
IOFFSET - The offset for each array slice. >0 slants to the right <0 to the left. BIAS - The bias to shift each array slice up by.
The following standard options influence this command:
AXIS, BORDER, JUSTIFY
Note that meddling with the ioffset
and bias
often will require you to
change the default plot range somewhat. It is also worth noting that if
you have TriD working you will probably be better off using
mesh3d or
a similar command - see the PDL::Graphics::TriD manpage.
$r=sequence(100)/50-1.0; $y=exp(-$r**2)*transpose(exp(-$r**2)) hi2d $y, {IOFF => 1.5, BIAS => 0.07};
Plot an arrow
Usage: arrow($x1, $y1, $x2, $y2, [, $opt]);
Plot an arrow from $x1, $y1
to $x2, $y2
. The arrow shape can be
set using the option Arrow
. See the documentation for general options
for details about this option (and the example below):
Example:
arrow(0, 1, 1, 2, {Arrow => {FS => 1, Angle => 60, Vent => 0.3, Size => 5}});
which draws a broad, large arrow from (0, 1) to (1, 2).
Draw a polygon
Usage: poly ( $x, $y )
Options recognised:
The following standard options influence this command:
AXIS, BORDER, COLOUR, FILLTYPE, HATCHING, JUSTIFY, LINESTYLE, LINEWIDTH
# Fill with hatching in two different colours $x=sequence(10)/10; # First fill with cyan hatching poly $x, $x**2, {COLOR=>5, FILL=>3}; hold; # Then do it over again with the hatching offset in phase: poly $x, $x**2, {COLOR=>6, FILL=>3, HATCH=>{PHASE=>0.5}}; release;
Plot a circle on the display using the fill setting.
Usage: circle($x, $y, $radius [, $opt]);
All arguments can alternatively be given in the options hash using the following options:
Plot an ellipse, optionally using fill style.
Usage: ellipse($x, $y, $a, $b, $theta [, $opt]);
All arguments can alternatively be given in the options hash using the following options:
$a
must be given.
$x
and $y
must be given.
Draw a rectangle.
Usage: rectangle($xcenter, $ycenter, $xside, $yside, [, $angle, $opt]);
This routine draws a rectangle with the chosen fill style. Internally
it calls the poly manpage which is somewhat slower than pgrect
but which
allows for rotated rectangles as well. The routine recognises the same
options as poly and in addition the following
Display 2 images as a vector field
Usage: vect ( $a, $b, [$scale, $pos, $transform, $misval] )
Notes: $transform
for image/cont etc. is used in the same way as the
TR()
array in the underlying PGPLOT FORTRAN routine but is,
fortunately, zero-offset. The transform()
routine can be used to
create this piddle.
This routine will plot a vector field. $a
is the horizontal component
and $b
the vertical component.
Options recognised:
SCALE - Set the scale factor for vector lengths. POS - Set the position of vectors. <0 - vector head at coordinate >0 - vector base at coordinate =0 - vector centered on the coordinate TRANSFORM - The pixel-to-world coordinate transform vector MISSING - Elements with this value are ignored.
The following standard options influence this command:
ARROW, ARROWSIZE, AXIS, BORDER, CHARSIZE, COLOUR, JUSTIFY, LINESTYLE, LINEWIDTH
$a=rvals(11,11,{Centre=>[5,5]}); $b=rvals(11,11,{Centre=>[0,0]}); vect $a, $b, {COLOR=>YELLOW, ARROWSIZE=>0.5, LINESTYLE=>dashed};
Create transform array for contour and image plotting
$win->transform([$xdim,$ydim], $options);
This function creates a transform array in the format required by the image and contouring routines. You must call it with the dimensions of your image as arguments or pass these as an anonymous hash - see the example below.
RefPos => [ [ $xpix, $ypix ], [ $xplot, $yplot ] ]
This will label pixel ($xpix,$ypix)
as being at position
($xplot,$yplot)
. The ImageCentre
option can be considered
to be a special case of this option, since the following are identical
(although one is a lot easier to type ;)
ImageCentre => [ $xc, $yc ] RefPos => [ [($nx-1)/2,($ny-1)/2], [ $xc, $yc ] ]
The values supplied in ImageCentre
are used
if both ImageCentre
and RefPos
are supplied in the
options list.
Example:
$im = rvals(100, 100); $w = PDL::Graphics::PGPLOT::Window->new(Device => '/xs'); $t = $w->transform(dims($im), {ImageCenter => 0, Pixinc => 5}); $w->imag($im, {Transform => $t});
Threaded line plotting
$win->tline($x, $y, $options);
This is a threaded interface to line
. This is convenient if you have
a 2D array and want to plot out every line in one go. The routine will
apply any options you apply in a ``reasonable'' way. In the sense that it
will loop over the options wrapping over if there are less options than
lines.
Example:
$h={Colour => ['Red', '1', 4], Linestyle => ['Solid' ,'Dashed']}; $tx=zeroes(100,5)->xlinvals(-5,5); $ty = $tx + $tx->yvals; $win->tline($tx, $ty, $h);
A threaded interface to points
Usage: tpoints($x, $y, $options);
This is a threaded interface to points
. This is convenient if you have
a 2D array and want to plot out every line in one go. The routine will
apply any options you apply in a ``reasonable'' way. In the sense that it
will loop over the options wrapping over if there are less options than
lines.
Example:
$h={Colour => ['Red', '1', 4], Linestyle => ['Solid' ,'Dashed']}; $tx=zeroes(100,5)->xlinvals(-5,5); $ty = $tx + $tx->yvals; tpoints($tx, $ty, $h);
Write text in a plot window at a specified position.
Usage: text ($text, $x, $y [, $opt])
Options recognised:
ANGLE
JUSTIFICATION
XPos
, YPos
, Text
BackgroundColour
Bg
and BackgroundColor
.
The following standard options influence this command:
COLOUR, CHARSIZE
line sequence(10), sequence(10)**2; text 'A parabola', 3, 9, {Justification => 1, Angle=>atan2(6,1)};
Add a legend to a plot
Usage: legend($text, $x, $y, [, $width], $opt]);
This function adds a legend to an existing plot. The action is primarily
controlled by information in the options hash, and the basic idea is that
$x
and $y
determines the upper left hand corner of the box in which
the legend goes. If the width is specified either as an argument or as
an option in the option hash this is used to determine the optimal character
size to fit the text into part of this width (defaults to 0.5 - see the
description of TextFraction
below). The rest of the width is filled out with
either lines or symbols according to the content of the LineStyle
,
Symbol
, Colour
and LineWidth
options.
The local options recognised are as follows:
Text
XPos
and YPos
Width
and Height
TextFraction
TextFraction
determines how much of this box should be devoted to text. This
defaults to 0.5. You can also use Fraction
as a synonym to this.
TextShift
VertSpace
or VSpace
VertSpace
option allows you to increase (or decrease) this gap in units of
the character height; a value of 0.5 would add half a character height to the
gap between lines, and -0.5 would remove the same distance.
The default value is 0.
BackgroundColour
Bg
and BackgroundColor
.
line $x, $y, {Color => 'Red', LineStyle => 'Solid'}; line $x2, $y2, {Color => 'Blue', 'LineStyle' => 'Dashed', LineWidth => 10};
legend ['A red line', 'A blue line'], 5, 5, {LineStyle => ['Solid', 'Dashed'], Colour => ['Red', 'Blue'] LineWidth => [undef, 10]}; # undef gives default.
Interactively read cursor positions.
Usage: ($x, $y, $ch, $xref, $yref) = cursor($opt)
This routine has no standard input parameters, but the type of cursor
can be set by setting the option Type
as a key in the anonymous hash
$opt
. The first three return values from the function are always
defined and gives the position selected by the user and the character
pressed.
Depending on the cursor type selected the last two arguments might also
be defined and these give a reference position. For instance if the cursor
is selected to be Rectangle
then the reference position gives one of
the corners of the rectangle and $x
and $y
the diagonally opposite
one.
Options recognised:
Default
(0),
RadialLine
(1), Rectangle
(2), TwoHorizontalLines
(3),
TwoVerticalLines
(4), HorizontalLine
(5), VerticalLine
(6)
and CrossHair
(7) respectively. The default cursor is just the normal
mouse cursor.
For the RadialLine
you must specify the reference point, whereas for
the Two(Vertical|Horizontal)Lines
cursor the X or Y reference point,
respectively, must be specified.
To select a region on a plot, use the rectangle cursor:
($x, $y, $ch, $xref, $yref) = cursor({Type => 'Rectangle'}); poly pdl($x, $xref, $xref, $x, $x), pdl($y, $y, $yref, $yref, $y);
To select a region of the X-axis:
($x1, $y1, $ch) = cursor({Type => 'VerticalLine'}); ($x2, $y2, $ch) = cursor({Type => 'TwoVerticalLines', XRef => $x1});
Open a new window. This sets the window ID, which is the one used when
accessing a window later using pgslct
. It also sets the window name
to something easily remembered if it has not been set before.
This routine sets up a new window with its shape and size. This is also where
the two options WindowXSize
and WindowYSize
are parsed. These are then
forgotten (well, they are stored in $self->{Options}, but forget that) and
the corresponding aspect ratio and window width is stored.
Alternatively, the AspectRatio
and WindowWidth
options are used to
set the view surface. The logic goes somewhat like this:
WindowXSize
and WindowYSize
are both non-zero, then those are used.
AspectRatio
is non-zero and WindowWidth
is zero,
WindowWidth
is calculated such that it a region with the given
aspect ratio will fit within the device's view surface.
AspectRatio
and WindowWidth
are zero, the device's
default AspectRatio
and WindowWidth
is used.
Finally the subpanels are set up using pgsubp
and colours and linewidth
are adjusted according to whether we have a hardcopy device or not.
This routine checks the status of the window. It returns OPEN if the window is open and CLOSED if it is closed.
This functions reopens a window. Since this is an internal function it does not have a lot of error-checking. Make sure the device is closed before calling this routine.
There is an unfortunate problem which pops up viz. that the window name
cannot be changed at this point since we are offering that to the rest of
the world. That might be sensible, but it means that the window name will
not reflect the id of the window - use id()
for that (this is also why
we do not call open_new_window
)
This routine advances one plot panel, updating the CurrentPanel as well. If the advance will proceed past the page the page will be erased. Also note that when you advance one panel the hold value will be changed.
This routine is a utility routine which checks if we need to move panel, and if so will do this. It also checks if it is necessary to advance panels, and whether they need to be erased.
This function is a cludgy utility function that expands an options hash to an array of hashes looping over options. This is mainly of use for ``threaded'' interfaces to standard plotting routines.
Access the options used when originally opening the window. At the moment this is not updated when the window is changed later.
Access the window ID that PGPLOT uses for the present window.
This function returns the device type of the present window.
Accessor to set and examine the name of a window.
Set focus for subsequent PGPLOT commands to this window.
Get general information about the PGPLOT environment.
@ans = $self->info( @item );
The valid values of @item
are as below, where case is not
important:
VERSION - What PGPLOT version is in use STATE - The status of the output device, this is returns 'OPEN' if the device is open and 'CLOSED' otherwise. USER - The username of the owner of the spawning program. NOW - The current date and time in the format 'dd-MMM-yyyy hh:mm'. Most people are likely to use Perl functions for this. DEVICE * - The current PGPLOT device or file, see also C<device> FILE * - The filename for the current device TYPE * - And the device type for the current device DEV/TYPE * - This combines DEVICE and TYPE in a form that can be used as input to C<new>. HARDCOPY * - This is flag which is set to 'YES' if the current device is a hardcopy device and 'NO' otherwise. TERMINAL * - This flag is set to 'YES' if the current device is the user's terminal and 'NO' otherwise. CURSOR * - A flag ('YES' or 'NO') to inform whether the current device has a cursor.
Those items marced with a *
only return a valid answer if
the window is open. A question mark (?
) is returned
if the item is not recognised or the information is not available.
This routine takes and array and returns the first hash reference found as well as those elements that are not hashes. Note the latter point because all other references to hashes in the array will be lost.
This is a convenience routine for parsing a set of options. It returns both the full set of options and those that the user has set.
Saves the PGPLOT state so that changes to settings can be made and then
the present state restored by _restore_status
.
Restore the PGPLOT state. See the _save_status manpage.
This routine checks and optionally alters the arguments given to it.
This is an internal routine that encapsulates all the nastiness of setting colours depending on the different PGPLOT colour models (although HLS is not supported).
The routine works in the following way:
ARRAY
or a PDL
reference. If it is not an error message is given.
If it is a PDL
reference it will be converted to an array ref.
pgqcol
). Should you wish to change that you need
to read the PGPLOT documentation - it is somewhat device dependent.
pgscr
command and we
are finished.
pgscrn
with no other error-checking. This
should be ok, as that routine returns a rather sensible error-message.
This internal routine is the default routine for parsing options. This routine deals with a subset of options that most routines will accept.
The coding tries to follow reasonable standards, so that all functions starting with an underscore should be considered as internal and should not be called from outside the package. In addition most routines has a set of options. These are encapsulated and are not accessible outside the routine. This is to avoid collisions between different variables.
Karl Glazebrook [kgb@aaoepp.aao.gov.au] modified by Jarle Brinchmann (jarle@astro.ox.ac.uk) who is also responsible for the OO interface, docs mangled by Tuomas J. Lukka (lukka@fas.harvard.edu) and Christian Soeller (c.soeller@auckland.ac.nz) Further contributions and bugfixes from Kaj Wiik, Doug Burke and many others.
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