NAME

PostScript::Simple - Produce PostScript files from Perl

SYNOPSIS

use PostScript::Simple;

# create a new PostScript object
$p = new PostScript::Simple(papersize => "A4",
                            colour => 1,
                            eps => 0,
                            units => "in");

# create a new page
$p->newpage;

# draw some lines and other shapes
$p->line(1,1, 1,4);
$p->linextend(2,4);
$p->box(1.5,1, 2,3.5);
$p->circle(2,2, 1);
$p->setlinewidth( 0.01 );
$p->curve(1,5, 1,7, 3,7, 3,5);
$p->curvextend(3,3, 5,3, 5,5);

# draw a rotated polygon in a different colour
$p->setcolour(0,100,200);
$p->polygon({rotate=>45}, 1,1, 1,2, 2,2, 2,1, 1,1);

# add some text in red
$p->setcolour("red");
$p->setfont("Times-Roman", 20);
$p->text(1,1, "Hello");

# write the output to a file
$p->output("file.ps");

DESCRIPTION

PostScript::Simple allows you to have a simple method of writing PostScript files from Perl. It has graphics primitives that allow lines, curves, circles, polygons and boxes to be drawn. Text can be added to the page using standard PostScript fonts.

The images can be single page EPS files, or multipage PostScript files. The image size can be set by using a recognised paper size ("A4", for example) or by giving dimensions. The units used can be specified ("mm" or "in", etc) and are the same as those used in TeX. The default unit is a bp, or a PostScript point, unlike TeX.

PREREQUISITES

This module requires strict and Exporter.

EXPORT

None.

CONSTRUCTOR

new(options)

Create a new PostScript::Simple object. The different options that can be set are:

units

Units that are to be used in the file. Common units would be mm, in, pt, bp, and cm. Others are as used in TeX. (Default: bp)

xsize

Specifies the width of the drawing area in units.

ysize

Specifies the height of the drawing area in units.

papersize

The size of paper to use, if xsize or ysize are not defined. This allows a document to easily be created using a standard paper size without having to remember the size of paper using PostScript points. Valid choices are currently "A3", "A4", "A5", and "Letter".

landscape

Use the landscape option to rotate the page by 90 degrees. The paper dimensions are also rotated, so that clipping will still work. (Note that the printer will still think that the paper is portrait.) (Default: 0)

copies

Set the number of copies that should be printed. (Default: 1)

clip

If set to 1, the image will be clipped to the xsize and ysize. This is most useful for an EPS image. (Default: 0)

colour

Specifies whether the image should be rendered in colour or not. If set to 0 (default) all requests for a colour are mapped to a greyscale. Otherwise the colour requested with setcolour or line is used. This option is present because most modern laser printers are only black and white. (Default: 0)

eps

Generate an EPS file, rather than a standard PostScript file. If set to 1, no newpage methods will actually create a new page. This option is probably the most useful for generating images to be imported into other applications, such as TeX. (Default: 1)

page

Specifies the initial page number of the (multi page) document. The page number is set with the Adobe DSC comments, and is used nowhere else. It only makes finding your pages easier. See also the newpage method. (Default: 1)

coordorigin

Defines the co-ordinate origin for each page produced. Valid arguments are LeftBottom, LeftTop, RightBottom and RightTop. The default is LeftBottom.

direction

The direction the co-ordinates go from the origin. Values can be RightUp, RightDown, LeftUp and LeftDown. The default value is RightUp.

reencode

Requests that a font re-encode function be added and that the 13 standard PostScript fonts get re-encoded in the specified encoding. The most popular choice (other than undef) is 'ISOLatin1Encoding' which selects the iso8859-1 encoding and fits most of western Europe, including the Scandinavia. Refer to Adobes Postscript documentation for other encodings.

The output file is, by default, re-encoded to ISOLatin1Encoding. To stop this happening, use 'reencode => undef'. To use the re-encoded font, '-iso' must be appended to the names of the fonts used, e.g. 'Helvetica-iso'.

Example:

$ref = new PostScript::Simple(landscape => 1,
                              eps => 0,
                              xsize => 4,
                              ysize => 3,
                              units => "in");

Create a document that is 4 by 3 inches and prints landscape on a page. It is not an EPS file, and must therefore use the newpage method.

$ref = new PostScript::Simple(eps => 1,
                              colour => 1,
                              xsize => 12,
                              ysize => 12,
                              units => "cm",
                              reencode => "ISOLatin1Encoding");

Create a 12 by 12 cm EPS image that is in colour. Note that "eps => 1" did not have to be specified because this is the default. Re-encode the standard fonts into the iso8859-1 encoding, providing all the special characters used in Western Europe. The newpage method should not be used.

OBJECT METHODS

Unless otherwise specified, object methods return 1 for success or 0 in some error condition (e.g. insufficient arguments). Error message text is also drawn on the page.

newpage([number])

Generates a new page on a PostScript file. If specified, number gives the number (or name) of the page. This method should not be used for EPS files.

The page number is automatically incremented each time this is called without a new page number, or decremented if the current page number is negative.

Example:

$p->newpage(1);
$p->newpage;
$p->newpage("hello");
$p->newpage(-6);
$p->newpage;

will generate five pages, numbered: 1, 2, "hello", -6, -7.

output(filename)

Writes the current PostScript out to the file named filename. Will destroy any existing file of the same name.

Use this method whenever output is required to disk. The current PostScript document in memory is not cleared, and can still be extended.

get

Returns the current document.

Use this method whenever output is required as a scalar. The current PostScript document in memory is not cleared, and can still be extended.

geteps

Returns the current document as a PostScript::Simple::EPS object. Only works if the current document is EPS.

This method calls new PostScript::Simple::EPS with all the default options. To change these, call it yourself as below, rather than using this method.

$eps = new PostScript::Simple::EPS(source => $ps->get);

setcolour((red, green, blue)|(name))

Sets the new drawing colour to the RGB values specified in red, green and blue. The values range from 0 to 255.

Alternatively, a colour name may be specified. Those currently defined are listed at the top of the PostScript::Simple module in the %pscolours hash and include the standard X-Windows colour names.

Example:

# set new colour to brown
$p->setcolour(200,100,0);
# set new colour to black
$p->setcolour("black");

setcmykcolour(cyan, magenta, yellow, black)

Sets the new drawing colour to the CMYK values specified in cyan, magenta, yellow} and black. The values range from 0 to 1. Note that PostScript::Simple does not do any colour management, so the output colour (as also with setcolour) may vary according to output device.

Example:

# set new colour to a shade of blue
$p->setcmykcolour(0.1, 0.5, 0, 0.2);
# set new colour to black
$p->setcmykcolour(0, 0, 0, 1);
# set new colour to a rich black
$p->setcmykcolour(0.5, 0.5, 0.5, 1);

setlinewidth(width)

Sets the new line width to width units.

Example:

# draw a line 10mm long and 4mm wide
$p = new PostScript::Simple(units => "mm");
$p->setlinewidth(4);
$p->line(10,10, 20,10);

line(x1,y1, x2,y2 [,red, green, blue])

Draws a line from the co-ordinates (x1,x2) to (x2,y2). If values are specified for red, green and blue, then the colour is set before the line is drawn.

Example:

# set the colour to black
$p->setcolour("black");

# draw a line in the current colour (black)
$p->line(10,10, 10,20);

# draw a line in red
$p->line(20,10, 20,20, 255,0,0);

# draw another line in red
$p->line(30,10, 30,20);

linextend(x,y)

Assuming the previous command was line, linextend, curve or curvextend, extend that line to include another segment to the co-ordinates (x,y). Behaviour after any other method is unspecified.

Example:

$p->line(10,10, 10,20);
$p->linextend(20,20);
$p->linextend(20,10);
$p->linextend(10,10);

Notes

The polygon method may be more appropriate.

arc([options,] x,y, radius, start_angle, end_angle)

Draws an arc on the circle of radius radius with centre (x,y). The arc starts at angle start_angle and finishes at end_angle. Angles are specified in degrees, where 0 is at 3 o'clock, and the direction of travel is anti-clockwise.

Any options are passed in a hash reference as the first parameter. The available option is:

filled => 1

If filled is 1 then the arc will be filled in.

Example:

# semi-circle
$p->arc(10, 10, 5, 0, 180);

# complete filled circle
$p->arc({filled=>1}, 30, 30, 10, 0, 360);

polygon([options,] x1,y1, x2,y2, ..., xn,yn)

The polygon method is multi-function, allowing many shapes to be created and manipulated. Polygon draws lines from (x1,y1) to (x2,y2) and then from (x2,y2) to (x3,y3) up to (xn-1,yn-1) to (xn,yn).

Any options are passed in a hash reference as the first parameter. The available options are as follows:

rotate => angle =item rotate => [angle,x,y]

Rotate the polygon by angle degrees anti-clockwise. If x and y are specified then use the co-ordinate (x,y) as the centre of rotation, otherwise use the co-ordinate (x1,y1) from the main polygon.

filled => 1

If filled is 1 then the PostScript output is set to fill the object rather than just draw the lines.

offset => [x,y]

Displace the object by the vector (x,y).

Example:

# draw a square with lower left point at (10,10)
$p->polygon(10,10, 10,20, 20,20, 20,10, 10,10);

# draw a filled square with lower left point at (20,20)
$p->polygon( {offset => [10,10], filled => 1},
            10,10, 10,20, 20,20, 20,10, 10,10);

# draw a filled square with lower left point at (10,10)
# rotated 45 degrees (about the point (10,10))
$p->polygon( {rotate => 45, filled => 1},
            10,10, 10,20, 20,20, 20,10, 10,10);

circle([options,] x,y, r)

Plot a circle with centre at (x,y) and radius of r.

There is only one option.

filled => 1

If filled is 1 then the PostScript output is set to fill the object rather than just draw the lines.

Example:

$p->circle(40,40, 20);
$p->circle( {filled => 1}, 62,31, 15);

circletext([options,] x, y, r, a, text)

Draw text in an arc centered about angle a with circle midpoint (x,y) and radius r.

There is only one option.

align => "alignment"

alignment can be 'inside' or 'outside'. The default is 'inside'.

Example:

# outside the radius, centered at 90 degrees from the origin
$p->circletext(40, 40, 20, 90, "Hello, Outside World!");
# inside the radius centered at 270 degrees from the origin
$p->circletext( {align => "inside"}, 40, 40, 20, 270, "Hello, Inside World!");

box(x1,y1, x2,y2 [, options])

Draw a rectangle from lower left co-ordinates (x1,y1) to upper right co-ordinates (y1,y2).

Options are:

filled => 1

If filled is 1 then fill the rectangle.

Example:

$p->box(10,10, 20,30);
$p->box( {filled => 1}, 10,10, 20,30);

Notes

The polygon method is far more flexible, but this method is quicker!

setfont(font, size)

Set the current font to the PostScript font font. Set the size in PostScript points to size.

Notes

This method must be called on every page before the text method is used.

text([options,] x,y, string)

Plot text on the current page with the lower left co-ordinates at (x,y) and using the current font. The text is specified in string.

Options are:

align => "alignment"

alignment can be 'left', 'centre' or 'right'. The default is 'left'.

rotate => angle

"rotate" degrees of rotation, defaults to 0 (i.e. no rotation). The angle to rotate the text, in degrees. Centres about (x,y) and rotates clockwise. (?). Default 0 degrees.

Example:

$p->setfont("Times-Roman", 12);
$p->text(40,40, "The frog sat on the leaf in the pond.");
$p->text( {align => 'centre'}, 140,40, "This is centered.");
$p->text( {rotate => 90}, 140,40, "This is rotated.");
$p->text( {rotate => 90, align => 'centre'}, 140,40, "This is both.");

curve( x1, y1, x2, y2, x3, y3, x4, y4 )

Create a curve from (x1, y1) to (x4, y4). (x2, y2) and (x3, y3) are the control points for the start- and end-points respectively.

curvextend( x1, y1, x2, y2, x3, y3 )

Assuming the previous command was line, linextend, curve or curvextend, extend that path with another curve segment to the co-ordinates (x3, y3). (x1, y1) and (x2, y2) are the control points. Behaviour after any other method is unspecified.

newpath

This method is used internally to begin a new drawing path - you should generally NEVER use it.

moveto( x, y )

This method is used internally to move the cursor to a new point at (x, y) - you will generally NEVER use this method.

importepsfile([options,] filename, x1,y1, x2,y2)

Imports an EPS file and scales/translates its bounding box to fill the area defined by lower left co-ordinates (x1,y1) and upper right co-ordinates (x2,y2). By default, if the co-ordinates have a different aspect ratio from the bounding box, the scaling is constrained on the greater dimension to keep the EPS fully inside the area.

Options are:

overlap => 1

If overlap is 1 then the scaling is calculated on the lesser dimension and the EPS can overlap the area.

stretch => 1

If stretch is 1 then fill the entire area, ignoring the aspect ratio. This option overrides overlap if both are given.

Example:

# Assume smiley.eps is a round smiley face in a square bounding box

# Scale it to a (10,10)(20,20) box
$p->importepsfile("smiley.eps", 10,10, 20,20);

# Keeps aspect ratio, constrained to smallest fit
$p->importepsfile("smiley.eps", 10,10, 30,20);

# Keeps aspect ratio, allowed to overlap for largest fit
$p->importepsfile( {overlap => 1}, "smiley.eps", 10,10, 30,20);

# Aspect ratio is changed to give exact fit
$p->importepsfile( {stretch => 1}, "smiley.eps", 10,10, 30,20);

importeps(filename, x,y)

Imports a PostScript::Simple::EPS object into the current document at position (x,y).

Example:

use PostScript::Simple;

# create a new PostScript object
$p = new PostScript::Simple(papersize => "A4",
                            colour => 1,
                            units => "in");

# create a new page
$p->newpage;

# create an eps object
$e = new PostScript::Simple::EPS(file => "test.eps");
$e->rotate(90);
$e->scale(0.5);

# add eps to the current page
$p->importeps($e, 10,50);

err()

Returns the last error generated.

Example:

unless ($ps->setcolour("purplewithyellowspots")) {
  print $ps->err();
}

# prints "bad colour name 'purplewithyellowspots'";

BUGS

Some current functionality may not be as expected, and/or may not work correctly. That's the fun with using code in development!

AUTHOR

The PostScript::Simple module was created by Matthew Newton, with ideas and suggestions from Mark Withall and many other people from around the world. Thanks!

Please see the README file in the distribution for more information about contributors.

Copyright (C) 2002-2014 Matthew C. Newton

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details, available at http://www.gnu.org/licenses/gpl.html.

SEE ALSO

PostScript::Simple::EPS