Free imager tutorial software for linux

Imager::Tutorial is an introduction to Imager.

Before you start

If you have the necessary knowledge, install the image format libraries you want Imager image file support for, and Imager itself, otherwise arrange to have it done.
You will also want some sort of image viewer tool, whether an image editor like Photoshop or the GIMP, or a web browser.

Hello Boxes! - A Simple Start

As with any perl program its useful to start with a #! line, and to enable strict mode:

#!/usr/bin/perl -w
# you might to use warnings; instead of the -w above
use strict;

These lines will be omitted in further examples.

As with any module, you need to load it:

use Imager;

Now create a image to draw on:

my $image = Imager->new(xsize => 100, ysize => 100);

and draw a couple of filled rectangles on it:

$image->box(xmin => 0, ymin => 0, xmax => 99, ymax => 99,
filled => 1, color => blue);
$image->box(xmin => 20, ymin => 20, xmax => 79, ymax => 79,
filled => 1, color => green);

Since the first box fills the whole image, it can be simplified to:

$image->box(filled => 1, color => blue);

and save it to a file:

$image->write(file=>tutorial1.ppm)
or die Cannot save tutorial1.ppm: , $image->errstr;

So our completed program is:

use Imager;

my $image = Imager->new(xsize => 100, ysize => 100);

$image->box(filled => 1, color => blue);
$image->box(xmin => 20, ymin => 20, xmax => 79, ymax => 79,
filled => 1, color => green);

$image->write(file=>tutorial1.ppm)
or die Cannot save tutorial1.ppm: , $image->errstr;

Prima::tutorial is an introductory tutorial.

Programming graphic interfaces is often considered somewhat boring, and not without a cause. It is a small pride in knowing that your buttons and scrollbars work exactly as millions of others buttons and scrollbars do, so whichever GUI toolkit is chosen, it is usually regarded as a tool of small importance, and the less obtrusive, the better.

Given that, and trying to live up to the famous Perl making easy things easy and hard things possible mantra, this manual page is an introductory tutorial meant to show how to write easy things easy. The hard things are explained in the other Prima manual pages ( see Prima ).

IPTables-tutorials aim is to explain iptables in a complete and simple way. The iptables-tutorial is currently rather stable, and contains information on all the currently available matches and targets (in kernel), as well as a couple of complete example scripts and explanations. It contains a complete section on iptables syntax, as well as other interesting commands such as iptables-save and iptables-restore.

The tutorial has recently been under heavy scrutiny and updating, as can be seen in this, the latest version of the tutorial. It is now also available in bookform from Lulu.com. If you feel like contributing or donating to the author of this tutorial, please do buy the book! Thank you!

If you need help, you are better off by asking the netfilter mailing list which you can reach at netfilter at lists.netfilter.org. For more information on this, visit the netfilter mailinglist page. You may also contact the linuxsecurity mailing list at security-discuss AT linuxsecurity dotcom. Both are fairly large, and should be able to help you much much better than I can.

yagg::Tutorial is a Perl module that contains a tutorial for yagg.

SYNOPSIS

# To use the generator
./yagg -m nonterminals.yg terminals.lg
./output/progs/generate 5

This tutorial will show you how to use yagg, by way of two examples. In the first example, we create a simple logical expression generator from scratch. In the second example, we create a more sophisticated logical expression generator from existing parser/lexer input files, such as those used by YACC/Bison and LEX/FLEX. These examples, plus another more sophisticated fault tree generator are included with the distribution in the examples/ directory.

It is assumed that the reader knows a little about formal grammars. Ideally, the reader would have some experience writing grammars for input to parser generators like YACC and Bison.

Imager script is a Perl extension for generating 24-bit images.

KDE Simple Programming Tutorial is a tutorial for developing a KDE application.

With the only requirement of a little C++ knowledge, and using the latest KDE snapshots, the reader will learn how to build his/her first KDE application from a simple "Hello world" button to a Web browser with a DCOP interface that communicates with a bookmark application running in a separate process.

Theres also a spanish and a romanian version of the documentation.

Webmasters Tools is a set of free open-source tools to do the work of the webmaster,
under the OSS licence.

Programs included:

metagen Program to generate meta-tags for your web pages.
metarep Report meta-tags and links in web pages.
updater Copy a part of a web page to all others.
outline Build a tutorial from simple unformatted text files.
makelist Build a page made of the list of links from a directory.

Web tools are free software; you can redistribute the archive and/or modify the programs under the terms of the OSS licence.

Imager::Color is a Perl module with color handling for Imager.

SYNOPSIS

$color = Imager::Color->new($red, $green, $blue);
$color = Imager::Color->new($red, $green, $blue, $alpha);
$color = Imager::Color->new("#C0C0FF"); # html color specification

$color->set($red, $green, $blue);
$color->set($red, $green, $blue, $alpha);
$color->set("#C0C0FF"); # html color specification

($red, $green, $blue, $alpha) = $color->rgba();
@hsv = $color->hsv(); # not implemented but proposed

$color->info();

if ($color->equals(other=>$other_color)) {
...
}

This module handles creating color objects used by imager. The idea is that in the future this module will be able to handle colorspace calculations as well.

new

This creates a color object to pass to functions that need a color argument.

set

This changes an already defined color. Note that this does not affect any places where the color has been used previously.

rgba

This returns the rgba code of the color the object contains.

info

Calling info merely dumps the relevant colorcode to the log.

equals(other=>$other_color)
equals(other=>$other_color, ignore_alpha=>1)

Compares $self and color $other_color returning true if the color components are the same.

Compares all four channels unless ignore_alpha is set. If ignore_alpha is set only the first three channels are compared.

You can specify colors in several different ways, you can just supply simple values:
simple numeric parameters - if you supply 3 or 4 numeric arguments, you get a color made up of those RGB (and possibly A) components.

a six hex digit web color, either RRGGBB or #RRGGBB
an eight hex digit web color, either RRGGBBAA or #RRGGBBAA.
a 3 hex digit web color, #RGB - a value of F becomes 255.
a color name, from whichever of the gimp Named_Colors file or X rgb.txt is found first. The same as using the name keyword.

You can supply named parameters:

red, green and blue, optionally shortened to r, g and b. The color components in the range 0 to 255.

# all of the following are equivalent
my $c1 = Imager::Color->new(red=>100, blue=>255, green=>0);
my $c2 = Imager::Color->new(r=>100, b=>255, g=>0);
my $c3 = Imager::Color->new(r=>100, blue=>255, g=>0);
hue, saturation and value, optionally shortened to h, s and v, to specify a HSV color. 0 new(hue=>120, value=>1, saturation=>0.5);
web, which can specify a 6 or 3 hex digit web color, in any of the forms #RRGGBB, #RGB, RRGGBB or RGB.
my $c1 = Imager::Color->new(web=>#FFC0C0); # pale red
gray or grey which specifies a single channel, from 0 to 255.
# exactly the same
my $c1 = Imager::Color->new(gray=>128);
my $c1 = Imager::Color->new(grey=>128);
rgb which takes a 3 member arrayref, containing each of the red, green and blue values.
# the same
my $c1 = Imager::Color->new(rgb=>[255, 100, 0]);
my $c1 = Imager::Color->new(r=>255, g=>100, b=>0);
hsv which takes a 3 member arrayref, containting each of hue, saturation and value.
# the same
my $c1 = Imager::Color->new(hsv=>[120, 0.5, 1]);
my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);

gimp which specifies a color from a GIMP palette file. You can specify the filename of the palette file with the palette parameter, or let Imager::Color look in various places, typically "$HOME/gimp-1.x/palettes/Named_Colors" with and without the version number, and in /usr/share/gimp/palettes/. The palette file must have color names.

my $c1 = Imager::Color->new(gimp=>snow);
my $c1 = Imager::Color->new(gimp=>snow, palette=>testimg/test_gimp_pal);

xname which specifies a color from an X11 rgb.txt file. You can specify the filename of the rgb.txt file with the palette parameter, or let Imager::Color look in various places, typically /usr/lib/X11/rgb.txt.

my $c1 = Imager::Color->new(xname=>blue) # usually RGB(0, 0, 255)

builtin which specifies a color from the built-in color table in Imager::Color::Table. The colors in this module are the same as the default X11 rgb.txt file.

my $c1 = Imager::Color->new(builtin=>black) # always RGB(0, 0, 0)

name which specifies a name from either a GIMP palette, an X rgb.txt file or the built-in color table, whichever is found first.

channel0, channel1, etc, each of which specifies a single channel. These can be abbreviated to c0, c1 etc.

channels which takes an arrayref of the channel values.

Optionally you can add an alpha channel to a color with the alpha or a parameter.

These color specifications can be used for both constructing new colors with the new() method and modifying existing colors with the set() method.