Web Development Blog » book review

Image manipulations with Imagemagick

Olaf — Tue, 05 May 2009 20:05:08 +0000

A very powerful tool for creating and manipulating images is ImageMagick. With this tools you can create drawings, modify existing images or just process images. The tool is available for Linux, windows and Mac based systems and is free available. Using the command line is Imagemagick the optimal tool to use image functions within your script or application.

Use Imagemagick to watermark your images, to create fancy e-cards or just to convert images into other formats. Basic operations are very easy like

convert resize 50% image.jpg new.png

This simple command will resize your jpg image and safe a copy as some new image in .png format. Just imagine how much code you need with the GD library. As a webmaster you will find ImageMagick with most of the web hosting accounts.

Check Google if you need example code and resources. If you can’t find the information you should try the book “ImageMagick tips and tricks“. This book full of information and tutorials is a good start to learn all basic functions of this powerful tool.

Inside the book you find instructions how to install ImageMagick on different platform and there also basic instructions on how-to install additional fonts. If you’re interested in this feature you should read this article too.

You will find real word examples for each command line tool. Each function has a few lessons of each chapter to train each function with a real world example:

Convert and mogrify

Both functions are used for transformations, while the convert creates a new image is the mogrify function used to change existing images. For examples:

crop an existing image and safe a cropped new version
convert sample.png crop 110x70+60+50 cropped.jpg

draw a line on white background inside a new image
mogrify size 80x100 xcwhite draw 'line 10,10 70,90' line.bmp

Composite and montage

These both functions are used to group or assemble multiple image sequences together like:

Mask an existing logo image with some background and safe it into the result image
composite -compose CopyOpacity logo_mask.png background.png result.png

Other functions like identify, display, import and conjure are explained too, check the book or the IM website for more information.

The book is written to use ImageMagick with php. Use above tools in your PHP code like:

$command = 'convert example.jpg new.png'; exec($command);

Instead of the PHP function exec it’s also possible to process the commands with functions like system, passthru or shell_exec.

After you got all the basic lessons you get some more practice:

How to call ImageMagick Command-line Utilities within PHP code
How to Save the Result of an Online Image Processing Task
How to Start Sessions for our Visitors
Building a Confirmation-Code Box
Online Image Water Marking
A complete E-card application
Learn how to add different text styles to your e-cards. The tutorial includes the complete code for the following features:
- Image gallery
- Image upload / remote copy
- custom text for the e-cards
- fomat text on images
- send the finished e-card by e-mail

While reading the book you should check this page for example code, screenshots and additional information. If you’re not sure if this book is written for you try this example chapter. The book was released in 2006 but is still “compatible” with current version of ImageMagick.

More ImageMagick resources

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Database Management with phpMyAdmin

Olaf — Mon, 12 May 2008 13:41:37 +0000

This is part one of the quick review of the book “Mastering phpMyAdmin for Effective MySQL Management” and the phpMyAdmin software.

This article/review is not just another review about phpMyAdmin, but more some information about features I haven’t used during the last years of PHP/MySQL web development.

About phpMyAdmin

PMA is a full featured tool to administrate your MySQL database server via a web browser. While the functions are almost unlimited, it’s also a powerful tool to maintain the database content even for less experienced users.

It’s already a year ago (or more) that I got the book “Mastering phpMyAdmin” as a present/reward for contributing some snippets on weberdev.com. Finally I found the time to read (most of) the book during a vacation. The book is great for webmasters using phpMyAdmin (PMA) the first time and also more advanced users. The book covers the installation, basic database interactions using PMA like simple INSERT or SELECT commands and also advanced features like the relational system provided by the phpMyAdmin software.

More advanced user should read the book to learn more about:

Changing the configuration fies to customize your current installation
how to handle binary data inside phpMyAdmin
saving export files on the server
better understanding on how-to import CSV files
complete database search
the PMA relational system
using the Mimer SQL validator
better understanding of the multi table query generator
using bookmarks for frequent used queries
building relational schema in PDF
mime based transformations
character sets and collations

While the book is published in 2004 (I see it was time for me to read), the descriptions and screen-shot are actual enough to translate the book information into the users work with the current version of phpMyAdmin.

The Installation part

I remember me my first installation of phpMyAdmin, the hardest part was to enter some configuration of paths and database connection parameters. The book shows clear information about
basic installation (one user with one database)

Multi server installation
Multiuser installation
restricting access to phpMyAdmin by IP and/or user

Sure over the years an experienced user will discover all types of installations, but using this book the user gets a better understanding of features like authentication types or Multi use/server configuration. I must say that the user restriction function in PMA are new to me, sure I didn’t needed them before. Restrict the access by IP address to allow access only in your companies network, this way a .htaccess user protection is more safe because you are able to control the access from outside of your network!

The Interface and basic database interactions

The PMA interface is very self-describing, I found a nice feature for people working with multiple databases accessed by the same user. The nested display will show tables for each database without selecting a different database.
Do you know the vertical mode for editing multiple records? with setting the configuration value $cfg['DefaultPropDisplay'] to “vertical” the records are arranged in vertical order. A great feature if you edit 2-3 records the same time.
While contributing to PHP forums I noticed often question about database fields from the “Blob” type. Sure it’s not a really good idea to store binary data inside a database, this book will give some useful guidance to store and read this type of content.

Import and export of data

Exporting content or complete database tables is a very common function in PMA, but do you noticed the export function even for results based on queries? I got this question very often: “could you send me just these data from that table?”, most of the time they got the whole table because it was much faster to export, Or better why not exporting single records from a complete result set?
Another useful feature is to export to the server, this function is available if you configure the safe_dir in your PMA configuration.

For all users on shared hosting platforms is this following feature very useful: By default the upload size and memory limit are very limited. Uploading data import files bigger than 2MB (compressed) could be a problem. The option “upload_dir” will help. Create one central folder and upload your import files via FTP, after then select the file from the select box on the import screen.

Searching and selecting data

Do you ever noticed the feature “database search”? Just access the search tab (without selecting a database table) and search for data using wild cards, an exact phrase or regular expressions get results from your whole database.

This was part one of the PMA / book review, if you like to read more about the relational system, bookmarks and MIME-based transformations subscribe to this blog post.Similar Posts: