Join David Powers for an in-depth discussion in this video Overview of my solution, part of Code Clinic: PHP.
The challenge is to take this folder of images…and find out which, if any, have been cropped…from larger images in the same folder.…The simple way would be to open the images…and check them visually, but that would be cheating.…We need to do it programmatically.…So let's see how PHP might help.…PHP has a wide choice…of image processing and generation functions.…The one that tends to be installed…on most versions of PHP is this one down here,…GD, so that's where I started.…
The GD imagecolorat function…gets the RGB value of a pixel.…My first attempt involved using this function…to try to find matching sequences of pixels in two images.…Early results were promising,…but it turned out to be a dead end.…JPEG is a lossy format,…which discards pixel information…each time the image is saved.…So trying to find exact matching sequences…was never going to work.…So next I turned to this,…the ImageMagick extention of PHP.…
Unfortunately, it's not normally bundled with PHP.…If we click here on installation, we can see…that it's a pecl extension and it's not bundled with PHP.…
David introduces challenges and provides an overview of his solutions in PHP. Challenges include topics such as statistical analysis, searching directories for images, and accessing peripheral devices.
Visit other courses in the series to see how to solve the exact same challenges in languages like C#, C++, Java, Python, and Ruby.
Skill Level Intermediate
Q: I'm encountering script errors message with the prime_dates.php file used in the "Priming the date_record column" movie in this course. How can I resolve these errors?
A: To avoid script errors, use bindValue() instead of bindParam() in
Line 9 of the prime_dates.php file. You can also download the latest
copy of the exercise files, which corrects this issue for you. For a
more in-depth explanation of the difference between bindValue() and
bindParam(), check out the "Binding input and output values" video (http://www.lynda.com/PHP-
Q: Why can't I access the Lake Pend Orielle site (http://lpo.dt.navy.mil)?
A: The Lake Pend Orielle site is not accessible in some geographical areas. We have contacted the owner of the server to try to resolve this issue.
Q: I am unable to access the Lake Pend Oreille data from outside the U.S.
A: A static copy of this data is provided here for lynda.com members outside of the U.S
Problem One: Statistical Analysis
Problem Two: Image Analysis
Problem Three: Eight Queens
Problem Four: Accessing Peripherals
Problem Five: Recursion and Directories
Problem Six: Building the Web
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