Join David Powers for an in-depth discussion in this video Calculating the scaling ratio, part of Code Clinic: PHP.
Before embarking on the PHP code…let's take a look at the ImageMagick documentation…for matching sub-images and shapes.…The key information is here.…It says the search basically does a compare…of the small image at every possible location…in the larger image.…As such, it's slow.…Very, very slow.…The best idea is to compare a very, very small sub-image…to find possible locations.…With that in mind,…the first task is to find out…how big the original images are…and calculate a scaling ratio…to generate smaller versions.…
So let's go to the PHP code.…In my editing program I've created a new file…called find underscore crop dot PHP…which is where I'll be building the main script.…I've saved it in the top level…of the problem 02 folder of my testing site.…I'm gonna begin by initializing some variables…that I'll paste in from variables dot txt…that you can find in the exercise files for this video.…The first four variables are the image folders…and then we've got three empty arrays for files…and their dimensions.…
To find the images that need to be tested…
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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