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Generating Colour Palettes From Images In PHP

4th August 2024 - 11 minutes read time

A common web design pattern is to incorporate an image into the design of the page. This creates a tighter integration with the image and the rest of the page.

The main issue in designing a page around the image is that the colours of the page must match the image. Otherwise this creates a dissonance between the image and the styles of the site.

In this article I will look at extracting a colour palette from an image so that it can be used in the design of a web page.

Creating A Character Bitmap In PHP

23rd June 2024 - 13 minutes read time

I was watching a video from NDC by Dylan Beattie the other day on The Story of Typography and a particular section stood out to me.

The talk ranges from the initial start of writing symbols to the formation of typography as an art form and the creation of eInk displays. Well worth a watch if you have some time to spare.

The part that was interesting to me was then discussing early word processors and the ASCII character standard. Early word processors couldn't store the amount of data required to fully render a font, so characters were rendered using a bitmap system.

Drawing A Parabolic Curve With Straight Lines In PHP

12th May 2024 - 16 minutes read time

A parabolic curve is a type of curve where every point is an equal distance from a focal point. There a number of different way to generate this sort of curve using math, but one of the simplest is to use straight lines to create the illusion of the curve.

The curve is created by diving two axis into equal points and then drawing a line from the first point on one axis to the last point on the opposite axis. Each line of the curve is drawn in the same way, repeating the process of drawing a line between opposite points for every point along the axis.

Creating Sparklines In PHP

17th September 2023 - 12 minutes read time

A sparkline is a very small line graph that is intended to convey some simple information, usually in terms of a numeric value over time. They tend to lack axes or other labels and are added to information readouts in order to expand on numbers in order to give them more context.

Sparklines tend to be around 20-30 pixels height and up to 150-200 pixels wide. The are generally best when you want to show between 5 and 15 items as adding more items to such a small graph can make things a little messy.

Generating Histogram Colour Analysis Graphs From Images In PHP

5th March 2023 - 29 minutes read time

If you've ever looked at the settings in a digital camera, or have experience with image processing programs like GIMP, then you may have seen a colour histogram. This is a simple graph that shows the amount of different shades of colour are present in the image.

They are created by looking at the number of colours in a given image and them mapping their red, green and blue values against a the frequency of their occurrence in the image.

Colour histograms are useful for looking at the overall colour distribution within an image and can also be used to simplify the colours of an image by restricting how much of a certain colour is allowed based on its frequency.

Drupal 9: Generating Header Images For Pages Of Content Using PHP

4th September 2022 - 25 minutes read time

Embedding image within pages of content helps both within the design of the page and when shared on social media. If you set up meta tags to point at a particular image then that image will appear when the page is shared on social media. This makes your page stand out more.

A while ago I added a header image to the articles in the form of a field that references a media item, which is quite typical when adding images to pages. To add an header image to an article I just had to upload an image and Drupal would handle the size, placement and meta data for that image.

With the field in place, however, I spent a while adding a default header image to new articles so I haven't been making good use of it. My GIMP skills aren't that amazing and so the prospect writing an article and spending time fiddling with text elements on an image every week wasn't that appealing.

Image Colorising In PHP

14th January 2019 - 4 minutes read time

Colorising images is fairly simple to accomplish, especially using PHP's GD library. All we need to do is load an image, create a blank image of the same size in a particular color and then merge the two images together.

In fact, we can do this entirely with the imagecopymerge() function, but creating a function to wrap all of this makes sense as well.

The following function takes an image resource (as created by imagecreatefrompng()), the red, green, and blue values of the color, and the percentage to overlay the color on top of the image. The percentage can be set to 0 for no effect and 100 to fully replace the image with the given color.