Done using GIMP 2.10.20 on Kubuntu Linux 18.04 LTS
Although the title is about using Layers, we will of course be using a number of the tools and techniques we have introduced previously. But we need to have a starting point, so I decided that I would like to develop a header image for this site, Ahuka Communications. I built this site using a WordPress theme that I like on the whole, but one thing I have always thought I would like to do is replace the built-in image which does not reflect what the site is about in way. Ahuka Communications is a place where I have placed various tutorials mostly related to using software. I first developed some of these materials when I was the Faculty Development Officer at Concordia University in Ann Arbor, Michigan. Some others I developed when I was assisting in courses at SmartPlanet (sadly, no longer what it was). Then I developed my LibreOffice series to use the techniques I first developed for Microsoft Office and apply them to Open Source. And of course, I am now in the middle of a series on GIMP.
So how can I create something that reflects all of that? That is the challenge I set myself. Let me first note that I am not really a programmer, and that means there are certain limits to what I can attempt. One limit that applies here is that I have an existing WordPress theme that I want to keep, so that means replacing the generic image it has with something new, and to do that most easily I need to create a replacement with the same dimensions. If I go into the WordPress Dashboard, to Appearance–>Header–>Header Image, I can see what I need. In this theme (Coraline, if you are interested), the image is 990×180, and WordPress helpfully suggests that if I change the image I keep the same dimensions. So that is what I will do.
So with that information, I can start. But before I get into GIMP, I need some assets. My first stop is the Wikipedia: Public Domain Image Resources page I mentioned in the previous tutorial. I saw a listing there for clker.com, which said it was a place for free and public domain images that can be used in OpenOffice, which sounded promising. I entered “Office computer” as a search term, and found a few likely images.
I then went to ClipartSpy, and did a similar search, but I did not like what I found for the licensing when I clicked through on a few images. Needpix.com seemed more promising since it said all the images were Public Domain.
I downloaded these six images from these sites, and I did not worry about the size, but if I was offered a smaller size I took it. I will trim them and resize them as necessary in GIMP, after all. I also went to Font Library to grab an Open Font Licensed font called Cooper-Hewitt. With all of my assets in hand, I was ready to begin.
In GIMP I started by opening up a new image with the 990×180 dimension, then filled it with the Blue Green gradient for a pleasant but not too busy background. To do this I went to Tools–>Paint Tools–Gradient. I clicked on the Top Left corner to start, and dragged down to the Bottom Right corner. Then I needed to start using my assets. I had six downloaded images, in a variety of sizes, some of which needed to be resized, and one cropped. Fortunately, the images all had transparent backgrounds, so I didn’t need to strip out a solid background, not that it is hard to do (just use color select on the background and delete it.)
I started by opening the images as six new layers. This way I could work with each image individually and move them around and resize them without any problems. To do this, go to File, then Open as Layers. I selected all six of the images, and each one is on its own individual layer. So you see GIMP really makes it easy to do this! And all of these layers have a transparent background, which is exactly what we want. Now we can use the “eye” icon to turn off all but one of these layers and focus on just one. To make it easier I did change a few file names to make them more understandable
The first layer had a an LCD screen, and it was not bad as it was, but it was in the exact center, so I used the Move tool to grab it and move it to the right. The second image was too big, but it only had one section I wanted to use, so a crop worked out here. I first opened the image separately to crop it, then opened the cropped image as a layer and deleted the old one. In GIMP, you can have several things open at once, and use tabs on top to switch between them:
In this example my logo project is on the left with the Blue Green gradient background, and my cropped image is on the right with a transparent background.
I continued with each image, resizing them to fit within my overall image border, and then made all of them visible at once. This way I could do any fine-tuning necessary with further resizing and moving. This is all so much easier when you have each thing on its own layer.
Then it was on to the Font. I liked Cooper-Hewitt, and as I said it is licensed under the Open Font License, so I downloaded the Zip file, extracted it, and then copied the font files folder to my ~/.fonts folder. I opened a tab in the bottom dialog box that already had Patterns, Gradients, etc. by clicking the right-hand “Configure this tab” button, then Add Tab, and then Fonts. I then clicked Refresh on the bottom, and my Cooper-Hewitt fonts all appeared in my list. You may remember this as being similar to how we added Patterns in a previous tutorial. GIMP is reasonably consistent in how it does things.
Now to put it to use. I created two new layers for two phrases: “Be more productive!”, and “Use software intelligently!” But I did not need to create a layer first, because when you user the Text tool GIMP automatically creates it on a Text layer. In fact, if you created a layer first, you would just wind up with two layers, and only one (the one GIMP created for you) would actually have the text. GIMP is doing by default what you should do anyway,so work with it and not against it. I first selected my font from the list (Cooper-Hewitt weight=712 Italic). I put the text on the layers in 20-point size, which in turn meant a little rearrangement of the images and resizing one of them. This gave me the result I wanted, and I exported it:
Now I have my image, so on to putting it into my WordPress theme. I went back to my WordPress Dashboard–>Appearance–>Header, and selected Header Image. I had already uploaded the new image to my Media Library, so all I needed to do was click Add new image, then select it in my Media Library, and it replaced the previous image. The last step was to click the Publish button, and now it graces every page on this site.
The individual images I used are all linked in their captions, and if you want to see my final GIMP native file with all of the layers, you can download it from here.
There is still more to learn about layers, so we shall continue.