Making an iWork-style toolbar icon
Posted on 31 March, 2009 at 9:44pm
In Mac OS X applications, toolbar icons are the illustrative UI shortcuts that appear beneath the title bar. You’ll see a few different styles of these depending on the application, but generally speaking they are relatively small and colorful, meant to be easy to remember. If you plan to design toolbar icons, you should start with the section devoted to them in the Apple Human Interface Guidelines.
While the HIG has a lot of good information, it doesn’t go into the details of implementation, so I’m going to go through the process of how I would design a toolbar icon. I’ve chosen the iWork style because I really like how crisp and clear they are, and I think they are a good model to work towards.
So let’s take a look at the Pages toolbar.
Let’s take a note from Gmail and add a “Labs” button. This imaginary feature would take the user to experimental or even user-made plugins and macros.
Step 1: Pick your metaphor
First we have to think about what kind of metaphor would best represent this feature. The HIG offers the following guideline:
“As a general rule, a toolbar icon that depicts an identifiable, real-world object or recognizable user-interface element gives first-time users a clue to its function and helps experienced users remember it.”
So what makes me think of experiments? A beaker seems like the obvious choice. Anyone with high-school chemistry would know that symbol. But before I draw anything I should do some research. I fire up Google Image Search and Flickr with a search for “beaker.” It looks like I have a couple of choices for the shape of the object.
This is actually the kind I was thinking of, but I think these kind of beakers are generally only used in stock photography. I’ve never seen or used one like it in an actual lab. I got a lot more results for this type:
This is also what I remember from science class. The other beaker style is perhaps a bit more recognizable, but in the interest of realism (and not looking too Weird Science) I decided to go with this one.
Step 2: Figure out your sizes
So you’ll notice that Pages’ icons are very crisp, with 1 pixel outlines at both the large and small sizes. This indicates that the designers created two sets of icons, one for the large size and one for the “use small icons” size. If they had only used one and resized it, the line would not be 1 pixel exactly on both. Whichever one that was resized would have fuzzy lines. If you have the time to do this, it’s a nice way to ensure that your icons will look good no matter what your user chooses (you can also selectively reduce detail/complexity at the smaller size to ease recognition).
I’m going to design my icon for the larger size (32×32) and then size it down as needed for the smaller size. Figure out what the “large” and “small” sizes for your app are and keep these in mind. For a pixel-crisp style like this you’ll want to design at the size the icon will appear.
Step 3: Vector outlines
Open up your drawing program of choice. I prefer Fireworks for this kind of icon because it allows me to work with vectors while zoomed in to look at where the pixels actually fall. Go ahead and trace or draw the basic shape. Keep perspective and lighting (which should be top-down) in mind. The HIG says: “The perspective of a toolbar icon is straight-on, as if it is sitting on a shelf in front of you.”
At this point it’s a good idea to look at the fingerprint of your icon. That’s what I call the silhouette of the shape. Icons with different functions should generally have distinct fingerprints. Check to make sure the shape is recognizable and not too similar to anything it’s going to be adjacent to.
Step 4: Color, detail and shading
Now it’s time to fill in the colors and details. I like to zoom in pretty close for this step, but I keep an eye on the actual-size icon as I work. (In Fireworks you can do this easily by selecting Window > Duplicate Window.)
Be brutal about cutting unnecessary shading and details. Show only what you need to in order for the user to get what the icon represents. In the case of the beaker, I added two embellishments; the bubbles, which indicate that the green goop is “active” (and hopefully expresses something experimental and/or volatile) and the volume markers, which help make the beaker more recognizable.
Don’t be afraid to use bright colors here. As the HIG says, “Making each toolbar icon distinct helps the user associate it with its purpose and locate it quickly. Variations in shape, color, and image all help to differentiate one toolbar icon from another.” Also make sure the colors that should be consistent between the icons are – highlights, shadows and outlines fall into this category.
One more thing that’s actually quite important. Watch your alpha! Make sure that things that should be transparent actually are (like shadows, or in the case of the beaker the glass). I like to work with a couple of different-color backgrounds to switch between as I draw, including one that’s the standard Leopard window color to see what it will look like in production. You have no idea what this icon might end up on top of in the future! (Er, avoiding the obvious dirty joke there.)
Step 5: Flatten and pixel-tweak
Save your file so you have the originals handy if you need to resize the icon, then go ahead and flatten your vector layers.
Time to break out the pencil tool! Start looking for places you can simplify your lines. Be especially ruthless around anti-aliased corners, which will have a mess of pixels you probably don’t need and will make your lines look fuzzy.
This is also where I add in line shading and other small details. You may not see much difference in the big, zoomed in picture, but at actual size the tweaked bitmap (right) looks much cleaner. Especially note the simplification of the spout shape.
So after fiddling with the pixels to my satisfaction, I’ll go ahead and plug it into the toolbar to see how it matches the other icons.
Step 6: Generate other sizes as needed
So I have the large-size icon but I’ll also need a smaller one. The first thing I do is size the icon down and clean up the lines. Then I’ll go over the details and make sure that nothing is lost at the smaller size. I noticed that if the spout was made any smaller, it became difficult to distinguish the shape, so I actually made the top of the beaker identical in both sizes. I also redrew the volume markers to fit better on the smaller icon.
So there you go! It seems like a tedious process, and in some ways it is (depending on your style, you may be able to skip pixel-tweaking), but once you get into the right mindset it’s not so bad. You just want to make sure you’re thinking small and keeping an eye on consistency.
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