Harvey balls are circles that are commonly filled in in 1/4 increments to illustrate a percentage such as 0%, 25%, 50%, 75% and 100%.  There is even a font now called Harvey Balls Font.

So what happens when these increments are insufficient and you need variations like 10%, 40%, etc.  You go to Google and do a couple searches and find that something this elemental is not so easy to find. Myself, I even checked www.istockphoto.com for stock images and came up empty.

This tutorial describes a couple techniques to create rating type images using GIMP.

1. Start GIMP and open a new round layer using Elipse tool – although a 50 pixel square image is the need I set it up as 54 pixels square to allow for some inconsistency when later doing moves and resaving.
2. Fill background with black
3. Select shrink – by 2 pixels
4. Edit – clear (you end up with a round image with a 2px border and clear background
5. Click/select measure tool
6. In this example divide the circle with each section growing by 36 degrees, so insert the measure tool at the very center pixel and move it to an edge/border approximately 36 degrees from the top center border which shows displays as 90 degrees.
7. Make a note of that location ( say 30,2 whatever it is )
8. In the toolbox switch to path tool
9. Click once in the images dead center
10. Click once at top dead center (in the border)
11. Incrementally click along the border until you reach the 36 degree location you noted earlier
12. Double-click on the path tool to open tool options and click on selection from path
13. Fill with background color
14. Save this as the first image

I tried simply adding a copy of the image as a 2nd layer and rotating 36 degrees but it seemed to not seat cleanly so I did the following:

1. Make a copy of the first image then open the copy and also open or re-open the first image.
2. Crop the copy as tightly as you can to the 36 degree pie section you created, eliminating the circle border. Save it if you wish as a template style image.
3. Do Tools –> Transform Tools –> Rotate and rotate the section about 36 degrees
4. Copy the 36 degree section to the original image.
5. Switch to the Move tool and move it in place such that it sits edge to edge alongside the first 10% rating. You may need to fill in a couple pixels that don’t match.
6. Save this under a new name as the 20% rating.
7. Repeat this process for each 10% increment.

Sometimes when the section rotates some pixels mess up – fix these up manually. For samples of images created using this technique visit: www.dottedi.biz/images/ratings/

Tags: 10% arc, Circle rating, Harvey Balls

This entry was posted on Friday, June 18th, 2010 at 8:24 am by bobmeetin and is filed under GIMP. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.