an Image Magick Tute by Flo
|An Ellipse has the same 360 degrees like a Circle that rotate around a center point. Picture a clock face: The Draw curve for an Ellipse starts at 3 o'clock and moves clockwise around until it returns to the 3 o'clock position. This will draw a complete 360-degree Ellipse.|
To Draw an Ellipse, you'll need 3 set of numbers:
1st Set: CENTER point of the Ellipse
2nd Set: HALF of Width and HALF of Height
3rd Set: START and END of curve
- Take an image of about 300x150 pixels to any of the Image Magick tool sites. The one I use is Arbor Hosting IM:
- On View page, click on Draw. On the Draw page, select "Ellipse" from the Primitives.
- Frst we'll center the Ellipse. Note the size of your image. For a 300x150, the center point will be +150+75. Type this into the Parameter box.
- The 2nd set of numbers tell how wide and how high the Radius (measured from center to edge) is to be. Let's use +180+140. Type this in.
- The 3rd set of numbers, starting the curve at 0 and ending at 360, to make the Ellipse complete, 360 degrees around its perimeter. +0+180 will make only half an Ellipse along the bottom part of the image.
+300+75 +180+140 +0+360
- Delete "white" in Fill Color box and leave blank. Type in Stroke Color box either a color name or hex number: e.g. #000099
- Stroke Width: start with 2, as it shows up better than 1
- Finally, click on the Draw button.
|DRAW AN EGG|
|The "proper" egg shape is an ellipse modified with one end smaller than the other. If we use a full 360 degree ellipse drawing, we won't get the standardized egg shape. BeeDiana has come up with the solution for us. She draws the egg in two halves, using a different center point and diameter for each half.|
||For a 200x300 transparent xc bg |
Top Half: 98,165 95,165 180,0
Bottom: 98,165 95,130 0,180
This egg drawing is half sized.
Here's a full-sized egg with the fill colors to show
where top and bottom meet.
Output as a png, rather than a gif or a jpeg. Truecolor Matte (to hold the transparent bg). The png will give very smooth lines along the curvers, whereas the gif and jpeg will "alias" along the curves. "Alias" means those pixelations that look like stairsteps. After you use the egg blank, though, you can output that result as a jpeg and keep the smooth curves.
- Center an ellipse somewhere else in the image, instead of always at the image center.
- Make ellipses higher than wide, too.
- Draw a Circle, using the Ellipse Primitive.
- Use larger Stroke Widths.
- Choose a color for the Fill Color.
- Draw partial ellipses, incorporate them into the image, as in "Bursting into View" and "Flo's Planet" below
- Remember, we are limited only by our own imaginations.
|Back to Flo's Image Magick Draw Tutes|