Creating a Fisheye Effect with FreeHand/Illustrator

[abeall]

I am looking to create a fisheye effect, similar to what can be found in computer vector drawing apps like Macromedia FreeHand or Adobe Illustrator:
http://www.vecpix.com/tutorials/freehand/images/fh004/3d_soccer09.gif

Note that this effect is not exactly the same as a fisheye lens. Here's a good example of what I want (screen captured from Freehand):
http://abeall.com/files/temp/fisheye.gif

1) Distortion area has a range of 1 to -1, where 1 pushes points that fall in the distortion area towards the edge, and -1 pulls points towards the center

2) The distortion area can be a circle or ellipse, though not a rotated ellipse.

3) Points outside the distortion area are not affected.

These values are known:
Each point x and y
Circle/ellipse center
Circle/ellipse width
Circle/ellipse height

Any help would be appreciated.

 

[abeall]

I got it working. For any future reference, here's what I did:

1) First I determine an radian angle between a given point and the ellipse center, like this:
atan2(p2.y - p1.y, p2.x - p1.x)
Where p1 is the ellipse center, p2 is the point to be deformed.

2) Then, based on that angle, I determine the point on the ellipse perimeter which intersects the center through that angle, like this:
r = 0.5 / sqrt( Math.cos(angle)/ellipse.width)^2 + (Math.sin(angle)/ellipse.height)^2 ) ;
x = center.x + r*cos(angle);
y = center.y + r*sin(angle);

3) Then I determine 2 distances: d1 is the distance from the ellipse center to the ellipse perimeter point as determined above, and d2 is the distance from the ellipse center to original point to be deformed. This gives me a weight via d2/d1.

4) I then re-plot the point based on quadratic interpolation:
-c *(t/d)*(t/d-2) + b
Where t is the time, or weight as determined above, b is the begin value (center point), c is the change in value (perimeter point - center point), and d is the duration, ie 1

It may be a strange approach, but it works.

- aaron

 

[tacman]

To create a fisheye effect in FreeHand or Illustrator, you can use the "Transform" tool and the "Distort" function. Here's how:

1. Start by importing your desired image or creating your own design in FreeHand or Illustrator.

2. Select the "Transform" tool from the toolbar. It looks like a black arrow with a curved line next to it.

3. Click on the image or object you want to apply the fisheye effect to. A bounding box with handles will appear around the object.

4. On the bounding box, click and drag the handle on the right side towards the center of the object. This will create a distortion effect.

5. To adjust the intensity of the distortion, go to the "Transform" panel or window (depending on your software version) and enter a value between 1 and -1 in the "Distortion" field. A value of 1 will push the points towards the edge, creating a more extreme fisheye effect, while a value of -1 will pull the points towards the center, creating a less intense effect.

6. You can also adjust the shape of the distortion area by clicking and dragging the handles on the bounding box. To create a circular distortion, hold down the "Shift" key while dragging the handles.

7. If you want to use specific values for the distortion area, such as the circle/ellipse center, width, and height, you can enter these values in the "Transform" panel or window as well.

8. Once you are satisfied with the fisheye effect, click on the "Apply" button in the "Transform" panel or window to finalize the transformation.

I hope this helps you achieve the desired fisheye effect in FreeHand or Illustrator. If you have any further questions, please feel free to ask. Happy designing!