5.14. Whirl and Pinch
| 5. Forvrengningsfiltra |

### 5.14. Whirl and Pinch

#### 5.14.1. Overview

Figur 17.85. Example for the Whirl and Pinch filter

Original image

Filter applied

«Whirl and Pinch» distorts your image in a concentric way.

«Whirl» (applying a non-zero Whirl angle) distorts the image much like the little whirlpool that appears when you empty your bath.

«Pinch», with a nil rotation, can be compared to applying your image to a soft rubber surface and squeezing the edges or corners. If the Pinch amount slider is set to a negative value, it will look as if someone tried to push a round object up toward you from behind the rubber skin. If the Pinch amount is set to a positive value, it looks like someone is dragging or sucking on the surface from behind, and away from you.

| Tips
The «pinch» effect can sometimes be used to compensate for image distortion produced by telephoto or fish-eye lenses («barrel distortion»).

Figur 17.86. Illustration

Original

Whirled

Pinched

#### 5.14.2. Activating the filter

You can find this filter through Filters → Distorts → Whirl and Pinch…

#### 5.14.3. Parameter Settings

Figur 17.87. «Whirl and Pinch» filter options

Presets, Preview, Split view

  | Notat
  These options are described in Del 2, «Common Features».

Whirl angle

  Clockwise or counter clockwise (-360 to +360). Controls how many degrees the affected part of the image is rotated.

Pinch amount

  Whirlpool depth(-1 to +1). Determines how strongly the affected part of the image is pinched.

Radius

  Whirlpool width (0.0-2.0). Determines how much of the image is affected by the distortion. If you set `Radius` to 2, the entire image will be affected. If you set `Radius` to 1, half the image will be affected. If `Radius` is set to 0, nothing will be affected (think of it as the radius in a circle with 0 in the center and 1 halfway out).

Use the selection as input, Use the entire layer as input

  | Notat
  These options are described in Del 2, «Common Features».

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