4.3. Curve Bend

4.3. Curve Bend
	4. 扭曲滤镜

4.3.1. Overview

图 17.37. Applying example for the Curve Bend filter

Original image

Filter “Curve Bend” applied

This filter allows you to create a curve that will be used to distort the active layer or selection. The distortion is applied gradually from an image or selection border to the other.

4.3.2. Activating the filter

You can find this filter through Filters → Distorts → Curve Bend….

4.3.3. Options

图 17.38. “Curve bend” filter options

Preview

The preview displays changes to image or selection without modifying the image until you press OK.

Preview once: This button allows you to update the preview each time you need it.
Automatic Preview: With this option, preview is changed in real time. This needs much calculation and may lengthen work. It is particularly evident when using “Rotation”.

Options

Rotate: There, you can set the application angle of filter (0-360 counter-clockwise). 0 is default setting: The curve will be applied from the upper border and/or from the lower. Set to 90, it will be applied from left border and/or from the right one.
Smoothing, Antialiasing: The distort process may create hard and stepped borders. These two options improve this aspect.
Work on copy: This option creates a new layer called “Curve_bend_dummy_layer_b” which becomes the active layer, allowing you to see changes to your image in normal size without modifying the original image until you press the OK button.

Modify Curves

In this grid, you have a marked horizontal line, with a node at both ends, which represents by default the upper border of image. If you click on this curve, a new node appears, that you can drag to modify the curve as you want. You can create several nodes on the curve.

You can have only two curves on the grid, one for the so named “upper” border and the other for the so named “lower” border. You can activate one of them by checking the Upper or Lower radio button.

If you use the Free Curve Type option, the curve you draw will replace the active curve.

Curve for Border

There you can select whether the active curve must be applied to the Upper or the Lower border, according to the rotation.

	小心
	Remember that the curve border depends on the rotation. For example, with Rotate = 90° the upper curve will actually be applied to the left border.

Curve Type

With the Smooth, you get automatically a well rounded curve when you drag a node.

The Free option allows you to draw a curve freely. It will replace the active curve.

Buttons

Copy: Copy the active curve to the other border.
Mirror: Mirror the active curve to the other border.
Swap: Swap the Upper and Lower curves.
Reset: Reset the active curve.
Open: Load the curve from a file.
Save: Save the curve to a file.