3.2. Focus Blur

3.2.1. Overview

图 17.9. The Focus Blur filter

Original

Focus Blur applied

Focus blur creates a blur in all directions around a focal point. The default focal point is the center of the layer or selection. You can change this focal point by dragging the center point. All other points and lines can also be dragged to adjust the shape and focus area of the image.

3.2.2. Options

图 17.10. Focus Blur filter dialog options with Geometry Options expanded

Presets, “Input Type”, Clipping, Blending Options, Preview, Split view

	注意
	These options are described in 第 2 节 “Common Features”.

Shape

Here, you can select the shape used for creating the focus blur. The choices are Circle, Square, Diamond, Horizontal and Vertical.

Blur type

The type of blur to use. The choices are Gaussian Blur and Lens Blur.

Blur radius

The size of the out-of-blur radius.

High quality (only available for Gaussian Blur)

Generate more accurate and consistent output. This is slower.

Highlight factor (only available for Lens Blur)

Relative highlight strength.

Highlight threshold (only available for Lens Blur)

Here you can set the minimum and maximum values for highlighting. It can be set either by dragging the black and white triangles, or inputting exact values into the number entry fields.

Geometry Options

These geometry related options can all be changed by using the visual on-canvas controls. In case you need more fine-grained control, they can be set manually here.

• Center X, Center Y

  Specifies the center X and Y position of the focus blur.

  Radius

  The radius of the outer focus region. Visible as the outer continuous line.

  Sharpness

  The radius of the inner focus region. Visible as the inner continuous line.

  Midpoint

  The focus transition midpoint. Shown as a dashed line. The area from the inner (sharpness) line to the midpoint, is where the focus area turns into the blurred area.

  Aspect ratio

  This controls the aspect ratio.

  Rotation

  This controls the rotation in degrees. You can either use the circular control or enter numbers.

On-canvas controls

This option (default) allows you to modify blur settings directly on canvas, for easier visual tweaking of blur settings. It displays lines in the selected shape with points on it. Both the lines and the points can be dragged with a mouse to change the focus center, the blurring area and other settings that are also available in the Geometry Options.