A glow effect applied to a given luminance range of the source image.
Box Glow differs from the standard Glow effect because it uses a box blurring algorithm. The details produced by this effect will consequently have sharp edges.
Effect Parameters
Frame Margin
The margin available around the frame. It is useful to increase this value when the effect renders pixels outside the area of the input frame. This parameter is only available in Motion and After Effects, since variable-sized output frames are not supported by Final Cut Pro or Final Cut Express.
Presets
Presets contain a snapshot of the plug-in parameters. The Presets control lets you choose among one of the presets built into the plug-in, save current parameter values to a preset file, or load an existing preset file from disk.
A preset file saved to disk via the "Save As" button can be loaded from another instance of the same plug-in by clicking the "Open" button. Presets generated in one host can also be loaded from the same plug-in when used in a different host.
Source Value, Aperture and Softness
The effect is applied to a given range of pixels, based on their luminance value. Luminance values range from 0 (black) to 1 (white). The "Source Value", "Source Aperture" and "Source Softness" parameters give you precise controls to define this range:
The "Source Luminance" parameter specifies the center of the range of pixels. For example, a value of 0.5 means that the effect is applied to pixels that are 50% bright.
The "Source Aperture" parameter controls the width of this range. For example, a value of 0.5 with aperture of 0.2 means that all pixels between 40% and 60% brightness will be used as the source for the effect. An aperture value of 1.0 means that the effect is applied to the entire image.
It may be desirable to have a smooth transition between the pixels that are within the range and those that fall outside it. The "Source Softness" parameter defines the width of this smooth border. By adding soft borders to the range (one at the start, one at the end) you eliminate the sharp transition. A softness of 1.0 means that the range is smoothed over the entire image.
Radius
The radius of the glow.
Strength
The strength of the glow. More precisely, this parameter controls the brightness and opacity of the glow when combined with the original image.
Saturation
The saturation value of the glow. When the "Use Image Colors" parameter is enabled, a higher saturation value may increase the visual connection of the glow with the pixels it originates from.
Opacity
The opacity of the glow when combined with the original image.
Use Image Colors
Controls whether the color of the glow is derived from the original colors in the image, or whether a single color is used.
Color
Defines the color of the glow, when the "Use Image Colors" parameter is disabled.
Mask
By default, the effect is applied to the entire image. The Mask parameter group gives you options for applying the effect only to specific parts of the image.
Mask Popup Menu
This popup menu lets you choose mask shape. The default setting is "None", which means that the effect is applied to the entire image. The available options include the most common shapes used for masking out effects. You may also supply your own mask shape by choosing the "Use Custom Mask" option in this parameter and dropping your own media into the "Custom Mask" image well parameter.
 Oval |  Rectangular |  Gradient |
 Bar |  Ring |  Custom Mask |
Custom Mask
This image well lets you supply your own mask shape when the "Use Custom Mask" option is set in the Mask popup menu parameter. Mask shapes should be grayscale images. In Final Cut Pro, Final Cut Express and Motion, this parameter is available as an image well. You can drag and drop any media currently imported in your project onto the image well to assign it to the parameter:
To clear an image previously assigned to the well in Final Cut Pro or Final Cut Express, right-click on the drop area and select the “Clear” option. To clear the image well in Motion simply drag any media away from the drop area. Image wells can be used with video as well as static images.
In After Effects, this parameter is available as a layer selection menu. Select an existing layer to assign its contents to the parameter. You can clear any layer selection by choosing the first option in the layer selection menu.
Mask Center
The position of the mask shape on the frame.
Mask Scale
The scaling factory of the mask.
Mask Aspect Ratio
The aspect ratio of the mask shape. The default value of 1 will generate a circle when the current shape is "Oval", and a square if the current shape is "Rectangular". An aspect ratio of 1 will also ensure that any custom mask image you supply via the image well is maintained at its native aspect ratio.
Mask Angle
The angle of rotation of the mask.
Mask Softness
Controls the smoothness of the transition between the in and out areas of the mask shape (indicated by white and black, respectively). When using a custom mask shape, this parameter controls a gaussian blur applied to the image to soften its color values.
Mask Invert
Controls whether the shape defined by the current settings is inverted. For example, an "Oval" mask will apply the effect inside the oval shape. By enabling this option, the effect will be applied outside the oval, hence simulating a common vignette.
Mask Preview
When this parameter is enabled, the effect renders a preview of the mask shape. This mode is helpful in setting up a precise mask shape when finalizing the effect setup.
High-precision Output
This parameter, available only inside Final Cut Pro, controls the color range of the final output. Although you will see no difference in the Canvas window (due to the fact that Final Cut Pro always previews in 8 bit color) high-precision clamping ensures that your output falls within a predictable range. This feature will often save you an extra post-processing step and come in handy when the only previewing device available is the built-in display.
Color Space
This parameter allows you to choose a working color space for the effect. When the “Linear” option is selected, the plug-in will convert all color values to a non-gamma-corrected format. When the “Uncorrected” option is selected, the color values supplied by the host will be used directly, without conversion. It may help to choose “Uncorrected” when dealing with smooth gradients or vector-art backgrounds, or if you have already applied gamma correction to your source media in a previous step of your workflow.