# class GlowFilter

#### package openfl.filters

#### extends BitmapFilter

Available on all platforms

The GlowFilter class lets you apply a glow effect to display objects. You have several options for the style of the glow, including inner or outer glow and knockout mode. The glow filter is similar to the drop shadow filter with the `distance` and `angle` properties of the drop shadow filter set to 0. You can apply the filter to any display object(that is, objects that inherit from the DisplayObject class), such as MovieClip, SimpleButton, TextField, and Video objects, as well as to BitmapData objects.

The use of filters depends on the object to which you apply the filter:

- To apply filters to display objects, use the `filters` property(inherited from DisplayObject). Setting the `filters` property of an object does not modify the object, and you can remove the filter by clearing the `filters` property.
- To apply filters to BitmapData objects, use the `BitmapData.applyFilter()` method. Calling `applyFilter()` on a BitmapData object takes the source BitmapData object and the filter object and generates a filtered image as a result.

If you apply a filter to a display object, the `cacheAsBitmap` property of the display object is set to `true`. If you clear all filters, the original value of `cacheAsBitmap` is restored.

This filter supports Stage scaling. However, it does not support general scaling, rotation, and skewing. If the object itself is scaled(if `scaleX` and `scaleY` are set to a value other than 1.0), the filter is not scaled. It is scaled only when the user zooms in on the Stage.

A filter is not applied if the resulting image exceeds the maximum dimensions. In AIR 1.5 and Flash Player 10, the maximum is 8,191 pixels in width or height, and the total number of pixels cannot exceed 16,777,215 pixels.(So, if an image is 8,191 pixels wide, it can only be 2,048 pixels high.) In Flash Player 9 and earlier and AIR 1.1 and earlier, the limitation is 2,880 pixels in height and 2,880 pixels in width. For example, if you zoom in on a large movie clip with a filter applied, the filter is turned off if the resulting image exceeds the maximum dimensions.

### Constructor

###

`new (color:Int = 0xFF0000, alpha:Float = 1, blurX:Float = 6, blurY:Float = 6, strength:Float = 2, quality:Int = 1, inner:Bool = false, knockout:Bool = false)`

Initializes a new GlowFilter instance with the specified parameters.

Parameters:

`color` | The color of the glow, in the hexadecimal format 0xRRGGBB. The default value is 0xFF0000.
`alpha` | The alpha transparency value for the color. Valid values are 0 to 1. For example, .25 sets a transparency value of 25%.
`blurX` | The amount of horizontal blur. Valid values are 0 to 255 (floating point). Values that are a power of 2(such as 2, 4, 8, 16 and 32) are optimized to render more quickly than other values.
`blurY` | The amount of vertical blur. Valid values are 0 to 255 (floating point). Values that are a power of 2(such as 2, 4, 8, 16 and 32) are optimized to render more quickly than other values.
`strength` | The strength of the imprint or spread. The higher the value, the more color is imprinted and the stronger the contrast between the glow and the background. Valid values are 0 to 255.
`quality` | The number of times to apply the filter. Use the BitmapFilterQuality constants: `BitmapFilterQuality.LOW` `BitmapFilterQuality.MEDIUM` `BitmapFilterQuality.HIGH` For more information, see the description of the `quality` property.
`inner` | Specifies whether the glow is an inner glow. The value `true` specifies an inner glow. The value `false` specifies an outer glow(a glow around the outer edges of the object).
`knockout` | Specifies whether the object has a knockout effect. The value `true` makes the object's fill transparent and reveals the background color of the document.

### Variables

###

`alpha:Float`

The alpha transparency value for the color. Valid values are 0 to 1. For example, .25 sets a transparency value of 25%. The default value is 1.

###

`blurX:Float`

The amount of horizontal blur. Valid values are 0 to 255(floating point). The default value is 6. Values that are a power of 2(such as 2, 4, 8, 16, and 32) are optimized to render more quickly than other values.

###

`blurY:Float`

The amount of vertical blur. Valid values are 0 to 255(floating point). The default value is 6. Values that are a power of 2(such as 2, 4, 8, 16, and 32) are optimized to render more quickly than other values.

###

`color:Int`

The color of the glow. Valid values are in the hexadecimal format 0xRRGGBB. The default value is 0xFF0000.

###

`inner:Bool`

Specifies whether the glow is an inner glow. The value `true` indicates an inner glow. The default is `false`, an outer glow (a glow around the outer edges of the object).

###

`read onlyknockout:Bool`

Specifies whether the object has a knockout effect. A value of `true` makes the object's fill transparent and reveals the background color of the document. The default value is `false` (no knockout effect).

###

`read onlyquality:Int`

The number of times to apply the filter. The default value is `BitmapFilterQuality.LOW`, which is equivalent to applying the filter once. The value `BitmapFilterQuality.MEDIUM` applies the filter twice; the value `BitmapFilterQuality.HIGH` applies it three times. Filters with lower values are rendered more quickly.

For most applications, a `quality` value of low, medium, or high is sufficient. Although you can use additional numeric values up to 15 to achieve different effects, higher values are rendered more slowly. Instead of increasing the value of `quality`, you can often get a similar effect, and with faster rendering, by simply increasing the values of the `blurX` and `blurY` properties.

###

`strength:Float`

The strength of the imprint or spread. The higher the value, the more color is imprinted and the stronger the contrast between the glow and the background. Valid values are 0 to 255. The default is 2.

### Inherited Variables

### Inherited Methods

#### Defined by BitmapFilter

###

`clone ():BitmapFilter`

Returns a BitmapFilter object that is an exact copy of the original BitmapFilter object.

Returns:

A BitmapFilter object.