The BlurFilter class lets you apply a blur visual effect to display objects. A blur effect softens the details of an image. You can produce blurs that range from a softly unfocused look to a Gaussian blur, a hazy appearance like viewing an image through semi-opaque glass. When the quality property of this filter is set to low, the result is a softly unfocused look. When the quality property is set to high, it approximates a Gaussian blur filter. 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.

To create a new filter, use the constructor new BlurFilter(). The use of filters depends on the object to which you apply the filter:

  • To apply filters to movie clips, text fields, buttons, and video, 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 remove 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 (scaleX and scaleY are not set to 100%), the filter effect 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. If, for example, 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 (blurX:Float = 4, blurY:Float = 4, quality:Int = 1)

Initializes the filter with the specified parameters. The default values create a soft, unfocused image.

Parameters:

blurX

The amount to blur horizontally. Valid values are from 0 to 255.0(floating-point value).

blurY

The amount to blur vertically. Valid values are from 0 to 255.0(floating-point value).

quality

The number of times to apply the filter. You can specify the quality using the BitmapFilterQuality constants:

          * `flash.filters.BitmapFilterQuality.LOW`

          * `flash.filters.BitmapFilterQuality.MEDIUM`

          * `flash.filters.BitmapFilterQuality.HIGH`

High quality approximates a Gaussian blur. For most applications, these three values are sufficient. Although you can use additional numeric values up to 15 to achieve different effects, be aware that higher values are rendered more slowly.

Variables

blurX:Float

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

quality:Int

The number of times to perform the blur. 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 and approximates a Gaussian blur. 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 increase the number of times the blur is applied, 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.

You can use the following BitmapFilterQuality constants to specify values of the quality property:

  • BitmapFilterQuality.LOW
  • BitmapFilterQuality.MEDIUM
  • BitmapFilterQuality.HIGH

Methods

Inherited Variables

Inherited Methods