The DropShadowFilter class lets you add a drop shadow to display objects. The shadow algorithm is based on the same box filter that the blur filter uses. You have several options for the style of the drop shadow, including inner or outer shadow and knockout mode. 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 value of 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. 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 (distance:Float = 4, angle:Float = 45, color:Int = 0, alpha:Float = 1, blurX:Float = 4, blurY:Float = 4, strength:Float = 1, quality:Int = 1, inner:Bool = false, knockout:Bool = false, hideObject:Bool = false)

Creates a new DropShadowFilter instance with the specified parameters.

Parameters:

distance

Offset distance for the shadow, in pixels.

angle

Angle of the shadow, 0 to 360 degrees(floating point).

color

Color of the shadow, in hexadecimal format 0xRRGGBB. The default value is 0x000000.

alpha

Alpha transparency value for the shadow color. Valid values are 0.0 to 1.0. For example, .25 sets a transparency value of 25%.

blurX

Amount of horizontal blur. Valid values are 0 to 255.0 (floating point).

blurY

Amount of vertical blur. Valid values are 0 to 255.0 (floating point).

strength

The strength of the imprint or spread. The higher the value, the more color is imprinted and the stronger the contrast between the shadow and the background. Valid values are 0 to 255.0.

quality

The number of times to apply the filter. Use the BitmapFilterQuality constants:

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

For more information about these values, see the quality property description.

inner

Indicates whether or not the shadow is an inner shadow. A value of true specifies an inner shadow. A value of false specifies an outer shadow

             (a shadow around the outer edges of the object).
knockout

Applies a knockout effect(true), which effectively makes the object's fill transparent and reveals the background color of the document.

hideObject

Indicates whether or not the object is hidden. A value of true indicates that the object itself is not drawn; only the shadow is visible.

Variables

alpha:Float

The alpha transparency value for the shadow color. Valid values are 0.0 to 1.0. For example, .25 sets a transparency value of 25%. The default value is 1.0.

angle:Float

The angle of the shadow. Valid values are 0 to 360 degrees(floating point). The default value is 45.

blurX:Float

The amount of horizontal blur. Valid values are 0 to 255.0(floating point). The default value is 4.0.

blurY:Float

The amount of vertical blur. Valid values are 0 to 255.0(floating point). The default value is 4.0.

color:Int

The color of the shadow. Valid values are in hexadecimal format 0xRRGGBB. The default value is 0x000000.

distance:Float

The offset distance for the shadow, in pixels. The default value is 4.0 (floating point).

hideObject:Bool

Indicates whether or not the object is hidden. The value true indicates that the object itself is not drawn; only the shadow is visible. The default is false(the object is shown).

inner:Bool

Indicates whether or not the shadow is an inner shadow. The value true indicates an inner shadow. The default is false, an outer shadow(a shadow around the outer edges of the object).

knockout:Bool

Applies a knockout effect(true), which effectively makes the object's fill transparent and reveals the background color of the document. The default is false(no knockout).

quality: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 shadow and the background. Valid values are from 0 to 255.0. The default is 1.0.

Methods

Inherited Variables

Inherited Methods