About blending modes 537
This code example consists of five logical sections. The first section imports the necessary
classes for the example. The second block of code creates a nested movie clip and loads a
JPEG image from a remote server. The third block of code creates a new BitmapData
instance named
perlinBmp, which is the same size as the dimensions of the Stage. The
perlinBmp instance contains the results of a Perlin noise effect, and is used later as a
parameter for the displacement map filter. The fourth block of code creates and applies
the displacement map filter effect to the dynamically loaded image created earlier. The
fifth, and final, block of code creates a listener for the mouse that regenerates the Perlin
noise that the displacement map filter uses whenever the user moves the mouse pointer.
3. Select Control > Test Movie to test the Flash document.
About blending modes
You can apply blend modes to movie clip objects by using the Flash workspace (Flash
Professional 8) or ActionScript (Flash Basic 8 and Flash Professional 8). At runtime, multiple
graphics are merged as one shape. For this reason, you cannot apply different blend modes to
different graphic symbols.
For more information on using ActionScript to apply blend modes, see “Applying blending
modes” on page 538.
Blend modes involve combining the colors of one image (the base image) with the colors of
another image (the blend image) to produce a third image. Each pixel value in an image is
processed with the corresponding pixel value of the other image to produce a pixel value for
that same position in the result.
The
MovieClip.blendMode property supports the following blend modes:
add Commonly used to create an animated lightening dissolve effect between two images.
alpha Commonly used to apply the transparency of the foreground on the background.
darken Commonly used to superimpose type.
difference Commonly used to create more vibrant colors.
erase Commonly used to cut out (erase) part of the background using the foreground alpha.
hardlight Commonly used to create shading effects.
invert Used to invert the background.
layer Used to force the creation of a temporary buffer for precomposition for a particular
movie clip.
lighten Commonly used to superimpose type.
multiply Commonly used to create shadows and depth effects.
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