Android™ Application Development - Bahar Ali Khan

gradientColors[1] = Color.YELLOW;
gradientColors[2] = Color.RED;
float[] gradientPositions = new float[3];
gradientPositions[0] = 0.0f;
gradientPositions[1] = 0.5f;
gradientPositions[2] = 1.0f;
Chapter 11: Advanced Android Development
RadialGradient radialGradientShader = new RadialGradient(centerX, centerY, radius,
gradientColors,
gradientPositions,
TileMode.CLAMP);
Each of the gradient Shaders (linear, radial, and sweep) lets you defi ne the gradient fi ll using either of
these techniques.
Using Shader Tile Modes
The brush sizes of the gradient Shaders are defi ned using explicit bounding rectangles or center points
and radius lengths; the Bitmap Shader implies a brush size through its bitmap size.
If the area defi ned by your Shader brush is smaller than the area being fi lled, the TileMode determines
how the remaining area will be covered.
❑ CLAMP Uses the edge colors of the Shader to fi ll the extra space.
❑ MIRROR Flips the Shader image horizontally and vertically so that each image seams with the
last.
❑ REPEAT Repeats the Shader image horizontally and vertically, but doesn’t fl ip it.
Using MaskFilters
The MaskFilter classes let you assign edge effects to your Paint.
Extensions to MaskFilter apply transformations to the alpha-channel of a Paint along its outer edge.
Android includes the following Mask Filters:
❑ BlurMaskFilter Specifi es a blur style and radius to feather the edges of your Paint.
❑ EmbossMaskFilter Specifi es the direction of the light source and ambient light level to add
an embossing effect.
To apply a Mask Filter, use the setMaskFilter method, passing in a MaskFilter object. The following
code snippet applies an EmbossMaskFilter to an existing Paint:
// Set the direction of the light source
float[] direction = new float[]{ 1, 1, 1 };
// Set the ambient light level
float light = 0.4f;
// Choose a level of specularity to apply
float specular = 6;
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