Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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LinearGradient subclass. The subclass can utilize the (accessible) properties and methods
in the superclass, and they can be referred to directly, as if they were declared directly
within the subclass; any subclass of Gradient would have this capability. You can see how
building a class library using inheritance can create efficiencies and ultimately speed development—not
to mention create more consistency for the user.
The create() method is the abstract method inherited from Gradient that needs to be
implemented. Again, implementing in this case means creating the method’s code block
(the areas between and including the curly braces). The create() method is where the
custom gradients are actually created.
Finally, the LinearGradient class includes setAxis() and getAxis() methods for specifying
which axis to draw the gradient across. I could have placed these two methods within
the Gradient superclass, but it was more appropriate to put them in the LinearGradient
subclass, as some gradients don’t utilize a dominant axis (e.g., radial gradients)—which
illustrates that although subclasses share certain features (inherited from their common
superclass), they may (and usually do) contain their own unique properties and methods
as well.
RadialGradient class
class RadialGradient extends Gradient {
//default constructor
RadialGradient() {
super();
}
//constructor
RadialGradient(color c1, color c2) {
this.c1 = c1;
this.c2 = c2;
}
//constructor
RadialGradient(color c1, color c2, Rectangle bounds) {
this.c1 = c1;
this.c2 = c2;
this.bounds = bounds;
}
// required: implemented create method
void create(){
float px = 0, py = 0, angle = 0;
float radius1 = bounds.width/2;
float radius2 = bounds.height/2;
float centerX = bounds.x+radius1;
float centerY = bounds.y+radius2;
float radiusMax = max(radius1, radius2);