Android library for drawing shapes on a canvas

In a View class, create an Artiste and a subclass of Shape.

artiste = new Artiste();
fivePointedStar = new FivePointedStar();

Configure your Shape.

fivePointedStar.setRotation(10);
fivePointedStar.setOutlined(true);

Give it some bounds.

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    fivePointedStar.setBounds(new Rect(0, 0, w, h));
}

Tell your Artiste to draw your Shape with some Paint on the Canvas.

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    artiste.drawShape(fivePointedStar).withPaint(paint).onCanvas(canvas);
}

The Shapes class contains some ready-made shapes: Triangle, Square, Pentagon, Hexagon, FivePointedStar, and Circle. These shapes are interchangeable and can be used as in the example above.

Triangle, Square, Pentagon, and Hexagon inherit from RegularConvexPolygon, which inherits from Shape.

FivePointedStar inherits from RegularStarPolygon, which also inherits from Shape.

Circle inherits directly from Shape.

Any Shape can be rotated with setRotation(float rotationDegrees).

Any subclass of RegularStarPolygon, including FivePointedStar, can be drawn with strokes connecting each vertex or with only the outline of the star. This is set by calling setOutlined(boolean outlined).

For example, the value of outlined for the red five-pointed star above is true. For the green eight-pointed star above, it's false.

Both configuration methods must be called before setBounds(Rect rect).

To create a new shape, extend RegularConvexPolygon or RegularStarPolygon if the shape you wish to draw is either of these kinds of shapes (search for "Regular Polygon" on Wikipedia for reference). For example:

public static class Tridecagon extends RegularConvexPolygon {
    @Override
    public int getNumberOfSides() {
        return 13;
    }
}

public static class Octagram extends RegularStarPolygon {
    @Override
    public int getNumberOfPoints() {
        return 8;
    }
    
    @Override
    public int getDensity() {
        return 3;
    }
}

Note: the "density" of a regular star polygon is the number of vertices, or points, to skip when drawing a line connecting two vertices. For example, one line of a five-pointed star starts at the first vertex, skips the second vertex (moving CW or CCW), and connects with the third vertex. Thus, a five-pointed star has a density of two.

If your shape is not a regular convex polygon or a regular star polygon, you can directly extend Shape. This is a little trickier. Look at RegularConvexPolygon, RegularStarPolygon, or Circle for guidance.

The MIT License (MIT)

Copyright (c) 2014 Matthew Logan

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