Primitive Shapes

Primitive shapes are the shapes that Context Free/CFDG knows how to draw onto a canvas. Whenever Context Free encounters a primitive shape in a shape rule it draws it immediately. There are four primitive shapes that are pre-defined in Context Free: squares, circles, triangles, or fills. Path declarations can be used to teach Context Free how to draw new primitive shapes.

The sizes of these primitive shapes are:

Squares are unit squares. If two squares are drawn one unit apart in x or y then that will be drawn edge-to-edge.

SQUARE []
SQUARE [x 1 b 0.5]  // gray square right next to the black square

Circles are unit circles. They have the same diameter as the side of a square.
Triangles are unit triangles. The have the same side length as squares.
Fills draw on the entire canvas with a solid color

Here is what the primitive shapes look like with respect to each other:

shape foo {
    SQUARE []
    CIRCLE [b 1]
 
    SQUARE [x 1.5]
    TRIANGLE [b 0.5 x 1.5]
 
    SQUARE [x 3]
    CIRCLE [b 1 x 3]
    TRIANGLE [b 0.5 x 3]
}

Unicode Ephemera

To facilitate code golf, some Unicode synonyms have been defined for the simple primitive shapes:

SQUARE:
- ⬛ (Black Large Square, U+2B1B)
- ◼ (Black Medium Square, U+25FC)
- ◾ (Black Medium Small Square, U+25FE)
- ￭ (Halfwidth Black Square, U+FFED)
CIRCLE:
- ⬤ (Black Large Circle, U+2B24)
- ⚫ (Medium Black Circle, U+26AB)
- ● (Black Circle, U+25CF)
TRIANGLE:
- ▲ (Black Up-Pointing Triangle, U+25B2)
- ▴ (Black Up-Pointing Small Triangle, U+25B4)