pen

The Scratch pen extension. Katnip detects the pen_ opcode prefix and adds the extension to the project automatically — there is nothing to enable.

Drawing

pen.down() -> void    ✅
pen.up() -> void      ✅
pen.clear() -> void   ✅
pen.stamp() -> void   ✅

pen.clear();
pen.down();
for (side, 4) {
    motion.forward(100);
    motion.turn(90);
}
pen.up();

Colour

pen.setHex(hex: str) -> void   ✅

pen.setHex("#ff8800");

Size

pen.setSize(size: num) -> void      ✅
pen.changeSize(dS: num) -> void     ✅

pen.setSize(3);
pen.changeSize(1);

stamp prints the sprite’s current costume onto the pen layer, at its current position, size, and direction.

Colour parameters

pen.setAttr(attr: ColorParam, value: num) -> void     ✅
pen.changeAttr(attr: ColorParam, dA: num) -> void     ✅

Pass the member or the literal — they compile to the same menu shadow:

pen.setAttr(pen.ColorParam.COLOR, 50);
pen.setAttr("color", 50);                # identical

proc rainbow(steps: num) -> void {
    pen.setAttr("color", 0);
    for (i, steps) {
        pen.changeAttr("color", 100 / steps);
        motion.forward(5);
        motion.turn(360 / steps);
    }
}

Full enum reference

pen.ColorParam	Value
COLOR	"color"
SATURATION	"saturation"
BRIGHTNESS	"brightness"
TRANSPARENCY	"transparency"