SketchWave Spade Demo

Control Panel for SWSpade Customization — Stage

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Control Panel

Spade Parameters ♠

(Drag the center dot to reposition the figure)

Scale: 0.450

Small (0.20) Large (1.0)

Stem Length: 5.0

Short Long

Stem Width: 2.00

Narrow Wide

Stem Power (cusp sharpness): 3

Round (1) Sharp (9)

Stem Offset: 3.5

Down (−5) Up (+7)

Rotation (°): 0

0° 360°

Stroke Thickness: 2

Stroke Color & Opacity

Opacity: 100

Fill Color & Opacity

Opacity: 100

Center Dot

Show center dot

Center = (0.0, 0.0)

Opacity (Alpha): 100

Transparent — enables motion trails

Speed (°/sec, −720 to 720): 45

CW (−) CCW (+)

Oscillates the body scale sinusoidally — the spade gently grows and shrinks. The stem adapts automatically. Try combining Pulse + Spin with low Background opacity for trailing effects!

Speed (Hz): 0.5

Slow (0.1 Hz) Fast (2.0 Hz)

Amount (scale units): 0.080

Subtle Dramatic

How SWSpade Is Built

SWSpade draws the playing-card spade ♠ using two parts:

Body — the classic inverted heart, rendered from a trigonometric parametric curve.
Stem — SWSpire with halfShape = true and rotationDeg = 180, producing a downward-pointing cusp arch below the body.

Body: Inverted Parametric Heart

x(t) = scale · a · sin³(t)
y(t) = −scale · (b·cos(t) + c·cos(2t) + d·cos(3t) + e·cos(4t))

Defaults: a=16, b=13, c=−5, d=−2, e=−1, scale=0.5
t ∈ [0, 2π),   200 sample points

The minus sign on y(t) flips the standard heart upside down so the sharp tip points upward — the classic spade orientation. The lobes curve downward to form the body base.

Stem: Half SWSpire Arch

The stem centre is computed by finding the minimum y of the body (the lowest point of the lobes) and placing the arch flat base there. With halfShape = true, the SWSpire draws a half-arch from that base down to a pointed cusp, completing the spade handle.

The Pulse Animation

Pulse oscillates the scale parameter sinusoidally. As the body grows or shrinks, the stem attachment point recalculates each frame so the stem always starts at the correct body bottom position.

Using the Controls

Scale — overall size of the body in grid units.
Stem Length — depth of the pointed cusp arch below the body.
Stem Width — half-width of the arch base at its widest point.
Stem Power — sharpness of the cusp. 1 = smooth arch; 9 = sharp spike.
Stem Offset — vertical shift of the stem center along the body axis. Positive moves the stem up toward the body; negative moves it farther below.
Rotation — static base rotation in degrees (CCW positive).
Pulse (accordion) — oscillates scale. Stem adapts automatically.
Spin (accordion) — continuous rotation. Combine with Pulse and low Background opacity for patterns.
Drag the center dot to reposition the figure.
Click the canvas to toggle the grid on/off.

Keyboard Shortcuts

s — Toggle spin
p — Toggle pulse
r — Factory reset
q — Stop all animations