spin - Canvas Rotation Function #

Rotate canvas around center point

Syntax #

(spin angle)           ; Rotate by angle in degrees
(resetSpin)            ; Reset rotation to zero
(smoothspin angle)     ; Smooth rotation animation

Parameters #

• angle: Rotation amount in degrees (positive = clockwise)

Behavior #

• Rotates entire canvas around the center point
• Accumulates rotation over multiple calls
• Smooth interpolation maintains visual quality
• Can be reset to zero with resetSpin

Examples #

Basic Rotation #

(spin 90)          ; Quarter turn clockwise
(spin -45)         ; 45 degrees counter-clockwise
(spin 0.5)         ; Very slow rotation

Animation Patterns #

(s0.1 (spin 1))       ; Continuous slow spin
(s1 (spin 15))        ; Discrete jumps every second
(repeat 360 i (spin 1)) ; Full rotation in steps

Combined Effects #

(zoom 1.02)        ; Slight zoom
(spin 2)           ; Plus rotation
(blur 0.5)         ; Soft edges

Reset and Control #

(spin 45)          ; Rotate 45 degrees
(resetSpin)        ; Back to zero
(smoothspin 30)    ; Smooth animated rotation

Implementation Notes #

• Uses optimized rotation matrices for performance
• Anti-aliasing prevents jagged edges during rotation
• Compatible with other transformations
• Deferred execution for embedded layers

Related Functions #

• zoom - Scale transformation
• scroll - Translation transformation
• resetSpin - Reset rotation state
• smoothspin - Animated rotation variant