; tangles
; bequa 85V50
(def num 2000)
(def phi (lambda (a)
 (mul (div (mul 2 PI) num) a)))
(map (lambda (a)
 (stroke
 (rect
 (add 550 (mul 100 (sin (phi a))))
 (add 150 (mul 100 (cos (phi a))))
 (mul 100 (cos (phi a))) 100) 1 "rgba(255,255,255,0.08)"))
 (range 0 (sub num 1) 1))

Ronin

This is a C implementation of Hundred Rabbits' Ronin, an image processing tool in form of a Lisp dialect.

Components

1. Language
   • Lisp(y)
     • Lexer
     • Parser
2. Canvas
3. Backend(s)
   • svg

Implementation details

language -> virtual canvas -> backend of choice (svg)

Language

The Ronin language consists of a lexer and a parser.

Library

Files

• (open name ~scale) Imports a graphic file with format.
• (import name ~shape) Imports a graphic file with format.
• (export ~format ~quality) Exports a graphic file with format.
• (files) Returns the list of loaded files.
• (print string) Exports string to file.

Shapes

• (pos ~x ~y) Returns a position shape.
• (line ax ay bx by) Returns a line shape.
• (size w h) Returns a size shape.
• (rect x y w h) Returns a rect shape.
• (circle cx cy r) Returns a circle shape.
• (ellipse cx cy rx ry) Returns a ellipse shape.
• (arc cx cy r sa ea) Returns an arc shape.
• (poly ...pos) Returns a poly shape.
• (text x y p t ~a ~f) Returns a text shape.
• (svg x y d) Returns a svg shape.

Canvas operations

• (color r g b ~a) Returns a color object.
• (hsl h s l ~a) returns a HSL color object
• (resize ~w) Resizes the canvas to target w and h, returns the rect.
• (rescale ~w ~h) Rescales the canvas to target ratio of w and h, returns the rect.
• (crop ~rect) Crop canvas to rect.
• (copy ~rect) Copy a section of the canvas.
• (paste copy ~rect) Paste a section of the canvas.
• (drag ~rect) Drag a part of the canvas.
• (view a b) View a part of the canvas.
• (pick ~shape) Returns the color of a pixel at pos, or of the average of the pixels in rect.
• (orient ~deg) Orient canvas with angle in degrees.
• (mirror) Mirror canvas, methods: x, y.
• (transform) The transform toolkit, methods push, pop, reset, move, scale, rotate.
• (stroke shape color ~thickness) Strokes a shape.
• (fill ~rect) Fills a shape.
• (clear ~rect) Clears a rect.
• (gradient line ~colors 'black']) Defines a gradient color.
• (guide shape color) Draws a shape on the guide layer.

Pixel operations

• (pixels fn ~q ~rect)
• (saturation pixel q) Change the saturation of pixels.
• (contrast pixel q) Change the contrast of pixels.
• (brightness pixel q) Change the brightness of pixels.
• (additive pixel q) Condense the data of pixels.
• (multiply pixel q) Change the color balance of pixels.
• (normalize pixel q) Normalize the color of pixels with another color.
• (lum color) Return the luminance of a color.

Strings

• (concat ...items) Concat multiple strings.
• (split string char) Split string at character.

Math

• (add ...args) Adds values.
• (sub ...args) Subtracts values.
• (mul ...args) Multiplies values.
• (div ...args) Divides values.
• (mod a b) Returns the modulo of a and b.
• (rad degrees) Convert radians to degrees.
• (deg radians) Convert degrees to radians.
• (clamp val min max) Clamps a value between min and max.
• (step val step)
• (min) Returns lowest value.
• (max) Returns highest value.
• (ceil) Rounds up to the nearest integer.
• (floor) Rounds down to the nearest integer.
• (round) Rounds to the nearest integer
• (sin)
• (cos)
• (log)
• (pow)
• (sqrt) Calculate the square root.
• (sq a) Calculate the square.
• (PI)
• (TWO_PI)
• (random ...args)

Logic

• (gt a b) Returns true if a is greater than b, else false.
• (lt a b) Returns true if a is less than b, else false.
• (eq a b) Returns true if a is equal to b, else false.
• (and ...args) Returns true if all conditions are true.
• (or a b ...rest) Returns true if at least one condition is true.
• (not a) Negation. Returns true if a is false. Returns false if a is true.
• (while fn action) While loop. Execute action for as long as fn is true.

Language

• (let name value)
• (def name value)
• (defn fname ~(...fnparams) ...instructions)
• (λ (...args) ...instructions)
• (if (condition) ...instruction-when-true ~...instruction-when-false)

Lists

• (each arr fn) Run a function for each element in a list.
• (map arr fn) Run a function on each element in a list.
• (filter arr fn) Remove from list, when function returns false.
• (reduce arr fn acc)
• (len item) Returns the length of a list.
• (cons arr ...items) Returns a new array with the items appended.
• (push arr ...items) Appends the items into the existing list.
• (pop arr) Pop the last item from the list and return the item.
• (first arr) Returns the first item of a list.
• (last arr) Returns the last
• (rest [_ ...arr]) Returns all arguments except the first
• (range start end ~step) Returns a list of numbers counting from start to end. Step defaults to 1.

Objects (maps)

• (get item key) Gets an object's parameter with name.
• (set item ...args) Sets an object's parameter with name as value.
• (of h ...keys) Gets object parameters with names.
• (object ...entries) Creates an object with provided entries.
• (keys item) Returns a list of the object's keys
• (values item) Returns a list of the object's values

Convolution filters

• (convolve kernel ~rect) Apply convolution filter with given kernel on an area.
• (blur) Returns the blur kernel.
• (sharpen) Returns the sharpen kernel.
• (edge) Returns the edge kernel.

Points

• (offset a b) Offsets pos a with pos b, returns a.
• (distance a b) Get distance between positions.

Utilities

• (echo ...args) Print arguments to interface.
• (debug arg) Print arguments to console.
• (time ~rate) Returns timestamp in milliseconds.

• (test name a b) Unit test. Checks if a is equal to b, logs results to console.
• (benchmark fn) Logs time taken to execute a function.
• (get-theme) Returns an object with current theme colors.
• (get-frame) Returns a shape object describing the current canvas.