### Draw Riso Layers to Screen with drawRiso

Source: https://antiboredom.github.io/p5.riso/index

Renders all Riso objects and layers onto the canvas. This function should be called at the end of 'setup' or 'draw' functions to preview the intended print output.

```javascript
function setup(){
  createCanvas(500, 500);

  let colors = ["red", "blue", "green", "black"];
  for (let i = 0; i < colors.length; i++) {
    let channel = new Riso(colors[i]); //create four color channels from array
    channel.fill(random(100, 200));
    channel.ellipse(random(0, width), random(0, height), 100, 100); //put a random ellipse on each
  }

  drawRiso(); //preview on screen
}
```

--------------------------------

### Export Riso Layers with exportRiso

Source: https://antiboredom.github.io/p5.riso/index

Exports all Riso layers as individual PNG files, suitable for printing with different ink colors. This function is typically called within an event listener (like 'mousePressed') or at the end of the 'setup' function.

```javascript
let blue;
let red;

function setup(){
  createCanvas(500, 500);

  blue = new Riso("blue");
  red = new Riso("red");
}

function draw() {
  clearRiso(); //clear screen every loop of draw

  blue.fill(map(mouseX, 0, width, 0, 255)); //set blue fill by mouse position
  red.fill(map(mouseY, 0, height, 0, 255)); //set red fill by mouse position

  blue.ellipse(200, 200, 100, 100); //draw ellipse to blue layer
  red.ellipse(250, 250, 100, 100); //draw ellipse to red layer
}

function mousePressed() { //when mouse is pressed
  exportRiso(); //export red and blue layers as pngs for printing
}
```

--------------------------------

### Set Pixel Density to 1 in p5.js

Source: https://antiboredom.github.io/p5.riso/index

Sets the pixel density for p5.js sketches to 1. This is crucial for ensuring that exported images from p5.riso have a consistent resolution (72 dpi) regardless of the screen's pixel density, preventing unexpected scaling issues on high-resolution displays. This function should be called within the `setup()` function of your p5.js sketch.

```javascript
function setup() {
  createCanvas(400, 400);
  pixelDensity(1);
}
```

--------------------------------

### Initialize and Draw with Riso Object (p5.js)

Source: https://antiboredom.github.io/p5.riso/index

Demonstrates how to initialize a Riso object for a specific color layer, set its opacity, draw shapes to it, and then render all layers to the screen. This is fundamental for creating multi-color risograph prints.

```javascript
let blueChannel;

function setup(){
  createCanvas(500, 500);
  blueChannel = new Riso("blue"); // instantiate riso object as blue layer
  blueChannel.fill(128); //set opacity
  blueChannel.rect(20, 20, 100, 100); //draw rect to blue layer
  drawRiso(); //draw to screen
}
```

--------------------------------

### Riso Constructor

Source: https://antiboredom.github.io/p5.riso/index

Initializes a Riso object, which represents a single-color graphics layer for Risograph printing. It can be configured with a specific color and dimensions.

```APIDOC
## new Riso(color, width, height)

### Description
The base Riso object is a single-color p5 graphics object. Its constructor can take 3 parameters.

### Method
`new Riso()`

### Parameters
#### Path Parameters
- **color** (string | array) - Required - A string set to a Risograph color name (e.g., "brightred", "blue", "orange") or an array with [r,g,b] values.
- **width** (number) - Optional - The width of the riso canvas. Defaults to the width of the sketch.
- **height** (number) - Optional - The height of the riso canvas. Defaults to the height of the sketch.

### Request Example
```javascript
let blueChannel; //declare riso object

function setup(){
  createCanvas(500, 500);
  blueChannel = new Riso("blue"); // instantiate riso object as blue layer
  blueChannel.fill(128); //set opacity
  blueChannel.rect(20, 20, 100, 100); //draw rect to blue layer
  drawRiso(); //draw to screen
}
```

### Response
#### Success Response (200)
This constructor does not return a value directly, but initializes a Riso graphics object.

#### Response Example
```json
{
  "message": "Riso object created successfully"
}
```

### Notes
Internally, the riso object extends p5's built-in graphics object. It is used similarly with a few exceptions.
Pay attention to the order that you create each Riso object (each color layer). The `drawRiso()` function will display the layers in the order they are created, with the last created layer on top. If the top layer has an opacity of 255, you may not be able to see the layers underneath. Different color combinations may result in different blended colors.

The following default colors are available: BLACK BURGUNDY BLUE GREEN MEDIUMBLUE BRIGHTRED RISOFEDERALBLUE PURPLE TEAL FLATGOLD HUNTERGREEN RED BROWN YELLOW MARINERED ORANGE FLUORESCENTPINK LIGHTGRAY METALLICGOLD CRIMSON FLUORESCENTORANGE CORNFLOWER SKYBLUE SEABLUE LAKE INDIGO MIDNIGHT MIST GRANITE CHARCOAL SMOKYTEAL STEEL SLATE TURQUOISE EMERALD GRASS FOREST SPRUCE MOSS SEAFOAM KELLYGREEN LIGHTTEAL IVY PINE LAGOON VIOLET ORCHID PLUM RAISIN GRAPE SCARLET TOMATO CRANBERRY MAROON RASPBERRYRED BRICK LIGHTLIME SUNFLOWER MELON APRICOT PAPRIKA PUMPKIN BRIGHTOLIVEGREEN BRIGHTGOLD COPPER MAHOGANY BISQUE BUBBLEGUM LIGHTMAUVE DARKMAUVE WINE GRAY CORAL WHITE AQUA MINT CLEARMEDIUM FLUORESCENTYELLOW FLUORESCENTRED FLUORESCENTGREEN
```

--------------------------------

### Apply Halftone Pattern with halftoneImage

Source: https://antiboredom.github.io/p5.riso/index

Applies a halftone pattern to an image, allowing customization of dot shape, frequency, angle, and intensity. Optional parameters include dot shape ('line', 'square', 'circle', 'ellipse', 'cross'), frequency (lpi), rotation angle, and intensity (threshold).

```javascript
let pink;
let img;

function preload() {
  img = loadImage('data/monkeys.jpg');
}

function setup() {
  pixelDensity(1);
  createCanvas(img.width, img.height);
  pink = new Riso('fluorescentpink'); // create pink layer
}

function draw() {
  background(220);
  clearRiso();

  let halftoned = halftoneImage(img, 'line', 3, 45, 90); // pass image to halftone with line dots, frequency of 3, angle of 45, and intensity of 90.
  pink.image(halftoned, 0, 0); // draw halftoned image

  drawRiso();
}
```

--------------------------------

### Map Image Colors to Riso Layers with extractMappedChannels

Source: https://antiboredom.github.io/p5.riso/index

Maps colors from an input image to Riso color layers. Returns an array of images, each corresponding to a Riso layer. Accepts an optional 'steps' parameter for mapping accuracy (lower is more accurate, but can cause memory issues) and a 'perceptual' boolean to align color matching with human perception.

```javascript
let layer1;
let layer2;

let img;

function preload() {
  img = loadImage("data/no_threat.jpg");
}

function setup() {
  pixelDensity(1);
  createCanvas(img.width, img.height);

  layer1 = new Riso("orange");
  layer2 = new Riso("green");

  let images = extractMappedChannels(img, 0.05);

  layer1.image(images[0], 0, 0);
  layer2.image(images[1], 0, 0);

  drawRiso();
}
```

--------------------------------

### Riso.image(img, x, y, width, height) - Draw image to Riso layer

Source: https://antiboredom.github.io/p5.riso/index

Draws a p5.js image, video, or graphics object onto a specified Riso layer. The image is converted to grayscale and its color will match the layer's color. The opacity is controlled by the layer's fill value. Optional width and height parameters can resize the image.

```javascript
let img;

function preload() {
  img = loadImage("cat.jpg");
}

function setup(){
  createCanvas(500, 500);

  let orange = new Riso("orange");
  orange.fill(200);
  orange.image(img, 0, 0);
  drawRiso();
}
```

--------------------------------

### extractRGBChannel(img, channel) - Extract color channels

Source: https://antiboredom.github.io/p5.riso/index

Extracts a specific color channel (red, green, or blue) from a p5.js image and returns it as a new image. The 'channel' parameter can be the channel name as a string or its corresponding number (0 for red, 1 for green, 2 for blue).

```javascript
// convert a color image into a red and blue print
let img;

function preload() {
  img = loadImage('cat.jpg')
}

function setup(){
  createCanvas(500, 500);

  let blue = new Riso("blue");
  let red = new Riso("red");

  let justBlues = extractRGBChannel(img, "blue"); //extract blue from img and save as new image
  let justReds = extractRGBChannel(img, "red"); //extract red from img and save as new image

  blue.image(justBlues, 0, 0); //draw justblues to blue layer
  red.image(justReds, 0, 0); //draw justred to red layer

  drawRiso();
}
```

--------------------------------

### Dither Image to One Color with ditherImage

Source: https://antiboredom.github.io/p5.riso/index

Reduces an image to a single color using dot patterns to simulate grayscale. Supports dither types: 'atkinson', 'floydsteinberg', 'bayer', or 'none'. The 'threshold' parameter applies only to 'bayer' and 'none' dither types, controlling the conversion point. 'none' simply thresholds pixels to black or clear.

```javascript
let black;
let img;
let ditherType = 'atkinson';

function preload() {
  img = loadImage('data/no_threat.jpg');
}

function setup() {
  pixelDensity(1);
  createCanvas(img.width, img.height);
  black = new Riso('black'); //create black layer
}

function draw() {
  background(220);
  let threshold = map(mouseX, 0, width, 0, 255); //change dither threshold with mouse position
  clearRiso();

  let dithered = ditherImage(img, ditherType, threshold);//pass image to dither
  black.image(dithered, 0, 0); //draw dithered image

  drawRiso();
}

function keyReleased() { //function to change dither type with a keypress
  if (key == 1) ditherType = 'atkinson';
  else if (key == 2) ditherType = 'floydsteinberg';
  else if (key == 3) ditherType = 'bayer';
  else if (key == 4) ditherType = 'none';
}
```

--------------------------------

### extractCMYKChannel(img, channel) - Extract CMYK color channels

Source: https://antiboredom.github.io/p5.riso/index

Extracts specific CMYK color channels (cyan, magenta, yellow, black) from a p5.js image and returns them as new images. The 'channel' parameter can be a channel name string, its corresponding number (0-3), or a channel set string (e.g., 'cy', 'mk', 'cyk').

```javascript
// convert a color image into a cyan and magenta print
let img;

function preload() {
  img = loadImage('cat.jpg')
}

function setup(){
  createCanvas(500, 500);

  let blue = new Riso("blue");
  let red = new Riso("red");

  let justCyan = extractCMYKChannel(img, "cyan"); //extract cyan from img
  let justMagenta = extractCMYKChannel(img, "magenta"); //extract magenta from img

  blue.image(justCyan, 0, 0); //draw justCyan to blue layer
  red.image(justMagenta, 0, 0); //draw justMagenta to red layer

  drawRiso();
}
```

--------------------------------

### risoNoFill() - Disable fill on all Riso layers

Source: https://antiboredom.github.io/p5.riso/index

A utility function that disables the fill for all Riso layers. This is a convenience function equivalent to calling noFill() on each Riso layer individually. It does not take any parameters.

```javascript
risoNoFill();
```

--------------------------------

### Riso.fill(value) - Set fill opacity

Source: https://antiboredom.github.io/p5.riso/index

Sets the fill opacity for a Riso layer. The value ranges from 0 (transparent) to 255 (opaque). This affects subsequent drawing operations on that layer. Requires a Riso object instance.

```javascript
function setup(){
  createCanvas(500, 500);
  let blueChannel = new Riso("blue"); //create riso object, set to blue

  blueChannel.fill(255); // completely opaque
  blueChannel.ellipse(0, 0, 100, 100); //draw ellipse on blue layer

  blueChannel.fill(50); // fairly transparent
  blueChannel.ellipse(50, 50, 100, 100);

  blueChannel.fill(3); // almost invisible
  blueChannel.ellipse(75, 75, 100, 100);

  drawRiso();
}
```

--------------------------------

### clearRiso() - Clear all Riso layers

Source: https://antiboredom.github.io/p5.riso/index

Clears all content from all Riso layers. This function is particularly useful when drawing to Riso layers within the draw() loop, allowing for dynamic updates. It does not take any parameters.

```javascript
clearRiso();
```

--------------------------------

### risoNoStroke() - Disable stroke on all Riso layers

Source: https://antiboredom.github.io/p5.riso/index

A utility function that disables the stroke for all Riso layers. This is a convenience function equivalent to calling noStroke() on each Riso layer individually. It does not take any parameters.

```javascript
risoNoStroke();
```

--------------------------------

### Riso.cutout(p5.Graphic) - Mask areas with another graphic

Source: https://antiboredom.github.io/p5.riso/index

Removes or masks portions of a Riso layer where it overlaps with another p5.js graphic object. This is useful for creating layered effects where one layer's content should not appear under another. It takes a p5.Graphic object as input.

```javascript
function setup(){
  createCanvas(500, 500);

  let blue = new Riso("blue"); //blue layer
  let red = new Riso("red"); //red layer

  blue.fill(255);
  blue.ellipse(130, 130, 100, 100);
  red.fill(255);
  red.textSize(100);
  red.text("hello",50, 170);

  //completely removes any intersection of red and blue
   //layers from the blue layer
  blue.cutout(red);
  drawRiso();
  }
```

--------------------------------

### Riso.stroke(value) - Set stroke opacity

Source: https://antiboredom.github.io/p5.riso/index

Sets the stroke opacity for a Riso layer. Similar to fill, the value ranges from 0 (transparent) to 255 (opaque). This affects the opacity of outlines drawn on the layer. Requires a Riso object instance.

```javascript
function setup(){
  createCanvas(500, 500);

  let orange = new Riso("orange");
  orange.stroke(255);
  orange.strokeWeight(5);
  orange.rect(50, 50, 100, 100);
  drawRiso();
}
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.