Drawing and colors

How to add new shapes to the page and create and use color swatches. By Ludwig Zeller

General information

basil.js does not have a screen or canvas
You cannot draw pixels
Instead you add InDesign objects to your pages
These can be used normally within InDesign afterwards
And you can undo them!

1. Filling the paper with a rect() by reading its size

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  b.println( "width " + b.width );
  b.println( "height " + b.height );
  b.rect(0,0,b.width,b.height);
};

b.go();

As there is no background() command in basil.js you should use rect() in order to change the background colour.

How to account for margins or bleed settings

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {

    b.noFill();
    b.stroke(0,255,0);

    b.canvasMode(b.MARGIN);
    b.rect(0,0,b.width,b.height);

    b.canvasMode(b.PAGE);
    b.rect(0,0,b.width,b.height);
    
    b.canvasMode(b.BLEED);
    b.rect(0,0,b.width,b.height);    

   //  the following examples only work for documents with facing pages

   b.canvasMode(b.FACING_MARGINS); 
   b.rect(0,0,b.width,b.height);

   b.canvasMode(b.FACING_PAGES);
   b.rect(0,0,b.width,b.height);

   b.canvasMode(b.FACING_BLEEDS); 
   b.rect(0,0,b.width,b.height);

}
b.go();

Using different canvas modes will position the origin of the coordinate system (think 0,0) to the appropriate spots in the canvas.
Additionally b.width and b.height will be updated to reflect the new size of the canvas.
You can still use other spots of the canvas with extreme coordinates as the canvas modes are not limiting you down to them.
Changing canvasMode() will reset any previous MatrixTransformations such as translate(), rotate() or scale()

2. Generate several swatches with color() and paint with rect()

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {

  b.colorMode(b.RGB); // this is the default anyways

  // create new RGB color
  var red = b.color(255,2,3); // variables can store data to be reused later
  var green = b.color(0,255,0,"green");

  b.fill( red );
  b.rect(0,0,b.width,50);
  b.fill( green );
  b.rect(0,50,b.width,50);

  // create new CMYK color
  var magenta = b.color(1,100,3,4);
  var yellow = b.color(0,0,100,0,"yellow");
  var grey = b.color(100);
  var lightGrey = b.color(5,"light grey");

  b.fill( magenta );
  b.rect(0,200,b.width,50);
  b.fill( yellow );
  b.rect(0,250,b.width,50);
  b.fill( grey );
  b.rect(0,300,b.width,50);
  b.fill( lightGrey );
  b.rect(0,350,b.width,50);

  // get a color from document
  var black = b.color("Black");
  b.fill( black );
  b.rect(0,500,b.width,50); 
}

b.go();

color() can accept between one and five parameters.
basil.js uses the number of given colour channels to decide whether to create a RGB or CMYK colour.
If the arguments do not clearly define the desired type of colour then the current basil.js colour mode is used.
The default basil.js colour mode is RGB
Please note that CMYK takes channel numbers between 0-100 where higher is darker (subtractive color), while RGB takes numbers between 0-255 where lower is darker (additive colour).

3. Using random() to pick a color and fill the background

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  // create new random RGB color
  var newRandomColor = b.color( b.random(255), b.random(255), b.random(255) );

  // fill rect with it
  b.fill( newRandomColor );
  b.rect(0,0,b.width,b.height);
}

b.go();

4. Using line() to create a cross

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  b.stroke( 100 );
  b.strokeWeight( 5 );
  // draw a cross 
  b.line(0,0,b.width,b.height);
  b.line(0,b.height,b.width,0);
}

b.go();

5. Using random() and ellipse() to fill the page with circles

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  var count = 23;

  b.doc();
  b.println( b.width+" x "+b.height);

  for (var i = 0; i < 23; i++) {
    var x = b.random(0, b.width);
    var y = b.random(0, b.height);
    var size = b.random(10, 123);
    b.ellipse(x, y, size, size);
  }
}

b.go();

This creates confetti

6. Using a for-loop and map() to create a gradient

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  var counter = 50;
  b.noStroke();
  var rectHeight = b.height/counter;

  for (var i = 0; i < counter; i++) {
    var y = b.map(i, 0,counter-1, 0,b.height-rectHeight);
    var fillTint = b.map(i, 0,counter-1, 100,0);

    b.fillTint( fillTint );
    b.rect(0,y, b.width,rectHeight);
  }
}

b.go();

8. Using random() and nested for loops to create a matrix of lines

#includepath "~/Documents/;%USERPROFILE%Documents";
#include "basiljs/bundle/basil.js";

function draw() {
  var tileCount = 10;
  var randomX = b.random(0,b.width);
  var randomY = b.random(0,b.height);

  b.strokeWeight(1);

  for (var gridY = 0; gridY <= tileCount; gridY++) {
    for (var gridX = 0; gridX <= tileCount; gridX++) {
      var posX = b.width/tileCount*gridX;
      var posY = b.height/tileCount*gridY;
      b.line(posX,posY,randomX,randomY);
    }
  }

};

b.go();