A CommonJS module written for component(1) to create image histograms from images or canvas objects. Example

$ component install scottcorbett/histogram

Simple example using a DOM image

var histogram = require("histogram");  
var result = histogram().forImg(document.getElementById("source_img"));  
var img = document.createElement("img");
img.src = result;  

Calling setRGB manually to keep count of tone values

var histogram = require("histogram");  
...
histogram().setRGB({r: 255, g:128, b:64});
histogram().setRGB({r: 128, g:128, b:128});
...
var result = histogram().draw();  
var img = document.createElement("img");
img.src = result;  

###histogram([conf]) Optional configuration object with any of the following values. Defaults are shown

{       
  width : 255, // width of the resulting image.
  height : 128, // height of the resulting image.
  red: #d55, // colour used for red in the graph.
  green: #5d5, // colour used for green in the graph. 
  blue: #55d, // colour used for blue in the graph.
  black: #555 // colour used for portions of the graph overlapped by all colours  
}

###.setConf(conf) Sets configuration used for drawing, expects an object the same as the constructor conf.

###.forImg(source) Creates an image histogram based off the img object passed in and returns a data url.

###.forCanvas(source) Creates an image histogram based off the canvas object passed in and returns a data url.

###.clearRGB() Clears the rgb values used to generated the histogram.

###.setRGB(val) Increments the RGB tone counts based off the object passed in. Expects an object in the this format;

{       
  r : 255,  
  g : 128,  
  b : 64  
}

###.draw() Generates the histogram based off the RGB tone counts set and returns a data url for the resulting image.

MIT