pixellist.js-e

## Copyright (c) 2015, Empirical Modelling Group
## All rights reserved.
##
## See LICENSE.txt

/*
 * Returns a PixelList drawable.  The ptrToData argument should be a pointer to a list of
 * integers.  The first four elements of the list represent the red, green, blue and
 * alpha components of the first pixel respectively (all in the range 0-255).  The
 * next four elements represent the second pixel, going from left to right along the
 * top line of the block.  The data list should contain data for an exact number
 * of rows of the specified width.  Although cumbersome a PixelList performs far
 * faster than trying to map each pixel to an individual EDEN observable for a
 * block of any significant size.
 * 
 * N.B. Unfortunately the alpha values are not true transparency.  That is, you
 * you can't see through to other objects drawn underneath on the canvas.  Alpha
 * values less than 255 just make the colours lighter.
 * 
 * Example:
 * ```
 * 	func colourMap {
 * 		para b;
 * 		auto data, i, j;
 * 		data = [];
 * 		for (j = 0; j <= 255; j++) {
 * 			for (i = 0; i <= 255; i++) {
 * 			append data, i;
 * 			append data, j;
 * 			append data, b;
 * 			append data, 255;
 * 		}
 * 		}
 * 	return data;
 *  }
 *  
 *  blue = 50;
 *  pixelData is colourMap(blue);
 *  pixels is PixelList(&pixelData, 20, 20, 256);
 *  picture is [pixels];
 *  
 *  @param [name]
 *  @param ptrToData pointer to list of R,G,B,Alpha values
 *  @param x x-position
 *  @param y y-position
 *  @param width
 *  
 * #canvas #pixellist
 */


func PixelList {
	${{
		var name;
		var argsProcessed;
		if (typeof(arguments[0]) == "string") {
			name = arguments[0];
			argsProcessed = 1;
		} else {
			argsProcessed = 0;
		}
		var ptrToData = arguments[argsProcessed];
		argsProcessed++;
		var x = arguments[argsProcessed];
		argsProcessed++;
		var y = arguments[argsProcessed];
		argsProcessed++;
		var width = arguments[argsProcessed];
		argsProcessed++;
		return new PixelList(name, ptrToData, x, y, width);
	}}$;
}

${{
PixelList = function(name, ptrToData, x, y, width) {
	this.name = edenUI.plugins.Canvas2D.initZoneFromName(name, "PixelList");
	this.obsName = root.currentObservableName();
	this.ptr = ptrToData;
	this.data = ptrToData instanceof Symbol? ptrToData.value() : [];
	this.x = x;
	this.y = y;
	this.width = width;
	this.height = this.data.length / (4 * width);
}

PixelList.prototype.draw = function (context) {
	var imageData = context.createImageData(this.width, this.height);
	var imageArr = imageData.data;
	var dataArr = this.data;
	var arrayLen = dataArr.length;
	for (var i = 0; i < arrayLen; i++) {
		imageArr[i] = dataArr[i];
	}
	context.putImageData(imageData, this.x, this.y);
}

PixelList.prototype.isHit = function (context, scale, x, y) {
	return x >= this.x && x < this.x + this.width && y >= this.y && y < this.y + this.height;
}

PixelList.prototype.toString = function() {
	var s = "PixelList(";
	if (this.name !== undefined) {
		s = s + Eden.edenCodeForValue(this.name) + ", ";
	}
	s = s + Eden.edenCodeForValues(this.ptr, this.x, this.y, this.width) + ")";
	return s;
}

PixelList.prototype.getEdenCode = PixelList.prototype.toString;

}}$;