Adding BTC exchange widget

server/btc.php

@@ -0,0 +1,67 @@
+<?php
+
+require_once("provider.php");
+
+class BTCExchangeProvider implements ServiceProvider {
+	// Widget properties
+	static $widgetName = "BTC Exchange";
+	static $widgetIcon = "btc.svg";
+
+	public $cpair;
+	public $width;
+	public $height;
+
+	function BTCExchangeProvider() {
+		$this->cpair = "EUR";
+		$this->width = 800;
+		$this->height = 100;
+		$this->font_size = 1;
+		$this->font_family = "Verdana";
+	}
+
+    public function getTunables() {
+		return array(
+			"currency"    => array("type" => "text", "display" => "Currency Pair", "value" => $this->cpair),
+			"font_family" => array("type" => "text", "display" => "Font Family", "value" => $this->font_family),
+			"font_size"   => array("type" => "fnum", "display" => "Font Size", "value" => $this->font_size)
+		);
+	}
+    public function setTunables($v) {
+		$this->cpair = strtoupper($v["currency"]["value"]);
+		$this->font_family = $v["font_family"]["value"];
+		$this->font_size = $v["font_size"]["value"];
+	}
+
+    public function shape() {
+		// Return default width/height
+		return array(
+			"width"       => $this->width,
+			"height"      => $this->height,
+			"resizable"   => true,
+			"keep_aspect" => false,
+		);
+    }
+
+    public function render() {
+		// Gather information from fixer.io
+		$raw = file_get_contents("https://api.bitcoinaverage.com/ticker/".$this->cpair."/");
+		$exchange = json_decode($raw, true);
+
+		$rate = $exchange["24h_avg"];
+
+		// Generate an SVG image out of this 
+		return sprintf(
+			'<svg width="%d" height="%d" version="1.1" xmlns="http://www.w3.org/2000/svg" 
+				xmlns:xlink="http://www.w3.org/1999/xlink">
+                <text text-anchor="middle" x="50%%" y="80%%" fill="black" style="font-size: %dpx; font-family: %s;">
+					%s/BTC %0.2f
+				</text>
+			</svg>', $this->width, $this->height,
+			    $this->font_size * $this->height, $this->font_family,
+				$this->cpair, $rate
+		);
+	}
+
+};
+
+?>

server/functions.php

@@ -5,6 +5,7 @@
 require_once("weather.php");
 require_once("currency.php");
 require_once("stock.php");
+require_once("btc.php");
 
 function array2js($a) {
 	if (is_array($a)) {