Added setup dialog for background.

script/BaseBackgroundDrawer.js

@@ -0,0 +1,38 @@
+/**
+ * Graph drawer.
+ */
+ 
+ 
+function CommonBackgroundStyle()
+{
+	this.commonColor   = '#ffffff';
+	this.commonOpacity = 1.0;
+}
+
+function PrintBackgroundStyle()
+{
+	this.commonColor   = '#ffffff';
+	this.commonOpacity = 1.0;
+}
+
+function BaseBackgroundDrawer(context)
+{   
+  this.context = context;
+}
+
+BaseBackgroundDrawer.prototype.Draw = function(style, width, height, position, scale) 
+{
+    var context = this.context;
+    
+    var rect = new Rect(position, position.add(new Point(width / scale, height / scale)));
+    
+    context.clearRect(-rect.minPoint.x, -rect.minPoint.y, rect.size().x + 1, rect.size().y + 1);
+    
+    if (style.commonOpacity > 0.0)
+    {
+        context.globalAlpha = style.commonOpacity;
+        context.fillStyle   = style.commonColor;
+        context.fillRect(-rect.minPoint.x, -rect.minPoint.y, rect.size().x + 1, rect.size().y + 1);
+        context.globalAlpha = 1.0;
+    }
+}