Class Scruffy::Layers::Base
In: lib/scruffy/layers/base.rb
Parent: Object

Scruffy::Layers::Base

Author:Brasten Sager
Extended By:A.J. Ostman
Created:August 5th, 2006
Last Modified:August 27, 2006

Scruffy::Layers::Base contains the basic functionality needed by the various types of graphs. The Base class is responsible holding layer information such as the title and data points.

When the graph is rendered, the graph renderer calls Base#render. Base#render sets up some standard information, and calculates the x,y coordinates of each data point. The draw() method, which should have been overridden by the current instance, is then called. The actual rendering of the graph takes place there.

Create New Graph Types

Assuming the information generated by Scruffy::Layers::Base is sufficient, you can create a new graph type simply by overriding the draw() method. See Base#draw for arguments.

Methods

Attributes

color  [R] 
complexity  [R] 
height  [R]  The following attributes are set during the layer‘s render process, and act more as a record of what just happened for later processes. height, width, min_value, max_value, color, opacity, complexity
max_value  [R] 
min_value  [R] 
opacity  [R] 
options  [RW] 
points  [RW] 
preferred_color  [RW] 
relevant_data  [RW] 
title  [RW]  The following attributes are user-definable at any time. title, points, relevant_data, preferred_color, options
width  [R]  The following attributes are set during the layer‘s render process, and act more as a record of what just happened for later processes. height, width, min_value, max_value, color, opacity, complexity

Public Class methods

Returns a new Base object.

Any options other that those specified below are stored in the @options variable for possible later use. This would be a good place to store options needed for a custom graph.

Options:

title:Name/title of data group
points:Array of data points
preferred_color:Color used to render this graph, overrides theme color.
relevant_data:Rarely used - indicates the data on this graph should not included in any graph data aggregations, such as averaging data points.

Public Instance methods

The lowest data point on this layer, or nil if relevant_data == false

The method called by Base#draw to render the graph.

svg:a Builder object to use for creating SVG code.
coords:An array of coordinates relating to the graph‘s data points. ie: [[100, 120], [200, 140], [300, 40]]
options:Optional arguments.

Returns a hash with information to be used by the legend.

Alternatively, returns nil if you don‘t want this layer to be in the legend, or an array of hashes if this layer should have multiple legend entries (stacked?)

By default, legend_data returns nil automatically if relevant_data is set to false or the @color attribute is nil. @color is set when the layer is rendered, so legends must be rendered AFTER layers.

Returns the value of relevant_data

Builds SVG code for this graph using the provided Builder object. This method actually generates data needed by this graph, then passes the rendering responsibilities to Base#draw.

svg:a Builder object used to create SVG code.

The sum of all values

The highest data point on this layer, or nil if relevant_data == false

Protected Instance methods

Optimistic generation of coordinates for layer to use. These coordinates are just a best guess, and can be overridden or thrown away (for example, this is overridden in pie charting and bar charts).

Converts a percentage into a pixel value, relative to the height.

Example:

  relative(5)   # On a 100px high layer, this returns 5.  200px high layer, this returns 10, etc.

Sets up several variables that almost every graph layer will need to render itself.

[Validate]