How to draw graph from a list of points? - graph

Question

In this answer to my recent question, there is some code that draws a graph, but I can't manage to edit it into something that accepts any list of points as a parameter.
I'd like the Drawing method to accept these parameters:
List of Vector2, Point or VertexPositionColor, I can work with whichever.
Offset for the whole graph
These optional requirements would be appreciated:
Color that may override VertexPositionColor's color and apply to all points.
Size of the graph, so it can be shrunk or expanded, either as Vector2 as multiplier, or Point as target size. Maybe even combine this with offset in Rectangle.
And if it's possible, I'd like to have it all in a class, so graphs can be used separately from each other, each with its own Effect.world matrix, etc.
Here is that code (by Niko Drašković):
Matrix worldMatrix;
Matrix viewMatrix;
Matrix projectionMatrix;
BasicEffect basicEffect;
VertexPositionColor[] pointList;
short[] lineListIndices;
protected override void Initialize()
{
int n = 300;
//GeneratePoints generates a random graph, implementation irrelevant
pointList = new VertexPositionColor[n];
for (int i = 0; i < n; i++)
pointList[i] = new VertexPositionColor() { Position = new Vector3(i, (float)(Math.Sin((i / 15.0)) * height / 2.0 + height / 2.0 + minY), 0), Color = Color.Blue };
//links the points into a list
lineListIndices = new short[(n * 2) - 2];
for (int i = 0; i < n - 1; i++)
{
lineListIndices[i * 2] = (short)(i);
lineListIndices[(i * 2) + 1] = (short)(i + 1);
}
worldMatrix = Matrix.Identity;
viewMatrix = Matrix.CreateLookAt(new Vector3(0.0f, 0.0f, 1.0f), Vector3.Zero, Vector3.Up);
projectionMatrix = Matrix.CreateOrthographicOffCenter(0, (float)GraphicsDevice.Viewport.Width, (float)GraphicsDevice.Viewport.Height, 0, 1.0f, 1000.0f);
basicEffect = new BasicEffect(graphics.GraphicsDevice);
basicEffect.World = worldMatrix;
basicEffect.View = viewMatrix;
basicEffect.Projection = projectionMatrix;
basicEffect.VertexColorEnabled = true; //important for color
base.Initialize();
}
And the drawing method:
foreach (EffectPass pass in basicEffect.CurrentTechnique.Passes)
{
pass.Apply();
GraphicsDevice.DrawUserIndexedPrimitives<VertexPositionColor>(
PrimitiveType.LineList,
pointList,
0,
pointList.Length,
lineListIndices,
0,
pointList.Length - 1
);
}

Answer 1

The Graph class that does the requested can be found here.About 200 lines of code seemed too much to paste here.
The Graph is drawn by passing a list of floats (optionally with colors) to its Draw(..) method.
Graph properties are:
Vector2 Position - the bottom left corner of the graph
Point Size - the width (.X) and height (.Y) of the graph. Horizontally, values will be distributed to exactly fit the width. Vertically, all values will be scaled with Size.Y / MaxValue.
float MaxValue - the value which will be at the top of the graph. All off the chart values (greater than MaxValue) will be set to this value.
GraphType Type - with possible values GraphType.Line and GraphType.Fill, determines if the graph will be drawn line only, or bottom filled.
The graph is drawn with a line list / triangle strip.