Make Chart Legend represent two colors - c#

I created a column chart in my application which look like this:
As you can see the positive values are green and the negative values are red. I need to represent this in the legend. I just don't know how.
What I already tried:
I added CustomItems to the Legend. Here is the code:
Legend currentLegend = chart.Legends.FindByName(chart.Series[series].Legend);
if (currentLegend != null)
{
currentLegend.LegendStyle = LegendStyle.Table;
LegendItem li = new LegendItem();
li.Name = series;
li.Color = Color.Red;
li.BorderColor = Color.Transparent;
currentLegend.CustomItems.Add(li);
}
This results in the following representation:
I could live with that. But as soon as I add further series to the chart the order of the elements gets destroyed. Here is an example:
I would like to have one of the two options:
keep the positive and negative color together
or an even better solution could be to have just one tile in the legend which is double colored. Something like this:
Could you please help me solving this issue?
Many thanks in advance!

Yes, you can do that. Note however that you can't really modify the original Legend. So for a perfect result you would need to create a new custom Legend instead.
See here for an example that does that; note especially the positioning..!
But maybe you can get away a little easier; see below!
The first rule to understand is that added LegendItems always go to the end of the list. So you can't keep them together, unless your added Series are at the start. You can do that by using Series.Insert(..) but using those two-color rectangles is much nicer, imo..
To show the graphics you want, simply create them as bitmaps, either on disk or on the fly and store them in the Images collection of the chart:
Legend L = chart1.Legends[0];
Series S = chart1.Series[0];
// either load an image from disk (or resources)
Image img = Image.FromFile(someImage);
// or create it on the fly:
Bitmap bmp = new Bitmap(32, 14);
using (Graphics G = Graphics.FromImage(bmp))
{
G.Clear(Color.Red);
G.FillPolygon(Brushes.LimeGreen, new Point[] { new Point(0,0),
new Point(32,0), new Point(0,14)});
}
Now add it to the chart's NamedImage collection:
chart1.Images.Add(new NamedImage("dia", bmp));
Now you can create as many LegendItems as you need:
LegendItem newItem = new LegendItem();
newItem.ImageStyle = LegendImageStyle.Rectangle;
newItem.Cells.Add(LegendCellType.Image, "dia", ContentAlignment.MiddleLeft);
newItem.Cells.Add(LegendCellType.Text, S.Name, ContentAlignment.MiddleLeft);
And add them to the Legend:
L.CustomItems.Add(newItem);
Unfortunately you can't delete the original item.
What you can do, besides creating a new Legend from scratch, is this:
Clear the text like this:
S.LegendText = " "; // blank, not empty!
As you have set the Colors of all the DataPoints anyway, you can also get rid of the blue rectangle:
S.Color = Color.Transparent;
This will also make all points without colors transparent, so make sure to color them all!
Note that some space in the Legend it still taken!
Here is the result, with a few colored points and your line series added:

Related

How can I put dots on the chart where my datapoints are?

I'm using the Windows.Forms.DataVisualization.Charting class to draw a simple char plotting a simple courb.
My courb is correclty plotted, but the points are not shown. Like dots or crosses where the points are.
I tried using datapoint.BackImage, but that doesn't show anything.
I'm sure that the image is found because I store other images in the exact same folder, and they are correctly read when I use the same path.
The code where I feed the DataPoint:
foreach (MesureTaille mesureTaille in tailles)
{
DataPoint point = new DataPoint(mesureTaille.age, mesureTaille.taille);
point.BackImage = string.Concat(
Application.StartupPath.Remove(Application.StartupPath.IndexOf("\\bin\\Debug")),
"/BackgoundImage/dot.png");
Serie_Age_Taille.Points.Add(point);
}
As DavidG and TaW pointed out, what I needed was Series.MarkerStyle :
// This line sets the dots !
Serie_Age_Taille.MarkerStyle = MarkerStyle.Cross;
foreach (MesureTaille mesureTaille in tailles)
{
// And I don't need to do anything on the DataPoints
DataPoint point = new DataPoint(mesureTaille.age, mesureTaille.taille);
Serie_Age_Taille.Points.Add(point);
}

Programmatic Creation of Chart and setting of its legends

I am creating Charts pie, bar and line and want to set their Legends along with valuea,Title of legend and point the values on Charts. how could i do so?
Usually you don't need to add a Legend as there is already a default one. But since you are creating a Chart in code you indeed have to code a little more. Adding a Legend is one of thoses things.
You have created a legend but instead of adding it you create another legend still. Instead write: chartA.Legends.Add(legend)
Note that the documentation (including Intellisense) is wrong on the constructor with a string paramenter! It works as expected, not as documented on MSDN!
What I suggested (chartA.Legends[0].Title = "someString";) works fine provided you have done all the other things you need:
You will also have to create (at least)
One ChartArea
One Series along with the ChartTypeyou want an..
..in order to make it show you also have to add a DataPoint.
Example:
Legend legend = new Legend();
Chart chartA = new Chart(); // <<---!
chartA.BackColor = Color.White;
chartA.Width = 370;
chartA.Height = 250;
chartA.Location = new Point(48, 35);
chartA.Name = textBox1.Text;
chartA.Legends.Add(legend); // <<---!
legend.Title = "Age of The Employees"; // <<---!
chartA.ChartAreas.Add(new ChartArea("ca")); // <<---!
chartA.ChartAreas["ca"].BackColor = Color.LightSeaGreen;
Series s1 = chartA.Series.Add("s1"); // <<---!
s1.ChartType = SeriesChartType.Pie;
s1.Points.AddY(12);
s1.Points.AddY(32);
..
The first Legend will automatically be filled with either one LegendItem per Series or (if you have a Pie chart) one item per DataPoint
Btw: You may have additional Legends but you will have to take care of their content and their position/docking..
Update: If you want to you can take control of both the Legend's Font and the TitleFont; It works the usual way, i.e. by creating a new Font, either from scratch of from the FontFamily of a Font:
legend.Font = new Font("Consolas", 10f);
legend.TitleFont = new Font(legend.Font.FontFamily, 14f);
You may want to insert a newline character (\n) into the title if it is too long to fit into a vertical Legend..

How to add spikes to line on Winform chart?

I am drawing a line on a graph from numbers read from a text file. There is a number on each line of the file which corresponds to the X co-ordinate while the Y co-ordinate is the line it is on.
The requirements have now changed to include "special events" where if the number on the line is followed by the word special a spike will appear like image below:
Currently the only way I can find is to use a line for each spike, however there could be a large of these special events and so needs to be modular. This seems an efficient and bad way to program it.
Is it possible to add the spikes to the same graph line? Or is it possible to use just one additional line and have it broken (invisible) and only show where the spikes are meant to be seen?
I have looked at using bar graphs but due to other items on the graph I cannot.
The DataPoints of a Line Chart are connected so it is not possble to really break it apart. However each segment leading to a DataPoint can have its own color and that includes Color.Transparent which lends itself to a simple trick..
Without adding extra Series or Annotations, your two questions can be solved like this:
To simply add the 'spikes' you show us in the 2nd graph, all you need to do is to insert 2 suitable datapoints, the 2nd being identical to the point the spike is connected to.
To add an unconnected line you need to 'jump' to its beginning by adding one extra point with a transparent color.
Here are two example methods:
void addSpike(Series s, int index, double spikeWidth)
{
DataPoint dp = s.Points[index];
DataPoint dp1 = new DataPoint(dp.XValue + spikeWidth, dp.YValues[0]);
s.Points.Insert(index+1, dp1);
s.Points.Insert(index+2, dp);
}
void addLine(Series s, int index, double spikeDist, double spikeWidth)
{
DataPoint dp = s.Points[index];
DataPoint dp1 = new DataPoint(dp.XValue + spikeDist, dp.YValues[0]);
DataPoint dp2 = new DataPoint(dp.XValue + spikeWidth, dp.YValues[0]);
DataPoint dp0 = dp.Clone();
dp1.Color = Color.Transparent;
dp2.Color = dp.Color;
dp2.BorderWidth = 2; // optional
dp0.Color = Color.Transparent;
s.Points.Insert(index + 1, dp1);
s.Points.Insert(index + 2, dp2);
s.Points.Insert(index + 3, dp0);
}
You can call them like this:
addSpike(chart1.Series[0], 3, 50d);
addLine(chart1.Series[0], 6, 30d, 80d);
Note that they add 2 or 3 DataPoints to the Points collection!
Of course you can set the Color and width (aka BorderWidth) of the extra lines as you wish and also include them in the params list..
If you want to keep the points collection unchanged you also can simply create one 'spikes series' and add the spike points there. The trick is to 'jump' to the new points with a transparent line!

How to change ILNumerics plot marker type?

I have set of random generated points in 3D Scene, and in runtime I want to change the type of point markers to, for example, triangles, as in the picture:
Is it possible? How can I achieve this? Also I need change color for some points.
Scene initialization code below:
ILArray<float> points = ILMath.tosingle(ILMath.randn(3, 1000));
var scene = new ILScene
{
new ILPlotCube(twoDMode: false)
{
new ILPoints
{
Positions = points,
Color = null,
Size = 2
}
}
};
Markers (ILMarker) and 'points' (ILPoints) are very different beasts. Markers are much more flexible configurable, mostly look nicer and are much more expensive to render. They commonly consist out of a border (line shape) and a filled area (triangles shape) and come with a number of predefined looks.
ILPoints on the other hand are designed to be fast and easy. one can easily create millions of points without decreasing the plotting performance. Don't try this with markers! But such points are what they are: filled circles. It's it. No borders, no different shapes.
However, if you want to give it a try - even for the 1000 points in your questions - you can do so. Just use an ILLinePlot instead and configure a marker for it. You may set the line color to Color.Empty to have the markers showing up alone.
new ILLinePlot(points, lineColor: Color.Empty, markerStyle: MarkerStyle.TriangleDown)
In order to get individual colors for individual point markers you would split your markers (points) up into individual set of points. Create an ILLinePlot for each set of points using the scheme described above.
The part of your question dealing with 'dynamic' is also easy: You can change the type of markers as well as any other property at runtime. Here is one simple example which toogles the markers between red triangle markers and white rectangle markers by clicking anywhere on the scene:
ilPanel1.Scene.MouseClick += (_s, _a) => {
if (_a.DirectionUp) return;
var lp = ilPanel1.Scene.First<ILLinePlot>();
if (lp != null) {
if (lp.Marker.Style == MarkerStyle.TriangleDown) {
lp.Marker.Style = MarkerStyle.Rectangle;
lp.Marker.Fill.Color = Color.White;
} else {
lp.Marker.Style = MarkerStyle.TriangleDown;
lp.Marker.Fill.Color = Color.Red;
}
lp.Configure();
ilPanel1.Refresh();
}
};

Labelling and circle a specific point in zedgraph

I am currently doing a project in which I've managed to identify the peak I want. However, I wanted to do more like circling the particular point with a label attached to it. Is it possible to do that in Zedgraph?
I've attached a snippet of my code which only include a text label to that point, and I wanted to do more so people will identify the point more easily.
PointPair pt = myCurve.Points[i-1];
const double offset = 0.8;
TextObj text = new TextObj("P", pt.X, pt.Y + offset,
CoordType.AxisXYScale, AlignH.Left, AlignV.Center);
text.ZOrder = ZOrder.A_InFront;
text.FontSpec.Border.IsVisible = false;
text.FontSpec.Fill.IsVisible = false;
text.FontSpec.Fill = new Fill( Color.FromArgb( 100, Color.White ) );
myPane.GraphObjList.Add(text);
Any help is appreciated! Thanks!
Make a LineItem as follows
LineItem line = new LineItem("Point", new double[] {pt.x}, new double[] {pt.y}, Color.Black, SymbolType.Circle);
line.Symbol.Size = 20;
line.Symbol.Fill = new Fill(Color.Transparent);
myPane.CurveList.Add(line);
This should create a large empty circle centered around your point. Obviously, you can adjust color and size as you see fit, and the ZOrder if you need to. You might want to adjust your legend so it doesn't include this point. Alternatively, you can name this line with your label and leave it in the legend as a way of tagging it. The only other way for a label is to do what you're doing, as I'm not sure of a way to associate labels directly to a line.

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