# Documentation

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## Annotating Plots

This example shows how to use annotations to add additional information to MATLAB® plots.

### What are Annotations?

Annotations are extra information added to a graph to help identify important information. Annotation types include:

• line

• arrow

• doublearrow

• textarrow

• textbox

• ellipse

• rectangle

### Create Graph to Annotate

Define and plot functions `f(x)` and `g(x)`.

```x = -3.0:0.01:3.0; f = x.^2; g = 5*sin(x) + 5; figure plot(x, f, 'r-') % plot f(x) in red hold on plot(x, g, 'b-') % plot g(x) in blue ylim([-3 12])```

To create annotations, use the `annotation` function. For example, add textarrow annotations to the graph to indicate where the two functions are equal.

The first input to the function specifies the type of annotation you want to create. For textarrows, the second input is the starting and ending x positions of the arrow. The third input is the starting and ending y positions of the arrow.

Annotations use normalized figure units rather than data units from the axis. This allows annotations to span multiple axes in a figure.

```ta1 = annotation('textarrow', [0.33 0.39], [0.21 0.30]); % Create a textarrow annotation at the first point ta2 = annotation('textarrow', [0.76 0.84], [0.67 0.67]); % Create a textarrow annotation at the second point```

### Get Annotation Properties

Like all graphics objects, annotations have properties that you can view and modify. These properties have default values. The display of the annotation object `ta1` shows the most commonly used properties of a textarrow, such as the `LineWidth` and the `X` and `Y` positions.

`ta1`
```ta1 = TextArrow with properties: String: {''} FontName: 'Helvetica' FontSize: 10 Color: [0 0 0] TextColor: [0 0 0] LineStyle: '-' LineWidth: 0.5000 HeadStyle: 'vback2' Position: [0.3300 0.2100 0.0600 0.0900] Units: 'normalized' X: [0.3300 0.3900] Y: [0.2100 0.3000] Show all properties ```

To access individual properties, use dot notation syntax `object.PropertyName`. For example, return the `Color` property of the textarrow annotation.

`ta1.Color`
```ans = 0 0 0 ```

### Change Annotation Properties

To customize the look of your annotation, change its property values using dot notation.

```ta1.String = 'f(x) = g(x)'; % set the text for the first annotation ta1.HorizontalAlignment = 'center'; % center the text ta1.Color = [0.8 0 1]; % make the 'textarrow' purple ta2.String = 'f(x) = g(x)'; % set the text for the second annotation ta2.HorizontalAlignment = 'center'; % Center the text ta2.Color = [0.8 0 1]; % make the 'textarrow' purple```

### View All Annotation Properties

Annotations have many properties that you can use to modify their appearance and behavior. To see all the properties of an annotation object, use the `get` command:

`get(ta2)`
``` BeingDeleted: 'off' BusyAction: 'queue' ButtonDownFcn: '' Children: [0x0 GraphicsPlaceholder] Color: [0.8000 0 1] CreateFcn: '' DeleteFcn: '' FontAngle: 'normal' FontName: 'Helvetica' FontSize: 10 FontUnits: 'points' FontWeight: 'normal' HandleVisibility: 'on' HeadLength: 10 HeadStyle: 'vback2' HeadWidth: 10 HitTest: 'on' HorizontalAlignment: 'center' Interpreter: 'tex' Interruptible: 'on' LineStyle: '-' LineWidth: 0.5000 Parent: [1x1 AnnotationPane] PickableParts: 'visible' Position: [0.7600 0.6700 0.0800 0] Selected: 'off' SelectionHighlight: 'on' String: 'f(x) = g(x)' Tag: '' TextBackgroundColor: 'none' TextColor: [0.8000 0 1] TextEdgeColor: 'none' TextLineWidth: 0.5000 TextMargin: 2 TextRotation: 0 Type: 'textarrowshape' UIContextMenu: [0x0 GraphicsPlaceholder] Units: 'normalized' UserData: [] VerticalAlignment: 'middle' Visible: 'on' X: [0.7600 0.8400] Y: [0.6700 0.6700] ```