Creating%20Custom%20Styles

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Learning Video Series Extending Map Suite
Lesson 2 Creating Custom Styles Learn the
basics of how to create your own custom styles
. Duration 45 minutes
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Agenda

• Answer the following questions.
• Why create custom styles?
• What are the important classes?
• What is required for a custom style?
• What overloads are recommended?
• Review a Custom Style.
• Review a Decision Based Custom Style.
• Review a caching Custom Style
• Answer additional questions.

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Why Create a Custom Style?

• Encapsulate custom logic.
• Draw styles based on time, scale or other
  values.
• Tweak our current styles.
• Adjust the look of roads for example.
• Integrating external data at runtime and
  caching.
• Cache values from expensive to retrieve sources.
• Composite existing styles.
• Create complex point styles.

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What are the Important Classes?

• GeoPen GeoBrush
• Used to draw on the GeoCanvas.
• Very similar to GDI pens brushes.
• Style
• Abstracts the look of your features.
• Provides a drawing API.
• Can be decision or drawing based.
• GeoCanvas
• A geographic drawing system.
• Provides APIs similar to that of GDI.

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What is Required for a Style?

• DrawCore()?
• This is the main drawing method of the style.
• You are responsible for drawing the features
  passed in on the GeoCanvas.
• This method can be chained to draw other styles.
• Important Caveats
• While this is the only required override you
  will find that there are a few other overloads
  that you should consider depending on what your
  style needs.

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What Overloads are Recommended?

• GetRequiredColumnNamesCore()?
• Provides a way to communicate to the rest of the
  framework what data columns you need to render
  your style.
• Note that if you are doing a composite style
  you will need to query your children as well.
• DrawSampleCore()
• Provides a sample image that can be used to
  create a legend.
• Some complex styles may find it difficult to
  provide this.

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Sample Code Overview

• The first sample shows how we can draw different
  sized points based on data from the feature.
• The second sample shows how we can choose
  different styles depending on time information in
  the feature.
• The third example shows how we can cache
  pre-known values to increase the speed of an
  existing ValueStyle

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Let's Look at Some Code! You can find the code
we will review in a zip file accompanying this
video on ThinkGeo.com. To compile the code it
requires you have installed a full or evaluation
edition of any Map Suite 3.0 product. You will
need to add the MapSuiteCore.DLL as a reference
in the project.
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Thank You For Watching! For More Samples and
Videos, Visit the Developers Blog Discussion Forum