svn - r34323 - trunk/spike/web/sphinx/source/
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svn_geotools
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Author: mbedward
Date: 2009-11-04 07:24:34 -0500 (Wed, 04 Nov 2009) New Revision: 34323 Added: trunk/spike/web/sphinx/source/examples/stylefunctionlab.rst Modified: trunk/spike/web/sphinx/source/examples/index.rst Log: New Style Function Lab page for examples - not finished Modified: trunk/spike/web/sphinx/source/examples/index.rst =================================================================== --- trunk/spike/web/sphinx/source/examples/index.rst 2009-11-04 12:17:11 UTC (rev 34322) +++ trunk/spike/web/sphinx/source/examples/index.rst 2009-11-04 12:24:34 UTC (rev 34323) @@ -10,5 +10,6 @@ crslab querylab stylelab + stylefunctionlab imagelab selectionlab Added: trunk/spike/web/sphinx/source/examples/stylefunctionlab.rst =================================================================== --- trunk/spike/web/sphinx/source/examples/stylefunctionlab.rst (rev 0) +++ trunk/spike/web/sphinx/source/examples/stylefunctionlab.rst 2009-11-04 12:24:34 UTC (rev 34323) @@ -0,0 +1,114 @@ +.. _stylefunctionlab: + +Style Function Lab +================== + +In :ref:`stylelab` we showed how to create simple rendering styles for features. In this lab we are going to +look at a slightly more complex example: displaying a shapfile with a style that uses a colour lookup table indexed +by the values of a chosen feature attribute. + +This lab uses GeoTools version 2.6.0 + +Dependencies +------------ + +Please ensure your pom.xml includes the following:: + + <dependencies> + <dependency> + <groupId>org.geotools</groupId> + <artifactId>gt-shapefile</artifactId> + <version>${geotools.version}</version> + </dependency> + <dependency> + <groupId>org.geotools</groupId> + <artifactId>gt-epsg-hsql</artifactId> + <version>${geotools.version}</version> + </dependency> + <dependency> + <groupId>org.geotools</groupId> + <artifactId>gt-swing</artifactId> + <version>${geotools.version}</version> + </dependency> + <dependency> + <groupId>org.geotools</groupId> + <artifactId>gt-render</artifactId> + <version>${geotools.version}</version> + <!-- For this module we explicitly exclude some of its own --> + <!-- dependencies from being downloaded because they are --> + <!-- big and we don't need them --> + <exclusions> + <exclusion> + <groupId>org.apache.xmlgraphics</groupId> + <artifactId>batik-transcoder</artifactId> + </exclusion> + </exclusions> + </dependency> + </dependencies> + +You can set the *geotools.version* property somewhere near the top of your pom.xml (see the :ref:`quickstart` if you're not sure how to do this). + +Example +------- + +The example code is available + * Directly from svn: StyleFunctionLab.java_ + * Included in the demo directory when you download the GeoTools source code + +.. _StyleFunctionLab.java: http://svn.osgeo.org/geotools/trunk/demo/example/src/main/java/org/geotools/demo/StyleFunctionLab.java + +Main application and display method +----------------------------------- + +Please create the file **StyleFunctionLab.java** then copy and paste in the following code: + + .. literalinclude:: ../../../../../demo/example/src/main/java/org/geotools/demo/StyleFunctionLab.java + :language: java + :start-after: // docs start source + :end-before: // docs end display + +If you worked through the :ref:`stylelab` most of this code will be *deja vu*. The only change is that we're now prompting the user to +select a feature attribute and passing the name of this to a new **createStyle** method. Let's look at that method now. + +Creating a dynamic Style +------------------------ + + .. literalinclude:: ../../../../../demo/example/src/main/java/org/geotools/demo/StyleFunctionLab.java + :language: java + :start-after: // docs start create style + :end-before: // docs end create style + +In :ref:`stylelab` we created Fill and Stroke objects with *literal* (ie. constant) expressions like this: + +.. sourcecode:: java + + // create a partially opaque outline stroke + Stroke stroke = styleFactory.createStroke( + filterFactory.literal(Color.BLUE), + filterFactory.literal(1), + filterFactory.literal(0.5)); + + // create a partial opaque fill + Fill fill = styleFactory.createFill( + filterFactory.literal(Color.CYAN), + filterFactory.literal(0.5)); + +But in the method above, we've replaced the constant colour expressions with a reference to the filter function **ColorLookupFunction** to make +feature colours dynamic, ie. each feature will be coloured based on its value for the selected attribute. + +The custom filter function +-------------------------- + +GeoTools provides a huge selection of filter functions that can be used not only to control all aspects of display but also to query feature +data in complex ways. This topic will be explored further in some of the other Labs. + +Meanwhile, we're going to look at how to create a custom function that GeoTools will call to provide colours as it draws each feature in the +shapefile. Here is the function code: + + .. literalinclude:: ../../../../../demo/example/src/main/java/org/geotools/demo/StyleFunctionLab.java + :language: java + :start-after: // docs start function + :end-before: // docs end source + +*To be continued...* + ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ GeoTools-commits mailing list [hidden email] https://lists.sourceforge.net/lists/listinfo/geotools-commits |
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