Eclipse plugin: Custom icon for a Marker

Question

I want to specify a custom icon for a marker. Sadly, the icon that I chose is not displayed.

Here's the relevant parts of the plugin.xml file (the project id "x"):

<extension
      id="xmlProblem"
      name="XML Problem"
      point="org.eclipse.core.resources.markers">
   <super type="org.eclipse.core.resources.problemmarker"/>
   <persistent
         value="true">
   </persistent>
</extension>

<extension
      point="org.eclipse.ui.ide.markerImageProviders">
   <imageprovider
         markertype="x.xmlProblem"
         icon="icons/marker.png"
         id="xmlProblemImageProvider">
   </imageprovider>
</extension>

I also tried specifying a class (implementing IMarkerImageProvider) instead of an icon, but that getImagePath() method of the class does not get called.

Any thoughts on how to make custom marker icons work?

Desperately, yours.

-Itay

Update

VonC's solution is pretty much correct, except that you must not specify org.eclipse.core.resources.problemmarker as a supertype of your marker. It worked only when I used org.eclipse.core.resources.textmarker as the only supertype.

Answer 1

See bug 260909 "markerImageProviders extension point does not work" (found after reading this thread)

Tod Creasey 2009-01-21 07:32:38 EST

We have never had the push to make this API because it has some inflexibility that made it generally not consumable - it was written early on to enable the first marker views for the 3 severities we use and as a result was not used by the markerSupport as it was not API.

It is confusing that we have an internal extension point (we don't generally do that) but removing it would likely break someone without warning.

[EDIT by Itay]

Following on Vonc's pointers, I eventually managed to make this thing work. Here are the relevant fragments from my plugin.xml (assuming the plugin name is a.b.c)

  <extension point="org.eclipse.core.resources.markers"   
        id="myMarker">
     <super type="org.eclipse.core.resources.textmarker"/>         
     <persistent value="true"/>
  </extension>

  <extension point="org.eclipse.ui.editors.annotationTypes">
     <type
        super="org.eclipse.ui.workbench.texteditor.warning"
        markerType="a.b.c.myMarker"
        name="a.b.c.myAnnotation"
        markerSeverity="1"/>
  </extension>

  <extension point="org.eclipse.ui.editors.markerAnnotationSpecification">
     <specification
        annotationType="a.b.c.myAnnotation"
        icon="icons/marker.png"
        verticalRulerPreferenceKey="myMarkerIndicationInVerticalRuler"
        verticalRulerPreferenceValue="true"/>
  </extension>

Pitfalls

• The super type of the marker must be set to org.eclipse.core.resources.textmarker. Any other value will prevent your custom icon from being used.
• When you create a marker in your code make sure its severity matches the severity value specified in the markerSeverity attribute at the org.eclipse.ui.editors.annotationTypes extension point. 1 means warning, etc.
• Make sure the icons folder is specified in your build.properties file (or the "build" tab at the plugin editor)
• The declaration above will only specify a custom icon. If you want to customize other attributes (color of indication at the overview ruler, etc.) follow the sample from here on which this solution is based.