Merge branch 'develop' into bug/JAL-2346annotationChoice

[jalview.git] / src / jalview / renderer / seqfeatures / FeatureColourFinder.java

diff --git a/src/jalview/renderer/seqfeatures/FeatureColourFinder.java b/src/jalview/renderer/seqfeatures/FeatureColourFinder.java
new file mode 100644 (file)
index 0000000..1db2004
--- /dev/null
+++ b/src/jalview/renderer/seqfeatures/FeatureColourFinder.java
@@ -0,0 +1,124 @@
+package jalview.renderer.seqfeatures;
+
+import jalview.api.FeatureRenderer;
+import jalview.api.FeaturesDisplayedI;
+import jalview.datamodel.SequenceI;
+import jalview.viewmodel.seqfeatures.FeatureRendererModel;
+
+import java.awt.Color;
+import java.awt.Graphics;
+import java.awt.image.BufferedImage;
+
+/**
+ * A helper class to find feature colour using an associated FeatureRenderer
+ * 
+ * @author gmcarstairs
+ *
+ */
+public class FeatureColourFinder
+{
+  /*
+   * the class we delegate feature finding to
+   */
+  private FeatureRenderer featureRenderer;
+
+  /*
+   * a 1-pixel image on which features can be drawn, for the case where
+   * transparency allows 'see-through' of multiple feature colours
+   */
+  private BufferedImage offscreenImage;
+
+  /**
+   * Constructor
+   * 
+   * @param fr
+   */
+  public FeatureColourFinder(FeatureRenderer fr)
+  {
+    featureRenderer = fr;
+    offscreenImage = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
+  }
+
+  /**
+   * Answers the feature colour to show for the given sequence and column
+   * position. This delegates to the FeatureRenderer to find the colour, which
+   * will depend on feature location, visibility, ordering, colour scheme, and
+   * whether or not transparency is applied. For feature rendering with
+   * transparency, this class provides a dummy 'offscreen' graphics context
+   * where multiple feature colours can be overlaid and the combined colour read
+   * back.
+   * <p>
+   * This method is not thread-safe when transparency is applied, since a shared
+   * BufferedImage would be used by all threads to hold the composite colour at
+   * a position. Each thread should use a separate instance of this class.
+   * 
+   * @param defaultColour
+   * @param seq
+   * @param column
+   *          alignment column position (base zero)
+   * @return
+   */
+  public Color findFeatureColour(Color defaultColour, SequenceI seq,
+          int column)
+  {
+    if (noFeaturesDisplayed())
+    {
+      return defaultColour;
+    }
+
+    Graphics g = null;
+
+    /*
+     * if transparency applies, provide a notional 1x1 graphics context 
+     * that has been primed with the default colour
+     */
+    if (featureRenderer.getTransparency() != 1f)
+    {
+      g = offscreenImage.getGraphics();
+      if (defaultColour != null)
+      {
+        offscreenImage.setRGB(0, 0, defaultColour.getRGB());
+      }
+    }
+
+    Color c = featureRenderer.findFeatureColour(seq, column, g);
+    if (c == null)
+    {
+      return defaultColour;
+    }
+
+    if (g != null)
+    {
+      c = new Color(offscreenImage.getRGB(0, 0));
+    }
+    return c;
+  }
+
+  /**
+   * Answers true if feature display is turned off, or there are no features
+   * configured to be visible
+   * 
+   * @return
+   */
+  boolean noFeaturesDisplayed()
+  {
+    if (featureRenderer == null
+            || !featureRenderer.getViewport().isShowSequenceFeatures())
+    {
+      return true;
+    }
+
+    if (!((FeatureRendererModel) featureRenderer).hasRenderOrder())
+    {
+      return true;
+    }
+
+    FeaturesDisplayedI displayed = featureRenderer.getFeaturesDisplayed();
+    if (displayed == null || displayed.getVisibleFeatureCount() == 0)
+    {
+      return true;
+    }
+
+    return false;
+  }
+}