Show F-Droid blue in feature image place when loading icons.

Prior to this it was black, which looked broken. This also ensures that
the blue is shown behind the dynamic colour when it is time to ease in
that colour.

app/src/main/java/org/fdroid/fdroid/views/apps/FeatureImage.java

@@ -14,6 +14,7 @@ import android.os.Build;
 import android.support.annotation.ColorInt;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.v4.content.ContextCompat;
 import android.support.v7.graphics.Palette;
 import android.support.v7.widget.AppCompatImageView;
 import android.text.TextUtils;
@@ -25,6 +26,8 @@ import com.nostra13.universalimageloader.core.ImageLoader;
 import com.nostra13.universalimageloader.core.assist.FailReason;
 import com.nostra13.universalimageloader.core.listener.ImageLoadingListener;
 
+import org.fdroid.fdroid.R;
+
 import java.util.Random;
 
 /**
@@ -58,23 +61,34 @@ public class FeatureImage extends AppCompatImageView {
     @Nullable
     private Paint[] trianglePaints;
 
-    private static final Paint WHITE_PAINT = new Paint();
+    /**
-
+     * F-Droid blue is shown behind the animation which eases in the feature graphics. This is
-    static {
+     * preferable to showing white behind, which can be a bit harsh.
-        WHITE_PAINT.setColor(Color.WHITE);
+     */
-        WHITE_PAINT.setStyle(Paint.Style.FILL);
+    @ColorInt
-    }
+    private int baseColour;
 
     public FeatureImage(Context context) {
         super(context);
+        init(context);
     }
 
     public FeatureImage(Context context, @Nullable AttributeSet attrs) {
         super(context, attrs);
+        init(context);
     }
 
     public FeatureImage(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
+        init(context);
+    }
+
+    private void init(Context context) {
+        float[] hsv = new float[3];
+        Color.colorToHSV(ContextCompat.getColor(context, R.color.fdroid_blue), hsv);
+        hsv[1] *= 0.5f;
+        hsv[2] *= 0.7f;
+        baseColour = Color.HSVToColor(hsv);
     }
 
     /**
@@ -118,7 +132,10 @@ public class FeatureImage extends AppCompatImageView {
         for (int i = 0; i < trianglePaints.length; i++) {
             trianglePaints[i] = random.nextBoolean() ? paintOne : paintTwo;
         }
+    }
 
+    public void setColorAndAnimateChange(@ColorInt int colour) {
+        setColour(colour);
         animateColourChange();
     }
 
@@ -210,6 +227,7 @@ public class FeatureImage extends AppCompatImageView {
                 paint.setAlpha(currentAlpha);
             }
 
+            canvas.drawColor(baseColour);
             for (int i = 0; i < triangles.length; i++) {
                 canvas.drawPath(triangles[i], trianglePaints[i]);
             }
@@ -252,7 +270,7 @@ public class FeatureImage extends AppCompatImageView {
                         @Override
                         public void onGenerated(Palette palette) {
                             if (palette != null) {
-                                setColour(palette.getDominantColor(Color.LTGRAY));
+                                setColorAndAnimateChange(palette.getDominantColor(Color.LTGRAY));
                             }
                         }
                     });

app/src/main/java/org/fdroid/fdroid/views/categories/AppCardController.java

@@ -10,6 +10,7 @@ import android.support.annotation.IdRes;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.ActivityOptionsCompat;
+import android.support.v4.content.ContextCompat;
 import android.support.v4.util.Pair;
 import android.support.v7.graphics.Palette;
 import android.support.v7.widget.RecyclerView;
@@ -120,7 +121,7 @@ public class AppCardController extends RecyclerView.ViewHolder implements ImageL
         ImageLoader.getInstance().displayImage(app.iconUrl, icon, displayImageOptions, this);
 
         if (featuredImage != null) {
-            featuredImage.setColour(0);
+            featuredImage.setColour(ContextCompat.getColor(activity, R.color.fdroid_blue));
             featuredImage.setImageDrawable(null);
 
             // Note: We could call the convenience function loadImageAndDisplay(ImageLoader, DisplayImageOptions, String, String)
@@ -183,7 +184,7 @@ public class AppCardController extends RecyclerView.ViewHolder implements ImageL
             new Palette.Builder(loadedImage).generate(new Palette.PaletteAsyncListener() {
                 @Override
                 public void onGenerated(Palette palette) {
-                    featuredImage.setColour(palette.getDominantColor(Color.LTGRAY));
+                    featuredImage.setColorAndAnimateChange(palette.getDominantColor(Color.LTGRAY));
                 }
             });
         }