Fixed task icon color

app/src/main/java/eu/faircode/email/ActivityBase.java

@@ -339,16 +339,6 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
         prefs.registerOnSharedPreferenceChangeListener(this);
 
         try {
-            Drawable d = getDrawable(R.drawable.baseline_mail_24);
-            Bitmap bm = Bitmap.createBitmap(
-                    d.getIntrinsicWidth(),
-                    d.getIntrinsicHeight(),
-                    Bitmap.Config.ARGB_8888);
-            Canvas canvas = new Canvas(bm);
-            d.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
-            d.setTint(Color.WHITE);
-            d.draw(canvas);
-
             boolean task_description = prefs.getBoolean("task_description", true);
             int colorPrimary = (task_description
                     ? Helper.resolveColor(this, androidx.appcompat.R.attr.colorPrimaryDark)
@@ -358,6 +348,18 @@ abstract class ActivityBase extends AppCompatActivity implements SharedPreferenc
                 colorPrimary = ColorUtils.setAlphaComponent(colorPrimary, 255);
             }
 
+            double lum = ColorUtils.calculateLuminance(colorPrimary);
+
+            Drawable d = getDrawable(R.drawable.baseline_mail_24);
+            Bitmap bm = Bitmap.createBitmap(
+                    d.getIntrinsicWidth(),
+                    d.getIntrinsicHeight(),
+                    Bitmap.Config.ARGB_8888);
+            Canvas canvas = new Canvas(bm);
+            d.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
+            d.setTint(lum > LUMINANCE_THRESHOLD ? Color.BLACK : Color.WHITE);
+            d.draw(canvas);
+
             ActivityManager.TaskDescription td = new ActivityManager.TaskDescription(
                     null, bm, colorPrimary);
             setTaskDescription(td);