Workaround AndroidX bug

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

@@ -35,7 +35,11 @@ import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.res.ColorStateList;
 import android.database.Cursor;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.ColorFilter;
+import android.graphics.ColorMatrix;
 import android.graphics.ColorMatrixColorFilter;
 import android.graphics.Paint;
 import android.graphics.Rect;
@@ -1392,26 +1396,44 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
             // For performance reasons the WebView is created when needed only
             if (!(vwBody instanceof WebView)) {
                 WebView webView = new WebView(context) {
+                    private Bitmap bm;
+                    private Canvas cc;
+                    private Paint paint = new Paint();
+                    private ColorFilter cf = new ColorMatrixColorFilter(new ColorMatrix(Helper.NEGATIVE));
+
                     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
                         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
                         int height = getMeasuredHeight();
                         if (height < tvBody.getMinHeight())
                             setMeasuredDimension(getMeasuredWidth(), tvBody.getMinHeight());
                     }
-                };
 
+                    @Override
+                    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
+                        super.onSizeChanged(w, h, oldw, oldh);
+                        bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
+                        cc = new Canvas(bm);
+                    }
+
+                    @Override
+                    protected void onDraw(Canvas canvas) {
                         if (dark) {
-                    float[] NEGATIVE = new float[]{
+                            super.onDraw(cc);
-                            -1, 0, 0, 0, 255, // red
+                            paint.setColorFilter(cf);
-                            0, -1, 0, 0, 255, // green
+                            canvas.drawBitmap(bm, 0, 0, paint);
-                            0, 0, -1, 0, 255, // blue
+                        } else
-                            0, 0, 0, 1, 0 // alpha
+                            super.onDraw(canvas);
+                    }
                 };
 
+                /*
+                // https://bugs.chromium.org/p/chromium/issues/detail?id=578150
+                if (dark) {
                     Paint paint = new Paint();
-                    paint.setColorFilter(new ColorMatrixColorFilter(NEGATIVE));
+                    paint.setColorFilter(new ColorMatrixColorFilter(Helper.NEGATIVE));
                     webView.setLayerType(View.LAYER_TYPE_HARDWARE, paint);
                 }
+                */
 
                 webView.setWebViewClient(new WebViewClient() {
                     public boolean shouldOverrideUrlLoading(WebView view, String url) {

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

@@ -132,6 +132,13 @@ public class Helper {
 
     static final float LOW_LIGHT = 0.6f;
 
+    static final float[] NEGATIVE = new float[]{
+            -1, 0, 0, 0, 255, // red
+            0, -1, 0, 0, 255, // green
+            0, 0, -1, 0, 255, // blue
+            0, 0, 0, 1, 0 // alpha
+    };
+
     static final String FAQ_URI = "https://github.com/M66B/open-source-email/blob/master/FAQ.md";
 
     static ThreadFactory backgroundThreadFactory = new ThreadFactory() {