Use system foreground & background color in SubtitleWebView

PiperOrigin-RevId: 309244671

library/ui/src/main/java/com/google/android/exoplayer2/ui/HtmlUtils.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ui;
+
+import android.graphics.Color;
+import androidx.annotation.ColorInt;
+import com.google.android.exoplayer2.util.Util;
+
+/**
+ * Utility methods for generating HTML and CSS for use with {@link SubtitleWebView} and {@link
+ * SpannedToHtmlConverter}.
+ */
+/* package */ final class HtmlUtils {
+
+  private HtmlUtils() {}
+
+  public static String toCssRgba(@ColorInt int color) {
+    return Util.formatInvariant(
+        "rgba(%d,%d,%d,%.3f)",
+        Color.red(color), Color.green(color), Color.blue(color), Color.alpha(color) / 255.0);
+  }
+}

library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java

@@ -16,7 +16,6 @@
  */
 package com.google.android.exoplayer2.ui;
 
-import android.graphics.Color;
 import android.graphics.Typeface;
 import android.text.Html;
 import android.text.Spanned;
@@ -25,7 +24,6 @@ import android.text.style.ForegroundColorSpan;
 import android.text.style.StyleSpan;
 import android.text.style.UnderlineSpan;
 import android.util.SparseArray;
-import androidx.annotation.ColorInt;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.text.span.HorizontalTextInVerticalContextSpan;
 import com.google.android.exoplayer2.text.span.RubySpan;
@@ -125,11 +123,12 @@ import java.util.regex.Pattern;
     if (span instanceof ForegroundColorSpan) {
       ForegroundColorSpan colorSpan = (ForegroundColorSpan) span;
       return Util.formatInvariant(
-          "<span style='color:%s;'>", toCssColor(colorSpan.getForegroundColor()));
+          "<span style='color:%s;'>", HtmlUtils.toCssRgba(colorSpan.getForegroundColor()));
     } else if (span instanceof BackgroundColorSpan) {
       BackgroundColorSpan colorSpan = (BackgroundColorSpan) span;
       return Util.formatInvariant(
-          "<span style='background-color:%s;'>", toCssColor(colorSpan.getBackgroundColor()));
+          "<span style='background-color:%s;'>",
+          HtmlUtils.toCssRgba(colorSpan.getBackgroundColor()));
     } else if (span instanceof HorizontalTextInVerticalContextSpan) {
       return "<span style='text-combine-upright:all;'>";
     } else if (span instanceof StyleSpan) {
@@ -186,12 +185,6 @@ import java.util.regex.Pattern;
     return null;
   }
 
-  private static String toCssColor(@ColorInt int color) {
-    return Util.formatInvariant(
-        "rgba(%d,%d,%d,%.3f)",
-        Color.red(color), Color.green(color), Color.blue(color), Color.alpha(color) / 255.0);
-  }
-
   private static Transition getOrCreate(SparseArray<Transition> transitions, int key) {
     @Nullable Transition transition = transitions.get(key);
     if (transition == null) {

library/ui/src/main/java/com/google/android/exoplayer2/ui/SubtitleWebView.java

@@ -157,11 +157,14 @@ import java.util.List;
                 + "bottom:0;"
                 + "left:0;"
                 + "right:0;"
+                + "color:%s;"
                 + "font-size:%s;"
-                + "color:red;"
                 + "\">",
+            HtmlUtils.toCssRgba(style.foregroundColor),
             convertTextSizeToCss(defaultTextSizeType, defaultTextSize)));
 
+    String backgroundColorCss = HtmlUtils.toCssRgba(style.backgroundColor);
+
     for (int i = 0; i < cues.size(); i++) {
       Cue cue = cues.get(i);
       float positionPercent = (cue.position != Cue.DIMEN_UNSET) ? (cue.position * 100) : 50;
@@ -203,6 +206,9 @@ import java.util.List;
       String textAlign = convertAlignmentToCss(cue.textAlignment);
       String writingMode = convertVerticalTypeToCss(cue.verticalType);
       String cueTextSizeCssPx = convertTextSizeToCss(cue.textSizeType, cue.textSize);
+      String windowCssColor =
+          HtmlUtils.toCssRgba(
+              cue.windowColorSet && applyEmbeddedStyles ? cue.windowColor : style.windowColor);
 
       String positionProperty;
       String lineProperty;
@@ -244,6 +250,7 @@ import java.util.List;
                       + "text-align:%s;"
                       + "writing-mode:%s;"
                       + "font-size:%s;"
+                      + "background-color:%s;"
                       + "transform:translate(%s%%,%s%%);"
                       + "\">",
                   positionProperty,
@@ -255,9 +262,12 @@ import java.util.List;
                   textAlign,
                   writingMode,
                   cueTextSizeCssPx,
+                  windowCssColor,
                   horizontalTranslatePercent,
                   verticalTranslatePercent))
+          .append(Util.formatInvariant("<span style=\"background-color:%s;\">", backgroundColorCss))
           .append(SpannedToHtmlConverter.convert(cue.text))
+          .append("</span>")
           .append("</div>");
     }
 

library/ui/src/test/java/com/google/android/exoplayer2/ui/HtmlUtilsTest.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2.ui;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.graphics.Color;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Tests for {@link HtmlUtils}. */
+@RunWith(AndroidJUnit4.class)
+public class HtmlUtilsTest {
+
+  @Test
+  public void toCssRgba_exactAlpha() {
+    String cssRgba = HtmlUtils.toCssRgba(Color.argb(51, 13, 23, 37));
+    assertThat(cssRgba).isEqualTo("rgba(13,23,37,0.200)");
+  }
+
+  @Test
+  public void toCssRgba_truncatedAlpha() {
+    String cssRgba = HtmlUtils.toCssRgba(Color.argb(100, 13, 23, 37));
+    assertThat(cssRgba).isEqualTo("rgba(13,23,37,0.392)");
+  }
+}