Implement fallback line spacing for BoringLayout

The fallback line spacing is a feature of extending the line height
when the fallback font has taller glyph. This was implemented to
StaticLayout in Android P but not yet implemented in BoringLayout.

This CL enables this feature to the BoringLayout as well.

Not to break existing apps, change this behavior only if the
targetSdk version is T or later.

Bug: 210923482
Test: atest FallbackLineSpacingTest BoringLayoutFallbackLineSpacingTest
Test: atest CtsGraphicsTestCases
Test: atest CtsTextTestCases
Change-Id: I6214d52cde25a044bc6e246d2118e35d3a243c9d

1 files changed, 67 insertions, 14 deletions

diff --git a/core/java/android/widget/TextView.java b/core/java/android/widget/TextView.java
index 014340197393..7327214c5389 100644
--- a/core/java/android/widget/TextView.java
+++ b/core/java/android/widget/TextView.java
@@ -48,6 +48,9 @@ import android.annotation.XmlRes;
 import android.app.Activity;
 import android.app.PendingIntent;
 import android.app.assist.AssistStructure;
+import android.app.compat.CompatChanges;
+import android.compat.annotation.ChangeId;
+import android.compat.annotation.EnabledSince;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.content.ClipData;
 import android.content.ClipDescription;
@@ -453,6 +456,22 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
     private static final int FLOATING_TOOLBAR_SELECT_ALL_REFRESH_DELAY = 500;
 
+    /**
+     * This change ID enables the fallback text line spacing (line height) for BoringLayout.
+     * @hide
+     */
+    @ChangeId
+    @EnabledSince(targetSdkVersion = Build.VERSION_CODES.TIRAMISU)
+    public static final long BORINGLAYOUT_FALLBACK_LINESPACING = 210923482L; // buganizer id
+
+    /**
+     * This change ID enables the fallback text line spacing (line height) for StaticLayout.
+     * @hide
+     */
+    @ChangeId
+    @EnabledSince(targetSdkVersion = Build.VERSION_CODES.P)
+    public static final long STATICLAYOUT_FALLBACK_LINESPACING = 37756858; // buganizer id
+
     // System wide time for last cut, copy or text changed action.
     static long sLastCutCopyOrTextChangedTime;
 
@@ -766,8 +785,13 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
     private boolean mListenerChanged = false;
     // True if internationalized input should be used for numbers and date and time.
     private final boolean mUseInternationalizedInput;
-    // True if fallback fonts that end up getting used should be allowed to affect line spacing.
-    /* package */ boolean mUseFallbackLineSpacing;
+
+    // Fallback fonts that end up getting used should be allowed to affect line spacing.
+    private static final int FALLBACK_LINE_SPACING_NONE = 0;
+    private static final int FALLBACK_LINE_SPACING_STATIC_LAYOUT_ONLY = 1;
+    private static final int FALLBACK_LINE_SPACING_ALL = 2;
+
+    private int mUseFallbackLineSpacing;
     // True if the view text can be padded for compat reasons, when the view is translated.
     private final boolean mUseTextPaddingForUiTranslation;
 
@@ -1479,7 +1503,13 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
         final int targetSdkVersion = context.getApplicationInfo().targetSdkVersion;
         mUseInternationalizedInput = targetSdkVersion >= VERSION_CODES.O;
-        mUseFallbackLineSpacing = targetSdkVersion >= VERSION_CODES.P;
+        if (CompatChanges.isChangeEnabled(BORINGLAYOUT_FALLBACK_LINESPACING)) {
+            mUseFallbackLineSpacing = FALLBACK_LINE_SPACING_ALL;
+        } else if (CompatChanges.isChangeEnabled(STATICLAYOUT_FALLBACK_LINESPACING)) {
+            mUseFallbackLineSpacing = FALLBACK_LINE_SPACING_STATIC_LAYOUT_ONLY;
+        } else {
+            mUseFallbackLineSpacing = FALLBACK_LINE_SPACING_NONE;
+        }
         // TODO(b/179693024): Use a ChangeId instead.
         mUseTextPaddingForUiTranslation = targetSdkVersion <= Build.VERSION_CODES.R;
 
@@ -4541,8 +4571,18 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
      * @attr ref android.R.styleable#TextView_fallbackLineSpacing
      */
     public void setFallbackLineSpacing(boolean enabled) {
-        if (mUseFallbackLineSpacing != enabled) {
-            mUseFallbackLineSpacing = enabled;
+        int fallbackStrategy;
+        if (enabled) {
+            if (CompatChanges.isChangeEnabled(BORINGLAYOUT_FALLBACK_LINESPACING)) {
+                fallbackStrategy = FALLBACK_LINE_SPACING_ALL;
+            } else {
+                fallbackStrategy = FALLBACK_LINE_SPACING_STATIC_LAYOUT_ONLY;
+            }
+        } else {
+            fallbackStrategy = FALLBACK_LINE_SPACING_NONE;
+        }
+        if (mUseFallbackLineSpacing != fallbackStrategy) {
+            mUseFallbackLineSpacing = fallbackStrategy;
             if (mLayout != null) {
                 nullLayouts();
                 requestLayout();
@@ -4560,7 +4600,17 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
      */
     @InspectableProperty
     public boolean isFallbackLineSpacing() {
-        return mUseFallbackLineSpacing;
+        return mUseFallbackLineSpacing != FALLBACK_LINE_SPACING_NONE;
+    }
+
+    private boolean isFallbackLineSpacingForBoringLayout() {
+        return mUseFallbackLineSpacing == FALLBACK_LINE_SPACING_ALL;
+    }
+
+    // Package privte for accessing from Editor.java
+    /* package */ boolean isFallbackLineSpacingForStaticLayout() {
+        return mUseFallbackLineSpacing == FALLBACK_LINE_SPACING_ALL
+                || mUseFallbackLineSpacing == FALLBACK_LINE_SPACING_STATIC_LAYOUT_ONLY;
     }
 
     /**
@@ -9148,7 +9198,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
 
             if (hintBoring == UNKNOWN_BORING) {
                 hintBoring = BoringLayout.isBoring(mHint, mTextPaint, mTextDir,
-                                                   mHintBoring);
+                        isFallbackLineSpacingForBoringLayout(), mHintBoring);
                 if (hintBoring != null) {
                     mHintBoring = hintBoring;
                 }
@@ -9190,7 +9240,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                         .setTextDirection(mTextDir)
                         .setLineSpacing(mSpacingAdd, mSpacingMult)
                         .setIncludePad(mIncludePad)
-                        .setUseLineSpacingFromFallbacks(mUseFallbackLineSpacing)
+                        .setUseLineSpacingFromFallbacks(isFallbackLineSpacingForStaticLayout())
                         .setBreakStrategy(mBreakStrategy)
                         .setHyphenationFrequency(mHyphenationFrequency)
                         .setJustificationMode(mJustificationMode)
@@ -9250,7 +9300,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                     .setTextDirection(mTextDir)
                     .setLineSpacing(mSpacingAdd, mSpacingMult)
                     .setIncludePad(mIncludePad)
-                    .setUseLineSpacingFromFallbacks(mUseFallbackLineSpacing)
+                    .setUseLineSpacingFromFallbacks(isFallbackLineSpacingForStaticLayout())
                     .setBreakStrategy(mBreakStrategy)
                     .setHyphenationFrequency(mHyphenationFrequency)
                     .setJustificationMode(mJustificationMode)
@@ -9259,7 +9309,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             result = builder.build();
         } else {
             if (boring == UNKNOWN_BORING) {
-                boring = BoringLayout.isBoring(mTransformed, mTextPaint, mTextDir, mBoring);
+                boring = BoringLayout.isBoring(mTransformed, mTextPaint, mTextDir,
+                        isFallbackLineSpacingForBoringLayout(), mBoring);
                 if (boring != null) {
                     mBoring = boring;
                 }
@@ -9303,7 +9354,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                     .setTextDirection(mTextDir)
                     .setLineSpacing(mSpacingAdd, mSpacingMult)
                     .setIncludePad(mIncludePad)
-                    .setUseLineSpacingFromFallbacks(mUseFallbackLineSpacing)
+                    .setUseLineSpacingFromFallbacks(isFallbackLineSpacingForStaticLayout())
                     .setBreakStrategy(mBreakStrategy)
                     .setHyphenationFrequency(mHyphenationFrequency)
                     .setJustificationMode(mJustificationMode)
@@ -9430,7 +9481,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
             }
 
             if (des < 0) {
-                boring = BoringLayout.isBoring(mTransformed, mTextPaint, mTextDir, mBoring);
+                boring = BoringLayout.isBoring(mTransformed, mTextPaint, mTextDir,
+                        isFallbackLineSpacingForBoringLayout(), mBoring);
                 if (boring != null) {
                     mBoring = boring;
                 }
@@ -9463,7 +9515,8 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                 }
 
                 if (hintDes < 0) {
-                    hintBoring = BoringLayout.isBoring(mHint, mTextPaint, mTextDir, mHintBoring);
+                    hintBoring = BoringLayout.isBoring(mHint, mTextPaint, mTextDir,
+                            isFallbackLineSpacingForBoringLayout(), mHintBoring);
                     if (hintBoring != null) {
                         mHintBoring = hintBoring;
                     }
@@ -9667,7 +9720,7 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         layoutBuilder.setAlignment(getLayoutAlignment())
                 .setLineSpacing(getLineSpacingExtra(), getLineSpacingMultiplier())
                 .setIncludePad(getIncludeFontPadding())
-                .setUseLineSpacingFromFallbacks(mUseFallbackLineSpacing)
+                .setUseLineSpacingFromFallbacks(isFallbackLineSpacingForStaticLayout())
                 .setBreakStrategy(getBreakStrategy())
                 .setHyphenationFrequency(getHyphenationFrequency())
                 .setJustificationMode(getJustificationMode())