[Badge] Add new 'offsetAlignmentMode' attribute that determines where…

… the offset starts for the badge.

PiperOrigin-RevId: 505222416

docs/components/BadgeDrawable.md

@@ -90,12 +90,13 @@ center, use `setHoriziontalOffset(int)` or `setVerticalOffset(int)`
 
 ### `BadgeDrawable` Attributes
 
-Feature       | Relevant attributes
-------------- | -----------------------------------------------
-Color         | `app:backgroundColor` <br> `app:badgeTextColor`
-Label         | `app:number`
-Label Length  | `app:maxCharacterCount`
-Badge Gravity | `app:badgeGravity`
+Feature          | Relevant attributes
+---------------- | -----------------------------------------------
+Color            | `app:backgroundColor` <br> `app:badgeTextColor`
+Label            | `app:number`
+Label Length     | `app:maxCharacterCount`
+Badge Gravity    | `app:badgeGravity`
+Offset Alignment | `app:offsetAlignmentMode`
 
 ### Talkback Support
 

lib/java/com/google/android/material/badge/BadgeDrawable.java

@@ -155,6 +155,27 @@ public class BadgeDrawable extends Drawable implements TextDrawableDelegate {
    */
   static final String DEFAULT_EXCEED_MAX_BADGE_NUMBER_SUFFIX = "+";
 
+  /**
+   * The badge offset begins at the edge of the anchor.
+   */
+  static final int OFFSET_ALIGNMENT_MODE_EDGE = 0;
+
+  /**
+   * Follows the legacy offset alignment behavior. The horizontal offset begins at a variable
+   * permanent inset from the edge of the anchor, and the vertical offset begins at the center
+   * of the badge aligned with the edge of the anchor.
+   */
+  static final int OFFSET_ALIGNMENT_MODE_LEGACY = 1;
+
+  /**
+   * Determines where the badge offsets begin in reference to the anchor.
+   *
+   * @hide
+   */
+  @IntDef({OFFSET_ALIGNMENT_MODE_EDGE, OFFSET_ALIGNMENT_MODE_LEGACY})
+  @Retention(RetentionPolicy.SOURCE)
+  @interface OffsetAlignmentMode {}
+
   @NonNull private final WeakReference<Context> contextRef;
   @NonNull private final MaterialShapeDrawable shapeDrawable;
   @NonNull private final TextDrawableHelper textDrawableHelper;
@@ -168,6 +189,8 @@ public class BadgeDrawable extends Drawable implements TextDrawableDelegate {
   private float cornerRadius;
   private float halfBadgeWidth;
   private float halfBadgeHeight;
+  private final int horizontalInset;
+  private final int horizontalInsetWithText;
 
   // Need to keep a local reference in order to support updating badge gravity.
   @Nullable private WeakReference<View> anchorViewRef;
@@ -259,6 +282,16 @@ private BadgeDrawable(
 
     this.state = new BadgeState(context, badgeResId, defStyleAttr, defStyleRes, savedState);
 
+    horizontalInset =
+        context
+            .getResources()
+            .getDimensionPixelSize(R.dimen.mtrl_badge_horizontal_edge_offset);
+
+    horizontalInsetWithText =
+        context
+            .getResources()
+            .getDimensionPixelSize(R.dimen.mtrl_badge_text_horizontal_edge_offset);
+
     restoreState();
   }
 
@@ -867,7 +900,7 @@ private void updateCenterAndBounds() {
       viewGroup.offsetDescendantRectToMyCoords(anchorView, anchorRect);
     }
 
-    calculateCenterAndBounds(context, anchorRect, anchorView);
+    calculateCenterAndBounds(anchorRect, anchorView);
 
     updateBadgeBounds(badgeBounds, badgeCenterX, badgeCenterY, halfBadgeWidth, halfBadgeHeight);
 
@@ -880,18 +913,38 @@ private void updateCenterAndBounds() {
   private int getTotalVerticalOffsetForState() {
     int vOffset =
         hasNumber() ? state.getVerticalOffsetWithText() : state.getVerticalOffsetWithoutText();
+    // If the offset alignment mode is at the edge of the anchor, we want to move the badge
+    // so that its origin is at the edge.
+    if (state.offsetAlignmentMode == OFFSET_ALIGNMENT_MODE_EDGE) {
+      vOffset -= Math.round(halfBadgeHeight);
+    }
     return vOffset + state.getAdditionalVerticalOffset();
   }
 
   private int getTotalHorizontalOffsetForState() {
     int hOffset =
         hasNumber() ? state.getHorizontalOffsetWithText() : state.getHorizontalOffsetWithoutText();
+    // If the offset alignment mode is legacy, then we want to add the legacy inset to the offset.
+    if (state.offsetAlignmentMode == OFFSET_ALIGNMENT_MODE_LEGACY) {
+      hOffset += hasNumber() ? horizontalInsetWithText : horizontalInset;
+    }
     return hOffset + state.getAdditionalHorizontalOffset();
   }
 
-  private void calculateCenterAndBounds(
-      @NonNull Context context, @NonNull Rect anchorRect, @NonNull View anchorView) {
+  private void calculateCenterAndBounds(@NonNull Rect anchorRect, @NonNull View anchorView) {
+    if (getNumber() <= MAX_CIRCULAR_BADGE_NUMBER_COUNT) {
+      cornerRadius = !hasNumber() ? state.badgeRadius : state.badgeWithTextRadius;
+      halfBadgeHeight = cornerRadius;
+      halfBadgeWidth = cornerRadius;
+    } else {
+      cornerRadius = state.badgeWithTextRadius;
+      halfBadgeHeight = cornerRadius;
+      String badgeText = getBadgeText();
+      halfBadgeWidth = textDrawableHelper.getTextWidth(badgeText) / 2f + state.badgeWidePadding;
+    }
+
     int totalVerticalOffset = getTotalVerticalOffsetForState();
+
     switch (state.getBadgeGravity()) {
       case BOTTOM_END:
       case BOTTOM_START:
@@ -904,43 +957,24 @@ private void calculateCenterAndBounds(
         break;
     }
 
-    if (getNumber() <= MAX_CIRCULAR_BADGE_NUMBER_COUNT) {
-      cornerRadius = !hasNumber() ? state.badgeRadius : state.badgeWithTextRadius;
-      halfBadgeHeight = cornerRadius;
-      halfBadgeWidth = cornerRadius;
-    } else {
-      cornerRadius = state.badgeWithTextRadius;
-      halfBadgeHeight = cornerRadius;
-      String badgeText = getBadgeText();
-      halfBadgeWidth = textDrawableHelper.getTextWidth(badgeText) / 2f + state.badgeWidePadding;
-    }
-
-    int inset =
-        context
-            .getResources()
-            .getDimensionPixelSize(
-                hasNumber()
-                    ? R.dimen.mtrl_badge_text_horizontal_edge_offset
-                    : R.dimen.mtrl_badge_horizontal_edge_offset);
-
     int totalHorizontalOffset = getTotalHorizontalOffsetForState();
 
-    // Update the centerX based on the badge width and 'inset' from start or end boundary of anchor.
+    // Update the centerX based on the badge width and offset from start or end boundary of anchor.
     switch (state.getBadgeGravity()) {
       case BOTTOM_START:
       case TOP_START:
         badgeCenterX =
             ViewCompat.getLayoutDirection(anchorView) == View.LAYOUT_DIRECTION_LTR
-                ? anchorRect.left - halfBadgeWidth + inset + totalHorizontalOffset
-                : anchorRect.right + halfBadgeWidth - inset - totalHorizontalOffset;
+                ? anchorRect.left - halfBadgeWidth + totalHorizontalOffset
+                : anchorRect.right + halfBadgeWidth - totalHorizontalOffset;
         break;
       case BOTTOM_END:
       case TOP_END:
       default:
         badgeCenterX =
             ViewCompat.getLayoutDirection(anchorView) == View.LAYOUT_DIRECTION_LTR
-                ? anchorRect.right + halfBadgeWidth - inset - totalHorizontalOffset
-                : anchorRect.left - halfBadgeWidth + inset + totalHorizontalOffset;
+                ? anchorRect.right + halfBadgeWidth - totalHorizontalOffset
+                : anchorRect.left - halfBadgeWidth + totalHorizontalOffset;
         break;
     }
   }

lib/java/com/google/android/material/badge/BadgeState.java

@@ -19,6 +19,7 @@
 import com.google.android.material.R;
 
 import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;
+import static com.google.android.material.badge.BadgeDrawable.OFFSET_ALIGNMENT_MODE_LEGACY;
 import static com.google.android.material.badge.BadgeDrawable.TOP_END;
 
 import android.content.Context;
@@ -41,6 +42,7 @@
 import androidx.annotation.StyleableRes;
 import androidx.annotation.XmlRes;
 import com.google.android.material.badge.BadgeDrawable.BadgeGravity;
+import com.google.android.material.badge.BadgeDrawable.OffsetAlignmentMode;
 import com.google.android.material.drawable.DrawableUtils;
 import com.google.android.material.internal.ThemeEnforcement;
 import com.google.android.material.resources.MaterialResources;
@@ -71,6 +73,9 @@ public final class BadgeState {
   final float badgeWithTextRadius;
   final float badgeWidePadding;
 
+  @OffsetAlignmentMode
+  int offsetAlignmentMode;
+
   BadgeState(
       Context context,
       @XmlRes int badgeResId,
@@ -98,6 +103,8 @@ public final class BadgeState {
         a.getDimensionPixelSize(
             R.styleable.Badge_badgeWithTextRadius,
             res.getDimensionPixelSize(R.dimen.mtrl_badge_with_text_radius));
+    offsetAlignmentMode =
+        a.getInt(R.styleable.Badge_offsetAlignmentMode, OFFSET_ALIGNMENT_MODE_LEGACY);
 
     currentState.alpha = storedState.alpha == State.NOT_SET ? 255 : storedState.alpha;
 

lib/java/com/google/android/material/badge/res-public/values/public.xml

@@ -23,6 +23,7 @@
   <public name="badgeGravity" type="attr"/>
   <public name="horizontalOffset" type="attr"/>
   <public name="verticalOffset" type="attr"/>
+  <public name="offsetAlignmentMode" type="attr"/>
   <public name="Widget.MaterialComponents.Badge" type="style"/>
   <public name="Widget.Material3.Badge" type="style"/>
 </resources>

lib/java/com/google/android/material/badge/res/values/attrs.xml

@@ -42,6 +42,16 @@
       <enum name="BOTTOM_START" value ="8388691"/>
     </attr>
 
+    <!-- Determines where the badge offsets begin in reference to the anchor. -->
+    <attr name="offsetAlignmentMode">
+      <!-- The offsets begin at the edge of the anchor. -->
+      <enum name="edge" value="0"/>
+      <!-- Follows the legacy offset alignment behavior. The horizontal offset begins at a variable
+           permanent inset from the edge of the anchor, and the vertical offset begins at the center
+           of the badge aligned with the edge of the anchor. -->
+      <enum name="legacy" value="1"/>
+    </attr>
+
     <!-- Offsets the badge horizontally towards the center of its anchor when
         the badge doesn't have text (is a "dot"). Defaults to 0. -->
     <attr name="horizontalOffset" format="dimension"/>

lib/java/com/google/android/material/badge/res/values/styles.xml

@@ -23,6 +23,7 @@
     <item name="backgroundColor">?attr/colorError</item>
     <item name="maxCharacterCount">@integer/mtrl_badge_max_character_count</item>
     <item name="badgeGravity">TOP_END</item>
+    <item name="offsetAlignmentMode">legacy</item>
   </style>
 
   <style name="Base.TextAppearance.MaterialComponents.Badge" parent="TextAppearance.AppCompat">