[Magnifier-32] Do not magnify outside selection

Currently, for selection, if we move one handle towards the other, the
moving handle will stop when the selection becomes 1 character long.
However, the magnifier would continue to follow the finger after this,
no longer being helpful for the selection.

This CL fixes this, by replicating what happens when the magnifier
reaches the end of the line also for the case when it reaches the other
handle.

Bug: 72314536
Test: manual testing (both English and Arabic)
Test: atest FrameworksCoreTests:android.widget.TextViewActivityTest
Test: atest CtsWidgetTestCases:android.widget.cts.TextViewTest
Change-Id: I5bde622421c7fb8ecce0ea00f0d8d2af7aa72cf4
(cherry picked from commit 2d6b40b82151aec9ff13478cd5fb58f4ab3fcb7a)
Merged-In: I5bde622421c7fb8ecce0ea00f0d8d2af7aa72cf4

1 files changed, 34 insertions, 11 deletions

diff --git a/core/java/android/widget/Editor.java b/core/java/android/widget/Editor.java
index 27dd39b3224f..b1410f17c0ed 100644
--- a/core/java/android/widget/Editor.java
+++ b/core/java/android/widget/Editor.java
@@ -4660,16 +4660,23 @@ public class Editor {
 
             final int trigger = getMagnifierHandleTrigger();
             final int offset;
+            final int otherHandleOffset;
             switch (trigger) {
-                case MagnifierHandleTrigger.INSERTION: // Fall through.
+                case MagnifierHandleTrigger.INSERTION:
+                    offset = mTextView.getSelectionStart();
+                    otherHandleOffset = -1;
+                    break;
                 case MagnifierHandleTrigger.SELECTION_START:
                     offset = mTextView.getSelectionStart();
+                    otherHandleOffset = mTextView.getSelectionEnd();
                     break;
                 case MagnifierHandleTrigger.SELECTION_END:
                     offset = mTextView.getSelectionEnd();
+                    otherHandleOffset = mTextView.getSelectionStart();
                     break;
                 default:
                     offset = -1;
+                    otherHandleOffset = -1;
                     break;
             }
 
@@ -4679,22 +4686,38 @@ public class Editor {
 
             final Layout layout = mTextView.getLayout();
             final int lineNumber = layout.getLineForOffset(offset);
-
-            // Horizontally move the magnifier smoothly but clamp inside the current line.
+            // Compute whether the selection handles are currently on the same line, and,
+            // in this particular case, whether the selected text is right to left.
+            final boolean sameLineSelection = otherHandleOffset != -1
+                    && lineNumber == layout.getLineForOffset(otherHandleOffset);
+            final boolean rtl = sameLineSelection
+                    && (offset < otherHandleOffset)
+                        != (getHorizontal(mTextView.getLayout(), offset)
+                            < getHorizontal(mTextView.getLayout(), otherHandleOffset));
+
+            // Horizontally move the magnifier smoothly, clamp inside the current line / selection.
             final int[] textViewLocationOnScreen = new int[2];
             mTextView.getLocationOnScreen(textViewLocationOnScreen);
             final float touchXInView = event.getRawX() - textViewLocationOnScreen[0];
-            final float lineLeft = mTextView.getLayout().getLineLeft(lineNumber)
-                    + mTextView.getTotalPaddingLeft() - mTextView.getScrollX();
-            final float lineRight = mTextView.getLayout().getLineRight(lineNumber)
-                    + mTextView.getTotalPaddingLeft() - mTextView.getScrollX();
+            float leftBound = mTextView.getTotalPaddingLeft() - mTextView.getScrollX();
+            float rightBound = mTextView.getTotalPaddingLeft() - mTextView.getScrollX();
+            if (sameLineSelection && ((trigger == MagnifierHandleTrigger.SELECTION_END) ^ rtl)) {
+                leftBound += getHorizontal(mTextView.getLayout(), otherHandleOffset);
+            } else {
+                leftBound += mTextView.getLayout().getLineLeft(lineNumber);
+            }
+            if (sameLineSelection && ((trigger == MagnifierHandleTrigger.SELECTION_START) ^ rtl)) {
+                rightBound += getHorizontal(mTextView.getLayout(), otherHandleOffset);
+            } else {
+                rightBound += mTextView.getLayout().getLineRight(lineNumber);
+            }
             final float contentWidth = Math.round(mMagnifier.getWidth() / mMagnifier.getZoom());
-            if (touchXInView < lineLeft - contentWidth / 2
-                    || touchXInView > lineRight + contentWidth / 2) {
-                // The touch is too out of the bounds of the current line, so hide the magnifier.
+            if (touchXInView < leftBound - contentWidth / 2
+                    || touchXInView > rightBound + contentWidth / 2) {
+                // The touch is too far from the current line / selection, so hide the magnifier.
                 return false;
             }
-            showPosInView.x = Math.max(lineLeft, Math.min(lineRight, touchXInView));
+            showPosInView.x = Math.max(leftBound, Math.min(rightBound, touchXInView));
 
             // Vertically snap to middle of current line.
             showPosInView.y = (mTextView.getLayout().getLineTop(lineNumber)