[Magnifier - 4] Batch of tweaks

* magnifier zoom from 1.5 to 1.25
* max scale from 10 to 4
* magnifier shows over the text if there is no more space above
  instead of showing underneath the cursor
* paused the blink while showing the magnifier and resumed when
  dismissing

Bug: 63531115
Test: bit FrameworksCoreTests:android.widget.TextViewActivityTest
Test: bit CtsWidgetTestCases:android.widget.cts.TextViewTest
Test: manual test that shows the magnifier working
Change-Id: Ief3e0b7dc9e287e7dd1a9102548b1861598b69c4

core/java/android/widget/Editor.java

@@ -165,7 +165,7 @@ public class Editor {
     private static final int MENU_ITEM_ORDER_PASTE_AS_PLAIN_TEXT = 11;
     private static final int MENU_ITEM_ORDER_PROCESS_TEXT_INTENT_ACTIONS_START = 100;
 
-    private static final float MAGNIFIER_ZOOM = 1.5f;
+    private static final float MAGNIFIER_ZOOM = 1.25f;
     @IntDef({MagnifierHandleTrigger.SELECTION_START,
             MagnifierHandleTrigger.SELECTION_END,
             MagnifierHandleTrigger.INSERTION})
@@ -4550,12 +4550,14 @@ public class Editor {
             final float centerYOnScreen = yPosInView + mTextView.getTotalPaddingTop()
                     - mTextView.getScrollY() + coordinatesOnScreen[1];
 
+            suspendBlink();
             mMagnifier.show(centerXOnScreen, centerYOnScreen, MAGNIFIER_ZOOM);
         }
 
         protected final void dismissMagnifier() {
             if (mMagnifier != null) {
                 mMagnifier.dismiss();
+                resumeBlink();
             }
         }
 

core/java/com/android/internal/widget/Magnifier.java

@@ -41,6 +41,8 @@ import com.android.internal.util.Preconditions;
  */
 public final class Magnifier {
     private static final String LOG_TAG = "magnifier";
+    private static final int MINIMUM_MAGNIFIER_SCALE = 1;
+    private static final int MAXIMUM_MAGNIFIER_SCALE = 4;
     // The view for which this magnifier is attached.
     private final View mView;
     // The window containing the magnifier.
@@ -94,7 +96,23 @@ public final class Magnifier {
      */
     public void show(@FloatRange(from=0) float centerXOnScreen,
             @FloatRange(from=0) float centerYOnScreen,
-            @FloatRange(from=1, to=10) float scale) {
+            @FloatRange(from=MINIMUM_MAGNIFIER_SCALE, to=MAXIMUM_MAGNIFIER_SCALE) float scale) {
+        if (scale > MAXIMUM_MAGNIFIER_SCALE) {
+            scale = MAXIMUM_MAGNIFIER_SCALE;
+        }
+
+        if (scale < MINIMUM_MAGNIFIER_SCALE) {
+            scale = MINIMUM_MAGNIFIER_SCALE;
+        }
+
+        if (centerXOnScreen < 0) {
+            centerXOnScreen = 0;
+        }
+
+        if (centerYOnScreen < 0) {
+            centerYOnScreen = 0;
+        }
+
         maybeResizeBitmap(scale);
         configureCoordinates(centerXOnScreen, centerYOnScreen);
         performPixelCopy();
@@ -144,12 +162,8 @@ public final class Magnifier {
 
         final int verticalMagnifierOffset = mView.getContext().getResources().getDimensionPixelSize(
                 R.dimen.magnifier_offset);
-        final int availableTopSpace = (mCenterZoomCoords.y - mWindowHeight / 2)
-                - verticalMagnifierOffset - (mBitmap.getHeight() / 2);
-
         mWindowCoords.x = mCenterZoomCoords.x - mWindowWidth / 2;
-        mWindowCoords.y = mCenterZoomCoords.y - mWindowHeight / 2
-                + verticalMagnifierOffset * (availableTopSpace > 0 ? -1 : 1);
+        mWindowCoords.y = mCenterZoomCoords.y - mWindowHeight / 2 - verticalMagnifierOffset;
     }
 
     private void performPixelCopy() {