Merge "Scale down the widget previews on similar scale as the spring load scale" into main
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 2741158..aa83c01 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -320,6 +320,8 @@
     <dimen name="bg_popup_item_height">52dp</dimen>
     <dimen name="bg_popup_item_vertical_padding">12dp</dimen>
     <dimen name="pre_drag_view_scale">6dp</dimen>
+    <!-- Minimum size of the widget dragged view to keep it visible under the finger. -->
+    <dimen name="widget_drag_view_min_scale_down_size">70dp</dimen>
     <!-- an icon with shortcuts must be dragged this far before the container is removed. -->
     <dimen name="deep_shortcuts_start_drag_threshold">16dp</dimen>
     <!-- Possibly related to b/235886078, icon needs to be scaled up to match expected visual size of 32 dp -->
diff --git a/src/com/android/launcher3/dragndrop/LauncherDragController.java b/src/com/android/launcher3/dragndrop/LauncherDragController.java
index f3708a2..29fc613 100644
--- a/src/com/android/launcher3/dragndrop/LauncherDragController.java
+++ b/src/com/android/launcher3/dragndrop/LauncherDragController.java
@@ -28,6 +28,7 @@
 import android.view.View;
 
 import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
 
 import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.DragSource;
@@ -36,6 +37,7 @@
 import com.android.launcher3.R;
 import com.android.launcher3.accessibility.DragViewStateAnnouncer;
 import com.android.launcher3.model.data.ItemInfo;
+import com.android.launcher3.widget.util.WidgetDragScaleUtils;
 
 /**
  * Drag controller for Launcher activity
@@ -43,7 +45,6 @@
 public class LauncherDragController extends DragController<Launcher> {
 
     private static final boolean PROFILE_DRAWING_DURING_DRAG = false;
-
     private final FlingToDeleteHelper mFlingToDeleteHelper;
 
     public LauncherDragController(Launcher launcher) {
@@ -92,8 +93,13 @@
                 && !mOptions.preDragCondition.shouldStartDrag(0);
 
         final Resources res = mActivity.getResources();
-        final float scaleDps = mIsInPreDrag
-                ? res.getDimensionPixelSize(R.dimen.pre_drag_view_scale) : 0f;
+
+        final float scalePx;
+        if (originalView.getViewType() == DraggableView.DRAGGABLE_WIDGET) {
+            scalePx = mIsInPreDrag ? 0f : getWidgetDragScalePx(drawable, view, dragInfo);
+        } else {
+            scalePx = mIsInPreDrag ? res.getDimensionPixelSize(R.dimen.pre_drag_view_scale) : 0f;
+        }
         final DragView dragView = mDragObject.dragView = drawable != null
                 ? new LauncherDragView(
                 mActivity,
@@ -102,7 +108,7 @@
                 registrationY,
                 initialDragViewScale,
                 dragViewScaleOnDrop,
-                scaleDps)
+                scalePx)
                 : new LauncherDragView(
                         mActivity,
                         view,
@@ -112,7 +118,7 @@
                         registrationY,
                         initialDragViewScale,
                         dragViewScaleOnDrop,
-                        scaleDps);
+                        scalePx);
         dragView.setItemInfo(dragInfo);
         mDragObject.dragComplete = false;
 
@@ -157,6 +163,29 @@
         return dragView;
     }
 
+
+    /**
+     * Returns the scale in terms of pixels (to be applied on width) to scale the preview
+     * during drag and drop.
+     */
+    @VisibleForTesting
+    float getWidgetDragScalePx(@Nullable Drawable drawable, @Nullable View view,
+            ItemInfo dragInfo) {
+        float draggedViewWidthPx = 0;
+        float draggedViewHeightPx = 0;
+
+        if (view != null) {
+            draggedViewWidthPx = view.getMeasuredWidth();
+            draggedViewHeightPx = view.getMeasuredHeight();
+        } else if (drawable != null) {
+            draggedViewWidthPx = drawable.getIntrinsicWidth();
+            draggedViewHeightPx = drawable.getIntrinsicHeight();
+        }
+
+        return WidgetDragScaleUtils.getWidgetDragScalePx(mActivity, mActivity.getDeviceProfile(),
+                draggedViewWidthPx, draggedViewHeightPx, dragInfo);
+    }
+
     @Override
     protected void exitDrag() {
         if (!mActivity.isInState(EDIT_MODE)) {
diff --git a/src/com/android/launcher3/widget/util/WidgetDragScaleUtils.java b/src/com/android/launcher3/widget/util/WidgetDragScaleUtils.java
new file mode 100644
index 0000000..b8e7248
--- /dev/null
+++ b/src/com/android/launcher3/widget/util/WidgetDragScaleUtils.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2024 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.android.launcher3.widget.util;
+
+import static com.android.launcher3.widget.util.WidgetSizes.getWidgetSizePx;
+
+import android.content.Context;
+import android.util.Size;
+
+import androidx.annotation.Px;
+
+import com.android.launcher3.DeviceProfile;
+import com.android.launcher3.R;
+import com.android.launcher3.model.data.ItemInfo;
+
+/** Utility classes to evaluate widget scale during drag and drops. **/
+public final class WidgetDragScaleUtils {
+    // Widgets are 5% scaled down relative to their size to have shadow display well inside the
+    // drop target frame (if its possible to scale it down within visible area under the finger).
+    private static final float WIDGET_SCALE_DOWN = 0.05f;
+
+    /**
+     * Returns the scale to be applied to given dragged view to scale it down relative to the
+     * spring loaded workspace. Applies additional scale down offset to get it a little inside
+     * the drop target frame. If the relative scale is smaller than minimum size needed to keep the
+     * view visible under the finger, scale down is performed only until the minimum size.
+     */
+    @Px
+    public static float getWidgetDragScalePx(Context context, DeviceProfile deviceProfile,
+            @Px float draggedViewWidthPx, @Px float draggedViewHeightPx, ItemInfo itemInfo) {
+        int minSize = context.getResources().getDimensionPixelSize(
+                R.dimen.widget_drag_view_min_scale_down_size);
+        Size widgetSizesPx = getWidgetSizePx(deviceProfile, itemInfo.spanX, itemInfo.spanY);
+
+        // We add workspace spring load scale, since the widget's drop target is also scaled, so
+        // the widget size is essentially that smaller.
+        float desiredWidgetScale = deviceProfile.getWorkspaceSpringLoadScale(context)
+                - WIDGET_SCALE_DOWN;
+        float desiredWidgetWidthPx = Math.max(minSize,
+                (desiredWidgetScale * widgetSizesPx.getWidth()));
+        float desiredWidgetHeightPx = Math.max(minSize,
+                desiredWidgetScale * widgetSizesPx.getHeight());
+
+        final float bitmapAspectRatio = draggedViewWidthPx / draggedViewHeightPx;
+        final float containerAspectRatio = desiredWidgetWidthPx / desiredWidgetHeightPx;
+
+        // This downscales large views to fit inside drop target frame. Smaller drawable views may
+        // be up-scaled if they are smaller than the min size;
+        final float scale = bitmapAspectRatio >= containerAspectRatio ? desiredWidgetWidthPx
+                / draggedViewWidthPx : desiredWidgetHeightPx / draggedViewHeightPx;
+        // scale in terms of dp to be applied to the drag shadow during drag and drop
+        return (draggedViewWidthPx * scale) - draggedViewWidthPx;
+    }
+}
diff --git a/tests/multivalentTests/src/com/android/launcher3/widget/util/WidgetDragScaleUtilsTest.kt b/tests/multivalentTests/src/com/android/launcher3/widget/util/WidgetDragScaleUtilsTest.kt
new file mode 100644
index 0000000..ec8c9c2
--- /dev/null
+++ b/tests/multivalentTests/src/com/android/launcher3/widget/util/WidgetDragScaleUtilsTest.kt
@@ -0,0 +1,148 @@
+/*
+ * Copyright (C) 2024 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.android.launcher3.widget.util
+
+import android.content.Context
+import android.graphics.Point
+import androidx.test.core.app.ApplicationProvider
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.SmallTest
+import com.android.launcher3.DeviceProfile
+import com.android.launcher3.LauncherAppState
+import com.android.launcher3.R
+import com.android.launcher3.model.data.ItemInfo
+import com.android.launcher3.util.ActivityContextWrapper
+import com.google.common.truth.Truth.assertThat
+import org.junit.Assume.assumeTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.ArgumentMatchers.any
+import org.mockito.Mockito
+import org.mockito.kotlin.doAnswer
+import org.mockito.kotlin.whenever
+
+@SmallTest
+@RunWith(AndroidJUnit4::class)
+class WidgetDragScaleUtilsTest {
+    private lateinit var context: Context
+    private lateinit var itemInfo: ItemInfo
+    private lateinit var deviceProfile: DeviceProfile
+
+    @Before
+    fun setup() {
+        context = ActivityContextWrapper(ApplicationProvider.getApplicationContext())
+
+        itemInfo = ItemInfo()
+
+        deviceProfile =
+            Mockito.spy(LauncherAppState.getIDP(context).getDeviceProfile(context).copy(context))
+
+        doAnswer {
+                return@doAnswer 0.8f
+            }
+            .whenever(deviceProfile)
+            .getWorkspaceSpringLoadScale(any(Context::class.java))
+        whenever(deviceProfile.cellSize).thenReturn(Point(CELL_SIZE, CELL_SIZE))
+        deviceProfile.cellLayoutBorderSpacePx = Point(CELL_SPACING, CELL_SPACING)
+        deviceProfile.widgetPadding.setEmpty()
+    }
+
+    @Test
+    fun getWidgetDragScalePx_largeDraggedView_downScaled() {
+        itemInfo.spanX = 2
+        itemInfo.spanY = 2
+        val widgetSize = WidgetSizes.getWidgetSizePx(deviceProfile, itemInfo.spanX, itemInfo.spanY)
+        // Assume dragged view was a drawable which was larger than widget's size.
+        val draggedViewWidthPx = widgetSize.width + 0.5f * widgetSize.width
+        val draggedViewHeightPx = widgetSize.height + 0.5f * widgetSize.height
+        // Returns negative scale pixels - i.e. downscaled
+        assertThat(
+                WidgetDragScaleUtils.getWidgetDragScalePx(
+                    context,
+                    deviceProfile,
+                    draggedViewWidthPx,
+                    draggedViewHeightPx,
+                    itemInfo
+                )
+            )
+            .isLessThan(0)
+    }
+
+    @Test
+    fun getWidgetDragScalePx_draggedViewSameAsWidgetSize_downScaled() {
+        itemInfo.spanX = 4
+        itemInfo.spanY = 2
+
+        val widgetSize = WidgetSizes.getWidgetSizePx(deviceProfile, itemInfo.spanX, itemInfo.spanY)
+        // Assume dragged view was a drawable which was larger than widget's size.
+        val draggedViewWidthPx = widgetSize.width.toFloat()
+        val draggedViewHeightPx = widgetSize.height.toFloat()
+        // Returns negative scale pixels - i.e. downscaled
+        // Even if dragged view was of same size as widget's drop target, to accommodate the spring
+        // load scaling of workspace and additionally getting the view inside of drop target frame,
+        // widget would be downscaled.
+        assertThat(
+                WidgetDragScaleUtils.getWidgetDragScalePx(
+                    context,
+                    deviceProfile,
+                    draggedViewWidthPx,
+                    draggedViewHeightPx,
+                    itemInfo
+                )
+            )
+            .isLessThan(0)
+    }
+
+    @Test
+    fun getWidgetDragScalePx_draggedViewSmallerThanMinSize_scaledSizeIsAtLeastMinSize() {
+        itemInfo.spanX = 1
+        itemInfo.spanY = 1
+        val minSizePx =
+            context.resources.getDimensionPixelSize(R.dimen.widget_drag_view_min_scale_down_size)
+
+        // Assume min size is greater than cell size, so that, we know the upscale of dragged view
+        // is due to min size enforcement.
+        assumeTrue(minSizePx > CELL_SIZE)
+
+        val draggedViewWidthPx = minSizePx - 15f
+        val draggedViewHeightPx = minSizePx - 15f
+
+        // Returns positive scale pixels - i.e. up-scaled
+        val finalScalePx =
+            WidgetDragScaleUtils.getWidgetDragScalePx(
+                context,
+                deviceProfile,
+                draggedViewWidthPx,
+                draggedViewHeightPx,
+                itemInfo
+            )
+
+        val effectiveWidthPx = draggedViewWidthPx + finalScalePx
+        val scaleFactor = (draggedViewWidthPx + finalScalePx) / draggedViewWidthPx
+        val effectiveHeightPx = scaleFactor * draggedViewHeightPx
+        // Both original height and width were smaller than min size, scaling them down below min
+        // size would have made them not visible under the finger. Here, as expected, widget is
+        // at least as large as min size.
+        assertThat(effectiveWidthPx).isAtLeast(minSizePx)
+        assertThat(effectiveHeightPx).isAtLeast(minSizePx)
+    }
+
+    companion object {
+        const val CELL_SIZE = 60
+        const val CELL_SPACING = 10
+    }
+}