Add Alignment Functionality for Sonar

Summary:
Part of a hackathon project. (https://fb.facebook.com/groups/230455004101832/permalink/454928784987785/)

We're adding an alignment mode for Sonar that shows the pixel level alignment.

Reviewed By: danielbuechele

Differential Revision: D9121197

fbshipit-source-id: 21af36fd7eeea631d580ccebff8e648fa276bf35

android/src/main/java/com/facebook/sonar/plugins/inspector/HighlightedOverlay.java

@@ -12,6 +12,7 @@ import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.os.Build;
 import android.view.View;
+import android.util.Log;
 
 /**
  * A singleton instance of a overlay drawable used for highlighting node bounds. See {@link
@@ -31,24 +32,49 @@ public class HighlightedOverlay {
    */
   public static void setHighlighted(
       View targetView, Rect margin, Rect padding, Rect contentBounds) {
-    if (!VIEW_OVERLAY_SUPPORT) {
+      setHighlightedAndAlignment(targetView, margin, padding, contentBounds, false);
-      return;
-    }
-
-    contentBounds.set(
-        contentBounds.left + padding.left,
-        contentBounds.top + padding.top,
-        contentBounds.right - padding.right,
-        contentBounds.bottom - padding.bottom);
-
-    padding = enclose(padding, contentBounds);
-    margin = enclose(margin, padding);
-
-    final float density = targetView.getContext().getResources().getDisplayMetrics().density;
-    final Drawable overlay = BoundsDrawable.getInstance(density, margin, padding, contentBounds);
-    targetView.getOverlay().add(overlay);
   }
 
+  public static void setHighlightedAndAlignment(
+      View targetView, Rect margin, Rect padding, Rect contentBounds, boolean isAlignmentMode) {
+        if (!VIEW_OVERLAY_SUPPORT) {
+          return;
+        }
+
+        contentBounds.set(
+            contentBounds.left + padding.left,
+            contentBounds.top + padding.top,
+            contentBounds.right - padding.right,
+            contentBounds.bottom - padding.bottom);
+
+        padding = enclose(padding, contentBounds);
+        margin = enclose(margin, padding);
+
+        final float density = targetView.getContext().getResources().getDisplayMetrics().density;
+        final Drawable overlay = BoundsDrawable.getInstance(density, margin, padding, contentBounds);
+
+        targetView.getOverlay().add(overlay);
+
+        if(isAlignmentMode) {
+          int[] coords = new int[2];
+          targetView.getLocationOnScreen(coords);
+          Rect lineContentBounds =
+              new Rect(
+                  coords[0] + contentBounds.left,
+                  coords[1] + contentBounds.top,
+                  coords[0] + contentBounds.right,
+                  coords[1] + contentBounds.bottom);
+
+          final Drawable lineOverlay = LinesDrawable.getInstance(density, margin, padding, lineContentBounds);
+
+          targetView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
+
+
+
+          targetView.getRootView().getOverlay().add(lineOverlay);
+        }
+      }
+
   public static void removeHighlight(View targetView) {
     if (!VIEW_OVERLAY_SUPPORT) {
       return;
@@ -56,6 +82,9 @@ public class HighlightedOverlay {
 
     final float density = targetView.getContext().getResources().getDisplayMetrics().density;
     final Drawable overlay = BoundsDrawable.getInstance(density);
+    final Drawable overlay2 = LinesDrawable.getInstance(density);
+    targetView.getRootView().getOverlay().remove(overlay2);
+
     targetView.getOverlay().remove(overlay);
   }
 

android/src/main/java/com/facebook/sonar/plugins/inspector/LinesDrawable.java

@@ -0,0 +1,92 @@
+/*
+ *  Copyright (c) 2018-present, Facebook, Inc.
+ *
+ *  This source code is licensed under the MIT license found in the LICENSE
+ *  file in the root directory of this source tree.
+ *
+ */
+
+package com.facebook.sonar.plugins.inspector;
+
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.ColorFilter;
+import android.graphics.Paint;
+import android.graphics.DashPathEffect;
+import android.graphics.PixelFormat;
+import android.graphics.Rect;
+import android.graphics.Region;
+import android.graphics.drawable.Drawable;
+import android.text.TextPaint;
+import javax.annotation.Nullable;
+
+public class LinesDrawable extends Drawable {
+  private static @Nullable LinesDrawable sInstance;
+
+  private final Rect mWorkRect;
+  private final Rect mMarginBounds;
+  private final Rect mPaddingBounds;
+  private final Rect mContentBounds;
+
+  private final float mDensity;
+
+  public static LinesDrawable getInstance(
+      float density, Rect marginBounds, Rect paddingBounds, Rect contentBounds) {
+    final LinesDrawable drawable = getInstance(density);
+    drawable.setBounds(marginBounds, paddingBounds, contentBounds);
+    return drawable;
+  }
+
+  public static LinesDrawable getInstance(float density) {
+    if (sInstance == null) {
+      sInstance = new LinesDrawable(density);
+    }
+    return sInstance;
+  }
+
+  private LinesDrawable(float density) {
+    mWorkRect = new Rect();
+    mMarginBounds = new Rect();
+    mPaddingBounds = new Rect();
+    mContentBounds = new Rect();
+
+    mDensity = density;
+  }
+
+  public void setBounds(Rect marginBounds, Rect paddingBounds, Rect contentBounds) {
+    mMarginBounds.set(marginBounds);
+    mPaddingBounds.set(paddingBounds);
+    mContentBounds.set(contentBounds);
+    setBounds(marginBounds);
+  }
+
+  @Override
+  public void draw(Canvas canvas) {
+
+    Paint dashPaint = new Paint();
+    dashPaint.setColor(0xFF800000);
+    dashPaint.setStyle(Paint.Style.STROKE);
+    dashPaint.setStrokeWidth(3);
+    dashPaint.setPathEffect(new DashPathEffect(new float[]{10, 10}, 0));
+
+    canvas.drawLine(mContentBounds.right, 0, mContentBounds.right, 100000, dashPaint);
+    canvas.drawLine(mContentBounds.left, 0, mContentBounds.left, 100000, dashPaint);
+    canvas.drawLine(0, mContentBounds.top, 100000, mContentBounds.top, dashPaint);
+    canvas.drawLine(0, mContentBounds.bottom, 100000, mContentBounds.bottom, dashPaint);
+  }
+
+  @Override
+  public void setAlpha(int alpha) {
+    // No-op
+  }
+
+  @Override
+  public void setColorFilter(ColorFilter colorFilter) {
+    // No-op
+  }
+
+  @Override
+  public int getOpacity() {
+    return PixelFormat.TRANSLUCENT;
+  }
+}