chrome/android/features/autofill_assistant/java/src/org/chromium/chrome/browser/autofill_assistant/carousel/AssistantActionsDecoration.java - chromium/src - Git at Google

 // Copyright 2019 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.chrome.browser.autofill_assistant.carousel;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.Path;
 import android.graphics.Rect;
 import android.graphics.RectF;
 import android.graphics.Region;
 import android.graphics.drawable.Drawable;
 import android.view.View;

 import androidx.annotation.NonNull;
 import androidx.recyclerview.widget.OrientationHelper;
 import androidx.recyclerview.widget.RecyclerView;

 import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.chrome.autofill_assistant.R;

 /**
  * Decoration added to the actions carousel that add offsets to each action to have the right inner
  * and outer spaces. When the carousel is scrollable, this decoration also:
  * - adds a white-to-transparent gradient to the left of the screen above all but the last action.
  * - adds a shadow to the last action when it's above other actions.
  * - fades actions the more they get close to the left screen.
  */
 class AssistantActionsDecoration extends RecyclerView.ItemDecoration {
     // The maximum opacity of the overlays drawn on top of children next to the last child,
     // where 0 means transparent and 1.0 fully opaque.
     private static final float OVERLAYS_MAX_OPACITY = 0.30f;

     // The shadow around the last button is composed of SHADOW_LAYERS layers with decreasing
     // opacity.
     private static final int SHADOW_LAYERS = 4;

     private final AssistantActionsCarouselCoordinator.CustomLayoutManager mLayoutManager;

     // Dimensions in device pixels.
     private final int mOuterSpace;
     private final int mInnerSpace;
     private final int mVerticalSpacing;
     private final int mVerticalInset;
     private final int mGradientWidth;
     private final int mLastChildBorderRadius;
     private final int mShadowColor;
     private final float mShadowLayerWidth;

     private final Drawable mGradientDrawable;
     private final Paint mShadowPaint = new Paint();
     private final Paint mOverlayPaint = new Paint();
     private final Path mLastChildPath = new Path();
     private final RectF mLastChildRect = new RectF();
     private final RectF mChildRect = new RectF();

     public AssistantActionsDecoration(Context context,
             AssistantActionsCarouselCoordinator.CustomLayoutManager layoutManager) {
         mLayoutManager = layoutManager;
         mOuterSpace = context.getResources().getDimensionPixelSize(
                 R.dimen.autofill_assistant_bottombar_horizontal_spacing);
         mInnerSpace = context.getResources().getDimensionPixelSize(
                 R.dimen.autofill_assistant_actions_spacing);
         mVerticalInset = context.getResources().getDimensionPixelSize(
                 R.dimen.autofill_assistant_button_bg_vertical_inset);

         // We remove mVerticalInset from the vertical spacing as that inset will be added above and
         // below the button by ButtonView.
         mVerticalSpacing = context.getResources().getDimensionPixelSize(
                                    R.dimen.autofill_assistant_bottombar_vertical_spacing)
                 - mVerticalInset;

         mGradientWidth = context.getResources().getDimensionPixelSize(
                 R.dimen.autofill_assistant_actions_gradient_width);
         mLastChildBorderRadius = context.getResources().getDimensionPixelSize(
                 R.dimen.autofill_assistant_button_corner_radius);
         mShadowColor = ApiCompatibilityUtils.getColor(
                 context.getResources(), R.color.autofill_assistant_actions_shadow_color);
         mShadowLayerWidth =
                 context.getResources().getDimension(R.dimen.autofill_assistant_actions_shadow_width)
                 / SHADOW_LAYERS;
         mGradientDrawable = context.getDrawable(R.drawable.autofill_assistant_actions_gradient);

         mShadowPaint.setAntiAlias(true);
         mShadowPaint.setDither(true);
         mShadowPaint.setStyle(Paint.Style.STROKE);
         mShadowPaint.setStrokeWidth(mShadowLayerWidth);

         mOverlayPaint.setColor(
                 ApiCompatibilityUtils.getColor(context.getResources(), R.color.sheet_bg_color));
     }

     @Override
     public void onDrawOver(@NonNull Canvas canvas, @NonNull RecyclerView parent,
             @NonNull RecyclerView.State state) {
         if (parent.getChildCount() <= 1) {
             return;
         }

         View lastChild = parent.getChildAt(parent.getChildCount() - 1);
         View beforeLastChild = parent.getChildAt(parent.getChildCount() - 2);
         mLastChildRect.left = lastChild.getLeft() + lastChild.getTranslationX();
         mLastChildRect.top = lastChild.getTop() + lastChild.getTranslationY() + mVerticalInset;
         mLastChildRect.right = lastChild.getRight() + lastChild.getTranslationX();
         mLastChildRect.bottom =
                 lastChild.getBottom() + lastChild.getTranslationY() - mVerticalInset;

         // Early return to avoid drawing last button decoration if no chip overlaps with the cancel
         // chip. Note that there are spurious updates where the last chip's position is
         // intermittently in the wrong position. The workaround is to check if the combined width of
         // all chips fits without scrolling or not.
         // TODO(b/144075373): Fix this properly by avoiding the spurious updates.
         OrientationHelper orientationHelper = mLayoutManager.mOrientationHelper;
         int sumDecoratedWidth = 0;
         for (int i = 0; i < parent.getChildCount(); ++i) {
             sumDecoratedWidth += orientationHelper.getDecoratedEnd(parent.getChildAt(i))
                     - orientationHelper.getDecoratedStart(parent.getChildAt(i));
         }
         if (sumDecoratedWidth < mLayoutManager.getWidth()) {
             return;
         }

         canvas.save();

         // Don't draw on the last child.
         mLastChildPath.reset();
         mLastChildPath.addRoundRect(
                 mLastChildRect, mLastChildBorderRadius, mLastChildBorderRadius, Path.Direction.CW);
         canvas.clipPath(mLastChildPath, Region.Op.DIFFERENCE);

         // Overlay children close to the last child with a semi-transparent paint.
         float lastChildRight = orientationHelper.getDecoratedEnd(lastChild);
         for (int i = parent.getChildCount() - 2; i >= 0; i--) {
             View child = parent.getChildAt(i);
             int left = Math.round(
                     orientationHelper.getDecoratedStart(child) + lastChild.getTranslationX());
             if (left >= lastChildRight) {
                 break;
             }

             int alpha = Math.round(
                     getBoundedLinearValue(left, 0, lastChildRight, OVERLAYS_MAX_OPACITY * 255, 0));
             mOverlayPaint.setColor(getColorWithAlpha(mOverlayPaint.getColor(), alpha));
             mChildRect.left = child.getLeft() + child.getTranslationX();
             mChildRect.right = child.getRight() + child.getTranslationX();
             mChildRect.top = child.getTop() + child.getTranslationY();
             mChildRect.bottom = child.getBottom() + child.getTranslationY();
             canvas.drawRect(mChildRect, mOverlayPaint);
         }

         // Draw a fixed size white-to-transparent linear gradient from left to right.
         mGradientDrawable.setBounds(
                 0, mVerticalSpacing, mGradientWidth, parent.getHeight() - mVerticalSpacing);
         mGradientDrawable.setAlpha(Math.round(getBoundedLinearValue(
                 beforeLastChild.getLeft(), lastChild.getLeft(), lastChild.getRight(), 255, 0)));
         mGradientDrawable.draw(canvas);

         canvas.restore();

         // Don't draw shadow around the last if it's animated.
         if (orientationHelper.getDecoratedStart(lastChild) != 0
                 || lastChild.getTranslationX() != 0) {
             return;
         }

         // Draw shadow composed of 4 layers of colors around the last child. We multiply the
         // original alpha of the shadow color by alphaRatio to hide the shadow when there is no
         // child behind the last child.
         float alphaRatio = getBoundedLinearValue(
                 beforeLastChild.getLeft(), lastChild.getLeft(), lastChild.getRight(), 1, 0);

         // originalAlpha is a value between 0 (transparent) and 255 (opaque).
         int originalAlpha = mShadowColor >>> 24;
         for (int i = 0; i < SHADOW_LAYERS; i++) {
             // The higher the layer, the lower its alpha.
             float layerAlphaRatio = ((float) SHADOW_LAYERS - i) / SHADOW_LAYERS;

             int color = getColorWithAlpha(
                     mShadowColor, Math.round(originalAlpha * alphaRatio * layerAlphaRatio));
             mShadowPaint.setColor(color);

             mChildRect.left = mLastChildRect.left - (i + 0.5f) * mShadowLayerWidth;
             mChildRect.right = mLastChildRect.right + (i + 0.5f) * mShadowLayerWidth;
             mChildRect.top = mLastChildRect.top - (i + 0.5f) * mShadowLayerWidth;
             mChildRect.bottom = mLastChildRect.bottom + (i + 0.5f) * mShadowLayerWidth;
             canvas.drawRoundRect(
                     mChildRect, mLastChildBorderRadius, mLastChildBorderRadius, mShadowPaint);
         }
     }

     private int getColorWithAlpha(int color, int alpha) {
         return (color & 0x00FFFFFF) | (alpha << 24);
     }

     @Override
     public void getItemOffsets(@NonNull Rect outRect, @NonNull View view,
             @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
         // Add vertical spacing above and below the view. This is necessary to display the shadow of
         // the last button correctly.
         outRect.top = mVerticalSpacing;
         outRect.bottom = mVerticalSpacing;

         if (state.getItemCount() <= 1) {
             return;
         }

         int position = parent.getChildAdapterPosition(view);

         // If old position != NO_POSITION, it means the carousel is being animated and we should
         // use that position in our logic.
         RecyclerView.ViewHolder viewHolder = parent.getChildViewHolder(view);
         if (viewHolder != null && viewHolder.getOldPosition() != RecyclerView.NO_POSITION) {
             position = viewHolder.getOldPosition();
         }

         if (position == RecyclerView.NO_POSITION) {
             return;
         }

         outRect.right = position == 0 ? mOuterSpace : mInnerSpace;
         if (position == state.getItemCount() - 1) {
             outRect.left = mOuterSpace;
         }
     }

     /**
      * Get the value f(x) such that:
      *  - f(x) = yMin for all x <= xMin
      *  - f(x) = yMax for all x >= xMax
      *  - (x, f(x)) is a point on the line drawn between (xMin, yMin) and (xMax, yMax)
      */
     private static float getBoundedLinearValue(
             float x, float xMin, float xMax, float yMin, float yMax) {
         if (x <= xMin) {
             return yMin;
         } else if (x >= xMax) {
             return yMax;
         } else {
             return yMin + (x - xMin) / (xMax - xMin) * (yMax - yMin);
         }
     }
 }
	// Copyright 2019 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.chrome.browser.autofill_assistant.carousel;

	import android.content.Context;
	import android.graphics.Canvas;
	import android.graphics.Paint;
	import android.graphics.Path;
	import android.graphics.Rect;
	import android.graphics.RectF;
	import android.graphics.Region;
	import android.graphics.drawable.Drawable;
	import android.view.View;

	import androidx.annotation.NonNull;
	import androidx.recyclerview.widget.OrientationHelper;
	import androidx.recyclerview.widget.RecyclerView;

	import org.chromium.base.ApiCompatibilityUtils;
	import org.chromium.chrome.autofill_assistant.R;

	/**
	* Decoration added to the actions carousel that add offsets to each action to have the right inner
	* and outer spaces. When the carousel is scrollable, this decoration also:
	* - adds a white-to-transparent gradient to the left of the screen above all but the last action.
	* - adds a shadow to the last action when it's above other actions.
	* - fades actions the more they get close to the left screen.
	*/
	class AssistantActionsDecoration extends RecyclerView.ItemDecoration {
	// The maximum opacity of the overlays drawn on top of children next to the last child,
	// where 0 means transparent and 1.0 fully opaque.
	private static final float OVERLAYS_MAX_OPACITY = 0.30f;

	// The shadow around the last button is composed of SHADOW_LAYERS layers with decreasing
	// opacity.
	private static final int SHADOW_LAYERS = 4;

	private final AssistantActionsCarouselCoordinator.CustomLayoutManager mLayoutManager;

	// Dimensions in device pixels.
	private final int mOuterSpace;
	private final int mInnerSpace;
	private final int mVerticalSpacing;
	private final int mVerticalInset;
	private final int mGradientWidth;
	private final int mLastChildBorderRadius;
	private final int mShadowColor;
	private final float mShadowLayerWidth;

	private final Drawable mGradientDrawable;
	private final Paint mShadowPaint = new Paint();
	private final Paint mOverlayPaint = new Paint();
	private final Path mLastChildPath = new Path();
	private final RectF mLastChildRect = new RectF();
	private final RectF mChildRect = new RectF();

	public AssistantActionsDecoration(Context context,
	AssistantActionsCarouselCoordinator.CustomLayoutManager layoutManager) {
	mLayoutManager = layoutManager;
	mOuterSpace = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_bottombar_horizontal_spacing);
	mInnerSpace = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_actions_spacing);
	mVerticalInset = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_button_bg_vertical_inset);

	// We remove mVerticalInset from the vertical spacing as that inset will be added above and
	// below the button by ButtonView.
	mVerticalSpacing = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_bottombar_vertical_spacing)
	- mVerticalInset;

	mGradientWidth = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_actions_gradient_width);
	mLastChildBorderRadius = context.getResources().getDimensionPixelSize(
	R.dimen.autofill_assistant_button_corner_radius);
	mShadowColor = ApiCompatibilityUtils.getColor(
	context.getResources(), R.color.autofill_assistant_actions_shadow_color);
	mShadowLayerWidth =
	context.getResources().getDimension(R.dimen.autofill_assistant_actions_shadow_width)
	/ SHADOW_LAYERS;
	mGradientDrawable = context.getDrawable(R.drawable.autofill_assistant_actions_gradient);

	mShadowPaint.setAntiAlias(true);
	mShadowPaint.setDither(true);
	mShadowPaint.setStyle(Paint.Style.STROKE);
	mShadowPaint.setStrokeWidth(mShadowLayerWidth);

	mOverlayPaint.setColor(
	ApiCompatibilityUtils.getColor(context.getResources(), R.color.sheet_bg_color));
	}

	@Override
	public void onDrawOver(@NonNull Canvas canvas, @NonNull RecyclerView parent,
	@NonNull RecyclerView.State state) {
	if (parent.getChildCount() <= 1) {
	return;
	}

	View lastChild = parent.getChildAt(parent.getChildCount() - 1);
	View beforeLastChild = parent.getChildAt(parent.getChildCount() - 2);
	mLastChildRect.left = lastChild.getLeft() + lastChild.getTranslationX();
	mLastChildRect.top = lastChild.getTop() + lastChild.getTranslationY() + mVerticalInset;
	mLastChildRect.right = lastChild.getRight() + lastChild.getTranslationX();
	mLastChildRect.bottom =
	lastChild.getBottom() + lastChild.getTranslationY() - mVerticalInset;

	// Early return to avoid drawing last button decoration if no chip overlaps with the cancel
	// chip. Note that there are spurious updates where the last chip's position is
	// intermittently in the wrong position. The workaround is to check if the combined width of
	// all chips fits without scrolling or not.
	// TODO(b/144075373): Fix this properly by avoiding the spurious updates.
	OrientationHelper orientationHelper = mLayoutManager.mOrientationHelper;
	int sumDecoratedWidth = 0;
	for (int i = 0; i < parent.getChildCount(); ++i) {
	sumDecoratedWidth += orientationHelper.getDecoratedEnd(parent.getChildAt(i))
	- orientationHelper.getDecoratedStart(parent.getChildAt(i));
	}
	if (sumDecoratedWidth < mLayoutManager.getWidth()) {
	return;
	}

	canvas.save();

	// Don't draw on the last child.
	mLastChildPath.reset();
	mLastChildPath.addRoundRect(
	mLastChildRect, mLastChildBorderRadius, mLastChildBorderRadius, Path.Direction.CW);
	canvas.clipPath(mLastChildPath, Region.Op.DIFFERENCE);

	// Overlay children close to the last child with a semi-transparent paint.
	float lastChildRight = orientationHelper.getDecoratedEnd(lastChild);
	for (int i = parent.getChildCount() - 2; i >= 0; i--) {
	View child = parent.getChildAt(i);
	int left = Math.round(
	orientationHelper.getDecoratedStart(child) + lastChild.getTranslationX());
	if (left >= lastChildRight) {
	break;
	}

	int alpha = Math.round(
	getBoundedLinearValue(left, 0, lastChildRight, OVERLAYS_MAX_OPACITY * 255, 0));
	mOverlayPaint.setColor(getColorWithAlpha(mOverlayPaint.getColor(), alpha));
	mChildRect.left = child.getLeft() + child.getTranslationX();
	mChildRect.right = child.getRight() + child.getTranslationX();
	mChildRect.top = child.getTop() + child.getTranslationY();
	mChildRect.bottom = child.getBottom() + child.getTranslationY();
	canvas.drawRect(mChildRect, mOverlayPaint);
	}

	// Draw a fixed size white-to-transparent linear gradient from left to right.
	mGradientDrawable.setBounds(
	0, mVerticalSpacing, mGradientWidth, parent.getHeight() - mVerticalSpacing);
	mGradientDrawable.setAlpha(Math.round(getBoundedLinearValue(
	beforeLastChild.getLeft(), lastChild.getLeft(), lastChild.getRight(), 255, 0)));
	mGradientDrawable.draw(canvas);

	canvas.restore();

	// Don't draw shadow around the last if it's animated.
	if (orientationHelper.getDecoratedStart(lastChild) != 0
	\|\| lastChild.getTranslationX() != 0) {
	return;
	}

	// Draw shadow composed of 4 layers of colors around the last child. We multiply the
	// original alpha of the shadow color by alphaRatio to hide the shadow when there is no
	// child behind the last child.
	float alphaRatio = getBoundedLinearValue(
	beforeLastChild.getLeft(), lastChild.getLeft(), lastChild.getRight(), 1, 0);

	// originalAlpha is a value between 0 (transparent) and 255 (opaque).
	int originalAlpha = mShadowColor >>> 24;
	for (int i = 0; i < SHADOW_LAYERS; i++) {
	// The higher the layer, the lower its alpha.
	float layerAlphaRatio = ((float) SHADOW_LAYERS - i) / SHADOW_LAYERS;

	int color = getColorWithAlpha(
	mShadowColor, Math.round(originalAlpha * alphaRatio * layerAlphaRatio));
	mShadowPaint.setColor(color);

	mChildRect.left = mLastChildRect.left - (i + 0.5f) * mShadowLayerWidth;
	mChildRect.right = mLastChildRect.right + (i + 0.5f) * mShadowLayerWidth;
	mChildRect.top = mLastChildRect.top - (i + 0.5f) * mShadowLayerWidth;
	mChildRect.bottom = mLastChildRect.bottom + (i + 0.5f) * mShadowLayerWidth;
	canvas.drawRoundRect(
	mChildRect, mLastChildBorderRadius, mLastChildBorderRadius, mShadowPaint);
	}
	}

	private int getColorWithAlpha(int color, int alpha) {
	return (color & 0x00FFFFFF) \| (alpha << 24);
	}

	@Override
	public void getItemOffsets(@NonNull Rect outRect, @NonNull View view,
	@NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
	// Add vertical spacing above and below the view. This is necessary to display the shadow of
	// the last button correctly.
	outRect.top = mVerticalSpacing;
	outRect.bottom = mVerticalSpacing;

	if (state.getItemCount() <= 1) {
	return;
	}

	int position = parent.getChildAdapterPosition(view);

	// If old position != NO_POSITION, it means the carousel is being animated and we should
	// use that position in our logic.
	RecyclerView.ViewHolder viewHolder = parent.getChildViewHolder(view);
	if (viewHolder != null && viewHolder.getOldPosition() != RecyclerView.NO_POSITION) {
	position = viewHolder.getOldPosition();
	}

	if (position == RecyclerView.NO_POSITION) {
	return;
	}

	outRect.right = position == 0 ? mOuterSpace : mInnerSpace;
	if (position == state.getItemCount() - 1) {
	outRect.left = mOuterSpace;
	}
	}

	/**
	* Get the value f(x) such that:
	* - f(x) = yMin for all x <= xMin
	* - f(x) = yMax for all x >= xMax
	* - (x, f(x)) is a point on the line drawn between (xMin, yMin) and (xMax, yMax)
	*/
	private static float getBoundedLinearValue(
	float x, float xMin, float xMax, float yMin, float yMax) {
	if (x <= xMin) {
	return yMin;
	} else if (x >= xMax) {
	return yMax;
	} else {
	return yMin + (x - xMin) / (xMax - xMin) * (yMax - yMin);
	}
	}
	}