content: /*
   * Copyright (C) 2017 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.setupwizardlib.view;
  
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.util.AttributeSet;
  import android.view.View;
  import android.widget.FrameLayout;
  import com.android.setupwizardlib.R;
  
  /**
   * A layout that will measure its children size based on the space it is given, by using its {@code
   * android:minWidth}, {@code android:minHeight}, {@code android:maxWidth}, and {@code
   * android:maxHeight} values.
   *
   * <p>Typically this is used to show an illustration image or video on the screen. For optimal UX,
   * those assets typically want to occupy the remaining space available on screen within a certain
   * range, and then stop scaling beyond the min/max size attributes. Therefore this view is typically
   * used inside a ScrollView with {@code fillViewport} set to true, together with a linear layout
   * weight or relative layout to fill the remaining space visible on screen.
   *
   * <p>When measuring, this view ignores its children and simply layout according to the minWidth /
   * minHeight given. Therefore it is common for children of this layout to have width / height set to
   * {@code match_parent}. The maxWidth / maxHeight values will then be applied to the children to
   * make sure they are not too big.
   */
  public class FillContentLayout extends FrameLayout {
  
    private int maxWidth;
    private int maxHeight;
  
    public FillContentLayout(Context context) {
      this(context, null);
    }
  
    public FillContentLayout(Context context, AttributeSet attrs) {
      this(context, attrs, R.attr.suwFillContentLayoutStyle);
    }
  
    public FillContentLayout(Context context, AttributeSet attrs, int defStyleAttr) {
      super(context, attrs, defStyleAttr);
      init(context, attrs, defStyleAttr);
    }
  
    private void init(Context context, AttributeSet attrs, int defStyleAttr) {
      TypedArray a =
          context.obtainStyledAttributes(attrs, R.styleable.SuwFillContentLayout, defStyleAttr, 0);
  
      maxHeight = a.getDimensionPixelSize(R.styleable.SuwFillContentLayout_android_maxHeight, -1);
      maxWidth = a.getDimensionPixelSize(R.styleable.SuwFillContentLayout_android_maxWidth, -1);
  
      a.recycle();
    }
  
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
      // Measure this view with the minWidth and minHeight, without asking the children.
      // (Children size is the drawable's intrinsic size, and we don't want that to influence
      // the size of the illustration).
      setMeasuredDimension(
          getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec),
          getDefaultSize(getSuggestedMinimumHeight(), heightMeasureSpec));
  
      int childCount = getChildCount();
      for (int i = 0; i < childCount; i++) {
        measureIllustrationChild(getChildAt(i), getMeasuredWidth(), getMeasuredHeight());
      }
    }
  
    private void measureIllustrationChild(View child, int parentWidth, int parentHeight) {
      // Modified from ViewGroup#measureChildWithMargins
      final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
  
      // Create measure specs that are no bigger than min(parentSize, maxSize)
  
      int childWidthMeasureSpec =
          getMaxSizeMeasureSpec(
              Math.min(maxWidth, parentWidth),
              getPaddingLeft() + getPaddingRight() + lp.leftMargin + lp.rightMargin,
              lp.width);
      int childHeightMeasureSpec =
          getMaxSizeMeasureSpec(
              Math.min(maxHeight, parentHeight),
              getPaddingTop() + getPaddingBottom() + lp.topMargin + lp.bottomMargin,
              lp.height);
  
      child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
    }
  
    private static int getMaxSizeMeasureSpec(int maxSize, int padding, int childDimension) {
      // Modified from ViewGroup#getChildMeasureSpec
      int size = Math.max(0, maxSize - padding);
  
      if (childDimension >= 0) {
        // Child wants a specific size... so be it
        return MeasureSpec.makeMeasureSpec(childDimension, MeasureSpec.EXACTLY);
      } else if (childDimension == LayoutParams.MATCH_PARENT) {
        // Child wants to be our size. So be it.
        return MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY);
      } else if (childDimension == LayoutParams.WRAP_CONTENT) {
        // Child wants to determine its own size. It can't be
        // bigger than us.
        return MeasureSpec.makeMeasureSpec(size, MeasureSpec.AT_MOST);
      }
      return 0;
    }
  }
  