src/Tizen.NUI/src/public/Layouting/LinearLayout.cs

   1 /* Copyright (c) 2020 Samsung Electronics Co., Ltd.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at
   6  *
   7  * http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  *
  15  */
  16
  17 using System;
  18 using System.ComponentModel;
  19 using Tizen.NUI.BaseComponents;
  20 using System.Collections.Generic;
  21 using System.Linq;
  22
  23 namespace Tizen.NUI
  24 {
  25     /// <summary>
  26     /// [Draft] This class implements a linear box layout, automatically handling right to left or left to right direction change.
  27     /// </summary>
  28     public class LinearLayout : LayoutGroup
  29     {
  30         private Alignment linearAlignment = Alignment.Top;
  31
  32         /// <summary>
  33         /// [Draft] Enumeration for the direction in which the content is laid out
  34         /// </summary>
  35         /// <since_tizen> 6 </since_tizen>
  36         public enum Orientation
  37         {
  38             /// <summary>
  39             /// Horizontal (row)
  40             /// </summary>
  41             Horizontal,
  42             /// <summary>
  43             /// Vertical (column)
  44             /// </summary>
  45             Vertical
  46         }
  47
  48         /// <summary>
  49         /// [Draft] Enumeration for the alignment of the linear layout items
  50         /// </summary>
  51         /// <since_tizen> 6 </since_tizen>
  52         [Obsolete("Deprecated in API9, will be removed in API11. Please use HorizontalAlignment and VerticalAlignment instead!")]
  53         public enum Alignment
  54         {
  55             /// <summary>
  56             /// At the left/right edge of the container (maps to LTR/RTL direction for horizontal orientation)
  57             /// </summary>
  58             Begin = 0x1,
  59             /// <summary>
  60             /// At the right/left edge of the container (maps to LTR/RTL direction for horizontal orientation)
  61             /// </summary>
  62             End = 0x2,
  63             /// <summary>
  64             /// At the horizontal center of the container
  65             /// </summary>
  66             CenterHorizontal = 0x4,
  67             /// <summary>
  68             /// At the top edge of the container
  69             /// </summary>
  70             Top = 0x8,
  71             /// <summary>
  72             /// At the bottom edge of the container
  73             /// </summary>
  74             Bottom = 0x10,
  75             /// <summary>
  76             /// At the vertical center of the container
  77             /// </summary>
  78             CenterVertical = 0x20,
  79             /// <summary>
  80             /// At the vertical and horizontal center of the container
  81             /// </summary>
  82             Center = 0x40
  83         }
  84
  85         struct HeightAndWidthState
  86         {
  87             public MeasuredSize.StateType widthState;
  88             public MeasuredSize.StateType heightState;
  89
  90             public HeightAndWidthState(MeasuredSize.StateType width, MeasuredSize.StateType height)
  91             {
  92                 widthState = width;
  93                 heightState = height;
  94             }
  95         }
  96
  97         /// <summary>
  98         /// [Draft] Get/Set the orientation in the layout
  99         /// </summary>
 100         /// <since_tizen> 6 </since_tizen>
 101         public LinearLayout.Orientation LinearOrientation
 102         {
 103             get
 104             {
 105                 return linearOrientation;
 106             }
 107             set
 108             {
 109                 linearOrientation = value;
 110                 RequestLayout();
 111             }
 112         }
 113
 114         /// <summary>
 115         /// [Draft] Get/Set the padding between cells in the layout
 116         /// </summary>
 117         /// <since_tizen> 6 </since_tizen>
 118         public Size2D CellPadding
 119         {
 120             get
 121             {
 122                 if (cellPadding == null)
 123                 {
 124                     cellPadding = new Size2D(0, 0);
 125                 }
 126
 127                 return cellPadding;
 128             }
 129             set
 130             {
 131                 cellPadding = value;
 132                 RequestLayout();
 133             }
 134         }
 135
 136
 137         /// <summary>
 138         /// [Draft] Get/Set the alignment in the layout
 139         /// </summary>
 140         /// <since_tizen> 6 </since_tizen>
 141         [Obsolete("Deprecated in API9, will be removed in API11. Please use HorizontalAlignment and VerticalAlignment properties instead!")]
 142         public LinearLayout.Alignment LinearAlignment
 143         {
 144             get
 145             {
 146                 return linearAlignment;
 147             }
 148
 149             set
 150             {
 151                 if (linearAlignment == value)
 152                 {
 153                     return;
 154                 }
 155
 156                 linearAlignment = value;
 157
 158                 switch (linearAlignment)
 159                 {
 160                     case Alignment.Begin:
 161                         HorizontalAlignment = HorizontalAlignment.Begin;
 162                         break;
 163                     case Alignment.End:
 164                         HorizontalAlignment = HorizontalAlignment.End;
 165                         break;
 166                     case Alignment.CenterHorizontal:
 167                         HorizontalAlignment = HorizontalAlignment.Center;
 168                         break;
 169                     case Alignment.Top:
 170                         VerticalAlignment = VerticalAlignment.Top;
 171                         break;
 172                     case Alignment.Bottom:
 173                         VerticalAlignment = VerticalAlignment.Bottom;
 174                         break;
 175                     case Alignment.CenterVertical:
 176                         VerticalAlignment = VerticalAlignment.Center;
 177                         break;
 178                     case Alignment.Center:
 179                         HorizontalAlignment = HorizontalAlignment.Center;
 180                         VerticalAlignment = VerticalAlignment.Center;
 181                         break;
 182                     default:
 183                         break;
 184                 }
 185             }
 186          }
 187
 188         /// <summary>
 189         /// Get/Set the horizontal alignment in the layout
 190         /// </summary>
 191         /// <since_tizen> 9 </since_tizen>
 192         public HorizontalAlignment HorizontalAlignment { get; set; } = HorizontalAlignment.Begin;
 193
 194         /// <summary>
 195         /// Get/Set the vertical alignment in the layout
 196         /// </summary>
 197         /// <since_tizen> 9 </since_tizen>
 198         public VerticalAlignment VerticalAlignment { get; set; } = VerticalAlignment.Top;
 199
 200         private float totalLength = 0.0f;
 201         private Size2D cellPadding = new Size2D(0, 0);
 202         private Orientation linearOrientation = Orientation.Horizontal;
 203
 204         /// <summary>
 205         /// [Draft] Constructor
 206         /// </summary>
 207         /// <since_tizen> 6 </since_tizen>
 208         public LinearLayout()
 209         {
 210         }
 211
 212         /// <summary>
 213         /// Measure the layout and its content to determine the measured width and the measured height.
 214         /// </summary>
 215         /// <param name="widthMeasureSpec">horizontal space requirements as imposed by the parent.</param>
 216         /// <param name="heightMeasureSpec">vertical space requirements as imposed by the parent.</param>
 217         /// <since_tizen> 6 </since_tizen>
 218         protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
 219         {
 220             if (linearOrientation == Orientation.Horizontal)
 221             {
 222                 MeasureHorizontal(widthMeasureSpec, heightMeasureSpec);
 223             }
 224             else
 225             {
 226                 MeasureVertical(widthMeasureSpec, heightMeasureSpec);
 227             }
 228         }
 229
 230         /// <summary>
 231         /// Layout should assign a size and position to each of its children.<br />
 232         /// </summary>
 233         /// <param name="changed">This is a new size or position for this layout.</param>
 234         /// <param name="left">Left position, relative to parent.</param>
 235         /// <param name="top"> Top position, relative to parent.</param>
 236         /// <param name="right">Right position, relative to parent.</param>
 237         /// <param name="bottom">Bottom position, relative to parent.</param>
 238         /// <since_tizen> 6 </since_tizen>
 239         protected override void OnLayout(bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 240         {
 241             if (linearOrientation == Orientation.Horizontal)
 242             {
 243                 LayoutHorizontal(left, top, right, bottom);
 244             }
 245             else
 246             {
 247                 LayoutVertical(left, top, right, bottom);
 248             }
 249         }
 250
 251
 252         private void MeasureWeightedChild(LayoutItem childLayout, float totalWeightLength, float totalWeight, float childWeight,
 253                                            MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec,
 254                                            HeightAndWidthState childState, Orientation orientation)
 255         {
 256             bool horizontal = false;
 257             if (orientation == Orientation.Horizontal)
 258             {
 259                 horizontal = true;
 260             }
 261
 262             float childsShare = totalWeightLength * (childWeight / totalWeight);
 263             float desiredWidth = childLayout.Owner.WidthSpecification;
 264             float desiredHeight = childLayout.Owner.HeightSpecification;
 265
 266             MeasureSpecification childWidthMeasureSpec;
 267             MeasureSpecification childHeightMeasureSpec;
 268
 269             if (horizontal)
 270             {
 271                 childWidthMeasureSpec = new MeasureSpecification(new LayoutLength(childsShare - (childLayout.Margin.Start + childLayout.Margin.End)), MeasureSpecification.ModeType.Exactly);
 272
 273                 childHeightMeasureSpec = GetChildMeasureSpecification(
 274                                             new MeasureSpecification(
 275                                                 new LayoutLength(heightMeasureSpec.Size - (childLayout.Margin.Top + childLayout.Margin.Bottom)),
 276                                                 heightMeasureSpec.Mode),
 277                                             new LayoutLength(Padding.Top + Padding.Bottom),
 278                                             new LayoutLength(desiredHeight));
 279             }
 280             else // vertical
 281             {
 282                 childWidthMeasureSpec = GetChildMeasureSpecification(
 283                                             new MeasureSpecification(
 284                                                 new LayoutLength(widthMeasureSpec.Size - (childLayout.Margin.Start + childLayout.Margin.End)),
 285                                                 widthMeasureSpec.Mode),
 286                                             new LayoutLength(Padding.Start + Padding.End),
 287                                             new LayoutLength(desiredWidth));
 288
 289                 childHeightMeasureSpec = new MeasureSpecification(new LayoutLength(childsShare - (childLayout.Margin.Top + childLayout.Margin.Bottom)), MeasureSpecification.ModeType.Exactly);
 290             }
 291
 292             childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
 293
 294             // Child may now not fit in horizontal dimension.
 295             if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 296             {
 297                 childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 298             }
 299
 300             // Child may now not fit in vertical dimension.
 301             if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 302             {
 303                 childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 304             }
 305         }
 306
 307         private void MeasureHorizontal(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
 308         {
 309             var widthMode = widthMeasureSpec.Mode;
 310             var heightMode = heightMeasureSpec.Mode;
 311             bool isWidthExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
 312             bool isHeightExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
 313             float maxHeight = 0.0f;
 314             float totalWeight = 0.0f;
 315             int childrenCount = IterateLayoutChildren().Count();
 316
 317             // Child layout, which wants to match its width to its parent's remaining width, is either following 1 or 2.
 318             // 1. Child layout whose Owner.WidthSpecification is LayoutParamPolicies.MatchParent.
 319             // 2. Child layout whose Owner.WidthSpecification is 0 and Owner.Weight is greater than 0.
 320             // The number of child layout which wants to match its width to its parent's remaining width.
 321             int childrenMatchParentCount = 0;
 322
 323             // Reset measure variable
 324             totalLength = 0.0f;
 325
 326             HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
 327                                                                      MeasuredSize.StateType.MeasuredSizeOK);
 328
 329             // 1ST PHASE:
 330             //
 331             // We measure all children whose width specification policy is WrapContent without weight.
 332             // After 1st phase, remaining width of parent is accumulated to calculate width of children
 333             // whose width specification policy is MatchParent.
 334             foreach (var childLayout in LayoutChildren)
 335             {
 336                 if (!childLayout.SetPositionByLayout)
 337                 {
 338                     continue;
 339                 }
 340                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 341                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 342                 float childWeight = childLayout.Owner.Weight;
 343                 Extents childMargin = childLayout.Margin;
 344                 float childMarginWidth = childMargin.Start + childMargin.End;
 345                 float childMarginHeight = childMargin.Top + childMargin.Bottom;
 346                 bool useRemainingWidth = (childDesiredWidth == 0) && (childWeight > 0);
 347
 348                 if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 349                 {
 350                     totalWeight += childWeight;
 351                     childrenMatchParentCount++;
 352                 }
 353
 354                 // MatchParent child layout's margin is not added to totalLength.
 355                 // Consequently, MatchParent child layout's margin is added to remaining size,
 356                 // so the margin is not shared with other MatchParent child layouts.
 357                 // e.g.
 358                 // LinearLayout has size 100.
 359                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 360                 // Child layout2 is MatchParent and its margin is 0.
 361                 // Then, child layout1's size is 30 and child layout2's size is 50.
 362                 if ((childDesiredWidth == LayoutParamPolicies.WrapContent) || ((childDesiredWidth >= 0) && (!useRemainingWidth)))
 363                 {
 364                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 365
 366                     float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 367
 368                     if (childMeasuredWidth < 0)
 369                     {
 370                         totalLength = Math.Max(totalLength, totalLength + childMarginWidth);
 371                     }
 372                     else
 373                     {
 374                         totalLength = Math.Max(totalLength, totalLength + childMeasuredWidth + childMarginWidth);
 375                     }
 376                 }
 377
 378                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 379                 {
 380                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 381                 }
 382                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 383                 {
 384                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 385                 }
 386
 387                 float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 388                 if (childMeasuredHeight < 0)
 389                 {
 390                     maxHeight = Math.Max(maxHeight, childMarginHeight);
 391                 }
 392                 else
 393                 {
 394                     maxHeight = Math.Max(maxHeight, childMeasuredHeight + childMarginHeight);
 395                 }
 396             } // 1ST PHASE foreach
 397
 398             totalLength = Math.Max(totalLength, totalLength + CellPadding.Width * (childrenCount - 1) + Padding.Start + Padding.End);
 399             float widthSize = Math.Max(totalLength, SuggestedMinimumWidth.AsDecimal());
 400             MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(widthSize), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
 401             widthSize = widthSizeAndState.Size.AsDecimal();
 402
 403             float remainingWidth = widthSize - totalLength;
 404             float totalWeightLength = 0.0f;
 405
 406             // Up to now, only WrapContent children's sizes are added to the totalLength.
 407             // Since the totalLength is used in OnLayout as the sum of all children's sizes,
 408             // the layout size is assigned to the totalLength if MatchParent child exists.
 409             if (childrenMatchParentCount > 0)
 410             {
 411                 totalLength = widthSize;
 412             }
 413
 414             // 2ND PHASE:
 415             //
 416             // We measure all children whose width specification policy is MatchParent without weight.
 417             // After 2nd phase, all children's widths are calculated without considering weight.
 418             // And the widths of all weighted children are accumulated to calculate weighted width.
 419             foreach (var childLayout in LayoutChildren)
 420             {
 421                 if (!childLayout.SetPositionByLayout)
 422                 {
 423                     continue;
 424                 }
 425                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 426                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 427                 float childWeight = childLayout.Owner.Weight;
 428                 Extents childMargin = childLayout.Margin;
 429                 bool useRemainingWidth = (childDesiredWidth == 0) && (childWeight > 0);
 430                 bool needToMeasure = false;
 431
 432                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 433                 {
 434                     if (isHeightExactly)
 435                     {
 436                         needToMeasure = true;
 437                     }
 438                     // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 439                     // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 440                     // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 441                     //
 442                     // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 443                     else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 444                     {
 445                         if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 446                         {
 447                             Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is MatchParent!");
 448                         }
 449                         else
 450                         {
 451                             Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is 0 with positive weight!");
 452                         }
 453                     }
 454                 }
 455
 456                 if (remainingWidth > 0)
 457                 {
 458                     if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 459                     {
 460                         if (isWidthExactly)
 461                         {
 462                             // In MeasureChildWithMargins(), it is assumed that widthMeasureSpec includes Padding.Start and Padding.End.
 463                             // Therefore, Padding.Start and Padding.End are added to widthMeasureSpec.Size before it is passed to MeasureChildWithMargins().
 464                             widthMeasureSpec.SetSize(new LayoutLength((int)(remainingWidth / childrenMatchParentCount) + Padding.Start + Padding.End));
 465                             needToMeasure = true;
 466                         }
 467                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 468                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 469                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 470                         //
 471                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 472                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 473                         {
 474                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 475                             {
 476                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is MatchParent!");
 477                             }
 478                             else
 479                             {
 480                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is 0 with positive weight!");
 481                             }
 482                         }
 483                     }
 484                 }
 485
 486                 if (needToMeasure == true)
 487                 {
 488                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 489                 }
 490
 491                 if ((childWeight > 0) && ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (childDesiredWidth == 0)))
 492                 {
 493                     float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 494
 495                     if (childMeasuredWidth < 0)
 496                     {
 497                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMargin.Start + childMargin.End);
 498                     }
 499                     else
 500                     {
 501                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMeasuredWidth + childMargin.Start + childMargin.End);
 502                     }
 503                 }
 504             } // 2ND PHASE foreach
 505
 506             // 3RD PHASE:
 507             //
 508             // We measure all weighted children whose owner has weight greater than 0.
 509             // After 3rd phase, all weighted children has width which is proportional to their weights
 510             // in remaining width of parent.
 511             if (totalWeight > 0.0f)
 512             {
 513                 foreach (LayoutItem childLayout in LayoutChildren)
 514                 {
 515                     if (!childLayout.SetPositionByLayout)
 516                     {
 517                         continue;
 518                     }
 519                     int childDesiredWidth = childLayout.Owner.WidthSpecification;
 520                     float childWeight = childLayout.Owner.Weight;
 521
 522                     if ((childWeight > 0) && ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (childDesiredWidth == 0)))
 523                     {
 524                         if (isWidthExactly)
 525                         {
 526                             MeasureWeightedChild(childLayout, totalWeightLength, totalWeight, childWeight,
 527                                                  widthMeasureSpec, heightMeasureSpec, childState,
 528                                                  Orientation.Horizontal);
 529                         }
 530                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 531                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 532                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 533                         //
 534                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 535                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 536                         {
 537                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 538                             {
 539                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is MatchParent!");
 540                             }
 541                             else
 542                             {
 543                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is 0 with positive weight!");
 544                             }
 545                         }
 546                     }
 547                 } // 3RD PHASE foreach
 548             }
 549
 550             maxHeight = Math.Max(maxHeight, maxHeight + (Padding.Top + Padding.Bottom));
 551             maxHeight = Math.Max(maxHeight, SuggestedMinimumHeight.AsRoundedValue());
 552
 553             widthSizeAndState.State = childState.widthState;
 554
 555             SetMeasuredDimensions(widthSizeAndState,
 556                                   ResolveSizeAndState(new LayoutLength(maxHeight), heightMeasureSpec, childState.heightState));
 557         } // MeasureHorizontal
 558
 559         private void MeasureVertical(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
 560         {
 561             var widthMode = widthMeasureSpec.Mode;
 562             var heightMode = heightMeasureSpec.Mode;
 563             bool isWidthExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
 564             bool isHeightExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
 565             float maxWidth = 0.0f;
 566             float totalWeight = 0.0f;
 567             int childrenCount = IterateLayoutChildren().Count();
 568
 569             // Child layout, which wants to match its height to its parent's remaining height, is either following 1 or 2.
 570             // 1. Child layout whose Owner.HeightSpecification is LayoutParamPolicies.MatchParent.
 571             // 2. Child layout whose Owner.HeightSpecification is 0 and Owner.Weight is greater than 0.
 572             // The number of child layout which wants to match its height to its parent's remaining height.
 573             int childrenMatchParentCount = 0;
 574
 575             // Reset measure variable
 576             totalLength = 0.0f;
 577
 578             HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
 579                                                                      MeasuredSize.StateType.MeasuredSizeOK);
 580
 581             // 1ST PHASE:
 582             //
 583             // We measure all children whose height specification policy is WrapContent without weight.
 584             // After 1st phase, remaining height of parent is accumulated to calculate height of children
 585             // whose height specification policy is MatchParent.
 586             foreach (var childLayout in LayoutChildren)
 587             {
 588                 if (!childLayout.SetPositionByLayout)
 589                 {
 590                     continue;
 591                 }
 592                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 593                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 594                 float childWeight = childLayout.Owner.Weight;
 595                 Extents childMargin = childLayout.Margin;
 596                 float childMarginWidth = childMargin.Start + childMargin.End;
 597                 float childMarginHeight = childMargin.Top + childMargin.Bottom;
 598                 bool useRemainingHeight = (childDesiredHeight == 0) && (childWeight > 0);
 599
 600                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 601                 {
 602                     totalWeight += childWeight;
 603                     childrenMatchParentCount++;
 604                 }
 605
 606                 // MatchParent child layout's margin is not added to totalLength.
 607                 // Consequently, MatchParent child layout's margin is added to remaining size,
 608                 // so the margin is not shared with other MatchParent child layouts.
 609                 // e.g.
 610                 // LinearLayout has size 100.
 611                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 612                 // Child layout2 is MatchParent and its margin is 0.
 613                 // Then, child layout1's size is 30 and child layout2's size is 50.
 614                 if ((childDesiredHeight == LayoutParamPolicies.WrapContent) || ((childDesiredHeight > 0) && (!useRemainingHeight)))
 615                 {
 616                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 617
 618                     float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 619
 620                     if (childMeasuredHeight < 0)
 621                     {
 622                         totalLength = Math.Max(totalLength, totalLength + childMarginHeight);
 623                     }
 624                     else
 625                     {
 626                         totalLength = Math.Max(totalLength, totalLength + childMeasuredHeight + childMarginHeight);
 627                     }
 628                 }
 629
 630                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 631                 {
 632                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 633                 }
 634                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 635                 {
 636                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 637                 }
 638
 639                 float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 640                 if (childMeasuredWidth < 0)
 641                 {
 642                     maxWidth = Math.Max(maxWidth, childMarginWidth);
 643                 }
 644                 else
 645                 {
 646                     maxWidth = Math.Max(maxWidth, childMeasuredWidth + childMarginWidth);
 647                 }
 648             } // 1ST PHASE foreach
 649
 650             totalLength = Math.Max(totalLength, totalLength + CellPadding.Height * (childrenCount - 1) + Padding.Top + Padding.Bottom);
 651             float heightSize = Math.Max(totalLength, SuggestedMinimumHeight.AsDecimal());
 652             MeasuredSize heightSizeAndState = ResolveSizeAndState(new LayoutLength(heightSize), heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
 653             heightSize = heightSizeAndState.Size.AsDecimal();
 654
 655             float remainingHeight = heightSize - totalLength;
 656             float totalWeightLength = 0.0f;
 657
 658             // Up to now, only WrapContent children's sizes are added to the totalLength.
 659             // Since the totalLength is used in OnLayout as the sum of all children's sizes,
 660             // the layout size is assigned to the totalLength if MatchParent child exists.
 661             if (childrenMatchParentCount > 0)
 662             {
 663                 totalLength = heightSize;
 664             }
 665
 666             // 2ND PHASE:
 667             //
 668             // We measure all children whose height specification policy is MatchParent without weight.
 669             // After 2nd phase, all children's heights are calculated without considering weight.
 670             // And the heights of all weighted children are accumulated to calculate weighted height.
 671             foreach (var childLayout in LayoutChildren)
 672             {
 673                 if (!childLayout.SetPositionByLayout)
 674                 {
 675                     continue;
 676                 }
 677                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 678                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 679                 float childWeight = childLayout.Owner.Weight;
 680                 Extents childMargin = childLayout.Margin;
 681                 bool useRemainingHeight = (childDesiredHeight == 0) && (childWeight > 0);
 682                 bool needToMeasure = false;
 683
 684                 if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 685                 {
 686                     if (isWidthExactly)
 687                     {
 688                         needToMeasure = true;
 689                     }
 690                     // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 691                     // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 692                     // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 693                     //
 694                     // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 695                     else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 696                     {
 697                         if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 698                         {
 699                             Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is MatchParent!");
 700                         }
 701                         else
 702                         {
 703                             Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s WidthSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s WidthSpecification is 0 with positive weight!");
 704                         }
 705                     }
 706                 }
 707
 708                 if (remainingHeight > 0)
 709                 {
 710                     if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 711                     {
 712                         if (isHeightExactly)
 713                         {
 714                             // In MeasureChildWithMargins(), it is assumed that heightMeasureSpec includes Padding.Top and Padding.Bottom.
 715                             // Therefore, Padding.Top and Padding.Bottom are added to heightMeasureSpec.Size before it is passed to MeasureChildWithMargins().
 716                             heightMeasureSpec.SetSize(new LayoutLength((int)(remainingHeight / childrenMatchParentCount) + Padding.Top + Padding.Bottom));
 717                             needToMeasure = true;
 718                         }
 719                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 720                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 721                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 722                         //
 723                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 724                         else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 725                         {
 726                             if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 727                             {
 728                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is MatchParent!");
 729                             }
 730                             else
 731                             {
 732                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is 0 with positive weight!");
 733                             }
 734                         }
 735                     }
 736                 }
 737
 738                 if (needToMeasure == true)
 739                 {
 740                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 741                 }
 742
 743                 if ((childWeight > 0) && ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (childDesiredHeight == 0)))
 744                 {
 745                     float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 746
 747                     if (childMeasuredHeight < 0)
 748                     {
 749                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMargin.Top + childMargin.Bottom);
 750                     }
 751                     else
 752                     {
 753                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMeasuredHeight + childMargin.Top + childMargin.Bottom);
 754                     }
 755                 }
 756             } // 2ND PHASE foreach
 757
 758             // 3RD PHASE:
 759             //
 760             // We measure all weighted children whose owner has weight greater than 0.
 761             // After 3rd phase, all weighted children has height which is proportional to their weights
 762             // in remaining height of parent.
 763             if (totalWeight > 0)
 764             {
 765                 foreach (var childLayout in LayoutChildren)
 766                 {
 767                     if (!childLayout.SetPositionByLayout)
 768                     {
 769                         continue;
 770                     }
 771                     int childDesiredHeight = childLayout.Owner.HeightSpecification;
 772                     float childWeight = childLayout.Owner.Weight;
 773
 774                     if ((childWeight > 0) && ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (childDesiredHeight == 0)))
 775                     {
 776                         if (isHeightExactly)
 777                         {
 778                             MeasureWeightedChild(childLayout, totalWeightLength, totalWeight, childWeight,
 779                                                  widthMeasureSpec, heightMeasureSpec, childState,
 780                                                  Orientation.Vertical);
 781                         }
 782                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 783                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 784                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 785                         //
 786                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 787                         else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 788                         {
 789                             if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 790                             {
 791                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is MatchParent!");
 792                             }
 793                             else
 794                             {
 795                                 Tizen.Log.Error("NUI", "There is a recursive reference! Parent layout(Owner: " + Owner + ")'s HeightSpecification is WrapContent and child layout(Owner: " + childLayout.Owner + ")'s HeightSpecification is 0 with positive weight!");
 796                             }
 797                         }
 798                     }
 799                 } // 3RD PHASE foreach
 800             }
 801
 802             maxWidth = Math.Max(maxWidth, maxWidth + (Padding.Start + Padding.End));
 803             maxWidth = Math.Max(maxWidth, SuggestedMinimumWidth.AsRoundedValue());
 804
 805             heightSizeAndState.State = childState.heightState;
 806
 807             SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(maxWidth), widthMeasureSpec, childState.widthState),
 808                                   heightSizeAndState);
 809         } // MeasureVertical
 810
 811         private void LayoutHorizontal(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 812         {
 813             bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
 814
 815             LayoutLength childTop = new LayoutLength(Padding.Top);
 816             LayoutLength childLeft = new LayoutLength(Padding.Start);
 817
 818             // Where bottom of child should go
 819             LayoutLength height = new LayoutLength(bottom - top);
 820
 821             // Space available for child
 822             LayoutLength childSpace = new LayoutLength(height - Padding.Top - Padding.Bottom);
 823
 824             var LinearChildren = IterateLayoutChildren();
 825             int count = LinearChildren.Count<LayoutItem>();
 826
 827             switch (HorizontalAlignment)
 828             {
 829                 case HorizontalAlignment.End:
 830                     // totalLength contains the padding already
 831                     // In case of RTL map END alignment to the left edge
 832                     if (isLayoutRtl)
 833                     {
 834                         childLeft = new LayoutLength(Padding.Start);
 835                     }
 836                     else
 837                     {
 838                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 839                     }
 840                     break;
 841                 case HorizontalAlignment.Center:
 842                     // totalLength contains the padding already
 843                     childLeft = new LayoutLength(Padding.Start + (right.AsDecimal() - left.AsDecimal() - totalLength) / 2.0f);
 844                     break;
 845                 case HorizontalAlignment.Begin: // FALL THROUGH (default)
 846                 default:
 847                     // totalLength contains the padding already
 848                     // In case of RTL map BEGIN alignment to the right edge
 849                     if (isLayoutRtl)
 850                     {
 851                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 852                     }
 853                     else
 854                     {
 855                         childLeft = new LayoutLength(Padding.Start);
 856                     }
 857                     break;
 858             }
 859
 860             int start = 0;
 861             int dir = 1;
 862
 863             // In case of RTL, start drawing from the last child.
 864             if (isLayoutRtl)
 865             {
 866                 start = count - 1;
 867                 dir = -1;
 868             }
 869
 870             for (int i = 0; i < count; i++)
 871             {
 872                 int childIndex = start + dir * i;
 873                 // Get a reference to the childLayout at the given index
 874                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 875
 876                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 877                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 878                 Extents childMargin = childLayout.Margin;
 879
 880                 switch (VerticalAlignment)
 881                 {
 882                     case VerticalAlignment.Bottom:
 883                         childTop = new LayoutLength(height - Padding.Bottom - childHeight - childMargin.Bottom);
 884                         break;
 885                     case VerticalAlignment.Center:
 886                         childTop = new LayoutLength(Padding.Top + ((childSpace - childHeight).AsDecimal() / 2.0f) + childMargin.Top - childMargin.Bottom);
 887                         break;
 888                     case VerticalAlignment.Top: // FALLTHROUGH default
 889                     default:
 890                         childTop = new LayoutLength(Padding.Top + childMargin.Top);
 891                         break;
 892                 }
 893                 childLeft += (isLayoutRtl ? childMargin.End : childMargin.Start);
 894                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 895                 childLeft += childWidth + (isLayoutRtl ? childMargin.Start : childMargin.End) + ((i < count - 1) ? CellPadding.Width : 0);
 896             }
 897         } // LayoutHorizontally
 898
 899         private void LayoutVertical(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 900         {
 901             LayoutLength childTop = new LayoutLength(Padding.Top);
 902             LayoutLength childLeft = new LayoutLength(Padding.Start);
 903
 904             // Where end of child should go
 905             LayoutLength width = new LayoutLength(right - left);
 906
 907             // Space available for child
 908             LayoutLength childSpace = new LayoutLength(width - Padding.Start - Padding.End);
 909
 910             var LinearChildren = IterateLayoutChildren();
 911             int count = LinearChildren.Count<LayoutItem>();
 912
 913             switch (VerticalAlignment)
 914             {
 915                 case VerticalAlignment.Bottom:
 916                     // totalLength contains the padding already
 917                     childTop = new LayoutLength(Padding.Top + bottom.AsDecimal() - top.AsDecimal() - totalLength);
 918                     break;
 919                 case VerticalAlignment.Center:
 920                     // totalLength contains the padding already
 921                     childTop = new LayoutLength(Padding.Top + (bottom.AsDecimal() - top.AsDecimal() - totalLength) / 2.0f);
 922                     break;
 923                 case VerticalAlignment.Top:  // FALL THROUGH (default)
 924                 default:
 925                     // totalLength contains the padding already
 926                     childTop = new LayoutLength(Padding.Top);
 927                     break;
 928             }
 929
 930             for (int i = 0; i < count; i++)
 931             {
 932                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 933
 934                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 935                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 936                 Extents childMargin = childLayout.Margin;
 937
 938                 childTop += childMargin.Top;
 939                 switch (HorizontalAlignment)
 940                 {
 941                     case HorizontalAlignment.Begin:
 942                     default:
 943                         {
 944                             childLeft = new LayoutLength(Padding.Start + childMargin.Start);
 945                             break;
 946                         }
 947                     case HorizontalAlignment.End:
 948                         {
 949                             childLeft = new LayoutLength(width - Padding.End - childWidth - childMargin.End);
 950                             break;
 951                         }
 952                     case HorizontalAlignment.Center:
 953                         {
 954                             childLeft = new LayoutLength(Padding.Start + ((childSpace - childWidth).AsDecimal() / 2.0f) + childMargin.Start - childMargin.End);
 955                             break;
 956                         }
 957                 }
 958                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 959                 childTop += childHeight + childMargin.Bottom + ((i < count - 1) ? CellPadding.Height : 0);
 960             }
 961         } // LayoutVertical
 962
 963         private void ForceUniformHeight(MeasureSpecification widthMeasureSpec)
 964         {
 965             // Pretend that the linear layout has an exact size. This is the measured height of
 966             // ourselves. The measured height should be the max height of the children, changed
 967             // to accommodate the heightMeasureSpec from the parent
 968             MeasureSpecification uniformMeasureSpec = new MeasureSpecification(MeasuredHeight.Size, MeasureSpecification.ModeType.Exactly);
 969             foreach (var childLayout in LayoutChildren)
 970             {
 971                 if (!childLayout.SetPositionByLayout)
 972                 {
 973                     continue;
 974                 }
 975                 int desiredChildHeight = childLayout.Owner.HeightSpecification;
 976                 int desiredChildWidth = childLayout.Owner.WidthSpecification;
 977
 978                 if (desiredChildHeight == LayoutParamPolicies.MatchParent)
 979                 {
 980                     // Temporarily force children to reuse their original measured width
 981                     int originalWidth = desiredChildWidth;
 982                     childLayout.Owner.WidthSpecification = (int)childLayout.MeasuredWidth.Size.AsRoundedValue();
 983                     // Remeasure with new dimensions
 984                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0),
 985                                              uniformMeasureSpec, new LayoutLength(0));
 986                     // Restore width specification
 987                     childLayout.Owner.WidthSpecification = originalWidth;
 988                 }
 989             }
 990         }
 991     } //LinearLayout
 992 } // namespace