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                 totalWeight += childWeight;
 349
 350                 if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 351                 {
 352                     childrenMatchParentCount++;
 353                 }
 354
 355                 // MatchParent child layout's margin is not added to totalLength.
 356                 // Consequently, MatchParent child layout's margin is added to remaining size,
 357                 // so the margin is not shared with other MatchParent child layouts.
 358                 // e.g.
 359                 // LinearLayout has size 100.
 360                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 361                 // Child layout2 is MatchParent and its margin is 0.
 362                 // Then, child layout1's size is 30 and child layout2's size is 50.
 363                 if ((childDesiredWidth == LayoutParamPolicies.WrapContent) || ((childDesiredWidth >= 0) && (!useRemainingWidth)))
 364                 {
 365                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 366
 367                     float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 368
 369                     if (childMeasuredWidth < 0)
 370                     {
 371                         totalLength = Math.Max(totalLength, totalLength + childMarginWidth);
 372                     }
 373                     else
 374                     {
 375                         totalLength = Math.Max(totalLength, totalLength + childMeasuredWidth + childMarginWidth);
 376                     }
 377                 }
 378
 379                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 380                 {
 381                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 382                 }
 383                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 384                 {
 385                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 386                 }
 387
 388                 float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 389                 if (childMeasuredHeight < 0)
 390                 {
 391                     maxHeight = Math.Max(maxHeight, childMarginHeight);
 392                 }
 393                 else
 394                 {
 395                     maxHeight = Math.Max(maxHeight, childMeasuredHeight + childMarginHeight);
 396                 }
 397             } // 1ST PHASE foreach
 398
 399             totalLength = Math.Max(totalLength, totalLength + CellPadding.Width * (childrenCount - 1) + Padding.Start + Padding.End);
 400             float widthSize = Math.Max(totalLength, SuggestedMinimumWidth.AsDecimal());
 401             MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(widthSize), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
 402             widthSize = widthSizeAndState.Size.AsDecimal();
 403
 404             float remainingWidth = widthSize - totalLength;
 405             float totalWeightLength = 0.0f;
 406
 407             // Up to now, only WrapContent children's sizes are added to the totalLength.
 408             // Since the totalLength is used in OnLayout as the sum of all children's sizes,
 409             // the layout size is assigned to the totalLength if MatchParent child exists.
 410             if (childrenMatchParentCount > 0)
 411             {
 412                 totalLength = widthSize;
 413             }
 414
 415             // 2ND PHASE:
 416             //
 417             // We measure all children whose width specification policy is MatchParent without weight.
 418             // After 2nd phase, all children's widths are calculated without considering weight.
 419             // And the widths of all weighted children are accumulated to calculate weighted width.
 420             foreach (var childLayout in LayoutChildren)
 421             {
 422                 if (!childLayout.SetPositionByLayout)
 423                 {
 424                     continue;
 425                 }
 426                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 427                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 428                 float childWeight = childLayout.Owner.Weight;
 429                 Extents childMargin = childLayout.Margin;
 430                 bool useRemainingWidth = (childDesiredWidth == 0) && (childWeight > 0);
 431                 bool needToMeasure = false;
 432
 433                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 434                 {
 435                     if (isHeightExactly)
 436                     {
 437                         needToMeasure = true;
 438                     }
 439                     // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 440                     // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 441                     // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 442                     //
 443                     // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 444                     else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 445                     {
 446                         if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 447                         {
 448                             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!");
 449                         }
 450                         else
 451                         {
 452                             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!");
 453                         }
 454                     }
 455                 }
 456
 457                 if (remainingWidth > 0)
 458                 {
 459                     if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 460                     {
 461                         if (isWidthExactly)
 462                         {
 463                             // In MeasureChildWithMargins(), it is assumed that widthMeasureSpec includes Padding.Start and Padding.End.
 464                             // Therefore, Padding.Start and Padding.End are added to widthMeasureSpec.Size before it is passed to MeasureChildWithMargins().
 465                             widthMeasureSpec.SetSize(new LayoutLength((int)(remainingWidth / childrenMatchParentCount) + Padding.Start + Padding.End));
 466                             needToMeasure = true;
 467                         }
 468                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 469                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 470                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 471                         //
 472                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 473                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 474                         {
 475                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 476                             {
 477                                 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!");
 478                             }
 479                             else
 480                             {
 481                                 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!");
 482                             }
 483                         }
 484                     }
 485                 }
 486
 487                 if (needToMeasure == true)
 488                 {
 489                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 490
 491                     if (childWeight > 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                 }
 505             } // 2ND PHASE foreach
 506
 507             // 3RD PHASE:
 508             //
 509             // We measure all weighted children whose owner has weight greater than 0.
 510             // After 3rd phase, all weighted children has width which is proportional to their weights
 511             // in remaining width of parent.
 512             if (totalWeight > 0.0f)
 513             {
 514                 foreach (LayoutItem childLayout in LayoutChildren)
 515                 {
 516                     if (!childLayout.SetPositionByLayout)
 517                     {
 518                         continue;
 519                     }
 520                     int childDesiredWidth = childLayout.Owner.WidthSpecification;
 521                     float childWeight = childLayout.Owner.Weight;
 522
 523                     if ((childWeight > 0) && ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (childDesiredWidth == 0)))
 524                     {
 525                         if (isWidthExactly)
 526                         {
 527                             MeasureWeightedChild(childLayout, totalWeightLength, totalWeight, childWeight,
 528                                                  widthMeasureSpec, heightMeasureSpec, childState,
 529                                                  Orientation.Horizontal);
 530                         }
 531                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 532                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 533                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 534                         //
 535                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 536                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 537                         {
 538                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 539                             {
 540                                 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!");
 541                             }
 542                             else
 543                             {
 544                                 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!");
 545                             }
 546                         }
 547                     }
 548                 } // 3RD PHASE foreach
 549             }
 550
 551             maxHeight = Math.Max(maxHeight, maxHeight + (Padding.Top + Padding.Bottom));
 552             maxHeight = Math.Max(maxHeight, SuggestedMinimumHeight.AsRoundedValue());
 553
 554             widthSizeAndState.State = childState.widthState;
 555
 556             SetMeasuredDimensions(widthSizeAndState,
 557                                   ResolveSizeAndState(new LayoutLength(maxHeight), heightMeasureSpec, childState.heightState));
 558         } // MeasureHorizontal
 559
 560         private void MeasureVertical(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
 561         {
 562             var widthMode = widthMeasureSpec.Mode;
 563             var heightMode = heightMeasureSpec.Mode;
 564             bool isWidthExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
 565             bool isHeightExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
 566             float maxWidth = 0.0f;
 567             float totalWeight = 0.0f;
 568             int childrenCount = IterateLayoutChildren().Count();
 569
 570             // Child layout, which wants to match its height to its parent's remaining height, is either following 1 or 2.
 571             // 1. Child layout whose Owner.HeightSpecification is LayoutParamPolicies.MatchParent.
 572             // 2. Child layout whose Owner.HeightSpecification is 0 and Owner.Weight is greater than 0.
 573             // The number of child layout which wants to match its height to its parent's remaining height.
 574             int childrenMatchParentCount = 0;
 575
 576             // Reset measure variable
 577             totalLength = 0.0f;
 578
 579             HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
 580                                                                      MeasuredSize.StateType.MeasuredSizeOK);
 581
 582             // 1ST PHASE:
 583             //
 584             // We measure all children whose height specification policy is WrapContent without weight.
 585             // After 1st phase, remaining height of parent is accumulated to calculate height of children
 586             // whose height specification policy is MatchParent.
 587             foreach (var childLayout in LayoutChildren)
 588             {
 589                 if (!childLayout.SetPositionByLayout)
 590                 {
 591                     continue;
 592                 }
 593                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 594                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 595                 float childWeight = childLayout.Owner.Weight;
 596                 Extents childMargin = childLayout.Margin;
 597                 float childMarginWidth = childMargin.Start + childMargin.End;
 598                 float childMarginHeight = childMargin.Top + childMargin.Bottom;
 599                 bool useRemainingHeight = (childDesiredHeight == 0) && (childWeight > 0);
 600
 601                 totalWeight += childWeight;
 602
 603                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 604                 {
 605                     childrenMatchParentCount++;
 606                 }
 607
 608                 // MatchParent child layout's margin is not added to totalLength.
 609                 // Consequently, MatchParent child layout's margin is added to remaining size,
 610                 // so the margin is not shared with other MatchParent child layouts.
 611                 // e.g.
 612                 // LinearLayout has size 100.
 613                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 614                 // Child layout2 is MatchParent and its margin is 0.
 615                 // Then, child layout1's size is 30 and child layout2's size is 50.
 616                 if ((childDesiredHeight == LayoutParamPolicies.WrapContent) || ((childDesiredHeight > 0) && (!useRemainingHeight)))
 617                 {
 618                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 619
 620                     float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 621
 622                     if (childMeasuredHeight < 0)
 623                     {
 624                         totalLength = Math.Max(totalLength, totalLength + childMarginHeight);
 625                     }
 626                     else
 627                     {
 628                         totalLength = Math.Max(totalLength, totalLength + childMeasuredHeight + childMarginHeight);
 629                     }
 630                 }
 631
 632                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 633                 {
 634                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 635                 }
 636                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 637                 {
 638                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 639                 }
 640
 641                 float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 642                 if (childMeasuredWidth < 0)
 643                 {
 644                     maxWidth = Math.Max(maxWidth, childMarginWidth);
 645                 }
 646                 else
 647                 {
 648                     maxWidth = Math.Max(maxWidth, childMeasuredWidth + childMarginWidth);
 649                 }
 650             } // 1ST PHASE foreach
 651
 652             totalLength = Math.Max(totalLength, totalLength + CellPadding.Height * (childrenCount - 1) + Padding.Top + Padding.Bottom);
 653             float heightSize = Math.Max(totalLength, SuggestedMinimumHeight.AsDecimal());
 654             MeasuredSize heightSizeAndState = ResolveSizeAndState(new LayoutLength(heightSize), heightMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
 655             heightSize = heightSizeAndState.Size.AsDecimal();
 656
 657             float remainingHeight = heightSize - totalLength;
 658             float totalWeightLength = 0.0f;
 659
 660             // Up to now, only WrapContent children's sizes are added to the totalLength.
 661             // Since the totalLength is used in OnLayout as the sum of all children's sizes,
 662             // the layout size is assigned to the totalLength if MatchParent child exists.
 663             if (childrenMatchParentCount > 0)
 664             {
 665                 totalLength = heightSize;
 666             }
 667
 668             // 2ND PHASE:
 669             //
 670             // We measure all children whose height specification policy is MatchParent without weight.
 671             // After 2nd phase, all children's heights are calculated without considering weight.
 672             // And the heights of all weighted children are accumulated to calculate weighted height.
 673             foreach (var childLayout in LayoutChildren)
 674             {
 675                 if (!childLayout.SetPositionByLayout)
 676                 {
 677                     continue;
 678                 }
 679                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 680                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 681                 float childWeight = childLayout.Owner.Weight;
 682                 Extents childMargin = childLayout.Margin;
 683                 bool useRemainingHeight = (childDesiredHeight == 0) && (childWeight > 0);
 684                 bool needToMeasure = false;
 685
 686                 if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 687                 {
 688                     if (isWidthExactly)
 689                     {
 690                         needToMeasure = true;
 691                     }
 692                     // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 693                     // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 694                     // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 695                     //
 696                     // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 697                     else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 698                     {
 699                         if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 700                         {
 701                             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!");
 702                         }
 703                         else
 704                         {
 705                             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!");
 706                         }
 707                     }
 708                 }
 709
 710                 if (remainingHeight > 0)
 711                 {
 712                     if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 713                     {
 714                         if (isHeightExactly)
 715                         {
 716                             // In MeasureChildWithMargins(), it is assumed that heightMeasureSpec includes Padding.Top and Padding.Bottom.
 717                             // Therefore, Padding.Top and Padding.Bottom are added to heightMeasureSpec.Size before it is passed to MeasureChildWithMargins().
 718                             heightMeasureSpec.SetSize(new LayoutLength((int)(remainingHeight / childrenMatchParentCount) + Padding.Top + Padding.Bottom));
 719                             needToMeasure = true;
 720                         }
 721                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 722                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 723                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 724                         //
 725                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 726                         else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 727                         {
 728                             if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 729                             {
 730                                 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!");
 731                             }
 732                             else
 733                             {
 734                                 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!");
 735                             }
 736                         }
 737                     }
 738                 }
 739
 740                 if (needToMeasure == true)
 741                 {
 742                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 743                 }
 744
 745                 if (childWeight > 0)
 746                 {
 747                     float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 748
 749                     if (childMeasuredHeight < 0)
 750                     {
 751                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMargin.Top + childMargin.Bottom);
 752                     }
 753                     else
 754                     {
 755                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMeasuredHeight + childMargin.Top + childMargin.Bottom);
 756                     }
 757                 }
 758             } // 2ND PHASE foreach
 759
 760             // 3RD PHASE:
 761             //
 762             // We measure all weighted children whose owner has weight greater than 0.
 763             // After 3rd phase, all weighted children has height which is proportional to their weights
 764             // in remaining height of parent.
 765             if (totalWeight > 0)
 766             {
 767                 foreach (var childLayout in LayoutChildren)
 768                 {
 769                     if (!childLayout.SetPositionByLayout)
 770                     {
 771                         continue;
 772                     }
 773                     int childDesiredHeight = childLayout.Owner.HeightSpecification;
 774                     float childWeight = childLayout.Owner.Weight;
 775
 776                     if ((childWeight > 0) && ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (childDesiredHeight == 0)))
 777                     {
 778                         if (isHeightExactly)
 779                         {
 780                             MeasureWeightedChild(childLayout, totalWeightLength, totalWeight, childWeight,
 781                                                  widthMeasureSpec, heightMeasureSpec, childState,
 782                                                  Orientation.Vertical);
 783                         }
 784                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 785                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 786                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 787                         //
 788                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 789                         else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 790                         {
 791                             if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 792                             {
 793                                 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!");
 794                             }
 795                             else
 796                             {
 797                                 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!");
 798                             }
 799                         }
 800                     }
 801                 } // 3RD PHASE foreach
 802             }
 803
 804             maxWidth = Math.Max(maxWidth, maxWidth + (Padding.Start + Padding.End));
 805             maxWidth = Math.Max(maxWidth, SuggestedMinimumWidth.AsRoundedValue());
 806
 807             heightSizeAndState.State = childState.heightState;
 808
 809             SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(maxWidth), widthMeasureSpec, childState.widthState),
 810                                   heightSizeAndState);
 811         } // MeasureVertical
 812
 813         private void LayoutHorizontal(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 814         {
 815             bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
 816
 817             LayoutLength childTop = new LayoutLength(Padding.Top);
 818             LayoutLength childLeft = new LayoutLength(Padding.Start);
 819
 820             // Where bottom of child should go
 821             LayoutLength height = new LayoutLength(bottom - top);
 822
 823             // Space available for child
 824             LayoutLength childSpace = new LayoutLength(height - Padding.Top - Padding.Bottom);
 825
 826             var LinearChildren = IterateLayoutChildren();
 827             int count = LinearChildren.Count<LayoutItem>();
 828
 829             switch (HorizontalAlignment)
 830             {
 831                 case HorizontalAlignment.End:
 832                     // totalLength contains the padding already
 833                     // In case of RTL map END alignment to the left edge
 834                     if (isLayoutRtl)
 835                     {
 836                         childLeft = new LayoutLength(Padding.Start);
 837                     }
 838                     else
 839                     {
 840                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 841                     }
 842                     break;
 843                 case HorizontalAlignment.Center:
 844                     // totalLength contains the padding already
 845                     childLeft = new LayoutLength(Padding.Start + (right.AsDecimal() - left.AsDecimal() - totalLength) / 2.0f);
 846                     break;
 847                 case HorizontalAlignment.Begin: // FALL THROUGH (default)
 848                 default:
 849                     // totalLength contains the padding already
 850                     // In case of RTL map BEGIN alignment to the right edge
 851                     if (isLayoutRtl)
 852                     {
 853                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 854                     }
 855                     else
 856                     {
 857                         childLeft = new LayoutLength(Padding.Start);
 858                     }
 859                     break;
 860             }
 861
 862             int start = 0;
 863             int dir = 1;
 864
 865             // In case of RTL, start drawing from the last child.
 866             if (isLayoutRtl)
 867             {
 868                 start = count - 1;
 869                 dir = -1;
 870             }
 871
 872             for (int i = 0; i < count; i++)
 873             {
 874                 int childIndex = start + dir * i;
 875                 // Get a reference to the childLayout at the given index
 876                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 877
 878                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 879                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 880                 Extents childMargin = childLayout.Margin;
 881
 882                 switch (VerticalAlignment)
 883                 {
 884                     case VerticalAlignment.Bottom:
 885                         childTop = new LayoutLength(height - Padding.Bottom - childHeight - childMargin.Bottom);
 886                         break;
 887                     case VerticalAlignment.Center:
 888                         childTop = new LayoutLength(Padding.Top + ((childSpace - childHeight).AsDecimal() / 2.0f) + childMargin.Top - childMargin.Bottom);
 889                         break;
 890                     case VerticalAlignment.Top: // FALLTHROUGH default
 891                     default:
 892                         childTop = new LayoutLength(Padding.Top + childMargin.Top);
 893                         break;
 894                 }
 895                 childLeft += (isLayoutRtl ? childMargin.End : childMargin.Start);
 896                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 897                 childLeft += childWidth + (isLayoutRtl ? childMargin.Start : childMargin.End) + ((i < count - 1) ? CellPadding.Width : 0);
 898             }
 899         } // LayoutHorizontally
 900
 901         private void LayoutVertical(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 902         {
 903             LayoutLength childTop = new LayoutLength(Padding.Top);
 904             LayoutLength childLeft = new LayoutLength(Padding.Start);
 905
 906             // Where end of child should go
 907             LayoutLength width = new LayoutLength(right - left);
 908
 909             // Space available for child
 910             LayoutLength childSpace = new LayoutLength(width - Padding.Start - Padding.End);
 911
 912             var LinearChildren = IterateLayoutChildren();
 913             int count = LinearChildren.Count<LayoutItem>();
 914
 915             switch (VerticalAlignment)
 916             {
 917                 case VerticalAlignment.Bottom:
 918                     // totalLength contains the padding already
 919                     childTop = new LayoutLength(Padding.Top + bottom.AsDecimal() - top.AsDecimal() - totalLength);
 920                     break;
 921                 case VerticalAlignment.Center:
 922                     // totalLength contains the padding already
 923                     childTop = new LayoutLength(Padding.Top + (bottom.AsDecimal() - top.AsDecimal() - totalLength) / 2.0f);
 924                     break;
 925                 case VerticalAlignment.Top:  // FALL THROUGH (default)
 926                 default:
 927                     // totalLength contains the padding already
 928                     childTop = new LayoutLength(Padding.Top);
 929                     break;
 930             }
 931
 932             for (int i = 0; i < count; i++)
 933             {
 934                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 935
 936                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 937                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 938                 Extents childMargin = childLayout.Margin;
 939
 940                 childTop += childMargin.Top;
 941                 switch (HorizontalAlignment)
 942                 {
 943                     case HorizontalAlignment.Begin:
 944                     default:
 945                         {
 946                             childLeft = new LayoutLength(Padding.Start + childMargin.Start);
 947                             break;
 948                         }
 949                     case HorizontalAlignment.End:
 950                         {
 951                             childLeft = new LayoutLength(width - Padding.End - childWidth - childMargin.End);
 952                             break;
 953                         }
 954                     case HorizontalAlignment.Center:
 955                         {
 956                             childLeft = new LayoutLength(Padding.Start + ((childSpace - childWidth).AsDecimal() / 2.0f) + childMargin.Start - childMargin.End);
 957                             break;
 958                         }
 959                 }
 960                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 961                 childTop += childHeight + childMargin.Bottom + ((i < count - 1) ? CellPadding.Height : 0);
 962             }
 963         } // LayoutVertical
 964
 965         private void ForceUniformHeight(MeasureSpecification widthMeasureSpec)
 966         {
 967             // Pretend that the linear layout has an exact size. This is the measured height of
 968             // ourselves. The measured height should be the max height of the children, changed
 969             // to accommodate the heightMeasureSpec from the parent
 970             MeasureSpecification uniformMeasureSpec = new MeasureSpecification(MeasuredHeight.Size, MeasureSpecification.ModeType.Exactly);
 971             foreach (var childLayout in LayoutChildren)
 972             {
 973                 if (!childLayout.SetPositionByLayout)
 974                 {
 975                     continue;
 976                 }
 977                 int desiredChildHeight = childLayout.Owner.HeightSpecification;
 978                 int desiredChildWidth = childLayout.Owner.WidthSpecification;
 979
 980                 if (desiredChildHeight == LayoutParamPolicies.MatchParent)
 981                 {
 982                     // Temporarily force children to reuse their original measured width
 983                     int originalWidth = desiredChildWidth;
 984                     childLayout.Owner.WidthSpecification = (int)childLayout.MeasuredWidth.Size.AsRoundedValue();
 985                     // Remeasure with new dimensions
 986                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0),
 987                                              uniformMeasureSpec, new LayoutLength(0));
 988                     // Restore width specification
 989                     childLayout.Owner.WidthSpecification = originalWidth;
 990                 }
 991             }
 992         }
 993     } //LinearLayout
 994 } // namespace