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("This has been deprecated in API9 and will be removed in API11. 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("This has been deprecated in API9 and will be removed in API11. 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                 bool useRemainingWidth = (childDesiredWidth == 0) && (childWeight > 0);
 346
 347                 if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 348                 {
 349                     totalWeight += childWeight;
 350                     childrenMatchParentCount++;
 351                 }
 352
 353                 // MatchParent child layout's margin is not added to totalLength.
 354                 // Consequently, MatchParent child layout's margin is added to remaining size,
 355                 // so the margin is not shared with other MatchParent child layouts.
 356                 // e.g.
 357                 // LinearLayout has size 100.
 358                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 359                 // Child layout2 is MatchParent and its margin is 0.
 360                 // Then, child layout1's size is 30 and child layout2's size is 50.
 361                 if ((childDesiredWidth == LayoutParamPolicies.WrapContent) || ((childDesiredWidth >= 0) && (!useRemainingWidth)))
 362                 {
 363                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 364
 365                     float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 366
 367                     if (childMeasuredWidth < 0)
 368                     {
 369                         totalLength = Math.Max(totalLength, totalLength + childMarginWidth);
 370                     }
 371                     else
 372                     {
 373                         totalLength = Math.Max(totalLength, totalLength + childMeasuredWidth + childMarginWidth);
 374                     }
 375                 }
 376
 377                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 378                 {
 379                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 380                 }
 381                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 382                 {
 383                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 384                 }
 385             } // 1ST PHASE foreach
 386
 387             totalLength = Math.Max(totalLength, totalLength + CellPadding.Width * (childrenCount - 1) + Padding.Start + Padding.End);
 388             float widthSize = Math.Max(totalLength, SuggestedMinimumWidth.AsDecimal());
 389             MeasuredSize widthSizeAndState = ResolveSizeAndState(new LayoutLength(widthSize), widthMeasureSpec, MeasuredSize.StateType.MeasuredSizeOK);
 390             widthSize = widthSizeAndState.Size.AsDecimal();
 391
 392             float remainingWidth = widthSize - totalLength;
 393             float totalWeightLength = 0.0f;
 394
 395             // Up to now, only WrapContent children's sizes are added to the totalLength.
 396             // Since the totalLength is used in OnLayout as the sum of all children's sizes,
 397             // the layout size is assigned to the totalLength if MatchParent child exists.
 398             if (childrenMatchParentCount > 0)
 399             {
 400                 totalLength = widthSize;
 401             }
 402
 403             // 2ND PHASE:
 404             //
 405             // We measure all children whose width specification policy is MatchParent without weight.
 406             // After 2nd phase, all children's widths are calculated without considering weight.
 407             // And the widths of all weighted children are accumulated to calculate weighted width.
 408             foreach (var childLayout in LayoutChildren)
 409             {
 410                 if (!childLayout.SetPositionByLayout)
 411                 {
 412                     continue;
 413                 }
 414                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 415                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 416                 float childWeight = childLayout.Owner.Weight;
 417                 Extents childMargin = childLayout.Margin;
 418                 bool useRemainingWidth = (childDesiredWidth == 0) && (childWeight > 0);
 419                 bool needToMeasure = false;
 420
 421                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 422                 {
 423                     if (isHeightExactly)
 424                     {
 425                         needToMeasure = true;
 426                     }
 427                     // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 428                     // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 429                     // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 430                     //
 431                     // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 432                     else if (Owner.HeightSpecification == LayoutParamPolicies.WrapContent)
 433                     {
 434                         if (childDesiredHeight == LayoutParamPolicies.MatchParent)
 435                         {
 436                             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!");
 437                         }
 438                         else
 439                         {
 440                             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!");
 441                         }
 442                     }
 443                 }
 444
 445                 if (remainingWidth > 0)
 446                 {
 447                     if ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (useRemainingWidth))
 448                     {
 449                         if (isWidthExactly)
 450                         {
 451                             // In MeasureChildWithMargins(), it is assumed that widthMeasureSpec includes Padding.Start and Padding.End.
 452                             // Therefore, Padding.Start and Padding.End are added to widthMeasureSpec.Size before it is passed to MeasureChildWithMargins().
 453                             widthMeasureSpec.SetSize(new LayoutLength((int)(remainingWidth / childrenMatchParentCount) + Padding.Start + Padding.End));
 454                             needToMeasure = true;
 455                         }
 456                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 457                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 458                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 459                         //
 460                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 461                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 462                         {
 463                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 464                             {
 465                                 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!");
 466                             }
 467                             else
 468                             {
 469                                 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!");
 470                             }
 471                         }
 472                     }
 473                 }
 474
 475                 if (needToMeasure == true)
 476                 {
 477                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 478                 }
 479
 480                 if ((childWeight > 0) && ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (childDesiredWidth == 0)))
 481                 {
 482                     float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 483
 484                     if (childMeasuredWidth < 0)
 485                     {
 486                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMargin.Start + childMargin.End);
 487                     }
 488                     else
 489                     {
 490                         totalWeightLength = Math.Max(totalWeightLength, totalWeightLength + childMeasuredWidth + childMargin.Start + childMargin.End);
 491                     }
 492                 }
 493             } // 2ND PHASE foreach
 494
 495             // 3RD PHASE:
 496             //
 497             // We measure all weighted children whose owner has weight greater than 0.
 498             // After 3rd phase, all weighted children has width which is proportional to their weights
 499             // in remaining width of parent.
 500             if (totalWeight > 0.0f)
 501             {
 502                 foreach (LayoutItem childLayout in LayoutChildren)
 503                 {
 504                     if (!childLayout.SetPositionByLayout)
 505                     {
 506                         continue;
 507                     }
 508                     int childDesiredWidth = childLayout.Owner.WidthSpecification;
 509                     float childWeight = childLayout.Owner.Weight;
 510
 511                     if ((childWeight > 0) && ((childDesiredWidth == LayoutParamPolicies.MatchParent) || (childDesiredWidth == 0)))
 512                     {
 513                         if (isWidthExactly)
 514                         {
 515                             MeasureWeightedChild(childLayout, totalWeightLength, totalWeight, childWeight,
 516                                                  widthMeasureSpec, heightMeasureSpec, childState,
 517                                                  Orientation.Horizontal);
 518                         }
 519                         // RelativeLayout's MatchParent children should not fill to the RelativeLayout.
 520                         // Because the children's sizes and positions are calculated by RelativeLayout's APIs.
 521                         // Therefore, not to fill the RelativeLayout, the mode is changed from Exactly to AtMost.
 522                         //
 523                         // Not to print the recursive reference error message for this case, Specification is checked if it is WrapContent.
 524                         else if (Owner.WidthSpecification == LayoutParamPolicies.WrapContent)
 525                         {
 526                             if (childDesiredWidth == LayoutParamPolicies.MatchParent)
 527                             {
 528                                 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!");
 529                             }
 530                             else
 531                             {
 532                                 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!");
 533                             }
 534                         }
 535                     }
 536                 }
 537             }
 538             // 3RD PHASE foreach
 539
 540             // Decide the max height among children.
 541             foreach (var childLayout in LayoutChildren)
 542             {
 543                 if (!childLayout.SetPositionByLayout)
 544                 {
 545                     continue;
 546                 }
 547
 548                 Extents childMargin = childLayout.Margin;
 549                 float childMarginHeight = childMargin.Top + childMargin.Bottom;
 550                 float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 551
 552                 if (childMeasuredHeight < 0)
 553                 {
 554                     maxHeight = Math.Max(maxHeight, childMarginHeight);
 555                 }
 556                 else
 557                 {
 558                     maxHeight = Math.Max(maxHeight, childMeasuredHeight + childMarginHeight);
 559                 }
 560             }
 561
 562             // Decide the max height compared with paddings and its suggested height.
 563             maxHeight = Math.Max(maxHeight, maxHeight + (Padding.Top + Padding.Bottom));
 564             maxHeight = Math.Max(maxHeight, SuggestedMinimumHeight.AsRoundedValue());
 565
 566             widthSizeAndState.State = childState.widthState;
 567
 568             SetMeasuredDimensions(widthSizeAndState,
 569                                   ResolveSizeAndState(new LayoutLength(maxHeight), heightMeasureSpec, childState.heightState));
 570         } // MeasureHorizontal
 571
 572         private void MeasureVertical(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
 573         {
 574             var widthMode = widthMeasureSpec.Mode;
 575             var heightMode = heightMeasureSpec.Mode;
 576             bool isWidthExactly = (widthMode == MeasureSpecification.ModeType.Exactly);
 577             bool isHeightExactly = (heightMode == MeasureSpecification.ModeType.Exactly);
 578             float maxWidth = 0.0f;
 579             float totalWeight = 0.0f;
 580             int childrenCount = IterateLayoutChildren().Count();
 581
 582             // Child layout, which wants to match its height to its parent's remaining height, is either following 1 or 2.
 583             // 1. Child layout whose Owner.HeightSpecification is LayoutParamPolicies.MatchParent.
 584             // 2. Child layout whose Owner.HeightSpecification is 0 and Owner.Weight is greater than 0.
 585             // The number of child layout which wants to match its height to its parent's remaining height.
 586             int childrenMatchParentCount = 0;
 587
 588             // Reset measure variable
 589             totalLength = 0.0f;
 590
 591             HeightAndWidthState childState = new HeightAndWidthState(MeasuredSize.StateType.MeasuredSizeOK,
 592                                                                      MeasuredSize.StateType.MeasuredSizeOK);
 593
 594             // 1ST PHASE:
 595             //
 596             // We measure all children whose height specification policy is WrapContent without weight.
 597             // After 1st phase, remaining height of parent is accumulated to calculate height of children
 598             // whose height specification policy is MatchParent.
 599             foreach (var childLayout in LayoutChildren)
 600             {
 601                 if (!childLayout.SetPositionByLayout)
 602                 {
 603                     continue;
 604                 }
 605                 int childDesiredWidth = childLayout.Owner.WidthSpecification;
 606                 int childDesiredHeight = childLayout.Owner.HeightSpecification;
 607                 float childWeight = childLayout.Owner.Weight;
 608                 Extents childMargin = childLayout.Margin;
 609                 float childMarginHeight = childMargin.Top + childMargin.Bottom;
 610                 bool useRemainingHeight = (childDesiredHeight == 0) && (childWeight > 0);
 611
 612                 if ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (useRemainingHeight))
 613                 {
 614                     totalWeight += childWeight;
 615                     childrenMatchParentCount++;
 616                 }
 617
 618                 // MatchParent child layout's margin is not added to totalLength.
 619                 // Consequently, MatchParent child layout's margin is added to remaining size,
 620                 // so the margin is not shared with other MatchParent child layouts.
 621                 // e.g.
 622                 // LinearLayout has size 100.
 623                 // Child layout1 is MatchParent and its margin is 20. (This margin is not ad
 624                 // Child layout2 is MatchParent and its margin is 0.
 625                 // Then, child layout1's size is 30 and child layout2's size is 50.
 626                 if ((childDesiredHeight == LayoutParamPolicies.WrapContent) || ((childDesiredHeight >= 0) && (!useRemainingHeight)))
 627                 {
 628                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0), heightMeasureSpec, new LayoutLength(0));
 629
 630                     float childMeasuredHeight = childLayout.MeasuredHeight.Size.AsDecimal();
 631
 632                     if (childMeasuredHeight < 0)
 633                     {
 634                         totalLength = Math.Max(totalLength, totalLength + childMarginHeight);
 635                     }
 636                     else
 637                     {
 638                         totalLength = Math.Max(totalLength, totalLength + childMeasuredHeight + childMarginHeight);
 639                     }
 640                 }
 641
 642                 if (childLayout.MeasuredWidth.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 643                 {
 644                     childState.widthState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 645                 }
 646                 if (childLayout.MeasuredHeight.State == MeasuredSize.StateType.MeasuredSizeTooSmall)
 647                 {
 648                     childState.heightState = MeasuredSize.StateType.MeasuredSizeTooSmall;
 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) && ((childDesiredHeight == LayoutParamPolicies.MatchParent) || (childDesiredHeight == 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                 }
 802             } // 3RD PHASE foreach
 803
 804             // Decide the max width among children.
 805             foreach (var childLayout in LayoutChildren)
 806             {
 807                 if (!childLayout.SetPositionByLayout)
 808                 {
 809                     continue;
 810                 }
 811
 812                 Extents childMargin = childLayout.Margin;
 813                 float childMarginWidth = childMargin.Start + childMargin.End;
 814                 float childMeasuredWidth = childLayout.MeasuredWidth.Size.AsDecimal();
 815
 816                 if (childMeasuredWidth < 0)
 817                 {
 818                     maxWidth = Math.Max(maxWidth, childMarginWidth);
 819                 }
 820                 else
 821                 {
 822                     maxWidth = Math.Max(maxWidth, childMeasuredWidth + childMarginWidth);
 823                 }
 824             }
 825
 826             // Decide the max width compared with paddings and its suggested width.
 827             maxWidth = Math.Max(maxWidth, maxWidth + (Padding.Start + Padding.End));
 828             maxWidth = Math.Max(maxWidth, SuggestedMinimumWidth.AsRoundedValue());
 829
 830             heightSizeAndState.State = childState.heightState;
 831
 832             SetMeasuredDimensions(ResolveSizeAndState(new LayoutLength(maxWidth), widthMeasureSpec, childState.widthState),
 833                                   heightSizeAndState);
 834         } // MeasureVertical
 835
 836         private void LayoutHorizontal(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 837         {
 838             bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
 839
 840             LayoutLength childTop = new LayoutLength(Padding.Top);
 841             LayoutLength childLeft = new LayoutLength(Padding.Start);
 842
 843             // Where bottom of child should go
 844             LayoutLength height = new LayoutLength(bottom - top);
 845
 846             // Space available for child
 847             LayoutLength childSpace = new LayoutLength(height - Padding.Top - Padding.Bottom);
 848
 849             var LinearChildren = IterateLayoutChildren();
 850             int count = LinearChildren.Count<LayoutItem>();
 851
 852             switch (HorizontalAlignment)
 853             {
 854                 case HorizontalAlignment.End:
 855                     // totalLength contains the padding already
 856                     // In case of RTL map END alignment to the left edge
 857                     if (isLayoutRtl)
 858                     {
 859                         childLeft = new LayoutLength(Padding.Start);
 860                     }
 861                     else
 862                     {
 863                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 864                     }
 865                     break;
 866                 case HorizontalAlignment.Center:
 867                     // totalLength contains the padding already
 868                     childLeft = new LayoutLength(Padding.Start + (right.AsDecimal() - left.AsDecimal() - totalLength) / 2.0f);
 869                     break;
 870                 case HorizontalAlignment.Begin: // FALL THROUGH (default)
 871                 default:
 872                     // totalLength contains the padding already
 873                     // In case of RTL map BEGIN alignment to the right edge
 874                     if (isLayoutRtl)
 875                     {
 876                         childLeft = new LayoutLength(Padding.Start + right.AsDecimal() - left.AsDecimal() - totalLength);
 877                     }
 878                     else
 879                     {
 880                         childLeft = new LayoutLength(Padding.Start);
 881                     }
 882                     break;
 883             }
 884
 885             int start = 0;
 886             int dir = 1;
 887
 888             // In case of RTL, start drawing from the last child.
 889             if (isLayoutRtl)
 890             {
 891                 start = count - 1;
 892                 dir = -1;
 893             }
 894
 895             for (int i = 0; i < count; i++)
 896             {
 897                 int childIndex = start + dir * i;
 898                 // Get a reference to the childLayout at the given index
 899                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 900
 901                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 902                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 903                 Extents childMargin = childLayout.Margin;
 904
 905                 switch (VerticalAlignment)
 906                 {
 907                     case VerticalAlignment.Bottom:
 908                         childTop = new LayoutLength(height - Padding.Bottom - childHeight - childMargin.Bottom);
 909                         break;
 910                     case VerticalAlignment.Center:
 911                         childTop = new LayoutLength(Padding.Top + ((childSpace - childHeight).AsDecimal() / 2.0f) + childMargin.Top - childMargin.Bottom);
 912                         break;
 913                     case VerticalAlignment.Top: // FALLTHROUGH default
 914                     default:
 915                         childTop = new LayoutLength(Padding.Top + childMargin.Top);
 916                         break;
 917                 }
 918                 childLeft += (isLayoutRtl ? childMargin.End : childMargin.Start);
 919                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 920                 childLeft += childWidth + (isLayoutRtl ? childMargin.Start : childMargin.End) + ((i < count - 1) ? CellPadding.Width : 0);
 921             }
 922         } // LayoutHorizontally
 923
 924         private void LayoutVertical(LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
 925         {
 926             LayoutLength childTop = new LayoutLength(Padding.Top);
 927             LayoutLength childLeft = new LayoutLength(Padding.Start);
 928
 929             // Where end of child should go
 930             LayoutLength width = new LayoutLength(right - left);
 931
 932             // Space available for child
 933             LayoutLength childSpace = new LayoutLength(width - Padding.Start - Padding.End);
 934
 935             var LinearChildren = IterateLayoutChildren();
 936             int count = LinearChildren.Count<LayoutItem>();
 937
 938             switch (VerticalAlignment)
 939             {
 940                 case VerticalAlignment.Bottom:
 941                     // totalLength contains the padding already
 942                     childTop = new LayoutLength(Padding.Top + bottom.AsDecimal() - top.AsDecimal() - totalLength);
 943                     break;
 944                 case VerticalAlignment.Center:
 945                     // totalLength contains the padding already
 946                     childTop = new LayoutLength(Padding.Top + (bottom.AsDecimal() - top.AsDecimal() - totalLength) / 2.0f);
 947                     break;
 948                 case VerticalAlignment.Top:  // FALL THROUGH (default)
 949                 default:
 950                     // totalLength contains the padding already
 951                     childTop = new LayoutLength(Padding.Top);
 952                     break;
 953             }
 954
 955             for (int i = 0; i < count; i++)
 956             {
 957                 LayoutItem childLayout = LinearChildren.ElementAt<LayoutItem>(i);
 958
 959                 LayoutLength childWidth = childLayout.MeasuredWidth.Size;
 960                 LayoutLength childHeight = childLayout.MeasuredHeight.Size;
 961                 Extents childMargin = childLayout.Margin;
 962
 963                 childTop += childMargin.Top;
 964                 switch (HorizontalAlignment)
 965                 {
 966                     case HorizontalAlignment.Begin:
 967                     default:
 968                         {
 969                             childLeft = new LayoutLength(Padding.Start + childMargin.Start);
 970                             break;
 971                         }
 972                     case HorizontalAlignment.End:
 973                         {
 974                             childLeft = new LayoutLength(width - Padding.End - childWidth - childMargin.End);
 975                             break;
 976                         }
 977                     case HorizontalAlignment.Center:
 978                         {
 979                             childLeft = new LayoutLength(Padding.Start + ((childSpace - childWidth).AsDecimal() / 2.0f) + childMargin.Start - childMargin.End);
 980                             break;
 981                         }
 982                 }
 983                 childLayout.Layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
 984                 childTop += childHeight + childMargin.Bottom + ((i < count - 1) ? CellPadding.Height : 0);
 985             }
 986         } // LayoutVertical
 987
 988         private void ForceUniformHeight(MeasureSpecification widthMeasureSpec)
 989         {
 990             // Pretend that the linear layout has an exact size. This is the measured height of
 991             // ourselves. The measured height should be the max height of the children, changed
 992             // to accommodate the heightMeasureSpec from the parent
 993             MeasureSpecification uniformMeasureSpec = new MeasureSpecification(MeasuredHeight.Size, MeasureSpecification.ModeType.Exactly);
 994             foreach (var childLayout in LayoutChildren)
 995             {
 996                 if (!childLayout.SetPositionByLayout)
 997                 {
 998                     continue;
 999                 }
1000                 int desiredChildHeight = childLayout.Owner.HeightSpecification;
1001                 int desiredChildWidth = childLayout.Owner.WidthSpecification;
1002
1003                 if (desiredChildHeight == LayoutParamPolicies.MatchParent)
1004                 {
1005                     // Temporarily force children to reuse their original measured width
1006                     int originalWidth = desiredChildWidth;
1007                     childLayout.Owner.WidthSpecification = (int)childLayout.MeasuredWidth.Size.AsRoundedValue();
1008                     // Remeasure with new dimensions
1009                     MeasureChildWithMargins(childLayout, widthMeasureSpec, new LayoutLength(0),
1010                                              uniformMeasureSpec, new LayoutLength(0));
1011                     // Restore width specification
1012                     childLayout.Owner.WidthSpecification = originalWidth;
1013                 }
1014             }
1015         }
1016     } //LinearLayout
1017 } // namespace