1 /* Copyright (c) 2020 Samsung Electronics Co., Ltd.
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
7 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 using System.ComponentModel;
19 using Tizen.NUI.BaseComponents;
20 using System.Runtime.InteropServices;
21 using System.Diagnostics;
22 using Tizen.NUI.Binding;
27 /// This class implements a flex layout.
28 /// The flex layout implementation is based on open source Facebook Yoga layout engine.
29 /// For more information about the flex layout API and how to use it please refer to https://yogalayout.com/docs/
30 /// We implement the subset of the API in the class below.
32 public class FlexLayout : LayoutGroup, global::System.IDisposable
37 [EditorBrowsable(EditorBrowsableState.Never)]
38 internal static readonly BindableProperty FlexItemProperty = BindableProperty.CreateAttached("FlexItem", typeof(HandleRef), typeof(FlexLayout), default(HandleRef));
41 /// FlexAlignmentSelfProperty
43 [EditorBrowsable(EditorBrowsableState.Never)]
44 public static readonly BindableProperty FlexAlignmentSelfProperty = BindableProperty.CreateAttached("FlexAlignmentSelf", typeof(AlignmentType), typeof(FlexLayout), AlignmentType.Auto, validateValue: ValidateEnum((int)AlignmentType.Auto, (int)AlignmentType.Stretch), propertyChanged: OnChildPropertyChanged);
47 /// FlexPositionTypeProperty
49 [EditorBrowsable(EditorBrowsableState.Never)]
50 public static readonly BindableProperty FlexPositionTypeProperty = BindableProperty.CreateAttached("FlexPositionType", typeof(PositionType), typeof(FlexLayout), PositionType.Relative, validateValue: ValidateEnum((int)PositionType.Relative, (int)PositionType.Absolute),
51 propertyChanged: (bindable, oldValue, newValue) =>
53 if (bindable is View view)
55 view.ExcludeLayouting = (PositionType)newValue == PositionType.Absolute;
58 defaultValueCreator: (bindable) =>
60 var view = (View)bindable;
61 if (view.ExcludeLayouting)
62 return PositionType.Absolute;
64 return PositionType.Relative;
69 /// AspectRatioProperty
71 [EditorBrowsable(EditorBrowsableState.Never)]
72 public static readonly BindableProperty FlexAspectRatioProperty = BindableProperty.CreateAttached("FlexAspectRatio", typeof(float), typeof(FlexLayout), FlexUndefined, validateValue: (bindable, value) => (float)value > 0, propertyChanged: OnChildPropertyChanged);
77 [EditorBrowsable(EditorBrowsableState.Never)]
78 public static readonly BindableProperty FlexBasisProperty = BindableProperty.CreateAttached("FlexBasis", typeof(float), typeof(FlexLayout), FlexUndefined, validateValue: (bindable, value) => (float)value >= 0, propertyChanged: OnChildPropertyChanged);
81 /// FlexShrinkProperty
83 [EditorBrowsable(EditorBrowsableState.Never)]
84 public static readonly BindableProperty FlexShrinkProperty = BindableProperty.CreateAttached("FlexShrink", typeof(float), typeof(FlexLayout), 1.0f, validateValue: (bindable, value) => (float)value >= 0, propertyChanged: OnChildPropertyChanged);
89 [EditorBrowsable(EditorBrowsableState.Never)]
90 public static readonly BindableProperty FlexGrowProperty = BindableProperty.CreateAttached("FlexGrow", typeof(float), typeof(FlexLayout), FlexUndefined, validateValue: (bindable, value) => (float)value >= 0, propertyChanged: OnChildPropertyChanged);
92 private static bool LayoutDebugFlex = false; // Debug flag
94 private global::System.Runtime.InteropServices.HandleRef swigCPtr;
95 private bool swigCMemOwn;
96 private bool disposed;
97 private bool isDisposeQueued = false;
99 private MeasureSpecification parentMeasureSpecificationWidth;
100 private MeasureSpecification parentMeasureSpecificationHeight;
102 private IntPtr _rootFlex; // Pointer to the unmanged flex layout class.
104 internal const float FlexUndefined = 10E20F; // Auto setting which is equivalent to WrapContent.
106 internal struct MeasuredSize
108 public MeasuredSize(float x, float y)
118 /// Gets the alignment self of the child view.
120 /// <seealso cref="SetFlexAlignmentSelf(View, AlignmentType)"/>
121 /// <param name="view">The child view.</param>
122 /// <returns> The value of alignment self.</returns>
123 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
124 /// <since_tizen> 8 </since_tizen>
125 public static AlignmentType GetFlexAlignmentSelf(View view) => GetAttachedValue<AlignmentType>(view, FlexAlignmentSelfProperty);
128 /// Gets the position type of the child view.
130 /// <seealso cref="SetFlexPositionType(View, PositionType)"/>
131 /// <param name="view">The child view.</param>
132 /// <returns> The value of position type</returns>
133 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
134 /// <since_tizen> 8 </since_tizen>
135 public static PositionType GetFlexPositionType(View view) => GetAttachedValue<PositionType>(view, FlexPositionTypeProperty);
138 /// Gets the aspect ratio of the child view.
140 /// <seealso cref="SetFlexAspectRatio(View, float)"/>
141 /// <param name="view">The child view.</param>
142 /// <returns> The value of aspect ratio</returns>
143 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
144 /// <since_tizen> 8 </since_tizen>
145 public static float GetFlexAspectRatio(View view) => GetAttachedValue<float>(view, FlexAspectRatioProperty);
148 /// Gets the basis of the child view.
150 /// <seealso cref="SetFlexBasis(View, float)"/>
151 /// <param name="view">The child view.</param>
152 /// <returns> The value of basis</returns>
153 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
154 /// <since_tizen> 8 </since_tizen>
155 public static float GetFlexBasis(View view) => GetAttachedValue<float>(view, FlexBasisProperty);
158 /// Gets the shrink of the child view.
160 /// <seealso cref="SetFlexShrink(View, float)"/>
161 /// <param name="view">The child view.</param>
162 /// <returns> The value of shrink</returns>
163 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
164 /// <since_tizen> 8 </since_tizen>
165 public static float GetFlexShrink(View view) => GetAttachedValue<float>(view, FlexShrinkProperty);
168 /// Gets the grow of the child view.
170 /// <seealso cref="SetFlexGrow(View, float)"/>
171 /// <param name="view">The child view.</param>
172 /// <returns> The value of grow</returns>
173 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
174 /// <since_tizen> 8 </since_tizen>
175 public static float GetFlexGrow(View view) => GetAttachedValue<float>(view, FlexGrowProperty);
178 /// Sets the alignment self of the child view.<br/>
179 /// Alignment self has the same options and effect as <see cref="ItemsAlignment"/> but instead of affecting the children within a container,
180 /// you can apply this property to a single child to change its alignment within its parent.<br/>
181 /// Alignment self overrides any option set by the parent with <see cref="ItemsAlignment"/>.
183 /// <param name="view">The child view.</param>
184 /// <param name="value">The value of alignment self.</param>
185 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
186 /// <exception cref="ArgumentException">The <paramref name="value"/> should be <see cref="AlignmentType"/>.</exception>
187 /// <since_tizen> 8 </since_tizen>
188 public static void SetFlexAlignmentSelf(View view, AlignmentType value) => SetAttachedValue(view, FlexAlignmentSelfProperty, value);
191 /// Sets the position type of the child view.<br/>
192 /// The position type of an element defines how it is positioned within its parent.
193 /// By default a child is positioned relatively. This means a child is positioned according to the normal flow of the layout,
194 /// and then offset relative to that position based on the values of <see cref="View.Margin"/>.<br/>
195 /// When positioned absolutely an element doesn't take part in the normal layout flow.
196 /// It is instead laid out independent of its siblings. The position is determined based on the <see cref="View.Margin"/>.
198 /// <param name="view">The child view.</param>
199 /// <param name="value">The value of position type.</param>
200 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
201 /// <exception cref="ArgumentException">The <paramref name="value"/> should be <see cref="PositionType"/>.</exception>
202 /// <since_tizen> 8 </since_tizen>
203 public static void SetFlexPositionType(View view, PositionType value) => SetAttachedValue(view, FlexPositionTypeProperty, value);
206 /// Sets the aspect ratio of the child view.
207 /// Aspect ratio Defines as the ratio between the width and the height of a node
208 /// e.g. if a node has an aspect ratio of 2 then its width is twice the size of its height.<br/>
209 /// Aspect ratio accepts any floating point value > 0. this has higher priority than flex grow.
211 /// <param name="view">The child view.</param>
212 /// <param name="value">The value of aspect ratio</param>
213 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
214 /// <exception cref="ArgumentException">The <paramref name="value"/> cannot be less than or equal to 0.0f.</exception>
215 /// <since_tizen> 8 </since_tizen>
216 public static void SetFlexAspectRatio(View view, float value) => SetAttachedValue(view, FlexAspectRatioProperty, value);
219 /// Sets the flex basis of the child view.
220 /// Flex basis is an axis-independent way of providing the default size of an item along the main axis.<br/>
221 /// Setting the flex basis of a child is similar to setting the width of that child if its parent is a container with <see cref="FlexDirection.Row"/>
222 /// or setting the height of a child if its parent is a container with <see cref="FlexDirection.Column"/>.<br/>
223 /// The flex basis of an item is the default size of that item, the size of the item before any flex grow and flex shrink calculations are performed.
225 /// <param name="view">The child view.</param>
226 /// <param name="value">The value of basis</param>
227 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
228 /// <exception cref="ArgumentException">The <paramref name="value"/> cannot be less than 0.0f.</exception>
229 /// <since_tizen> 8 </since_tizen>
230 public static void SetFlexBasis(View view, float value) => SetAttachedValue(view, FlexBasisProperty, value);
233 /// Sets the flex shrink of the child view.
234 /// Flex shrink describes how to shrink children along the main axis in the case that the total size of the children overflow the size of the container on the main axis.<br/>
235 /// Flex shrink is very similar to flex grow and can be thought of in the same way if any overflowing size is considered to be negative remaining space.
236 /// These two properties also work well together by allowing children to grow and shrink as needed.<br/>
237 /// Flex shrink accepts any floating point value >= 0, with 1 being the default value. A container will shrink its children weighted by the child's flex shrink value.
239 /// <param name="view">The child view.</param>
240 /// <param name="value">The value of shrink</param>
241 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
242 /// <exception cref="ArgumentException">The <paramref name="value"/> cannot be less than 0.0f.</exception>
243 /// <since_tizen> 8 </since_tizen>
244 public static void SetFlexShrink(View view, float value) => SetAttachedValue(view, FlexShrinkProperty, value);
247 /// Sets the grow of the child view.
248 /// Flex grow describes how any space within a container should be distributed among its children along the main axis.
249 /// After laying out its children, a container will distribute any remaining space according to the flex grow values specified by its children.<br/>
250 /// Flex grow accepts any floating point value >= 0, with 0 being the default value.<br/>
251 /// A container will distribute any remaining space among its children weighted by the child's flex grow value.
253 /// <param name="view">The child view.</param>
254 /// <param name="value">The value of flex</param>
255 /// <exception cref="ArgumentNullException">The <paramref name="view"/> cannot be null.</exception>
256 /// <exception cref="ArgumentException">The <paramref name="value"/> cannot be less than 0.0f.</exception>
257 /// <since_tizen> 8 </since_tizen>
258 public static void SetFlexGrow(View view, float value) => SetAttachedValue(view, FlexGrowProperty, value);
260 [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
261 internal delegate void ChildMeasureCallback(global::System.IntPtr child, float width, int measureModeWidth, float height, int measureModeHeight, out MeasuredSize measureSize);
263 event ChildMeasureCallback measureChildDelegate; // Stores a delegate to the child measure callback. Used for all children of this FlexLayout.
265 internal FlexLayout(global::System.IntPtr cPtr, bool cMemoryOwn)
267 swigCMemOwn = cMemoryOwn;
268 swigCPtr = new global::System.Runtime.InteropServices.HandleRef(this, cPtr);
269 _rootFlex = Interop.FlexLayout.FlexLayout_New();
270 measureChildDelegate = new ChildMeasureCallback(measureChild);
273 internal static global::System.Runtime.InteropServices.HandleRef getCPtr(FlexLayout obj)
275 return (obj == null) ? new global::System.Runtime.InteropServices.HandleRef(null, global::System.IntPtr.Zero) : obj.swigCPtr;
279 /// <since_tizen> 6 </since_tizen>
280 public void Dispose()
282 // Throw exception if Dispose() is called in separate thread.
283 if (!Window.IsInstalled())
285 throw new System.InvalidOperationException("This API called from separate thread. This API must be called from MainThread.");
290 Dispose(DisposeTypes.Implicit);
294 Dispose(DisposeTypes.Explicit);
295 System.GC.SuppressFinalize(this);
300 /// <since_tizen> 6 </since_tizen>
301 protected virtual void Dispose(DisposeTypes type)
308 if (type == DisposeTypes.Explicit)
311 // Release your own managed resources here.
312 // You should release all of your own disposable objects here.
316 // Release your own unmanaged resources here.
317 // You should not access any managed member here except static instance.
318 // because the execution order of Finalizes is non-deterministic.
319 if (swigCPtr.Handle != global::System.IntPtr.Zero)
324 Interop.FlexLayout.delete_FlexLayout(swigCPtr);
326 swigCPtr = new global::System.Runtime.InteropServices.HandleRef(null, global::System.IntPtr.Zero);
332 /// Creates a FlexLayout object.
334 /// <since_tizen> 6 </since_tizen>
335 public FlexLayout() : this(Interop.FlexLayout.FlexLayout_New(), true)
337 if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
340 internal static FlexLayout DownCast(BaseHandle handle)
342 FlexLayout ret = new FlexLayout(Interop.FlexLayout.FlexLayout_DownCast(BaseHandle.getCPtr(handle)), true);
343 if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
347 internal FlexLayout(FlexLayout other) : this(Interop.FlexLayout.new_FlexLayout__SWIG_1(FlexLayout.getCPtr(other)), true)
349 if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
352 internal FlexLayout.AlignmentType GetFlexAlignment()
354 FlexLayout.AlignmentType ret = (FlexLayout.AlignmentType)Interop.FlexLayout.FlexLayout_GetFlexAlignment(swigCPtr);
355 if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
359 internal FlexLayout.AlignmentType GetFlexItemsAlignment()
361 FlexLayout.AlignmentType ret = (FlexLayout.AlignmentType)Interop.FlexLayout.FlexLayout_GetFlexItemsAlignment(swigCPtr);
362 if (NDalicPINVOKE.SWIGPendingException.Pending) throw NDalicPINVOKE.SWIGPendingException.Retrieve();
367 /// Gets/Sets the flex direction in the layout.
368 /// The direction of the main-axis which determines the direction that flex items are laid out.
370 /// <exception cref="InvalidEnumArgumentException">Thrown when using invalid arguments that are enumerators.</exception>
371 /// <since_tizen> 6 </since_tizen>
372 public FlexDirection Direction
374 get => (FlexDirection)Interop.FlexLayout.FlexLayout_GetFlexDirection(swigCPtr);
377 if (value < FlexDirection.Column || value > FlexDirection.RowReverse)
378 throw new InvalidEnumArgumentException(nameof(Direction));
380 Interop.FlexLayout.FlexLayout_SetFlexDirection(swigCPtr, (int)value);
386 /// Gets/Sets the justification in the layout.
387 /// Justify content describes how to align children within the main axis of their container.<br/>
388 /// For example, you can use this property to center a child horizontally within a container with <see cref="Direction"/> set to <see cref="FlexDirection.Row"/>
389 /// or vertically within a container with <see cref="Direction"/> set to <see cref="FlexDirection.Column"/>.
391 /// <exception cref="InvalidEnumArgumentException">Thrown when using invalid arguments that are enumerators.</exception>
392 /// <since_tizen> 6 </since_tizen>
393 public FlexJustification Justification
395 get => (FlexJustification)Interop.FlexLayout.FlexLayout_GetFlexJustification(swigCPtr);
398 if (value < FlexJustification.FlexStart || value > FlexJustification.SpaceAround)
399 throw new InvalidEnumArgumentException(nameof(Justification));
401 Interop.FlexLayout.FlexLayout_SetFlexJustification(swigCPtr, (int)value);
407 /// Gets/Sets the wrap in the layout.
408 /// The flex wrap property is set on containers and controls what happens when children overflow the size of the container along the main axis.<br/>
409 /// By default children are forced into a single line (which can shrink elements).<br/>
410 /// If wrapping is allowed items are wrapped into multiple lines along the main axis if needed. wrap reverse behaves the same, but the order of the lines is reversed.<br/>
411 /// When wrapping lines <see cref="Alignment"/> can be used to specify how the lines are placed in the container.
413 /// <exception cref="InvalidEnumArgumentException">Thrown when using invalid arguments that are enumerators.</exception>
414 /// <since_tizen> 6 </since_tizen>
415 public FlexWrapType WrapType
417 get => (FlexWrapType)Interop.FlexLayout.FlexLayout_GetFlexWrap(swigCPtr);
420 if (value != FlexWrapType.NoWrap && value != FlexWrapType.Wrap)
421 throw new InvalidEnumArgumentException(nameof(WrapType));
423 Interop.FlexLayout.FlexLayout_SetFlexWrap(swigCPtr, (int)value);
430 /// Gets/Sets the alignment of the layout content.
431 /// Alignment defines the distribution of lines along the cross-axis.<br/>
432 /// This only has effect when items are wrapped to multiple lines using flex wrap.
434 /// <exception cref="InvalidEnumArgumentException">Thrown when using invalid arguments that are enumerators.</exception>
435 /// <since_tizen> 6 </since_tizen>
436 public AlignmentType Alignment
438 get => GetFlexAlignment();
441 if (value < AlignmentType.Auto || value > AlignmentType.Stretch)
442 throw new InvalidEnumArgumentException(nameof(Alignment));
444 Interop.FlexLayout.FlexLayout_SetFlexAlignment(swigCPtr, (int)value);
450 /// Gets/Sets the alignment of the layout items.
451 /// Items alignment describes how to align children along the cross axis of their container.<br/>
452 /// Align items is very similar to <see cref="Justification"/> but instead of applying to the main axis, align items applies to the cross axis.
454 /// <exception cref="InvalidEnumArgumentException">Thrown when using invalid arguments that are enumerators.</exception>
455 /// <since_tizen> 6 </since_tizen>
456 public AlignmentType ItemsAlignment
458 get => GetFlexItemsAlignment();
461 if (value < AlignmentType.Auto || value > AlignmentType.Stretch)
462 throw new InvalidEnumArgumentException(nameof(ItemsAlignment));
464 Interop.FlexLayout.FlexLayout_SetFlexItemsAlignment(swigCPtr, (int)value);
470 /// Enumeration for the direction of the main axis in the flex container.
471 /// This determines the direction that flex items are laid out in the flex container.
473 /// <since_tizen> 6 </since_tizen>
474 public enum FlexDirection
477 /// The flexible items are displayed vertically as a column
481 /// The flexible items are displayed vertically as a column, but in reverse order
485 /// The flexible items are displayed horizontally as a row
489 /// The flexible items are displayed horizontally as a row, but in reverse order
495 /// Enumeration for the alignment of the flex items when the items do not use all available space on the main-axis.
497 /// <since_tizen> 6 </since_tizen>
498 public enum FlexJustification
501 /// Items are positioned at the beginning of the container.
505 /// Items are positioned at the center of the container.
509 /// Items are positioned at the end of the container.
513 /// Items are positioned with equal space between the lines.
517 /// Items are positioned with equal space before, between, and after the lines.<br/>
518 /// Compared to <see cref="FlexJustification.SpaceBetween"/> using <see cref="FlexJustification.SpaceAround"/>
519 /// will result in space being distributed to the beginning of the first child and end of the last child.
525 /// Enumeration for the wrap type of the flex container when there is no enough room for all the items on one flex line.
527 /// <since_tizen> 6 </since_tizen>
528 public enum FlexWrapType
531 /// Flex items laid out in single line (shrunk to fit the flex container along the main axis)
535 /// Flex items laid out in multiple lines if needed
541 /// Enumeration for the alignment of the flex items or lines when the items or lines do not use all the available space on the cross-axis.
543 /// <since_tizen> 6 </since_tizen>
544 public enum AlignmentType
547 /// Inherits the same alignment from the parent
551 /// At the beginning of the container
555 /// At the center of the container
559 /// At the end of the container
563 /// Stretch to fit the container
569 /// Enumeration for the position type of the flex item how it is positioned within its parent.
571 /// <since_tizen> 8 </since_tizen>
572 public enum PositionType
575 /// Flex items laid out relatively.
579 /// Flex items laid out absolutely.
584 private void measureChild(global::System.IntPtr childPtr, float width, int measureModeWidth, float height, int measureModeHeight, out MeasuredSize measureSize)
586 // We need to measure child layout
587 View child = Registry.GetManagedBaseHandleFromNativePtr(childPtr) as View;
590 measureSize.width = 0;
591 measureSize.height = 0;
595 LayoutItem childLayout = child.Layout;
597 MeasureSpecification childWidthMeasureSpec = GetChildMeasureSpecification(
598 new MeasureSpecification(
599 new LayoutLength(parentMeasureSpecificationWidth.Size - (child.Margin.Start + child.Margin.End)),
600 parentMeasureSpecificationWidth.Mode),
601 new LayoutLength(Padding.Start + Padding.End),
602 new LayoutLength(child.WidthSpecification));
604 MeasureSpecification childHeightMeasureSpec = GetChildMeasureSpecification(
605 new MeasureSpecification(
606 new LayoutLength(parentMeasureSpecificationHeight.Size - (child.Margin.Top + child.Margin.Bottom)),
607 parentMeasureSpecificationHeight.Mode),
608 new LayoutLength(Padding.Top + Padding.Bottom),
609 new LayoutLength(child.HeightSpecification));
611 childLayout.Measure(childWidthMeasureSpec, childHeightMeasureSpec);
613 measureSize.width = childLayout.MeasuredWidth.Size.AsRoundedValue();
614 measureSize.height = childLayout.MeasuredHeight.Size.AsRoundedValue();
617 void InsertChild(LayoutItem child)
619 // Store created node for child
620 IntPtr childPtr = Interop.FlexLayout.FlexLayout_AddChildWithMargin(swigCPtr, View.getCPtr(child.Owner), Extents.getCPtr(child.Owner.Margin), measureChildDelegate, LayoutChildren.Count - 1);
621 HandleRef childHandleRef = new HandleRef(child.Owner, childPtr);
622 SetAttachedValue(child.Owner, FlexItemProperty, childHandleRef);
626 /// Callback when child is added to container.<br />
627 /// Derived classes can use this to set their own child properties on the child layout's owner.<br />
629 /// <param name="child">The Layout child.</param>
630 /// <exception cref="ArgumentNullException"> Thrown when child is null. </exception>
631 /// <since_tizen> 6 </since_tizen>
632 protected override void OnChildAdd(LayoutItem child)
636 throw new ArgumentNullException(nameof(child));
642 /// Callback when child is removed from container.<br />
644 /// <param name="child">The Layout child.</param>
645 /// <since_tizen> 6 </since_tizen>
646 protected override void OnChildRemove(LayoutItem child)
648 // When child View is removed from it's parent View (that is a Layout) then remove it from the layout too.
649 // FlexLayout refers to the child as a View not LayoutItem.
650 Interop.FlexLayout.FlexLayout_RemoveChild(swigCPtr, child);
654 /// Measure the layout and its content to determine the measured width and the measured height.<br />
656 /// <param name="widthMeasureSpec">horizontal space requirements as imposed by the parent.</param>
657 /// <param name="heightMeasureSpec">vertical space requirements as imposed by the parent.</param>
658 /// <since_tizen> 6 </since_tizen>
659 protected override void OnMeasure(MeasureSpecification widthMeasureSpec, MeasureSpecification heightMeasureSpec)
661 bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
662 Extents padding = Owner.Padding;
664 Interop.FlexLayout.FlexLayout_SetPadding(swigCPtr, Extents.getCPtr(padding));
666 float width = FlexUndefined; // Behaves as WrapContent (Flex Auto)
667 float height = FlexUndefined; // Behaves as WrapContent (Flex Auto)
669 if (widthMeasureSpec.Mode == MeasureSpecification.ModeType.Exactly || widthMeasureSpec.Mode == MeasureSpecification.ModeType.AtMost)
671 width = widthMeasureSpec.Size.AsDecimal();
674 if (heightMeasureSpec.Mode == MeasureSpecification.ModeType.Exactly || heightMeasureSpec.Mode == MeasureSpecification.ModeType.AtMost)
676 height = heightMeasureSpec.Size.AsDecimal();
679 // Save measureSpec to measure children.
680 // In other Layout, we can pass it as parameter to measuring child but in FlexLayout we can't
681 // because measurChild function is called by native callback.
682 parentMeasureSpecificationWidth = widthMeasureSpec;
683 parentMeasureSpecificationHeight = heightMeasureSpec;
685 Extents zeroMargin = new Extents();
687 // Assign child properties
688 for (int i = 0; i < LayoutChildren.Count; i++)
690 LayoutItem layoutItem = LayoutChildren[i];
691 View Child = layoutItem?.Owner;
692 HandleRef childHandleRef = (HandleRef)Child.GetValue(FlexItemProperty);
693 if (childHandleRef.Handle == IntPtr.Zero || Child == null)
696 if (layoutItem.Owner.ExcludeLayouting)
698 MeasureChildWithoutPadding(layoutItem, widthMeasureSpec, heightMeasureSpec);
702 AlignmentType flexAlignemnt = GetFlexAlignmentSelf(Child);
703 PositionType positionType = GetFlexPositionType(Child);
704 float flexAspectRatio = GetFlexAspectRatio(Child);
705 float flexBasis = GetFlexBasis(Child);
706 float flexShrink = GetFlexShrink(Child);
707 float flexGrow = GetFlexGrow(Child);
708 Extents childMargin = Child.ExcludeLayouting ? zeroMargin : layoutItem.Margin;
710 Interop.FlexLayout.FlexLayout_SetMargin(childHandleRef, Extents.getCPtr(childMargin));
711 Interop.FlexLayout.FlexLayout_SetFlexAlignmentSelf(childHandleRef, (int)flexAlignemnt);
712 Interop.FlexLayout.FlexLayout_SetFlexPositionType(childHandleRef, (int)positionType);
713 Interop.FlexLayout.FlexLayout_SetFlexAspectRatio(childHandleRef, flexAspectRatio);
714 Interop.FlexLayout.FlexLayout_SetFlexBasis(childHandleRef, flexBasis);
715 Interop.FlexLayout.FlexLayout_SetFlexShrink(childHandleRef, flexShrink);
716 Interop.FlexLayout.FlexLayout_SetFlexGrow(childHandleRef, flexGrow);
719 Interop.FlexLayout.FlexLayout_CalculateLayout(swigCPtr, width, height, isLayoutRtl);
720 zeroMargin.Dispose();
722 LayoutLength flexLayoutWidth = new LayoutLength(Interop.FlexLayout.FlexLayout_GetWidth(swigCPtr));
723 LayoutLength flexLayoutHeight = new LayoutLength(Interop.FlexLayout.FlexLayout_GetHeight(swigCPtr));
725 Debug.WriteLineIf(LayoutDebugFlex, "FlexLayout OnMeasure width:" + flexLayoutWidth.AsRoundedValue()
726 + " height:" + flexLayoutHeight.AsRoundedValue());
728 SetMeasuredDimensions(GetDefaultSize(flexLayoutWidth, widthMeasureSpec),
729 GetDefaultSize(flexLayoutHeight, heightMeasureSpec));
733 /// Assign a size and position to each of its children.<br />
735 /// <param name="changed">This is a new size or position for this layout.</param>
736 /// <param name="left">Left position, relative to parent.</param>
737 /// <param name="top"> Top position, relative to parent.</param>
738 /// <param name="right">Right position, relative to parent.</param>
739 /// <param name="bottom">Bottom position, relative to parent.</param>
740 /// <since_tizen> 6 </since_tizen>
741 protected override void OnLayout(bool changed, LayoutLength left, LayoutLength top, LayoutLength right, LayoutLength bottom)
744 bool isLayoutRtl = Owner.LayoutDirection == ViewLayoutDirectionType.RTL;
745 LayoutLength width = right - left;
746 LayoutLength height = bottom - top;
748 // Call to FlexLayout implementation to calculate layout values for later retrieval.
749 Interop.FlexLayout.FlexLayout_CalculateLayout(swigCPtr, width.AsDecimal(), height.AsDecimal(), isLayoutRtl);
751 int count = LayoutChildren.Count;
752 for (int childIndex = 0; childIndex < count; childIndex++)
754 LayoutItem childLayout = LayoutChildren[childIndex];
755 if (childLayout != null)
757 if (!childLayout.Owner.ExcludeLayouting)
759 // Get the frame for the child, start, top, end, bottom.
760 Vector4 frame = new Vector4(Interop.FlexLayout.FlexLayout_GetNodeFrame(swigCPtr, childIndex), true);
761 childLayout.Layout(new LayoutLength(frame.X), new LayoutLength(frame.Y), new LayoutLength(frame.Z), new LayoutLength(frame.W));
765 LayoutForIndependentChild();
768 } // namesspace Tizen.NUI