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Terminal.Gui/Terminal.Gui/View/View.Layout.cs
2024-10-24 15:26:13 -06:00

1209 lines
44 KiB
C#

#nullable enable
using System.Diagnostics;
using Microsoft.CodeAnalysis;
namespace Terminal.Gui;
public partial class View // Layout APIs
{
#region Frame/Position/Dimension
/// <summary>
/// Indicates whether the specified SuperView-relative coordinates are within the View's <see cref="Frame"/>.
/// </summary>
/// <param name="location">SuperView-relative coordinate</param>
/// <returns><see langword="true"/> if the specified SuperView-relative coordinates are within the View.</returns>
public virtual bool Contains (in Point location) { return Frame.Contains (location); }
private Rectangle? _frame;
/// <summary>Gets or sets the absolute location and dimension of the view.</summary>
/// <value>
/// The rectangle describing absolute location and dimension of the view, in coordinates relative to the
/// <see cref="SuperView"/>'s Content, which is bound by <see cref="GetContentSize ()"/>.
/// </value>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// Frame is relative to the <see cref="SuperView"/>'s Content, which is bound by <see cref="GetContentSize ()"/>
/// .
/// </para>
/// <para>
/// Setting Frame will set <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>, and <see cref="Height"/> to absoulte values.
/// </para>
/// <para>
/// Changing this property will result in <see cref="NeedsLayout"/> and <see cref="NeedsDisplay"/> to be set, resulting in the
/// view being laid out and redrawn as appropriate in the next iteration of the <see cref="MainLoop"/>.
/// </para>
/// </remarks>
public Rectangle Frame
{
get
{
if (_needsLayout)
{
//Debug.WriteLine("Frame_get with _layoutNeeded");
}
return _frame ?? Rectangle.Empty;
}
set
{
// This will set _frame, call SetsNeedsLayout, and raise OnViewportChanged/ViewportChanged
if (SetFrame (value with { Width = Math.Max (value.Width, 0), Height = Math.Max (value.Height, 0) }))
{
// If Frame gets set, set all Pos/Dim to Absolute values.
_x = _frame!.Value.X;
_y = _frame!.Value.Y;
_width = _frame!.Value.Width;
_height = _frame!.Value.Height;
// Implicit layout is ok here because we are setting the Frame directly.
Layout ();
}
}
}
/// <summary>
/// INTERNAL API - Sets _frame, calls SetsNeedsLayout, and raises OnViewportChanged/ViewportChanged
/// </summary>
/// <param name="frame"></param>
/// <returns><see langword="true"/> if the frame was changed.</returns>
private bool SetFrame (in Rectangle frame)
{
if (_frame == frame)
{
return false;
}
var oldViewport = Rectangle.Empty;
if (IsInitialized)
{
oldViewport = Viewport;
}
// This is the only place where _frame should be set directly. Use Frame = or SetFrame instead.
_frame = frame;
SetAdornmentFrames ();
SetNeedsDisplay ();
SetNeedsLayout ();
// BUGBUG: When SetFrame is called from Frame_set, this event gets raised BEFORE OnResizeNeeded. Is that OK?
OnViewportChanged (new (IsInitialized ? Viewport : Rectangle.Empty, oldViewport));
return true;
}
/// <summary>Gets the <see cref="Frame"/> with a screen-relative location.</summary>
/// <returns>The location and size of the view in screen-relative coordinates.</returns>
public virtual Rectangle FrameToScreen ()
{
Rectangle screen = Frame;
View? current = SuperView;
while (current is { })
{
if (current is Adornment adornment)
{
// Adornments don't have SuperViews; use Adornment.FrameToScreen override
// which will give us the screen coordinates of the parent
Rectangle parentScreen = adornment.FrameToScreen ();
// Now add our Frame location
parentScreen.Offset (screen.X, screen.Y);
return parentScreen;
}
Point viewportOffset = current.GetViewportOffsetFromFrame ();
viewportOffset.Offset (current.Frame.X - current.Viewport.X, current.Frame.Y - current.Viewport.Y);
screen.X += viewportOffset.X;
screen.Y += viewportOffset.Y;
current = current.SuperView;
}
return screen;
}
/// <summary>
/// Converts a screen-relative coordinate to a Frame-relative coordinate. Frame-relative means relative to the
/// View's <see cref="SuperView"/>'s <see cref="Viewport"/>.
/// </summary>
/// <returns>The coordinate relative to the <see cref="SuperView"/>'s <see cref="Viewport"/>.</returns>
/// <param name="location">Screen-relative coordinate.</param>
public virtual Point ScreenToFrame (in Point location)
{
if (SuperView is null)
{
return new (location.X - Frame.X, location.Y - Frame.Y);
}
Point superViewViewportOffset = SuperView.GetViewportOffsetFromFrame ();
superViewViewportOffset.Offset (-SuperView.Viewport.X, -SuperView.Viewport.Y);
Point frame = location;
frame.Offset (-superViewViewportOffset.X, -superViewViewportOffset.Y);
frame = SuperView.ScreenToFrame (frame);
frame.Offset (-Frame.X, -Frame.Y);
return frame;
}
// helper for X, Y, Width, Height setters to ensure consistency
private void PosDimSet ()
{
SetNeedsLayout ();
if (_x is PosAbsolute && _y is PosAbsolute && _width is DimAbsolute && _height is DimAbsolute)
{
// Implicit layout is ok here because all Pos/Dim are Absolute values.
Layout ();
}
}
private Pos _x = Pos.Absolute (0);
/// <summary>Gets or sets the X position for the view (the column).</summary>
/// <value>The <see cref="Pos"/> object representing the X position.</value>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// The position is relative to the <see cref="SuperView"/>'s Content, which is bound by
/// <see cref="GetContentSize ()"/>.
/// </para>
/// <para>
/// If set to a relative value (e.g. <see cref="Pos.Center"/>) the value is indeterminate until the view has been
/// laid out (e.g. <see cref="Layout(System.Drawing.Size)"/> has been called).
/// </para>
/// <para>
/// Changing this property will result in <see cref="NeedsLayout"/> and <see cref="NeedsDisplay"/> to be set, resulting in the
/// view being laid out and redrawn as appropriate in the next iteration of the <see cref="MainLoop"/>.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated.
/// </para>
/// <para>The default value is <c>Pos.At (0)</c>.</para>
/// </remarks>
public Pos X
{
get => VerifyIsInitialized (_x, nameof (X));
set
{
if (Equals (_x, value))
{
return;
}
_x = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (X)} cannot be null");
PosDimSet ();
}
}
private Pos _y = Pos.Absolute (0);
/// <summary>Gets or sets the Y position for the view (the row).</summary>
/// <value>The <see cref="Pos"/> object representing the Y position.</value>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// The position is relative to the <see cref="SuperView"/>'s Content, which is bound by
/// <see cref="GetContentSize ()"/>.
/// </para>
/// <para>
/// If set to a relative value (e.g. <see cref="Pos.Center"/>) the value is indeterminate until the view has been
/// laid out (e.g. <see cref="Layout(System.Drawing.Size)"/> has been called).
/// </para>
/// <para>
/// Changing this property will result in <see cref="NeedsLayout"/> and <see cref="NeedsDisplay"/> to be set, resulting in the
/// view being laid out and redrawn as appropriate in the next iteration of the <see cref="MainLoop"/>.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated.
/// </para>
/// <para>The default value is <c>Pos.At (0)</c>.</para>
/// </remarks>
public Pos Y
{
get => VerifyIsInitialized (_y, nameof (Y));
set
{
if (Equals (_y, value))
{
return;
}
_y = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Y)} cannot be null");
PosDimSet ();
}
}
private Dim? _height = Dim.Absolute (0);
/// <summary>Gets or sets the height dimension of the view.</summary>
/// <value>The <see cref="Dim"/> object representing the height of the view (the number of rows).</value>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// The dimension is relative to the <see cref="SuperView"/>'s Content, which is bound by
/// <see cref="GetContentSize ()"/> .
/// </para>
/// <para>
/// If set to a relative value (e.g. <see cref="DimFill"/>) the value is indeterminate until the view has been
/// laid out (e.g. <see cref="Layout(System.Drawing.Size)"/> has been called).
/// </para>
/// <para>
/// Changing this property will result in <see cref="NeedsLayout"/> and <see cref="NeedsDisplay"/> to be set, resulting in the
/// view being laid out and redrawn as appropriate in the next iteration of the <see cref="MainLoop"/>.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated.
/// </para>
/// <para>The default value is <c>Dim.Sized (0)</c>.</para>
/// </remarks>
public Dim? Height
{
get => VerifyIsInitialized (_height, nameof (Height));
set
{
if (Equals (_height, value))
{
return;
}
_height = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Height)} cannot be null");
// Reset TextFormatter - Will be recalculated in SetTextFormatterSize
TextFormatter.ConstrainToHeight = null;
PosDimSet ();
}
}
private Dim? _width = Dim.Absolute (0);
/// <summary>Gets or sets the width dimension of the view.</summary>
/// <value>The <see cref="Dim"/> object representing the width of the view (the number of columns).</value>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// The dimension is relative to the <see cref="SuperView"/>'s Content, which is bound by
/// <see cref="GetContentSize ()"/>
/// .
/// </para>
/// <para>
/// If set to a relative value (e.g. <see cref="DimFill"/>) the value is indeterminate until the view has been
/// laid out (e.g. <see cref="Layout(System.Drawing.Size)"/> has been called).
/// </para>
/// <para>
/// Changing this property will result in <see cref="NeedsLayout"/> and <see cref="NeedsDisplay"/> to be set, resulting in the
/// view being laid out and redrawn as appropriate in the next iteration of the <see cref="MainLoop"/>.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated.
/// </para>
/// <para>The default value is <c>Dim.Sized (0)</c>.</para>
/// </remarks>
public Dim? Width
{
get => VerifyIsInitialized (_width, nameof (Width));
set
{
if (Equals (_width, value))
{
return;
}
_width = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Width)} cannot be null");
// Reset TextFormatter - Will be recalculated in SetTextFormatterSize
TextFormatter.ConstrainToWidth = null;
PosDimSet ();
}
}
#endregion Frame/Position/Dimension
#region Core Layout API
/// <summary>
/// Performs layout of the view and its subviews within the specified content size.
/// </summary>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// This method is intended to be called by the layout engine to
/// prepare the view for layout and is exposed as a public API primarily for testing purposes.
/// </para>
/// </remarks>
/// <param name="contentSize"></param>
/// <returns><see langword="false"/>If the view could not be laid out (typically because a dependencies was not ready). </returns>
public bool Layout (Size contentSize)
{
if (SetRelativeLayout (contentSize))
{
LayoutSubviews ();
// Debug.Assert(!NeedsLayout);
return true;
}
return false;
}
/// <summary>
/// Performs layout of the view and its subviews using the content size of either the <see cref="SuperView"/> or <see cref="Application.Screen"/>.
/// </summary>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// This method is intended to be called by the layout engine to
/// prepare the view for layout and is exposed as a public API primarily for testing purposes.
/// </para>
/// </remarks>
/// <returns><see langword="false"/>If the view could not be laid out (typically because dependency was not ready). </returns>
public bool Layout ()
{
return Layout (GetContainerSize ());
}
/// <summary>
/// Sets the position and size of this view, relative to the SuperView's ContentSize (nominally the same as
/// <c>this.SuperView.GetContentSize ()</c>) based on the values of <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>,
/// and <see cref="Height"/>.
/// </summary>
/// <remarks>
/// <para>
/// If <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>, or <see cref="Height"/> are
/// absolute, they will be updated to reflect the new size and position of the view. Otherwise, they
/// are left unchanged.
/// </para>
/// <para>
/// This method does not arrange subviews or adornments. It is intended to be called by the layout engine to
/// prepare the view for layout and is exposed as a public API primarily for testing purposes.
/// </para>
/// <para>
/// Some subviews may have SetRelativeLayout called on them as a side effect, particularly in DimAuto scenarios.
/// </para>
/// </remarks>
/// <param name="superviewContentSize">
/// The size of the SuperView's content (nominally the same as <c>this.SuperView.GetContentSize ()</c>).
/// </param>
/// <returns><see langword="true"/> if successful. <see langword="false"/> means a dependent View still needs layout.</returns>
public bool SetRelativeLayout (Size superviewContentSize)
{
Debug.Assert (_x is { });
Debug.Assert (_y is { });
Debug.Assert (_width is { });
Debug.Assert (_height is { });
CheckDimAuto ();
// TODO: Should move to View.LayoutSubviews?
SetTextFormatterSize ();
int newX, newW, newY, newH;
try
{
// Calculate the new X, Y, Width, and Height
// If the Width or Height is Dim.Auto, calculate the Width or Height first. Otherwise, calculate the X or Y first.
if (_width.Has<DimAuto> (out _))
{
newW = _width.Calculate (0, superviewContentSize.Width, this, Dimension.Width);
newX = _x.Calculate (superviewContentSize.Width, newW, this, Dimension.Width);
if (newW != Frame.Width)
{
// Pos.Calculate gave us a new position. We need to redo dimension
newW = _width.Calculate (newX, superviewContentSize.Width, this, Dimension.Width);
}
}
else
{
newX = _x.Calculate (superviewContentSize.Width, _width, this, Dimension.Width);
newW = _width.Calculate (newX, superviewContentSize.Width, this, Dimension.Width);
}
if (_height.Has<DimAuto> (out _))
{
newH = _height.Calculate (0, superviewContentSize.Height, this, Dimension.Height);
newY = _y.Calculate (superviewContentSize.Height, newH, this, Dimension.Height);
if (newH != Frame.Height)
{
// Pos.Calculate gave us a new position. We need to redo dimension
newH = _height.Calculate (newY, superviewContentSize.Height, this, Dimension.Height);
}
}
else
{
newY = _y.Calculate (superviewContentSize.Height, _height, this, Dimension.Height);
newH = _height.Calculate (newY, superviewContentSize.Height, this, Dimension.Height);
}
}
catch (LayoutException le)
{
//Debug.WriteLine ($"A Dim/PosFunc function threw (typically this is because a dependent View was not laid out)\n{le}.");
return false;
}
Rectangle newFrame = new (newX, newY, newW, newH);
if (Frame != newFrame)
{
// Set the frame. Do NOT use `Frame` as it overwrites X, Y, Width, and Height
// This will set _frame, call SetsNeedsLayout, and raise OnViewportChanged/ViewportChanged
SetFrame (newFrame);
if (_x is PosAbsolute)
{
_x = Frame.X;
}
if (_y is PosAbsolute)
{
_y = Frame.Y;
}
if (_width is DimAbsolute)
{
_width = Frame.Width;
}
if (_height is DimAbsolute)
{
_height = Frame.Height;
}
if (!string.IsNullOrEmpty (Title))
{
SetTitleTextFormatterSize ();
}
SuperView?.SetNeedsDisplay ();
}
if (TextFormatter.ConstrainToWidth is null)
{
TextFormatter.ConstrainToWidth = GetContentSize ().Width;
}
if (TextFormatter.ConstrainToHeight is null)
{
TextFormatter.ConstrainToHeight = GetContentSize ().Height;
}
return true;
}
/// <summary>
/// INTERNAL API - Causes the view's subviews and adornments to be laid out within the view's content areas. Assumes the view's relative layout has been set via <see cref="SetRelativeLayout"/>.
/// </summary>
/// <remarks>
/// <para>
/// See the View Layout Deep Dive for more information:
/// <see href="https://gui-cs.github.io/Terminal.GuiV2Docs/docs/layout.html"/>
/// </para>
/// <para>
/// The position and dimensions of the view are indeterminate until the view has been initialized. Therefore, the
/// behavior of this method is indeterminate if <see cref="IsInitialized"/> is <see langword="false"/>.
/// </para>
/// <para>Raises the <see cref="SubviewsLaidOut"/> event before it returns.</para>
/// </remarks>
internal void LayoutSubviews ()
{
if (!NeedsLayout)
{
return;
}
CheckDimAuto ();
Size contentSize = GetContentSize ();
OnSubviewLayout (new (contentSize));
SubviewLayout?.Invoke(this, new (contentSize));
// The Adornments already have their Frame's set by SetRelativeLayout so we call LayoutSubViews vs. Layout here.
if (Margin is { Subviews.Count: > 0 })
{
Margin.LayoutSubviews ();
}
if (Border is { Subviews.Count: > 0 })
{
Border.LayoutSubviews ();
}
if (Padding is { Subviews.Count: > 0 })
{
Padding.LayoutSubviews ();
}
// Sort out the dependencies of the X, Y, Width, Height properties
HashSet<View> nodes = new ();
HashSet<(View, View)> edges = new ();
CollectAll (this, ref nodes, ref edges);
List<View> ordered = TopologicalSort (SuperView!, nodes, edges);
List<View> redo = new ();
foreach (View v in ordered)
{
if (!v.Layout (contentSize))
{
redo.Add (v);
}
}
bool layoutStillNeeded = false;
//foreach (View v in redo)
//{
// if (!v.Layout (contentSize))
// {
// layoutStillNeeded = true;
// }
//}
if (redo.Count > 0)
{
foreach (View v in ordered)
{
if (!v.Layout (contentSize))
{
layoutStillNeeded = true;
Debug.Fail("ugh");
}
}
}
// If the 'to' is rooted to 'from' it's a special-case.
// Use Layout with the ContentSize of the 'from'.
// See the Nested_SubViews_Ref_Topmost_SuperView unit test
if (edges.Count > 0 && GetTopSuperView () is { })
{
foreach ((View from, View to) in edges)
{
// QUESTION: Do we test this with adornments well enough?
to.Layout (from.GetContentSize ());
}
}
_needsLayout = layoutStillNeeded;
OnSubviewsLaidOut (new (contentSize));
SubviewsLaidOut?.Invoke (this, new (contentSize));
}
/// <summary>
/// Called from <see cref="LayoutSubviews"/> before any subviews
/// have been laid out.
/// </summary>
/// <remarks>
/// Override to perform tasks when the layout is changing.
/// </remarks>
protected virtual void OnSubviewLayout (LayoutEventArgs args) { }
/// <summary>Raised by <see cref="LayoutSubviews"/> before any subviews
/// have been laid out.</summary>
/// <remarks>
/// Subscribe to this event to perform tasks when the layout is changing.
/// </remarks>
public event EventHandler<LayoutEventArgs>? SubviewLayout;
/// <summary>
/// Called from <see cref="LayoutSubviews"/> after all sub-views
/// have been laid out.
/// </summary>
/// <remarks>
/// Override to perform tasks after the <see cref="View"/> has been resized or the layout has
/// otherwise changed.
/// </remarks>
protected virtual void OnSubviewsLaidOut (LayoutEventArgs args) { }
/// <summary>Raised after all sub-views have been laid out.</summary>
/// <remarks>
/// Subscribe to this event to perform tasks after the <see cref="View"/> has been resized or the layout has
/// otherwise changed.
/// </remarks>
public event EventHandler<LayoutEventArgs>? SubviewsLaidOut;
#endregion Core Layout API
#region NeedsLayout
// We expose no setter for this to ensure that the ONLY place it's changed is in SetNeedsLayout
private bool _needsLayout = true;
/// <summary>
/// Indicates the View's Frame or the layout of the View's subviews (including Adornments) have
/// changed since the last time the View was laid out.
/// </summary>
/// <remarks>
/// <para>Used to prevent <see cref="Layout()"/> from needlessly computing
/// layout.
/// </para>
/// </remarks>
/// <value>
/// <see langword="true"/> if layout is needed.
/// </value>
public bool NeedsLayout => _needsLayout;
/// <summary>
/// Sets <see cref="NeedsLayout"/> to return <see langword="true"/>, indicating this View and all of it's subviews (including adornments) need to be laid out in the next Application iteration.
/// </summary>
/// <remarks>
/// <para>
/// The <see cref="MainLoop"/> will cause <see cref="Layout()"/> to be called on the next <see cref="Application.Iteration"/> so there is normally no reason to call see <see cref="Layout()"/>.
/// </para>
/// </remarks>
public void SetNeedsLayout ()
{
_needsLayout = true;
if (Margin is { Subviews.Count: > 0 })
{
Margin.SetNeedsLayout ();
}
if (Border is { Subviews.Count: > 0 })
{
Border.SetNeedsLayout ();
}
if (Padding is { Subviews.Count: > 0 })
{
Padding.SetNeedsLayout ();
}
// Use a stack to avoid recursion
Stack<View> stack = new Stack<View> (Subviews);
while (stack.Count > 0)
{
View current = stack.Pop ();
if (!current.NeedsLayout)
{
current._needsLayout = true;
if (current.Margin is { Subviews.Count: > 0 })
{
current.Margin.SetNeedsLayout ();
}
if (current.Border is { Subviews.Count: > 0 })
{
current.Border.SetNeedsLayout ();
}
if (current.Padding is { Subviews.Count: > 0 })
{
current.Padding.SetNeedsLayout ();
}
foreach (View subview in current.Subviews)
{
stack.Push (subview);
}
}
}
TextFormatter.NeedsFormat = true;
if (SuperView is { NeedsLayout: false })
{
SuperView?.SetNeedsLayout ();
}
if (this is not Adornment adornment)
{
return;
}
if (adornment.Parent is { NeedsLayout: false })
{
adornment.Parent?.SetNeedsLayout ();
}
}
#endregion NeedsLayout
#region Topological Sort
/// <summary>
/// INTERNAL API - Collects all views and their dependencies from a given starting view for layout purposes. Used by
/// <see cref="TopologicalSort"/> to create an ordered list of views to layout.
/// </summary>
/// <param name="from">The starting view from which to collect dependencies.</param>
/// <param name="nNodes">A reference to a set of views representing nodes in the layout graph.</param>
/// <param name="nEdges">
/// A reference to a set of tuples representing edges in the layout graph, where each tuple consists of a pair of views
/// indicating a dependency.
/// </param>
internal void CollectAll (View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
foreach (View? v in from.InternalSubviews)
{
nNodes.Add (v);
CollectPos (v.X, v, ref nNodes, ref nEdges);
CollectPos (v.Y, v, ref nNodes, ref nEdges);
CollectDim (v.Width, v, ref nNodes, ref nEdges);
CollectDim (v.Height, v, ref nNodes, ref nEdges);
}
}
/// <summary>
/// INTERNAL API - Collects dimension (where Width or Height is `DimView`) dependencies for a given view.
/// </summary>
/// <param name="dim">The dimension (width or height) to collect dependencies for.</param>
/// <param name="from">The view for which to collect dimension dependencies.</param>
/// <param name="nNodes">A reference to a set of views representing nodes in the layout graph.</param>
/// <param name="nEdges">
/// A reference to a set of tuples representing edges in the layout graph, where each tuple consists of a pair of views
/// indicating a dependency.
/// </param>
internal void CollectDim (Dim? dim, View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
if (dim!.Has<DimView> (out DimView dv))
{
if (dv.Target != this)
{
nEdges.Add ((dv.Target!, from));
}
}
if (dim!.Has<DimCombine> (out DimCombine dc))
{
CollectDim (dc.Left, from, ref nNodes, ref nEdges);
CollectDim (dc.Right, from, ref nNodes, ref nEdges);
}
}
/// <summary>
/// INTERNAL API - Collects position (where X or Y is `PosView`) dependencies for a given view.
/// </summary>
/// <param name="pos">The position (X or Y) to collect dependencies for.</param>
/// <param name="from">The view for which to collect position dependencies.</param>
/// <param name="nNodes">A reference to a set of views representing nodes in the layout graph.</param>
/// <param name="nEdges">
/// A reference to a set of tuples representing edges in the layout graph, where each tuple consists of a pair of views
/// indicating a dependency.
/// </param>
internal void CollectPos (Pos pos, View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
// TODO: Use Pos.Has<T> instead.
switch (pos)
{
case PosView pv:
Debug.Assert (pv.Target is { });
if (pv.Target != this)
{
nEdges.Add ((pv.Target!, from));
}
return;
case PosCombine pc:
CollectPos (pc.Left, from, ref nNodes, ref nEdges);
CollectPos (pc.Right, from, ref nNodes, ref nEdges);
break;
}
}
// https://en.wikipedia.org/wiki/Topological_sorting
internal static List<View> TopologicalSort (
View superView,
IEnumerable<View> nodes,
ICollection<(View From, View To)> edges
)
{
List<View> result = new ();
// Set of all nodes with no incoming edges
HashSet<View> noEdgeNodes = new (nodes.Where (n => edges.All (e => !e.To.Equals (n))));
while (noEdgeNodes.Any ())
{
// remove a node n from S
View n = noEdgeNodes.First ();
noEdgeNodes.Remove (n);
// add n to tail of L
if (n != superView)
{
result.Add (n);
}
// for each node m with an edge e from n to m do
foreach ((View From, View To) e in edges.Where (e => e.From.Equals (n)).ToArray ())
{
View m = e.To;
// remove edge e from the graph
edges.Remove (e);
// if m has no other incoming edges then
if (edges.All (me => !me.To.Equals (m)) && m != superView)
{
// insert m into S
noEdgeNodes.Add (m);
}
}
}
if (!edges.Any ())
{
return result;
}
foreach ((View from, View to) in edges)
{
if (from == to)
{
// if not yet added to the result, add it and remove from edge
if (result.Find (v => v == from) is null)
{
result.Add (from);
}
edges.Remove ((from, to));
}
else if (from.SuperView == to.SuperView)
{
// if 'from' is not yet added to the result, add it
if (result.Find (v => v == from) is null)
{
result.Add (from);
}
// if 'to' is not yet added to the result, add it
if (result.Find (v => v == to) is null)
{
result.Add (to);
}
// remove from edge
edges.Remove ((from, to));
}
else if (from != superView?.GetTopSuperView (to, from) && !ReferenceEquals (from, to))
{
if (ReferenceEquals (from.SuperView, to))
{
throw new LayoutException (
$"ComputedLayout for \"{superView}\": \"{to}\" "
+ $"references a SubView (\"{from}\")."
);
}
throw new LayoutException (
$"ComputedLayout for \"{superView}\": \"{from}\" "
+ $"linked with \"{to}\" was not found. Did you forget to add it to {superView}?"
);
}
}
// return L (a topologically sorted order)
return result;
} // TopologicalSort
#endregion Topological Sort
#region Utilities
/// <summary>
/// INTERNAL API - Gets the size of the SuperView's content (nominally the same as
/// the SuperView's <see cref="GetContentSize ()"/>) or the screen size if there's no SuperView.
/// </summary>
/// <returns></returns>
private Size GetContainerSize ()
{
// TODO: Get rid of refs to Top
Size superViewContentSize = SuperView?.GetContentSize () ??
(Application.Top is { } && Application.Top != this && Application.Top.IsInitialized
? Application.Top.GetContentSize ()
: Application.Screen.Size);
return superViewContentSize;
}
// BUGBUG: This method interferes with Dialog/MessageBox default min/max size.
// TODO: Get rid of MenuBar coupling as part of https://github.com/gui-cs/Terminal.Gui/issues/2975
/// <summary>
/// Gets a new location of the <see cref="View"/> that is within the Viewport of the <paramref name="viewToMove"/>'s
/// <see cref="View.SuperView"/> (e.g. for dragging a Window). The `out` parameters are the new X and Y coordinates.
/// </summary>
/// <remarks>
/// If <paramref name="viewToMove"/> does not have a <see cref="View.SuperView"/> or it's SuperView is not
/// <see cref="Application.Top"/> the position will be bound by <see cref="Application.Screen"/>.
/// </remarks>
/// <param name="viewToMove">The View that is to be moved.</param>
/// <param name="targetX">The target x location.</param>
/// <param name="targetY">The target y location.</param>
/// <param name="nx">The new x location that will ensure <paramref name="viewToMove"/> will be fully visible.</param>
/// <param name="ny">The new y location that will ensure <paramref name="viewToMove"/> will be fully visible.</param>
/// <returns>
/// Either <see cref="Application.Top"/> (if <paramref name="viewToMove"/> does not have a Super View) or
/// <paramref name="viewToMove"/>'s SuperView. This can be used to ensure LayoutSubviews is called on the correct View.
/// </returns>
internal static View? GetLocationEnsuringFullVisibility (
View viewToMove,
int targetX,
int targetY,
out int nx,
out int ny
)
{
int maxDimension;
View? superView;
if (viewToMove is not Toplevel || viewToMove?.SuperView is null || viewToMove == Application.Top || viewToMove?.SuperView == Application.Top)
{
maxDimension = Application.Screen.Width;
superView = Application.Top;
}
else
{
// Use the SuperView's Viewport, not Frame
maxDimension = viewToMove!.SuperView.Viewport.Width;
superView = viewToMove.SuperView;
}
if (superView?.Margin is { } && superView == viewToMove!.SuperView)
{
maxDimension -= superView.GetAdornmentsThickness ().Left + superView.GetAdornmentsThickness ().Right;
}
if (viewToMove!.Frame.Width <= maxDimension)
{
nx = Math.Max (targetX, 0);
nx = nx + viewToMove.Frame.Width > maxDimension ? Math.Max (maxDimension - viewToMove.Frame.Width, 0) : nx;
if (nx > viewToMove.Frame.X + viewToMove.Frame.Width)
{
nx = Math.Max (viewToMove.Frame.Right, 0);
}
}
else
{
nx = targetX;
}
//System.Diagnostics.Debug.WriteLine ($"nx:{nx}, rWidth:{rWidth}");
var menuVisible = false;
var statusVisible = false;
if (viewToMove?.SuperView is null || viewToMove == Application.Top || viewToMove?.SuperView == Application.Top)
{
menuVisible = Application.Top?.MenuBar?.Visible == true;
}
else
{
View? t = viewToMove!.SuperView;
while (t is { } and not Toplevel)
{
t = t.SuperView;
}
if (t is Toplevel topLevel)
{
menuVisible = topLevel.MenuBar?.Visible == true;
}
}
if (viewToMove?.SuperView is null || viewToMove == Application.Top || viewToMove?.SuperView == Application.Top)
{
maxDimension = menuVisible ? 1 : 0;
}
else
{
maxDimension = 0;
}
ny = Math.Max (targetY, maxDimension);
if (viewToMove?.SuperView is null || viewToMove == Application.Top || viewToMove?.SuperView == Application.Top)
{
maxDimension = statusVisible ? Application.Screen.Height - 1 : Application.Screen.Height;
}
else
{
maxDimension = statusVisible ? viewToMove!.SuperView.Viewport.Height - 1 : viewToMove!.SuperView.Viewport.Height;
}
if (superView?.Margin is { } && superView == viewToMove?.SuperView)
{
maxDimension -= superView.GetAdornmentsThickness ().Top + superView.GetAdornmentsThickness ().Bottom;
}
ny = Math.Min (ny, maxDimension);
if (viewToMove?.Frame.Height <= maxDimension)
{
ny = ny + viewToMove.Frame.Height > maxDimension
? Math.Max (maxDimension - viewToMove.Frame.Height, menuVisible ? 1 : 0)
: ny;
if (ny > viewToMove.Frame.Y + viewToMove.Frame.Height)
{
ny = Math.Max (viewToMove.Frame.Bottom, 0);
}
}
//System.Diagnostics.Debug.WriteLine ($"ny:{ny}, rHeight:{rHeight}");
return superView!;
}
#endregion Utilities
#region Diagnostics and Verification
// Diagnostics to highlight when X or Y is read before the view has been initialized
private Pos VerifyIsInitialized (Pos pos, string member)
{
//#if DEBUG
// if (pos.ReferencesOtherViews () && !IsInitialized)
// {
// Debug.WriteLine (
// $"WARNING: {member} = {pos} of {this} is dependent on other views and {member} "
// + $"is being accessed before the View has been initialized. This is likely a bug."
// );
// }
//#endif // DEBUG
return pos;
}
// Diagnostics to highlight when Width or Height is read before the view has been initialized
private Dim? VerifyIsInitialized (Dim? dim, string member)
{
//#if DEBUG
// if (dim.ReferencesOtherViews () && !IsInitialized)
// {
// Debug.WriteLine (
// $"WARNING: {member} = {dim} of {this} is dependent on other views and {member} "
// + $"is being accessed before the View has been initialized. This is likely a bug."
// );
// }
//#endif // DEBUG
return dim;
}
/// <summary>Gets or sets whether validation of <see cref="Pos"/> and <see cref="Dim"/> occurs.</summary>
/// <remarks>
/// Setting this to <see langword="true"/> will enable validation of <see cref="X"/>, <see cref="Y"/>,
/// <see cref="Width"/>, and <see cref="Height"/> during set operations and in <see cref="LayoutSubviews"/>. If invalid
/// settings are discovered exceptions will be thrown indicating the error. This will impose a performance penalty and
/// thus should only be used for debugging.
/// </remarks>
public bool ValidatePosDim { get; set; }
// TODO: Move this logic into the Pos/Dim classes
/// <summary>
/// Throws an <see cref="InvalidOperationException"/> if any SubViews are using Dim objects that depend on this
/// Views dimensions.
/// </summary>
/// <exception cref="InvalidOperationException"></exception>
private void CheckDimAuto ()
{
if (!ValidatePosDim || !IsInitialized)
{
return;
}
var widthAuto = Width as DimAuto;
var heightAuto = Height as DimAuto;
// Verify none of the subviews are using Dim objects that depend on the SuperView's dimensions.
foreach (View view in Subviews)
{
if (widthAuto is { } && widthAuto.Style.FastHasFlags (DimAutoStyle.Content) && ContentSizeTracksViewport)
{
ThrowInvalid (view, view.Width, nameof (view.Width));
ThrowInvalid (view, view.X, nameof (view.X));
}
if (heightAuto is { } && heightAuto.Style.FastHasFlags (DimAutoStyle.Content) && ContentSizeTracksViewport)
{
ThrowInvalid (view, view.Height, nameof (view.Height));
ThrowInvalid (view, view.Y, nameof (view.Y));
}
}
return;
void ThrowInvalid (View view, object? checkPosDim, string name)
{
object? bad = null;
switch (checkPosDim)
{
case Pos pos and PosAnchorEnd:
break;
case Pos pos and not PosAbsolute and not PosView and not PosCombine:
bad = pos;
break;
case Pos pos and PosCombine:
// Recursively check for not Absolute or not View
ThrowInvalid (view, (pos as PosCombine)?.Left, name);
ThrowInvalid (view, (pos as PosCombine)?.Right, name);
break;
case Dim dim and DimAuto:
break;
case Dim dim and DimFill:
break;
case Dim dim and not DimAbsolute and not DimView and not DimCombine:
bad = dim;
break;
case Dim dim and DimCombine:
// Recursively check for not Absolute or not View
ThrowInvalid (view, (dim as DimCombine)?.Left, name);
ThrowInvalid (view, (dim as DimCombine)?.Right, name);
break;
}
if (bad != null)
{
throw new LayoutException (
$"{view.GetType ().Name}.{name} = {bad.GetType ().Name} "
+ $"which depends on the SuperView's dimensions and the SuperView uses Dim.Auto."
);
}
}
}
#endregion Diagnostics and Verification
}