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Terminal.Gui/Terminal.Gui/View/Layout/ViewLayout.cs

1477 lines
56 KiB
C#

using System.Diagnostics;
namespace Terminal.Gui;
/// <summary>
/// <para>Indicates the LayoutStyle for the <see cref="View"/>.</para>
/// <para>
/// If Absolute, the <see cref="View.X"/>, <see cref="View.Y"/>, <see cref="View.Width"/>, and
/// <see cref="View.Height"/> objects are all absolute values and are not relative. The position and size of the
/// view is described by <see cref="View.Frame"/>.
/// </para>
/// <para>
/// If Computed, one or more of the <see cref="View.X"/>, <see cref="View.Y"/>, <see cref="View.Width"/>, or
/// <see cref="View.Height"/> objects are relative to the <see cref="View.SuperView"/> and are computed at layout
/// time.
/// </para>
/// </summary>
public enum LayoutStyle
{
/// <summary>
/// Indicates the <see cref="View.X"/>, <see cref="View.Y"/>, <see cref="View.Width"/>, and
/// <see cref="View.Height"/> objects are all absolute values and are not relative. The position and size of the view
/// is described by <see cref="View.Frame"/>.
/// </summary>
Absolute,
/// <summary>
/// Indicates one or more of the <see cref="View.X"/>, <see cref="View.Y"/>, <see cref="View.Width"/>, or
/// <see cref="View.Height"/> objects are relative to the <see cref="View.SuperView"/> and are computed at layout time.
/// The position and size of the view will be computed based on these objects at layout time. <see cref="View.Frame"/>
/// will provide the absolute computed values.
/// </summary>
Computed
}
public partial class View
{
#region Frame
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 <see cref="Bounds"/>.
/// </value>
/// <remarks>
/// <para>Frame is relative to the <see cref="SuperView"/>'s <see cref="Bounds"/>.</para>
/// <para>
/// Setting Frame will set <see cref="X"/>, <see cref="Y"/>, <see cref="Width"/>, and <see cref="Height"/> to the
/// values of the corresponding properties of the <paramref name="value"/> parameter.
/// </para>
/// <para>This causes <see cref="LayoutStyle"/> to be <see cref="LayoutStyle.Absolute"/>.</para>
/// <para>
/// Altering the Frame will eventually (when the view hierarchy is next laid out via see
/// cref="LayoutSubviews"/>) cause <see cref="LayoutSubview(View, Rectangle)"/> and
/// <see cref="OnDrawContent(Rectangle)"/>
/// methods to be called.
/// </para>
/// </remarks>
public Rectangle Frame
{
get => _frame;
set
{
_frame = value with { Width = Math.Max (value.Width, 0), Height = Math.Max (value.Height, 0) };
// If Frame gets set, by definition, the View is now LayoutStyle.Absolute, so
// set all Pos/Dim to Absolute values.
_x = _frame.X;
_y = _frame.Y;
_width = _frame.Width;
_height = _frame.Height;
// TODO: Figure out if the below can be optimized.
if (IsInitialized /*|| LayoutStyle == LayoutStyle.Absolute*/)
{
LayoutAdornments ();
SetTextFormatterSize ();
SetNeedsLayout ();
SetNeedsDisplay ();
}
}
}
/// <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 ret = Frame;
View super = SuperView;
while (super is { })
{
Point boundsOffset = super.GetBoundsOffset ();
ret.X += super.Frame.X + boundsOffset.X;
ret.Y += super.Frame.Y + boundsOffset.Y;
super = super.SuperView;
}
return ret;
}
/// <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="Bounds"/>.
/// </summary>
/// <returns>The coordinate relative to the <see cref="SuperView"/>'s <see cref="Bounds"/>.</returns>
/// <param name="x">Screen-relative column.</param>
/// <param name="y">Screen-relative row.</param>
public Point ScreenToFrame (int x, int y)
{
Point superViewBoundsOffset = SuperView?.GetBoundsOffset () ?? Point.Empty;
var ret = new Point (x - Frame.X - superViewBoundsOffset.X, y - Frame.Y - superViewBoundsOffset.Y);
if (SuperView is { })
{
Point superFrame = SuperView.ScreenToFrame (x - superViewBoundsOffset.X, y - superViewBoundsOffset.Y);
ret = new (superFrame.X - Frame.X, superFrame.Y - Frame.Y);
}
return ret;
}
private Pos _x = Pos.At (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>
/// If set to a relative value (e.g. <see cref="Pos.Center"/>) the value is indeterminate until the view has been
/// initialized ( <see cref="IsInitialized"/> is true) and <see cref="SetRelativeLayout(Rectangle)"/> has been
/// called.
/// </para>
/// <para>
/// Changing this property will eventually (when the view is next drawn) cause the
/// <see cref="LayoutSubview(View, Rectangle)"/> and <see cref="OnDrawContent(Rectangle)"/> methods to be called.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated. If the new value is not of type
/// <see cref="Pos.PosAbsolute"/> the <see cref="LayoutStyle"/> will change to <see cref="LayoutStyle.Computed"/>.
/// </para>
/// <para>The default value is <c>Pos.At (0)</c>.</para>
/// </remarks>
public Pos X
{
get => VerifyIsInitialized (_x, nameof (X));
set
{
_x = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (X)} cannot be null");
OnResizeNeeded ();
}
}
private Pos _y = Pos.At (0);
/// <summary>Gets or sets the Y position for the view (the row).</summary>
/// <value>The <see cref="Pos"/> object representing the Y position.</value>
/// <remarks>
/// <para>
/// If set to a relative value (e.g. <see cref="Pos.Center"/>) the value is indeterminate until the view has been
/// initialized ( <see cref="IsInitialized"/> is true) and <see cref="SetRelativeLayout(Rectangle)"/> has been
/// called.
/// </para>
/// <para>
/// Changing this property will eventually (when the view is next drawn) cause the
/// <see cref="LayoutSubview(View, Rectangle)"/> and <see cref="OnDrawContent(Rectangle)"/> methods to be called.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated. If the new value is not of type
/// <see cref="Pos.PosAbsolute"/> the <see cref="LayoutStyle"/> will change to <see cref="LayoutStyle.Computed"/>.
/// </para>
/// <para>The default value is <c>Pos.At (0)</c>.</para>
/// </remarks>
public Pos Y
{
get => VerifyIsInitialized (_y, nameof (Y));
set
{
_y = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Y)} cannot be null");
OnResizeNeeded ();
}
}
private Dim _height = Dim.Sized (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>
/// If set to a relative value (e.g. <see cref="Dim.Fill(int)"/>) the value is indeterminate until the view has
/// been initialized ( <see cref="IsInitialized"/> is true) and <see cref="SetRelativeLayout(Rectangle)"/> has been
/// called.
/// </para>
/// <para>
/// Changing this property will eventually (when the view is next drawn) cause the
/// <see cref="LayoutSubview(View, Rectangle)"/> and <see cref="OnDrawContent(Rectangle)"/> methods to be called.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated. If the new value is not of type
/// <see cref="Dim.DimAbsolute"/> the <see cref="LayoutStyle"/> will change to <see cref="LayoutStyle.Computed"/>.
/// </para>
/// <para>The default value is <c>Dim.Sized (0)</c>.</para>
/// </remarks>
public Dim Height
{
get => VerifyIsInitialized (_height, nameof (Height));
set
{
_height = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Height)} cannot be null");
if (AutoSize)
{
throw new InvalidOperationException (@$"Must set AutoSize to false before setting {nameof (Height)}.");
}
//if (ValidatePosDim) {
bool isValidNewAutoSize = AutoSize && IsValidAutoSizeHeight (_height);
if (IsAdded && AutoSize && !isValidNewAutoSize)
{
throw new InvalidOperationException (
@$"Must set AutoSize to false before setting the {nameof (Height)}."
);
}
//}
OnResizeNeeded ();
}
}
private Dim _width = Dim.Sized (0);
/// <summary>Gets or sets the width dimension of the view.</summary>
/// <value>The <see cref="Dim"/> object representing the width of the view (the number of columns).</value>
/// <remarks>
/// <para>
/// If set to a relative value (e.g. <see cref="Dim.Fill(int)"/>) the value is indeterminate until the view has
/// been initialized ( <see cref="IsInitialized"/> is true) and <see cref="SetRelativeLayout(Rectangle)"/> has been
/// called.
/// </para>
/// <para>
/// Changing this property will eventually (when the view is next drawn) cause the
/// <see cref="LayoutSubview(View, Rectangle)"/> and <see cref="OnDrawContent(Rectangle)"/> methods to be called.
/// </para>
/// <para>
/// Changing this property will cause <see cref="Frame"/> to be updated. If the new value is not of type
/// <see cref="Dim.DimAbsolute"/> the <see cref="LayoutStyle"/> will change to <see cref="LayoutStyle.Computed"/>.
/// </para>
/// <para>The default value is <c>Dim.Sized (0)</c>.</para>
/// </remarks>
public Dim Width
{
get => VerifyIsInitialized (_width, nameof (Width));
set
{
_width = value ?? throw new ArgumentNullException (nameof (value), @$"{nameof (Width)} cannot be null");
if (AutoSize)
{
throw new InvalidOperationException (@$"Must set AutoSize to false before setting {nameof (Width)}.");
}
bool isValidNewAutoSize = AutoSize && IsValidAutoSizeWidth (_width);
if (IsAdded && AutoSize && !isValidNewAutoSize)
{
throw new InvalidOperationException (@$"Must set AutoSize to false before setting {nameof (Width)}.");
}
OnResizeNeeded ();
}
}
#endregion Frame
#region Bounds
/// <summary>
/// The bounds represent the View-relative rectangle used for this view; the area inside of the view where
/// subviews and content are presented.
/// </summary>
/// <value>The rectangle describing the location and size of the area where the views' subviews and content are drawn.</value>
/// <remarks>
/// <para>
/// If <see cref="LayoutStyle"/> is <see cref="LayoutStyle.Computed"/> the value of Bounds is indeterminate until
/// the view has been initialized ( <see cref="IsInitialized"/> is true) and <see cref="LayoutSubviews"/> has been
/// called.
/// </para>
/// <para>
/// Updates to the Bounds updates <see cref="Frame"/>, and has the same effect as updating the
/// <see cref="Frame"/>.
/// </para>
/// <para>
/// Altering the Bounds will eventually (when the view is next laid out) cause the
/// <see cref="LayoutSubview(View, Rectangle)"/> and <see cref="OnDrawContent(Rectangle)"/> methods to be called.
/// </para>
/// <para>
/// Because <see cref="Bounds"/> coordinates are relative to the upper-left corner of the <see cref="View"/>, the
/// coordinates of the upper-left corner of the rectangle returned by this property are (0,0). Use this property to
/// obtain the size of the area of the view for tasks such as drawing the view's contents.
/// </para>
/// </remarks>
public virtual Rectangle Bounds
{
get
{
#if DEBUG
if (LayoutStyle == LayoutStyle.Computed && !IsInitialized)
{
Debug.WriteLine (
$"WARNING: Bounds is being accessed before the View has been initialized. This is likely a bug in {this}"
);
}
#endif // DEBUG
if (Margin is null || Border is null || Padding is null)
{
return Rectangle.Empty with { Size = Frame.Size };
}
Thickness totalThickness = GetAdornmentsThickness ();
int width = Math.Max (0, Frame.Size.Width - totalThickness.Horizontal);
int height = Math.Max (0, Frame.Size.Height - totalThickness.Vertical);
return Rectangle.Empty with { Size = new (width, height) };
}
set
{
// TODO: Should we enforce Bounds.X/Y == 0? The code currently ignores value.X/Y which is
// TODO: correct behavior, but is silent. Perhaps an exception?
#if DEBUG
if (value.Location != Point.Empty)
{
Debug.WriteLine (
$"WARNING: Bounds.Location must always be 0,0. Location ({value.Location}) is ignored. {this}"
);
}
#endif // DEBUG
Thickness totalThickness = GetAdornmentsThickness ();
Frame = Frame with
{
Size = new (value.Size.Width + totalThickness.Horizontal, value.Size.Height + totalThickness.Vertical)
};
}
}
/// <summary>Converts a <see cref="Bounds"/>-relative rectangle to a screen-relative rectangle.</summary>
public Rectangle BoundsToScreen (in Rectangle bounds)
{
// Translate bounds to Frame (our SuperView's Bounds-relative coordinates)
Point boundsOffset = GetBoundsOffset ();
Rectangle screen = FrameToScreen ();
screen.Offset (boundsOffset.X + bounds.X, boundsOffset.Y + bounds.Y);
return new (screen.Location, bounds.Size);
}
/// <summary>Converts a screen-relative coordinate to a bounds-relative coordinate.</summary>
/// <returns>The coordinate relative to this view's <see cref="Bounds"/>.</returns>
/// <param name="x">Screen-relative column.</param>
/// <param name="y">Screen-relative row.</param>
public Point ScreenToBounds (int x, int y)
{
Point screen = ScreenToFrame (x, y);
Point boundsOffset = GetBoundsOffset ();
return new (screen.X - boundsOffset.X, screen.Y - boundsOffset.Y);
}
/// <summary>
/// Helper to get the X and Y offset of the Bounds from the Frame. This is the sum of the Left and Top properties
/// of <see cref="Margin"/>, <see cref="Border"/> and <see cref="Padding"/>.
/// </summary>
public virtual Point GetBoundsOffset ()
{
if (Padding is null)
{
return Point.Empty;
}
return Padding.Thickness.GetInside (Padding.Frame).Location;
}
#endregion Bounds
#region Adornments
// TODO: Move this to Adornment as a static factory method
/// <summary>
/// This internal method is overridden by Adornment to do nothing to prevent recursion during View construction.
/// And, because Adornments don't have Adornments. It's internal to support unit tests.
/// </summary>
/// <param name="adornmentType"></param>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="ArgumentException"></exception>
internal virtual Adornment CreateAdornment (Type adornmentType)
{
void ThicknessChangedHandler (object sender, EventArgs e)
{
if (IsInitialized)
{
LayoutAdornments ();
}
SetNeedsLayout ();
SetNeedsDisplay ();
}
Adornment adornment;
adornment = Activator.CreateInstance (adornmentType, this) as Adornment;
adornment.ThicknessChanged += ThicknessChangedHandler;
return adornment;
}
/// <summary>
/// The <see cref="Adornment"/> that enables separation of a View from other SubViews of the same
/// SuperView. The margin offsets the <see cref="Bounds"/> from the <see cref="Frame"/>.
/// </summary>
/// <remarks>
/// <para>
/// The adornments (<see cref="Margin"/>, <see cref="Border"/>, and <see cref="Padding"/>) are not part of the
/// View's content and are not clipped by the View's Clip Area.
/// </para>
/// <para>
/// Changing the size of an adornment (<see cref="Margin"/>, <see cref="Border"/>, or <see cref="Padding"/>) will
/// change the size of <see cref="Frame"/> and trigger <see cref="LayoutSubviews"/> to update the layout of the
/// <see cref="SuperView"/> and its <see cref="Subviews"/>.
/// </para>
/// </remarks>
public Margin Margin { get; private set; }
/// <summary>
/// The <see cref="Adornment"/> that offsets the <see cref="Bounds"/> from the <see cref="Margin"/>.
/// The Border provides the space for a visual border (drawn using
/// line-drawing glyphs) and the Title. The Border expands inward; in other words if `Border.Thickness.Top == 2` the
/// border and title will take up the first row and the second row will be filled with spaces.
/// </summary>
/// <remarks>
/// <para><see cref="BorderStyle"/> provides a simple helper for turning a simple border frame on or off.</para>
/// <para>
/// The adornments (<see cref="Margin"/>, <see cref="Border"/>, and <see cref="Padding"/>) are not part of the
/// View's content and are not clipped by the View's Clip Area.
/// </para>
/// <para>
/// Changing the size of a frame (<see cref="Margin"/>, <see cref="Border"/>, or <see cref="Padding"/>) will
/// change the size of the <see cref="Frame"/> and trigger <see cref="LayoutSubviews"/> to update the layout of the
/// <see cref="SuperView"/> and its <see cref="Subviews"/>.
/// </para>
/// </remarks>
public Border Border { get; private set; }
/// <summary>Gets or sets whether the view has a one row/col thick border.</summary>
/// <remarks>
/// <para>
/// This is a helper for manipulating the view's <see cref="Border"/>. Setting this property to any value other
/// than <see cref="LineStyle.None"/> is equivalent to setting <see cref="Border"/>'s
/// <see cref="Adornment.Thickness"/> to `1` and <see cref="BorderStyle"/> to the value.
/// </para>
/// <para>
/// Setting this property to <see cref="LineStyle.None"/> is equivalent to setting <see cref="Border"/>'s
/// <see cref="Adornment.Thickness"/> to `0` and <see cref="BorderStyle"/> to <see cref="LineStyle.None"/>.
/// </para>
/// <para>For more advanced customization of the view's border, manipulate see <see cref="Border"/> directly.</para>
/// </remarks>
public LineStyle BorderStyle
{
get => Border.LineStyle;
set
{
if (value != LineStyle.None)
{
Border.Thickness = new (1);
}
else
{
Border.Thickness = new (0);
}
Border.LineStyle = value;
LayoutAdornments ();
SetNeedsLayout ();
}
}
/// <summary>
/// The <see cref="Adornment"/> inside of the view that offsets the <see cref="Bounds"/>
/// from the <see cref="Border"/>.
/// </summary>
/// <remarks>
/// <para>
/// The adornments (<see cref="Margin"/>, <see cref="Border"/>, and <see cref="Padding"/>) are not part of the
/// View's content and are not clipped by the View's Clip Area.
/// </para>
/// <para>
/// Changing the size of a frame (<see cref="Margin"/>, <see cref="Border"/>, or <see cref="Padding"/>) will
/// change the size of the <see cref="Frame"/> and trigger <see cref="LayoutSubviews"/> to update the layout of the
/// <see cref="SuperView"/> and its <see cref="Subviews"/>.
/// </para>
/// </remarks>
public Padding Padding { get; private set; }
/// <summary>
/// <para>Gets the thickness describing the sum of the Adornments' thicknesses.</para>
/// </summary>
/// <returns>A thickness that describes the sum of the Adornments' thicknesses.</returns>
public Thickness GetAdornmentsThickness () { return Margin.Thickness + Border.Thickness + Padding.Thickness; }
/// <summary>Overriden by <see cref="Adornment"/> to do nothing, as the <see cref="Adornment"/> does not have adornments.</summary>
internal virtual void LayoutAdornments ()
{
if (Margin is null)
{
return; // CreateAdornments () has not been called yet
}
if (Margin.Frame.Size != Frame.Size)
{
Margin._frame = Rectangle.Empty with { Size = Frame.Size };
Margin.X = 0;
Margin.Y = 0;
Margin.Width = Frame.Size.Width;
Margin.Height = Frame.Size.Height;
Margin.SetNeedsLayout ();
Margin.SetNeedsDisplay ();
}
Rectangle border = Margin.Thickness.GetInside (Margin.Frame);
if (border != Border.Frame)
{
Border._frame = border;
Border.X = border.Location.X;
Border.Y = border.Location.Y;
Border.Width = border.Size.Width;
Border.Height = border.Size.Height;
Border.SetNeedsLayout ();
Border.SetNeedsDisplay ();
}
Rectangle padding = Border.Thickness.GetInside (Border.Frame);
if (padding != Padding.Frame)
{
Padding._frame = padding;
Padding.X = padding.Location.X;
Padding.Y = padding.Location.Y;
Padding.Width = padding.Size.Width;
Padding.Height = padding.Size.Height;
Padding.SetNeedsLayout ();
Padding.SetNeedsDisplay ();
}
}
#endregion Adornments
#region AutoSize
private bool _autoSize;
/// <summary>
/// Gets or sets a flag that determines whether the View will be automatically resized to fit the <see cref="Text"/>
/// within <see cref="Bounds"/>.
/// <para>
/// The default is <see langword="false"/>. Set to <see langword="true"/> to turn on AutoSize. If
/// <see langword="true"/> then <see cref="Width"/> and <see cref="Height"/> will be used if <see cref="Text"/> can
/// fit; if <see cref="Text"/> won't fit the view will be resized as needed.
/// </para>
/// <para>
/// If <see cref="AutoSize"/> is set to <see langword="true"/> then <see cref="Width"/> and <see cref="Height"/>
/// will be changed to <see cref="Dim.DimAbsolute"/> if they are not already.
/// </para>
/// <para>
/// If <see cref="AutoSize"/> is set to <see langword="false"/> then <see cref="Width"/> and <see cref="Height"/>
/// will left unchanged.
/// </para>
/// </summary>
public virtual bool AutoSize
{
get => _autoSize;
set
{
if (Width != Dim.Sized (0) && Height != Dim.Sized (0))
{
Debug.WriteLine (
$@"WARNING: {GetType ().Name} - Setting {nameof (AutoSize)} invalidates {nameof (Width)} and {nameof (Height)}."
);
}
bool v = ResizeView (value);
TextFormatter.AutoSize = v;
if (_autoSize != v)
{
_autoSize = v;
TextFormatter.NeedsFormat = true;
UpdateTextFormatterText ();
OnResizeNeeded ();
}
}
}
/// <summary>If <paramref name="autoSize"/> is true, resizes the view.</summary>
/// <param name="autoSize"></param>
/// <returns></returns>
private bool ResizeView (bool autoSize)
{
if (!autoSize)
{
return false;
}
var boundsChanged = true;
Size newFrameSize = GetAutoSize ();
if (IsInitialized && newFrameSize != Frame.Size)
{
if (ValidatePosDim)
{
// BUGBUG: This ain't right, obviously. We need to figure out how to handle this.
boundsChanged = ResizeBoundsToFit (newFrameSize);
}
else
{
Height = newFrameSize.Height;
Width = newFrameSize.Width;
}
}
return boundsChanged;
}
/// <summary>Determines if the View's <see cref="Height"/> can be set to a new value.</summary>
/// <remarks>TrySetHeight can only be called when AutoSize is true (or being set to true).</remarks>
/// <param name="desiredHeight"></param>
/// <param name="resultHeight">
/// Contains the width that would result if <see cref="Height"/> were set to
/// <paramref name="desiredHeight"/>"/>
/// </param>
/// <returns>
/// <see langword="true"/> if the View's <see cref="Height"/> can be changed to the specified value. False
/// otherwise.
/// </returns>
internal bool TrySetHeight (int desiredHeight, out int resultHeight)
{
int h = desiredHeight;
bool canSetHeight;
switch (Height)
{
case Dim.DimCombine _:
case Dim.DimView _:
case Dim.DimFill _:
// It's a Dim.DimCombine and so can't be assigned. Let it have it's height anchored.
h = Height.Anchor (h);
canSetHeight = !ValidatePosDim;
break;
case Dim.DimFactor factor:
// Tries to get the SuperView height otherwise the view height.
int sh = SuperView is { } ? SuperView.Frame.Height : h;
if (factor.IsFromRemaining ())
{
sh -= Frame.Y;
}
h = Height.Anchor (sh);
canSetHeight = !ValidatePosDim;
break;
default:
canSetHeight = true;
break;
}
resultHeight = h;
return canSetHeight;
}
/// <summary>Determines if the View's <see cref="Width"/> can be set to a new value.</summary>
/// <remarks>TrySetWidth can only be called when AutoSize is true (or being set to true).</remarks>
/// <param name="desiredWidth"></param>
/// <param name="resultWidth">
/// Contains the width that would result if <see cref="Width"/> were set to
/// <paramref name="desiredWidth"/>"/>
/// </param>
/// <returns>
/// <see langword="true"/> if the View's <see cref="Width"/> can be changed to the specified value. False
/// otherwise.
/// </returns>
internal bool TrySetWidth (int desiredWidth, out int resultWidth)
{
int w = desiredWidth;
bool canSetWidth;
switch (Width)
{
case Dim.DimCombine _:
case Dim.DimView _:
case Dim.DimFill _:
// It's a Dim.DimCombine and so can't be assigned. Let it have it's Width anchored.
w = Width.Anchor (w);
canSetWidth = !ValidatePosDim;
break;
case Dim.DimFactor factor:
// Tries to get the SuperView Width otherwise the view Width.
int sw = SuperView is { } ? SuperView.Frame.Width : w;
if (factor.IsFromRemaining ())
{
sw -= Frame.X;
}
w = Width.Anchor (sw);
canSetWidth = !ValidatePosDim;
break;
default:
canSetWidth = true;
break;
}
resultWidth = w;
return canSetWidth;
}
/// <summary>Resizes the View to fit the specified size. Factors in the HotKey.</summary>
/// <remarks>ResizeBoundsToFit can only be called when AutoSize is true (or being set to true).</remarks>
/// <param name="size"></param>
/// <returns>whether the Bounds was changed or not</returns>
private bool ResizeBoundsToFit (Size size)
{
//if (AutoSize == false) {
// throw new InvalidOperationException ("ResizeBoundsToFit can only be called when AutoSize is true");
//}
var boundsChanged = false;
bool canSizeW = TrySetWidth (size.Width - GetHotKeySpecifierLength (), out int rW);
bool canSizeH = TrySetHeight (size.Height - GetHotKeySpecifierLength (false), out int rH);
if (canSizeW)
{
boundsChanged = true;
_width = rW;
}
if (canSizeH)
{
boundsChanged = true;
_height = rH;
}
if (boundsChanged)
{
Bounds = new (Bounds.X, Bounds.Y, canSizeW ? rW : Bounds.Width, canSizeH ? rH : Bounds.Height);
}
return boundsChanged;
}
#endregion AutoSize
#region Layout Engine
/// <summary>
/// Controls how the View's <see cref="Frame"/> is computed during <see cref="LayoutSubviews"/>. If the style is
/// set to <see cref="LayoutStyle.Absolute"/>, LayoutSubviews does not change the <see cref="Frame"/>. If the style is
/// <see cref="LayoutStyle.Computed"/> the <see cref="Frame"/> is updated using the <see cref="X"/>, <see cref="Y"/>,
/// <see cref="Width"/>, and <see cref="Height"/> properties.
/// </summary>
/// <remarks>
/// <para>
/// Setting this property to <see cref="LayoutStyle.Absolute"/> will cause <see cref="Frame"/> to determine the
/// size and position of the view. <see cref="X"/> and <see cref="Y"/> will be set to <see cref="Dim.DimAbsolute"/>
/// using <see cref="Frame"/>.
/// </para>
/// <para>
/// Setting this property to <see cref="LayoutStyle.Computed"/> will cause the view to use the
/// <see cref="LayoutSubviews"/> method to size and position of the view. If either of the <see cref="X"/> and
/// <see cref="Y"/> properties are `null` they will be set to <see cref="Pos.PosAbsolute"/> using the current value
/// of <see cref="Frame"/>. If either of the <see cref="Width"/> and <see cref="Height"/> properties are `null`
/// they will be set to <see cref="Dim.DimAbsolute"/> using <see cref="Frame"/>.
/// </para>
/// </remarks>
/// <value>The layout style.</value>
public LayoutStyle LayoutStyle
{
get
{
if (_x is Pos.PosAbsolute
&& _y is Pos.PosAbsolute
&& _width is Dim.DimAbsolute
&& _height is Dim.DimAbsolute)
{
return LayoutStyle.Absolute;
}
return LayoutStyle.Computed;
}
}
#endregion Layout Engine
internal bool LayoutNeeded { get; private set; } = true;
#nullable enable
/// <summary>Finds which view that belong to the <paramref name="start"/> superview at the provided location.</summary>
/// <param name="start">The superview where to look for.</param>
/// <param name="x">The column location in the superview.</param>
/// <param name="y">The row location in the superview.</param>
/// <param name="findAdornments">TODO: Remove this in PR #3273</param>
/// <returns>
/// The view that was found at the <paramref name="x"/> and <paramref name="y"/> coordinates.
/// <see langword="null"/> if no view was found.
/// </returns>
// CONCURRENCY: This method is not thread-safe.
// Undefined behavior and likely program crashes are exposed by unsynchronized access to InternalSubviews.
public static View? FindDeepestView (View? start, int x, int y, bool findAdornments = false)
{
if (start is null || !start.Visible)
{
return null;
}
if (!start.Frame.Contains (x, y))
{
return null;
}
if (findAdornments)
{
// TODO: This is a temporary hack for PR #3273; it is not actually used anywhere but unit tests at this point.
if (start.Margin.Thickness.Contains (start.Margin.Frame, x, y))
{
return start.Margin;
}
if (start.Border.Thickness.Contains (start.Border.Frame, x, y))
{
return start.Border;
}
if (start.Padding.Thickness.Contains (start.Padding.Frame, x, y))
{
return start.Padding;
}
}
if (start.InternalSubviews is { Count: > 0 })
{
Point boundsOffset = start.GetBoundsOffset ();
int rx = x - (start.Frame.X + boundsOffset.X);
int ry = y - (start.Frame.Y + boundsOffset.Y);
for (int i = start.InternalSubviews.Count - 1; i >= 0; i--)
{
View v = start.InternalSubviews [i];
if (v.Visible && v.Frame.Contains (rx, ry))
{
View? deep = FindDeepestView (v, rx, ry, findAdornments);
return deep ?? v;
}
}
}
return start;
}
#nullable restore
/// <summary>Fired after the View's <see cref="LayoutSubviews"/> method has completed.</summary>
/// <remarks>
/// Subscribe to this event to perform tasks when the <see cref="View"/> has been resized or the layout has
/// otherwise changed.
/// </remarks>
public event EventHandler<LayoutEventArgs> LayoutComplete;
/// <summary>Fired after the View's <see cref="LayoutSubviews"/> method has completed.</summary>
/// <remarks>
/// Subscribe to this event to perform tasks when the <see cref="View"/> has been resized or the layout has
/// otherwise changed.
/// </remarks>
public event EventHandler<LayoutEventArgs> LayoutStarted;
/// <summary>
/// Invoked when a view starts executing or when the dimensions of the view have changed, for example in response
/// to the container view or terminal resizing.
/// </summary>
/// <remarks>
/// <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="LayoutComplete"/> event) before it returns.</para>
/// </remarks>
public virtual void LayoutSubviews ()
{
if (!IsInitialized)
{
Debug.WriteLine (
$"WARNING: LayoutSubviews called before view has been initialized. This is likely a bug in {this}"
);
}
if (!LayoutNeeded)
{
return;
}
LayoutAdornments ();
Rectangle oldBounds = Bounds;
OnLayoutStarted (new () { OldBounds = oldBounds });
SetTextFormatterSize ();
// 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);
foreach (View v in ordered)
{
LayoutSubview (v, new (GetBoundsOffset (), Bounds.Size));
}
// If the 'to' is rooted to 'from' and the layoutstyle is Computed it's a special-case.
// Use LayoutSubview with the Frame of the 'from'
if (SuperView is { } && GetTopSuperView () is { } && LayoutNeeded && edges.Count > 0)
{
foreach ((View from, View to) in edges)
{
LayoutSubview (to, from.Frame);
}
}
LayoutNeeded = false;
OnLayoutComplete (new () { OldBounds = oldBounds });
}
/// <summary>Indicates that the view does not need to be laid out.</summary>
protected void ClearLayoutNeeded () { LayoutNeeded = false; }
/// <summary>
/// Raises the <see cref="LayoutComplete"/> event. Called from <see cref="LayoutSubviews"/> before all sub-views
/// have been laid out.
/// </summary>
internal virtual void OnLayoutComplete (LayoutEventArgs args) { LayoutComplete?.Invoke (this, args); }
/// <summary>
/// Raises the <see cref="LayoutStarted"/> event. Called from <see cref="LayoutSubviews"/> before any subviews
/// have been laid out.
/// </summary>
internal virtual void OnLayoutStarted (LayoutEventArgs args) { LayoutStarted?.Invoke (this, args); }
/// <summary>
/// Called whenever the view needs to be resized. This is called whenever <see cref="Frame"/>,
/// <see cref="View.X"/>, <see cref="View.Y"/>, <see cref="View.Width"/>, or <see cref="View.Height"/> changes.
/// </summary>
/// <remarks>
/// <para>
/// Determines the relative bounds of the <see cref="View"/> and its <see cref="Frame"/>s, and then calls
/// <see cref="SetRelativeLayout(Rectangle)"/> to update the view.
/// </para>
/// </remarks>
internal void OnResizeNeeded ()
{
// TODO: Identify a real-world use-case where this API should be virtual.
// TODO: Until then leave it `internal` and non-virtual
// First try SuperView.Bounds, then Application.Top, then Driver.Bounds.
// Finally, if none of those are valid, use int.MaxValue (for Unit tests).
Rectangle relativeBounds = SuperView is { IsInitialized: true } ? SuperView.Bounds :
Application.Top is { } && Application.Top.IsInitialized ? Application.Top.Bounds :
Application.Driver?.Bounds ?? new Rectangle (0, 0, int.MaxValue, int.MaxValue);
SetRelativeLayout (relativeBounds);
// TODO: Determine what, if any of the below is actually needed here.
if (IsInitialized)
{
if (AutoSize)
{
SetFrameToFitText ();
SetTextFormatterSize ();
}
LayoutAdornments ();
SetNeedsLayout ();
SetNeedsDisplay ();
}
}
/// <summary>
/// Sets the internal <see cref="LayoutNeeded"/> flag for this View and all of it's subviews and it's SuperView.
/// The main loop will call SetRelativeLayout and LayoutSubviews for any view with <see cref="LayoutNeeded"/> set.
/// </summary>
internal void SetNeedsLayout ()
{
if (LayoutNeeded)
{
return;
}
LayoutNeeded = true;
foreach (View view in Subviews)
{
view.SetNeedsLayout ();
}
TextFormatter.NeedsFormat = true;
SuperView?.SetNeedsLayout ();
}
/// <summary>
/// Applies the view's position (<see cref="X"/>, <see cref="Y"/>) and dimension (<see cref="Width"/>, and
/// <see cref="Height"/>) to <see cref="Frame"/>, given a rectangle describing the SuperView's Bounds (nominally the
/// same as <c>this.SuperView.Bounds</c>).
/// </summary>
/// <param name="superviewBounds">
/// The rectangle describing the SuperView's Bounds (nominally the same as
/// <c>this.SuperView.Bounds</c>).
/// </param>
internal void SetRelativeLayout (Rectangle superviewBounds)
{
Debug.Assert (_x is { });
Debug.Assert (_y is { });
Debug.Assert (_width is { });
Debug.Assert (_height is { });
int newX, newW, newY, newH;
var autosize = Size.Empty;
if (AutoSize)
{
// Note this is global to this function and used as such within the local functions defined
// below. In v2 AutoSize will be re-factored to not need to be dealt with in this function.
autosize = GetAutoSize ();
}
// TODO: Since GetNewLocationAndDimension does not depend on View, it can be moved into PosDim.cs
// TODO: to make architecture more clean. Do this after DimAuto is implemented and the
// TODO: View.AutoSize stuff is removed.
// Returns the new dimension (width or height) and location (x or y) for the View given
// the superview's Bounds
// the current Pos (View.X or View.Y)
// the current Dim (View.Width or View.Height)
// This method is called recursively if pos is Pos.PosCombine
(int newLocation, int newDimension) GetNewLocationAndDimension (
bool width,
Rectangle superviewBounds,
Pos pos,
Dim dim,
int autosizeDimension
)
{
// Gets the new dimension (width or height, dependent on `width`) of the given Dim given:
// location: the current location (x or y)
// dimension: the new dimension (width or height) (if relevant for Dim type)
// autosize: the size to use if autosize = true
// This method is recursive if d is Dim.DimCombine
int GetNewDimension (Dim d, int location, int dimension, int autosize)
{
int newDimension;
switch (d)
{
case Dim.DimCombine combine:
// TODO: Move combine logic into DimCombine?
int leftNewDim = GetNewDimension (combine._left, location, dimension, autosize);
int rightNewDim = GetNewDimension (combine._right, location, dimension, autosize);
if (combine._add)
{
newDimension = leftNewDim + rightNewDim;
}
else
{
newDimension = leftNewDim - rightNewDim;
}
newDimension = AutoSize && autosize > newDimension ? autosize : newDimension;
break;
case Dim.DimFactor factor when !factor.IsFromRemaining ():
newDimension = d.Anchor (dimension);
newDimension = AutoSize && autosize > newDimension ? autosize : newDimension;
break;
case Dim.DimAbsolute:
// DimAbsolute.Anchor (int width) ignores width and returns n
newDimension = Math.Max (d.Anchor (0), 0);
// BUGBUG: AutoSize does two things: makes text fit AND changes the view's dimensions
newDimension = AutoSize && autosize > newDimension ? autosize : newDimension;
break;
case Dim.DimFill:
default:
newDimension = Math.Max (d.Anchor (dimension - location), 0);
newDimension = AutoSize && autosize > newDimension ? autosize : newDimension;
break;
}
return newDimension;
}
int newDimension, newLocation;
int superviewDimension = width ? superviewBounds.Width : superviewBounds.Height;
// Determine new location
switch (pos)
{
case Pos.PosCenter posCenter:
// For Center, the dimension is dependent on location, but we need to force getting the dimension first
// using a location of 0
newDimension = Math.Max (GetNewDimension (dim, 0, superviewDimension, autosizeDimension), 0);
newLocation = posCenter.Anchor (superviewDimension - newDimension);
newDimension = Math.Max (
GetNewDimension (dim, newLocation, superviewDimension, autosizeDimension),
0
);
break;
case Pos.PosCombine combine:
// TODO: Move combine logic into PosCombine?
int left, right;
(left, newDimension) = GetNewLocationAndDimension (
width,
superviewBounds,
combine._left,
dim,
autosizeDimension
);
(right, newDimension) = GetNewLocationAndDimension (
width,
superviewBounds,
combine._right,
dim,
autosizeDimension
);
if (combine._add)
{
newLocation = left + right;
}
else
{
newLocation = left - right;
}
newDimension = Math.Max (
GetNewDimension (dim, newLocation, superviewDimension, autosizeDimension),
0
);
break;
case Pos.PosAnchorEnd:
case Pos.PosAbsolute:
case Pos.PosFactor:
case Pos.PosFunc:
case Pos.PosView:
default:
newLocation = pos?.Anchor (superviewDimension) ?? 0;
newDimension = Math.Max (
GetNewDimension (dim, newLocation, superviewDimension, autosizeDimension),
0
);
break;
}
return (newLocation, newDimension);
}
// horizontal/width
(newX, newW) = GetNewLocationAndDimension (true, superviewBounds, _x, _width, autosize.Width);
// vertical/height
(newY, newH) = GetNewLocationAndDimension (false, superviewBounds, _y, _height, autosize.Height);
Rectangle r = new (newX, newY, newW, newH);
if (Frame != r)
{
// Set the frame. Do NOT use `Frame` as it overwrites X, Y, Width, and Height, making
// the view LayoutStyle.Absolute.
_frame = r;
if (_x is Pos.PosAbsolute)
{
_x = Frame.X;
}
if (_y is Pos.PosAbsolute)
{
_y = Frame.Y;
}
if (_width is Dim.DimAbsolute)
{
_width = Frame.Width;
}
if (_height is Dim.DimAbsolute)
{
_height = Frame.Height;
}
SetNeedsLayout ();
SetNeedsDisplay ();
}
if (AutoSize)
{
if (autosize.Width == 0 || autosize.Height == 0)
{
// Set the frame. Do NOT use `Frame` as it overwrites X, Y, Width, and Height, making
// the view LayoutStyle.Absolute.
_frame = _frame with { Size = autosize };
if (autosize.Width == 0)
{
_width = 0;
}
if (autosize.Height == 0)
{
_height = 0;
}
}
else if (!SetFrameToFitText ())
{
SetTextFormatterSize ();
}
SetNeedsLayout ();
SetNeedsDisplay ();
}
}
internal void CollectAll (View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
// BUGBUG: This should really only work on initialized subviews
foreach (View v in from.InternalSubviews /*.Where(v => v.IsInitialized)*/)
{
nNodes.Add (v);
if (v.LayoutStyle != LayoutStyle.Computed)
{
continue;
}
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);
}
}
internal void CollectDim (Dim dim, View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
switch (dim)
{
case Dim.DimView dv:
// See #2461
//if (!from.InternalSubviews.Contains (dv.Target)) {
// throw new InvalidOperationException ($"View {dv.Target} is not a subview of {from}");
//}
if (dv.Target != this)
{
nEdges.Add ((dv.Target, from));
}
return;
case Dim.DimCombine dc:
CollectDim (dc._left, from, ref nNodes, ref nEdges);
CollectDim (dc._right, from, ref nNodes, ref nEdges);
break;
}
}
internal void CollectPos (Pos pos, View from, ref HashSet<View> nNodes, ref HashSet<(View, View)> nEdges)
{
switch (pos)
{
case Pos.PosView pv:
// See #2461
//if (!from.InternalSubviews.Contains (pv.Target)) {
// throw new InvalidOperationException ($"View {pv.Target} is not a subview of {from}");
//}
if (pv.Target != this)
{
nEdges.Add ((pv.Target, from));
}
return;
case Pos.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 InvalidOperationException (
$"ComputedLayout for \"{superView}\": \"{to}\" references a SubView (\"{from}\")."
);
}
throw new InvalidOperationException (
$"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
private void LayoutSubview (View v, Rectangle contentArea)
{
//if (v.LayoutStyle == LayoutStyle.Computed) {
v.SetRelativeLayout (contentArea);
//}
v.LayoutSubviews ();
v.LayoutNeeded = false;
}
#region Diagnostics
// 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 (LayoutStyle == LayoutStyle.Computed && !IsInitialized)
{
Debug.WriteLine (
$"WARNING: \"{this}\" has not been initialized; {member} is indeterminate: {dim}. This is potentially a bug."
);
}
#endif // DEBUG
return dim;
}
// 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 (LayoutStyle == LayoutStyle.Computed && !IsInitialized)
{
Debug.WriteLine (
$"WARNING: \"{this}\" has not been initialized; {member} is indeterminate {pos}. This is potentially a bug."
);
}
#endif // DEBUG
return pos;
}
/// <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; }
#endregion
}