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Terminal.Gui/Terminal.Gui/Core/PosDim.cs
2020-06-08 10:01:10 +01:00

566 lines
17 KiB
C#

//
// PosDim.cs: Pos and Dim objects for view dimensions.
//
// Authors:
// Miguel de Icaza (miguel@gnome.org)
//
using System;
namespace Terminal.Gui {
/// <summary>
/// Describes the position of a <see cref="View"/> which can be an absolute value, a percentage, centered, or
/// relative to the ending dimension. Integer values are implicitly convertible to
/// an absolute <see cref="Pos"/>. These objects are created using the static methods Percent,
/// AnchorEnd, and Center. The <see cref="Pos"/> objects can be combined with the addition and
/// subtraction operators.
/// </summary>
/// <remarks>
/// <para>
/// Use the <see cref="Pos"/> objects on the X or Y properties of a view to control the position.
/// </para>
/// <para>
/// These can be used to set the absolute position, when merely assigning an
/// integer value (via the implicit integer to <see cref="Pos"/> conversion), and they can be combined
/// to produce more useful layouts, like: Pos.Center - 3, which would shift the postion
/// of the <see cref="View"/> 3 characters to the left after centering for example.
/// </para>
/// <para>
/// It is possible to reference coordinates of another view by using the methods
/// Left(View), Right(View), Bottom(View), Top(View). The X(View) and Y(View) are
/// aliases to Left(View) and Top(View) respectively.
/// </para>
/// </remarks>
public class Pos {
internal virtual int Anchor (int width)
{
return 0;
}
class PosFactor : Pos {
float factor;
public PosFactor (float n)
{
this.factor = n;
}
internal override int Anchor (int width)
{
return (int)(width * factor);
}
public override string ToString ()
{
return $"Pos.Factor({factor})";
}
}
/// <summary>
/// Creates a percentage <see cref="Pos"/> object
/// </summary>
/// <returns>The percent <see cref="Pos"/> object.</returns>
/// <param name="n">A value between 0 and 100 representing the percentage.</param>
/// <example>
/// This creates a <see cref="TextField"/>that is centered horizontally, is 50% of the way down,
/// is 30% the height, and is 80% the width of the <see cref="View"/> it added to.
/// <code>
/// var textView = new TextView () {
/// X = Pos.Center (),
/// Y = Pos.Percent (50),
/// Width = Dim.Percent (80),
/// Height = Dim.Percent (30),
/// };
/// </code>
/// </example>
public static Pos Percent (float n)
{
if (n < 0 || n > 100)
throw new ArgumentException ("Percent value must be between 0 and 100");
return new PosFactor (n / 100);
}
static PosAnchorEnd endNoMargin;
class PosAnchorEnd : Pos {
int n;
public PosAnchorEnd (int n)
{
this.n = n;
}
internal override int Anchor (int width)
{
return width - n;
}
public override string ToString ()
{
return $"Pos.AnchorEnd(margin={n})";
}
}
/// <summary>
/// Creates a <see cref="Pos"/> object that is anchored to the end (right side or bottom) of the dimension,
/// useful to flush the layout from the right or bottom.
/// </summary>
/// <returns>The <see cref="Pos"/> object anchored to the end (the bottom or the right side).</returns>
/// <param name="margin">Optional margin to place to the right or below.</param>
/// <example>
/// This sample shows how align a <see cref="Button"/> to the bottom-right of a <see cref="View"/>.
/// <code>
/// // See Issue #502
/// anchorButton.X = Pos.AnchorEnd () - (Pos.Right (anchorButton) - Pos.Left (anchorButton));
/// anchorButton.Y = Pos.AnchorEnd (1);
/// </code>
/// </example>
public static Pos AnchorEnd (int margin = 0)
{
if (margin < 0)
throw new ArgumentException ("Margin must be positive");
if (margin == 0) {
if (endNoMargin == null)
endNoMargin = new PosAnchorEnd (0);
return endNoMargin;
}
return new PosAnchorEnd (margin);
}
internal class PosCenter : Pos {
internal override int Anchor (int width)
{
return width / 2;
}
public override string ToString ()
{
return "Pos.Center";
}
}
static PosCenter pCenter;
/// <summary>
/// Returns a <see cref="Pos"/> object that can be used to center the <see cref="View"/>
/// </summary>
/// <returns>The center Pos.</returns>
/// <example>
/// This creates a <see cref="TextField"/>that is centered horizontally, is 50% of the way down,
/// is 30% the height, and is 80% the width of the <see cref="View"/> it added to.
/// <code>
/// var textView = new TextView () {
/// X = Pos.Center (),
/// Y = Pos.Percent (50),
/// Width = Dim.Percent (80),
/// Height = Dim.Percent (30),
/// };
/// </code>
/// </example>
public static Pos Center ()
{
if (pCenter == null)
pCenter = new PosCenter ();
return pCenter;
}
class PosAbsolute : Pos {
int n;
public PosAbsolute (int n) { this.n = n; }
public override string ToString ()
{
return $"Pos.Absolute({n})";
}
internal override int Anchor (int width)
{
return n;
}
}
/// <summary>
/// Creates an Absolute <see cref="Pos"/> from the specified integer value.
/// </summary>
/// <returns>The Absolute <see cref="Pos"/>.</returns>
/// <param name="n">The value to convert to the <see cref="Pos"/> .</param>
public static implicit operator Pos (int n)
{
return new PosAbsolute (n);
}
/// <summary>
/// Creates an Absolute <see cref="Pos"/> from the specified integer value.
/// </summary>
/// <returns>The Absolute <see cref="Pos"/>.</returns>
/// <param name="n">The value to convert to the <see cref="Pos"/>.</param>
public static Pos At (int n)
{
return new PosAbsolute (n);
}
class PosCombine : Pos {
Pos left, right;
bool add;
public PosCombine (bool add, Pos left, Pos right)
{
this.left = left;
this.right = right;
this.add = add;
}
internal override int Anchor (int width)
{
var la = left.Anchor (width);
var ra = right.Anchor (width);
if (add)
return la + ra;
else
return la - ra;
}
public override string ToString ()
{
return $"Pos.Combine ({left.ToString ()}{(add ? '+' : '-')}{right.ToString ()})";
}
}
static PosCombine posCombine;
/// <summary>
/// Adds a <see cref="Terminal.Gui.Pos"/> to a <see cref="Terminal.Gui.Pos"/>, yielding a new <see cref="Pos"/>.
/// </summary>
/// <param name="left">The first <see cref="Terminal.Gui.Pos"/> to add.</param>
/// <param name="right">The second <see cref="Terminal.Gui.Pos"/> to add.</param>
/// <returns>The <see cref="Pos"/> that is the sum of the values of <c>left</c> and <c>right</c>.</returns>
public static Pos operator + (Pos left, Pos right)
{
PosCombine newPos = new PosCombine (true, left, right);
if (posCombine?.ToString () != newPos.ToString ()) {
var view = left as PosView;
if (view != null) {
view.Target.SetNeedsLayout ();
}
}
return posCombine = newPos;
}
/// <summary>
/// Subtracts a <see cref="Terminal.Gui.Pos"/> from a <see cref="Terminal.Gui.Pos"/>, yielding a new <see cref="Pos"/>.
/// </summary>
/// <param name="left">The <see cref="Terminal.Gui.Pos"/> to subtract from (the minuend).</param>
/// <param name="right">The <see cref="Terminal.Gui.Pos"/> to subtract (the subtrahend).</param>
/// <returns>The <see cref="Pos"/> that is the <c>left</c> minus <c>right</c>.</returns>
public static Pos operator - (Pos left, Pos right)
{
PosCombine newPos = new PosCombine (false, left, right);
if (posCombine?.ToString () != newPos.ToString ()) {
var view = left as PosView;
if (view != null)
view.Target.SetNeedsLayout ();
}
return posCombine = newPos;
}
internal class PosView : Pos {
public View Target;
int side;
public PosView (View view, int side)
{
Target = view;
this.side = side;
}
internal override int Anchor (int width)
{
switch (side) {
case 0: return Target.Frame.X;
case 1: return Target.Frame.Y;
case 2: return Target.Frame.Right;
case 3: return Target.Frame.Bottom;
default:
return 0;
}
}
public override string ToString ()
{
string tside;
switch (side) {
case 0: tside = "x"; break;
case 1: tside = "y"; break;
case 2: tside = "right"; break;
case 3: tside = "bottom"; break;
default: tside = "unknown"; break;
}
return $"Pos.View(side={tside}, target={Target.ToString ()}";
}
}
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Left (X) position of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos Left (View view) => new PosView (view, 0);
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Left (X) position of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos X (View view) => new PosView (view, 0);
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Top (Y) position of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos Top (View view) => new PosView (view, 1);
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Top (Y) position of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos Y (View view) => new PosView (view, 1);
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Right (X+Width) coordinate of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos Right (View view) => new PosView (view, 2);
/// <summary>
/// Returns a <see cref="Pos"/> object tracks the Bottom (Y+Height) coordinate of the specified <see cref="View"/>
/// </summary>
/// <returns>The <see cref="Pos"/> that depends on the other view.</returns>
/// <param name="view">The <see cref="View"/> that will be tracked.</param>
public static Pos Bottom (View view) => new PosView (view, 3);
}
/// <summary>
/// Dim properties of a <see cref="View"/> to control the position.
/// </summary>
/// <remarks>
/// <para>
/// Use the Dim objects on the Width or Height properties of a <see cref="View"/> to control the position.
/// </para>
/// <para>
/// These can be used to set the absolute position, when merely assigning an
/// integer value (via the implicit integer to Pos conversion), and they can be combined
/// to produce more useful layouts, like: Pos.Center - 3, which would shift the postion
/// of the <see cref="View"/> 3 characters to the left after centering for example.
/// </para>
/// </remarks>
public class Dim {
internal virtual int Anchor (int width)
{
return 0;
}
internal class DimFactor : Dim {
float factor;
public DimFactor (float n)
{
this.factor = n;
}
internal override int Anchor (int width)
{
return (int)(width * factor);
}
public override string ToString ()
{
return $"Dim.Factor({factor})";
}
public override int GetHashCode () => factor.GetHashCode ();
public override bool Equals (object other) => other is DimFactor f && f.factor == factor;
}
/// <summary>
/// Creates a percentage <see cref="Dim"/> object
/// </summary>
/// <returns>The percent <see cref="Dim"/> object.</returns>
/// <param name="n">A value between 0 and 100 representing the percentage.</param>
/// <example>
/// This initializes a <see cref="TextField"/>that is centered horizontally, is 50% of the way down,
/// is 30% the height, and is 80% the width of the <see cref="View"/> it added to.
/// <code>
/// var textView = new TextView () {
/// X = Pos.Center (),
/// Y = Pos.Percent (50),
/// Width = Dim.Percent (80),
/// Height = Dim.Percent (30),
/// };
/// </code>
/// </example>
public static Dim Percent (float n)
{
if (n < 0 || n > 100)
throw new ArgumentException ("Percent value must be between 0 and 100");
return new DimFactor (n / 100);
}
internal class DimAbsolute : Dim {
int n;
public DimAbsolute (int n) { this.n = n; }
public override string ToString ()
{
return $"Dim.Absolute({n})";
}
internal override int Anchor (int width)
{
return n;
}
public override int GetHashCode () => n.GetHashCode ();
public override bool Equals (object other) => other is DimAbsolute abs && abs.n == n;
}
internal class DimFill : Dim {
int margin;
public DimFill (int margin) { this.margin = margin; }
public override string ToString ()
{
return $"Dim.Fill(margin={margin})";
}
internal override int Anchor (int width)
{
return width - margin;
}
public override int GetHashCode () => margin.GetHashCode ();
public override bool Equals (object other) => other is DimFill fill && fill.margin == margin;
}
static DimFill zeroMargin;
/// <summary>
/// Initializes a new instance of the <see cref="Dim"/> class that fills the dimension, but leaves the specified number of colums for a margin.
/// </summary>
/// <returns>The Fill dimension.</returns>
/// <param name="margin">Margin to use.</param>
public static Dim Fill (int margin = 0)
{
if (margin == 0) {
if (zeroMargin == null)
zeroMargin = new DimFill (0);
return zeroMargin;
}
return new DimFill (margin);
}
/// <summary>
/// Creates an Absolute <see cref="Dim"/> from the specified integer value.
/// </summary>
/// <returns>The Absolute <see cref="Dim"/>.</returns>
/// <param name="n">The value to convert to the pos.</param>
public static implicit operator Dim (int n)
{
return new DimAbsolute (n);
}
/// <summary>
/// Creates an Absolute <see cref="Dim"/> from the specified integer value.
/// </summary>
/// <returns>The Absolute <see cref="Dim"/>.</returns>
/// <param name="n">The value to convert to the <see cref="Dim"/>.</param>
public static Dim Sized (int n)
{
return new DimAbsolute (n);
}
class DimCombine : Dim {
Dim left, right;
bool add;
public DimCombine (bool add, Dim left, Dim right)
{
this.left = left;
this.right = right;
this.add = add;
}
internal override int Anchor (int width)
{
var la = left.Anchor (width);
var ra = right.Anchor (width);
if (add)
return la + ra;
else
return la - ra;
}
}
/// <summary>
/// Adds a <see cref="Terminal.Gui.Dim"/> to a <see cref="Terminal.Gui.Dim"/>, yielding a new <see cref="Dim"/>.
/// </summary>
/// <param name="left">The first <see cref="Terminal.Gui.Dim"/> to add.</param>
/// <param name="right">The second <see cref="Terminal.Gui.Dim"/> to add.</param>
/// <returns>The <see cref="Dim"/> that is the sum of the values of <c>left</c> and <c>right</c>.</returns>
public static Dim operator + (Dim left, Dim right)
{
return new DimCombine (true, left, right);
}
/// <summary>
/// Subtracts a <see cref="Terminal.Gui.Dim"/> from a <see cref="Terminal.Gui.Dim"/>, yielding a new <see cref="Dim"/>.
/// </summary>
/// <param name="left">The <see cref="Terminal.Gui.Dim"/> to subtract from (the minuend).</param>
/// <param name="right">The <see cref="Terminal.Gui.Dim"/> to subtract (the subtrahend).</param>
/// <returns>The <see cref="Dim"/> that is the <c>left</c> minus <c>right</c>.</returns>
public static Dim operator - (Dim left, Dim right)
{
return new DimCombine (false, left, right);
}
internal class DimView : Dim {
public View Target;
int side;
public DimView (View view, int side)
{
Target = view;
this.side = side;
}
internal override int Anchor (int width)
{
switch (side) {
case 0: return Target.Frame.Height;
case 1: return Target.Frame.Width;
default:
return 0;
}
}
}
/// <summary>
/// Returns a <see cref="Dim"/> object tracks the Width of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Dim"/> of the other <see cref="View"/>.</returns>
/// <param name="view">The view that will be tracked.</param>
public static Dim Width (View view) => new DimView (view, 1);
/// <summary>
/// Returns a <see cref="Dim"/> object tracks the Height of the specified <see cref="View"/>.
/// </summary>
/// <returns>The <see cref="Dim"/> of the other <see cref="View"/>.</returns>
/// <param name="view">The view that will be tracked.</param>
public static Dim Height (View view) => new DimView (view, 0);
}
}