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Terminal.Gui/Terminal.Gui/Views/Button.cs
2020-06-08 23:45:31 +01:00

256 lines
7.2 KiB
C#

//
// Button.cs: Button control
//
// Authors:
// Miguel de Icaza (miguel@gnome.org)
//
using System;
using NStack;
namespace Terminal.Gui {
/// <summary>
/// Button is a <see cref="View"/> that provides an item that invokes an <see cref="Action"/> when activated by the user.
/// </summary>
/// <remarks>
/// <para>
/// Provides a button showing text invokes an <see cref="Action"/> when clicked on with a mouse
/// or when the user presses SPACE, ENTER, or hotkey. The hotkey is specified by the first uppercase
/// letter in the button.
/// </para>
/// <para>
/// When the button is configured as the default (<see cref="IsDefault"/>) and the user presses
/// the ENTER key, if no other <see cref="View"/> processes the <see cref="KeyEvent"/>, the <see cref="Button"/>'s
/// <see cref="Action"/> will be invoked.
/// </para>
/// </remarks>
public class Button : View {
ustring text;
ustring shown_text;
Rune hot_key;
int hot_pos = -1;
bool is_default;
TextAlignment textAlignment = TextAlignment.Centered;
/// <summary>
/// Gets or sets whether the <see cref="Button"/> is the default action to activate in a dialog.
/// </summary>
/// <value><c>true</c> if is default; otherwise, <c>false</c>.</value>
public bool IsDefault {
get => is_default;
set {
is_default = value;
SetWidthHeight (Text, is_default);
Update ();
}
}
/// <summary>
/// Clicked <see cref="Action"/>, raised when the button is clicked.
/// </summary>
/// <remarks>
/// Client code can hook up to this event, it is
/// raised when the button is activated either with
/// the mouse or the keyboard.
/// </remarks>
public Action Clicked;
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Computed"/> layout.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
public Button () : this (string.Empty) { }
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Computed"/> layout.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="text">The button's text</param>
/// <param name="is_default">
/// If <c>true</c>, a special decoration is used, and the user pressing the enter key
/// in a <see cref="Dialog"/> will implicitly activate this button.
/// </param>
public Button (ustring text, bool is_default = false) : base ()
{
CanFocus = true;
Text = text ?? string.Empty;
this.IsDefault = is_default;
int w = SetWidthHeight (text, is_default);
Frame = new Rect (Frame.Location, new Size (w, 1));
}
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Absolute"/> layout, based on the given text
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="x">X position where the button will be shown.</param>
/// <param name="y">Y position where the button will be shown.</param>
/// <param name="text">The button's text</param>
public Button (int x, int y, ustring text) : this (x, y, text, false) { }
/// <summary>
/// Initializes a new instance of <see cref="Button"/> using <see cref="LayoutStyle.Absolute"/> layout, based on the given text.
/// </summary>
/// <remarks>
/// The width of the <see cref="Button"/> is computed based on the
/// text length. The height will always be 1.
/// </remarks>
/// <param name="x">X position where the button will be shown.</param>
/// <param name="y">Y position where the button will be shown.</param>
/// <param name="text">The button's text</param>
/// <param name="is_default">
/// If <c>true</c>, a special decoration is used, and the user pressing the enter key
/// in a <see cref="Dialog"/> will implicitly activate this button.
/// </param>
public Button (int x, int y, ustring text, bool is_default)
: base (new Rect (x, y, text.Length + 4 + (is_default ? 2 : 0), 1))
{
CanFocus = true;
Text = text ?? string.Empty;
this.IsDefault = is_default;
}
int SetWidthHeight (ustring text, bool is_default)
{
int w = text.Length + 4 + (is_default ? 2 : 0);
Width = w;
Height = 1;
Frame = new Rect (Frame.Location, new Size (w, 1));
return w;
}
/// <summary>
/// The text displayed by this <see cref="Button"/>.
/// </summary>
public ustring Text {
get {
return text;
}
set {
SetWidthHeight (value, is_default);
text = value;
Update ();
}
}
/// <summary>
/// Sets or gets the text alignment for the <see cref="Button"/>.
/// </summary>
public TextAlignment TextAlignment {
get => textAlignment;
set {
textAlignment = value;
Update ();
}
}
Rune _leftBracket = new Rune (Driver.LeftBracket);
Rune _rightBracket = new Rune (Driver.RightBracket);
Rune _leftDefault = new Rune (Driver.LeftDefaultIndicator);
Rune _rightDefault = new Rune (Driver.RightDefaultIndicator);
internal void Update ()
{
if (IsDefault)
shown_text = ustring.Make (_leftBracket) + ustring.Make (_leftDefault) + " " + text + " " + ustring.Make (_rightDefault) + ustring.Make (_rightBracket);
else
shown_text = ustring.Make (_leftBracket) + " " + text + " " + ustring.Make (_rightBracket);
shown_text = GetTextFromHotKey (shown_text, '_', out hot_pos, out hot_key);
SetNeedsDisplay ();
}
int c_hot_pos;
///<inheritdoc/>
public override void Redraw (Rect bounds)
{
Driver.SetAttribute (HasFocus ? ColorScheme.Focus : ColorScheme.Normal);
Move (0, 0);
var caption = GetTextAlignment (shown_text, hot_pos, out int s_hot_pos, TextAlignment);
c_hot_pos = s_hot_pos;
Driver.AddStr (caption);
if (c_hot_pos != -1) {
Move (c_hot_pos, 0);
Driver.SetAttribute (HasFocus ? ColorScheme.HotFocus : ColorScheme.HotNormal);
Driver.AddRune (hot_key);
}
}
///<inheritdoc/>
public override void PositionCursor ()
{
Move (c_hot_pos == -1 ? 1 : c_hot_pos, 0);
}
bool CheckKey (KeyEvent key)
{
if ((char)key.KeyValue == hot_key) {
this.SuperView.SetFocus (this);
Clicked?.Invoke ();
return true;
}
return false;
}
///<inheritdoc/>
public override bool ProcessHotKey (KeyEvent kb)
{
if (kb.IsAlt)
return CheckKey (kb);
return false;
}
///<inheritdoc/>
public override bool ProcessColdKey (KeyEvent kb)
{
if (IsDefault && kb.KeyValue == '\n') {
Clicked?.Invoke ();
return true;
}
return CheckKey (kb);
}
///<inheritdoc/>
public override bool ProcessKey (KeyEvent kb)
{
var c = kb.KeyValue;
if (c == '\n' || c == ' ' || Rune.ToUpper ((uint)c) == hot_key) {
Clicked?.Invoke ();
return true;
}
return base.ProcessKey (kb);
}
///<inheritdoc/>
public override bool MouseEvent (MouseEvent me)
{
if (me.Flags == MouseFlags.Button1Clicked) {
if (!HasFocus) {
SuperView.SetFocus (this);
SetNeedsDisplay ();
}
Clicked?.Invoke ();
return true;
}
return false;
}
}
}