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MLEM/MLEM.Ui/Elements/Element.cs

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49 KiB
C#

using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using MLEM.Extensions;
using MLEM.Input;
using MLEM.Misc;
using MLEM.Textures;
using MLEM.Ui.Style;
namespace MLEM.Ui.Elements {
/// <summary>
/// This class represents a generic base class for ui elements of a <see cref="UiSystem"/>.
/// </summary>
public abstract class Element : GenericDataHolder {
/// <summary>
/// A list of all of this element's direct children.
/// Use <see cref="AddChild{T}"/> or <see cref="RemoveChild"/> to manipulate this list while calling all of the necessary callbacks.
/// </summary>
protected readonly List<Element> Children = new List<Element>();
private readonly List<Element> sortedChildren = new List<Element>();
/// <summary>
/// A sorted version of <see cref="Children"/>. The children are sorted by their <see cref="Priority"/>.
/// </summary>
protected List<Element> SortedChildren {
get {
this.UpdateSortedChildrenIfDirty();
return this.sortedChildren;
}
}
private bool sortedChildrenDirty;
private UiSystem system;
/// <summary>
/// The ui system that this element is currently a part of
/// </summary>
public UiSystem System {
get => this.system;
internal set {
this.system = value;
this.Controls = value?.Controls;
if (this.system != null)
this.InitStyle(this.system.Style);
}
}
/// <summary>
/// The controls that this element's <see cref="System"/> uses
/// </summary>
public UiControls Controls;
/// <summary>
/// The input handler that this element's <see cref="Controls"/> use
/// </summary>
protected InputHandler Input => this.Controls.Input;
/// <summary>
/// This element's parent element.
/// If this element has no parent (it is the <see cref="RootElement"/> of a ui system), this value is <c>null</c>.
/// </summary>
public Element Parent { get; private set; }
/// <summary>
/// This element's <see cref="RootElement"/>.
/// Note that this value is set even if this element has a <see cref="Parent"/>. To get the element that represents the root element, use <see cref="RootElement.Element"/>.
/// </summary>
public RootElement Root { get; internal set; }
/// <summary>
/// The scale that this ui element renders with
/// </summary>
public float Scale => this.Root.ActualScale;
private Anchor anchor;
/// <summary>
/// The <see cref="Anchor"/> that this element uses for positioning within its parent
/// </summary>
public Anchor Anchor {
get => this.anchor;
set {
if (this.anchor == value)
return;
this.anchor = value;
this.SetAreaDirty();
}
}
private Vector2 size;
/// <summary>
/// The size of this element, where X represents the width and Y represents the height.
/// If the x or y value of the size is between 0 and 1, the size will be seen as a percentage of its parent's size rather than as an absolute value.
/// If the x (or y) value of the size is negative, the width (or height) is seen as a percentage of the element's resulting height (or width).
/// If <see cref="SetWidthBasedOnChildren"/> is true, this property's X value is ignored and overridden. If <see cref="SetHeightBasedOnChildren"/> is true, this property's Y value is ignored and overridden.
/// </summary>
/// <example>
/// The following example combines both types of percentage-based sizing.
/// If this element is inside of a <see cref="Parent"/> whose width is 20, this element's width will be set to <c>0.5 * 20 = 10</c>, and its height will be set to <c>2.5 * 10 = 25</c>.
/// <code>
/// element.Size = new Vector2(0.5F, -2.5F);
/// </code>
/// </example>
public Vector2 Size {
get => this.size;
set {
if (this.size == value)
return;
this.size = value;
this.SetAreaDirty();
}
}
/// <summary>
/// The <see cref="Size"/>, but with <see cref="Scale"/> applied.
/// </summary>
public Vector2 ScaledSize => this.size * this.Scale;
private Vector2 offset;
/// <summary>
/// This element's offset from its default position, which is dictated by its <see cref="Anchor"/>.
/// Note that, depending on the side that the element is anchored to, this offset moves it in a different direction.
/// </summary>
public Vector2 PositionOffset {
get => this.offset;
set {
if (this.offset == value)
return;
this.offset = value;
this.SetAreaDirty();
}
}
/// <summary>
/// The <see cref="PositionOffset"/>, but with <see cref="Scale"/> applied.
/// </summary>
public Vector2 ScaledOffset => this.offset * this.Scale;
/// <summary>
/// The padding that this element has.
/// The padding is subtracted from the element's <see cref="Size"/>, and it is an area that the element does not extend into. This means that this element's resulting <see cref="DisplayArea"/> does not include this padding.
/// </summary>
public Padding Padding;
/// <summary>
/// The <see cref="Padding"/>, but with <see cref="Scale"/> applied.
/// </summary>
public Padding ScaledPadding => this.Padding * this.Scale;
private Padding childPadding;
/// <summary>
/// The child padding that this element has.
/// The child padding moves any <see cref="Children"/> added to this element inwards by the given amount in each direction.
/// </summary>
public Padding ChildPadding {
get => this.childPadding;
set {
if (this.childPadding == value)
return;
this.childPadding = value;
this.SetAreaDirty();
}
}
/// <summary>
/// The <see cref="ChildPadding"/>, but with <see cref="Scale"/> applied.
/// </summary>
public Padding ScaledChildPadding => this.childPadding * this.Scale;
/// <summary>
/// This element's current <see cref="Area"/>, but with <see cref="ScaledChildPadding"/> applied.
/// </summary>
public RectangleF ChildPaddedArea => this.UnscrolledArea.Shrink(this.ScaledChildPadding);
private RectangleF area;
/// <summary>
/// This element's area, without respecting its <see cref="ScrollOffset"/>.
/// This area is updated automatically to fit this element's sizing and positioning properties.
/// </summary>
public RectangleF UnscrolledArea {
get {
this.UpdateAreaIfDirty();
return this.area;
}
}
private bool areaDirty;
private int areaUpdateRecursionCount;
/// <summary>
/// The <see cref="UnscrolledArea"/> of this element, but with <see cref="ScaledScrollOffset"/> applied.
/// </summary>
public RectangleF Area => this.UnscrolledArea.OffsetCopy(this.ScaledScrollOffset);
/// <summary>
/// The area that this element is displayed in, which is <see cref="Area"/> shrunk by this element's <see cref="ScaledPadding"/>.
/// This is the property that should be used for drawing this element, as well as mouse input handling and culling.
/// </summary>
public RectangleF DisplayArea => this.Area.Shrink(this.ScaledPadding);
/// <summary>
/// The offset that this element has as a result of <see cref="Panel"/> scrolling.
/// </summary>
public Vector2 ScrollOffset;
/// <summary>
/// The <see cref="ScrollOffset"/>, but with <see cref="Scale"/> applied.
/// </summary>
public Vector2 ScaledScrollOffset => this.ScrollOffset * this.Scale;
private bool isHidden;
/// <summary>
/// Set this property to <c>true</c> to cause this element to be hidden.
/// Hidden elements don't receive input events, aren't rendered and don't factor into auto-anchoring.
/// </summary>
public bool IsHidden {
get => this.isHidden;
set {
if (this.isHidden == value)
return;
this.isHidden = value;
this.SetAreaDirty();
}
}
private int priority;
/// <summary>
/// The priority of this element as part of its <see cref="Parent"/> element.
/// A higher priority means the element will be drawn first and, if auto-anchoring is used, anchored higher up within its parent.
/// </summary>
public int Priority {
get => this.priority;
set {
if (this.priority == value)
return;
this.priority = value;
if (this.Parent != null)
this.Parent.SetSortedChildrenDirty();
}
}
/// <summary>
/// This element's transform matrix.
/// Can easily be scaled using <see cref="ScaleTransform"/>.
/// Note that, when this is non-null, a new <see cref="SpriteBatch.Begin"/> call is used for this element.
/// </summary>
public Matrix Transform = Matrix.Identity;
/// <summary>
/// The call that this element should make to <see cref="SpriteBatch"/> to begin drawing.
/// Note that, when this is non-null, a new <see cref="SpriteBatch.Begin"/> call is used for this element.
/// </summary>
public BeginDelegate BeginImpl;
/// <summary>
/// Set this field to false to disallow the element from being selected.
/// An unselectable element is skipped by automatic navigation and its <see cref="OnSelected"/> callback will never be called.
/// </summary>
public bool CanBeSelected = true;
/// <summary>
/// Set this field to false to disallow the element from reacting to being moused over.
/// </summary>
public bool CanBeMoused = true;
/// <summary>
/// Set this field to false to disallow this element's <see cref="OnPressed"/> and <see cref="OnSecondaryPressed"/> events to be called.
/// </summary>
public bool CanBePressed = true;
/// <summary>
/// Set this field to false to cause auto-anchored siblings to ignore this element as a possible anchor point.
/// </summary>
public bool CanAutoAnchorsAttach = true;
/// <summary>
/// Set this field to true to cause this element's height to be automatically calculated based on the area that its <see cref="Children"/> take up.
/// </summary>
public bool SetHeightBasedOnChildren;
/// <summary>
/// Set this field to true to cause this element's width to be automatically calculated based on the area that is <see cref="Children"/> take up.
/// </summary>
public bool SetWidthBasedOnChildren;
/// <summary>
/// Set this field to true to cause this element's final display area to never exceed that of its <see cref="Parent"/>.
/// If the resulting area is too large, the size of this element is shrunk to fit the target area.
/// This can be useful if an element should fill the remaining area of a parent exactly.
/// </summary>
public bool PreventParentSpill;
/// <summary>
/// The transparency (alpha value) that this element is rendered with.
/// Note that, when <see cref="Draw"/> is called, this alpha value is multiplied with the <see cref="Parent"/>'s alpha value and passed down to this element's <see cref="Children"/>.
/// </summary>
public float DrawAlpha = 1;
/// <summary>
/// Stores whether this element is currently being moused over or touched.
/// </summary>
public bool IsMouseOver { get; protected set; }
/// <summary>
/// Stores whether this element is its <see cref="Root"/>'s <see cref="RootElement.SelectedElement"/>.
/// </summary>
public bool IsSelected { get; protected set; }
/// <summary>
/// Event that is called after this element is drawn, but before its children are drawn
/// </summary>
public DrawCallback OnDrawn;
/// <summary>
/// Event that is called when this element is updated
/// </summary>
public TimeCallback OnUpdated;
/// <summary>
/// Event that is called when this element is pressed
/// </summary>
public GenericCallback OnPressed;
/// <summary>
/// Event that is called when this element is pressed using the secondary action
/// </summary>
public GenericCallback OnSecondaryPressed;
/// <summary>
/// Event that is called when this element's <see cref="IsSelected"/> is turned true
/// </summary>
public GenericCallback OnSelected;
/// <summary>
/// Event that is called when this element's <see cref="IsSelected"/> is turned false
/// </summary>
public GenericCallback OnDeselected;
/// <summary>
/// Event that is called when this element starts being moused over
/// </summary>
public GenericCallback OnMouseEnter;
/// <summary>
/// Event that is called when this element stops being moused over
/// </summary>
public GenericCallback OnMouseExit;
/// <summary>
/// Event that is called when this element starts being touched
/// </summary>
public GenericCallback OnTouchEnter;
/// <summary>
/// Event that is called when this element stops being touched
/// </summary>
public GenericCallback OnTouchExit;
/// <summary>
/// Event that is called when text input is made.
/// When an element uses this event, it should call <see cref="TextInputWrapper.EnsureExists"/> on construction to ensure that a text input wrapper was set.
///
/// Note that this event is called for every element, even if it is not selected.
/// Also note that if <see cref="TextInputWrapper.RequiresOnScreenKeyboard"/> is true, this event is never called.
/// </summary>
public TextInputCallback OnTextInput;
/// <summary>
/// Event that is called when this element's <see cref="DisplayArea"/> is changed.
/// </summary>
public GenericCallback OnAreaUpdated;
/// <summary>
/// Event that is called when the element that is currently being moused changes within the ui system.
/// Note that the event fired doesn't necessarily correlate to this specific element.
/// </summary>
public OtherElementCallback OnMousedElementChanged;
/// <summary>
/// Event that is called when the element that is currently being touched changes within the ui system.
/// Note that the event fired doesn't necessarily correlate to this specific element.
/// </summary>
public OtherElementCallback OnTouchedElementChanged;
/// <summary>
/// Event that is called when the element that is currently selected changes within the ui system.
/// Note that the event fired doesn't necessarily correlate to this specific element.
/// </summary>
public OtherElementCallback OnSelectedElementChanged;
/// <summary>
/// Event that is called when the next element to select when pressing tab is calculated.
/// To cause a different element than the default one to be selected, return it during this event.
/// </summary>
public TabNextElementCallback GetTabNextElement;
/// <summary>
/// Event that is called when the next element to select when using gamepad input is calculated.
/// To cause a different element than the default one to be selected, return it during this event.
/// </summary>
public GamepadNextElementCallback GetGamepadNextElement;
/// <summary>
/// Event that is called when a child is added to this element using <see cref="AddChild{T}"/>
/// </summary>
public OtherElementCallback OnChildAdded;
/// <summary>
/// Event that is called when a child is removed from this element using <see cref="RemoveChild"/>
/// </summary>
public OtherElementCallback OnChildRemoved;
/// <summary>
/// A style property that contains the selection indicator that is displayed on this element if it is the <see cref="RootElement.SelectedElement"/>
/// </summary>
public StyleProp<NinePatch> SelectionIndicator;
/// <summary>
/// A style property that contains the sound effect that is played when this element's <see cref="OnPressed"/> is called
/// </summary>
public StyleProp<SoundEffectInfo> ActionSound;
/// <summary>
/// A style property that contains the sound effect that is played when this element's <see cref="OnSecondaryPressed"/> is called
/// </summary>
public StyleProp<SoundEffectInfo> SecondActionSound;
/// <summary>
/// Creates a new element with the given anchor and size and sets up some default event reactions.
/// </summary>
/// <param name="anchor">This element's <see cref="Anchor"/></param>
/// <param name="size">This element's default <see cref="Size"/></param>
protected Element(Anchor anchor, Vector2 size) {
this.anchor = anchor;
this.size = size;
this.OnMouseEnter += element => this.IsMouseOver = true;
this.OnMouseExit += element => this.IsMouseOver = false;
this.OnTouchEnter += element => this.IsMouseOver = true;
this.OnTouchExit += element => this.IsMouseOver = false;
this.OnSelected += element => this.IsSelected = true;
this.OnDeselected += element => this.IsSelected = false;
this.GetTabNextElement += (backward, next) => next;
this.GetGamepadNextElement += (dir, next) => next;
this.SetAreaDirty();
}
/// <summary>
/// Adds a child to this element.
/// </summary>
/// <param name="element">The child element to add</param>
/// <param name="index">The index to add the child at, or -1 to add it to the end of the <see cref="Children"/> list</param>
/// <typeparam name="T">The type of child to add</typeparam>
/// <returns>This element, for chaining</returns>
public T AddChild<T>(T element, int index = -1) where T : Element {
if (index < 0 || index > this.Children.Count)
index = this.Children.Count;
this.Children.Insert(index, element);
element.Parent = this;
element.AndChildren(e => {
e.Root = this.Root;
e.System = this.System;
this.Root?.OnElementAdded(e);
this.OnChildAdded?.Invoke(this, e);
});
this.SetSortedChildrenDirty();
element.SetAreaDirty();
return element;
}
/// <summary>
/// Removes the given child from this element.
/// </summary>
/// <param name="element">The child element to remove</param>
public void RemoveChild(Element element) {
this.Children.Remove(element);
// set area dirty here so that a dirty call is made
// upwards to us if the element is auto-positioned
element.SetAreaDirty();
element.Parent = null;
element.AndChildren(e => {
e.Root = null;
e.System = null;
this.Root?.OnElementRemoved(e);
this.OnChildRemoved?.Invoke(this, e);
});
this.SetSortedChildrenDirty();
}
/// <summary>
/// Removes all children from this element that match the given condition.
/// </summary>
/// <param name="condition">The condition that determines if a child should be removed</param>
public void RemoveChildren(Func<Element, bool> condition = null) {
for (var i = this.Children.Count - 1; i >= 0; i--) {
var child = this.Children[i];
if (condition == null || condition(child)) {
this.RemoveChild(child);
}
}
}
/// <summary>
/// Causes <see cref="SortedChildren"/> to be recalculated as soon as possible.
/// </summary>
public void SetSortedChildrenDirty() {
this.sortedChildrenDirty = true;
}
/// <summary>
/// Updates the <see cref="SortedChildren"/> list if <see cref="SetSortedChildrenDirty"/> is true.
/// </summary>
public void UpdateSortedChildrenIfDirty() {
if (this.sortedChildrenDirty)
this.ForceUpdateSortedChildren();
}
/// <summary>
/// Forces an update of the <see cref="SortedChildren"/> list.
/// </summary>
public virtual void ForceUpdateSortedChildren() {
this.sortedChildrenDirty = false;
this.sortedChildren.Clear();
this.sortedChildren.AddRange(this.Children);
this.sortedChildren.Sort((e1, e2) => e1.Priority.CompareTo(e2.Priority));
}
/// <summary>
/// Causes this element's <see cref="Area"/> to be recalculated as soon as possible.
/// If this element is auto-anchored or its parent automatically changes its size based on its children, this element's parent's area is also marked dirty.
/// </summary>
public void SetAreaDirty() {
this.areaDirty = true;
if (this.Parent != null && (this.Anchor >= Anchor.AutoLeft || this.Parent.SetWidthBasedOnChildren || this.Parent.SetHeightBasedOnChildren))
this.Parent.SetAreaDirty();
}
/// <summary>
/// Updates this element's <see cref="Area"/> list if <see cref="areaDirty"/> is true.
/// </summary>
public void UpdateAreaIfDirty() {
if (this.areaDirty)
this.ForceUpdateArea();
}
/// <summary>
/// Forces this element's <see cref="Area"/> to be updated if it is not <see cref="IsHidden"/>.
/// This method also updates all of this element's <see cref="Children"/>'s areas.
/// </summary>
public virtual void ForceUpdateArea() {
this.areaDirty = false;
if (this.IsHidden)
return;
var parentArea = this.Parent != null ? this.Parent.ChildPaddedArea : (RectangleF) this.system.Viewport;
var parentCenterX = parentArea.X + parentArea.Width / 2;
var parentCenterY = parentArea.Y + parentArea.Height / 2;
var actualSize = this.CalcActualSize(parentArea);
var pos = new Vector2();
switch (this.anchor) {
case Anchor.TopLeft:
case Anchor.AutoLeft:
case Anchor.AutoInline:
case Anchor.AutoInlineIgnoreOverflow:
pos.X = parentArea.X + this.ScaledOffset.X;
pos.Y = parentArea.Y + this.ScaledOffset.Y;
break;
case Anchor.TopCenter:
case Anchor.AutoCenter:
pos.X = parentCenterX - actualSize.X / 2 + this.ScaledOffset.X;
pos.Y = parentArea.Y + this.ScaledOffset.Y;
break;
case Anchor.TopRight:
case Anchor.AutoRight:
pos.X = parentArea.Right - actualSize.X - this.ScaledOffset.X;
pos.Y = parentArea.Y + this.ScaledOffset.Y;
break;
case Anchor.CenterLeft:
pos.X = parentArea.X + this.ScaledOffset.X;
pos.Y = parentCenterY - actualSize.Y / 2 + this.ScaledOffset.Y;
break;
case Anchor.Center:
pos.X = parentCenterX - actualSize.X / 2 + this.ScaledOffset.X;
pos.Y = parentCenterY - actualSize.Y / 2 + this.ScaledOffset.Y;
break;
case Anchor.CenterRight:
pos.X = parentArea.Right - actualSize.X - this.ScaledOffset.X;
pos.Y = parentCenterY - actualSize.Y / 2 + this.ScaledOffset.Y;
break;
case Anchor.BottomLeft:
pos.X = parentArea.X + this.ScaledOffset.X;
pos.Y = parentArea.Bottom - actualSize.Y - this.ScaledOffset.Y;
break;
case Anchor.BottomCenter:
pos.X = parentCenterX - actualSize.X / 2 + this.ScaledOffset.X;
pos.Y = parentArea.Bottom - actualSize.Y - this.ScaledOffset.Y;
break;
case Anchor.BottomRight:
pos.X = parentArea.Right - actualSize.X - this.ScaledOffset.X;
pos.Y = parentArea.Bottom - actualSize.Y - this.ScaledOffset.Y;
break;
}
if (this.Anchor >= Anchor.AutoLeft) {
Element previousChild;
if (this.Anchor == Anchor.AutoInline || this.Anchor == Anchor.AutoInlineIgnoreOverflow) {
previousChild = this.GetOlderSibling(e => !e.IsHidden && e.CanAutoAnchorsAttach);
} else {
previousChild = this.GetLowestOlderSibling(e => !e.IsHidden && e.CanAutoAnchorsAttach);
}
if (previousChild != null) {
var prevArea = previousChild.GetAreaForAutoAnchors();
switch (this.Anchor) {
case Anchor.AutoLeft:
case Anchor.AutoCenter:
case Anchor.AutoRight:
pos.Y = prevArea.Bottom + this.ScaledOffset.Y;
break;
case Anchor.AutoInline:
var newX = prevArea.Right + this.ScaledOffset.X;
if (newX + actualSize.X <= parentArea.Right) {
pos.X = newX;
pos.Y = prevArea.Y + this.ScaledOffset.Y;
} else {
pos.Y = prevArea.Bottom + this.ScaledOffset.Y;
}
break;
case Anchor.AutoInlineIgnoreOverflow:
pos.X = prevArea.Right + this.ScaledOffset.X;
pos.Y = prevArea.Y + this.ScaledOffset.Y;
break;
}
}
}
if (this.PreventParentSpill) {
if (pos.X < parentArea.X)
pos.X = parentArea.X;
if (pos.Y < parentArea.Y)
pos.Y = parentArea.Y;
if (pos.X + actualSize.X > parentArea.Right)
actualSize.X = parentArea.Right - pos.X;
if (pos.Y + actualSize.Y > parentArea.Bottom)
actualSize.Y = parentArea.Bottom - pos.Y;
}
this.area = new RectangleF(pos, actualSize);
this.System.OnElementAreaUpdated?.Invoke(this);
foreach (var child in this.Children)
child.ForceUpdateArea();
if (this.Children.Count > 0) {
Element foundChild = null;
if (this.SetHeightBasedOnChildren) {
var lowest = this.GetLowestChild(e => !e.IsHidden);
if (lowest != null) {
var newHeight = (lowest.UnscrolledArea.Bottom - pos.Y + this.ScaledChildPadding.Bottom) / this.Scale;
if (!newHeight.Equals(this.size.Y, 0.01F)) {
this.size.Y = newHeight;
foundChild = lowest;
}
}
}
if (this.SetWidthBasedOnChildren) {
var rightmost = this.GetRightmostChild(e => !e.IsHidden);
if (rightmost != null) {
var newWidth = (rightmost.UnscrolledArea.Right - pos.X + this.ScaledChildPadding.Right) / this.Scale;
if (!newWidth.Equals(this.size.X, 0.01F)) {
this.size.X = newWidth;
foundChild = rightmost;
}
}
}
if (foundChild != null) {
this.areaUpdateRecursionCount++;
if (this.areaUpdateRecursionCount >= 16) {
throw new ArithmeticException($"The area of {this} with root {this.Root?.Name} has recursively updated too often. Does its child {foundChild} contain any conflicting auto-sizing settings?");
} else {
this.ForceUpdateArea();
}
} else {
this.areaUpdateRecursionCount = 0;
}
}
}
/// <summary>
/// Calculates the actual size that this element should take up, based on the area that its parent encompasses.
/// By default, this is based on the information specified in <see cref="Size"/>'s documentation.
/// </summary>
/// <param name="parentArea">This parent's area, or the ui system's viewport if it has no parent</param>
/// <returns>The actual size of this element, taking <see cref="Scale"/> into account</returns>
protected virtual Vector2 CalcActualSize(RectangleF parentArea) {
var ret = new Vector2(
this.size.X > 1 ? this.ScaledSize.X : parentArea.Width * this.size.X,
this.size.Y > 1 ? this.ScaledSize.Y : parentArea.Height * this.size.Y);
if (this.size.X < 0)
ret.X = -this.size.X * ret.Y;
if (this.size.Y < 0)
ret.Y = -this.size.Y * ret.X;
return ret;
}
/// <summary>
/// Returns the area that should be used for determining where auto-anchoring children should attach.
/// </summary>
/// <returns>The area for auto anchors</returns>
protected virtual RectangleF GetAreaForAutoAnchors() {
return this.UnscrolledArea;
}
/// <summary>
/// Returns this element's lowest child element (in terms of y position) that matches the given condition.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <returns>The lowest element, or null if no such element exists</returns>
public Element GetLowestChild(Func<Element, bool> condition = null) {
Element lowest = null;
foreach (var child in this.Children) {
if (condition != null && !condition(child))
continue;
if (child.Anchor > Anchor.TopRight && child.Anchor < Anchor.AutoLeft)
continue;
if (lowest == null || child.UnscrolledArea.Bottom >= lowest.UnscrolledArea.Bottom)
lowest = child;
}
return lowest;
}
/// <summary>
/// Returns this element's rightmost child (in terms of x position) that matches the given condition.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <returns>The rightmost element, or null if no such element exists</returns>
public Element GetRightmostChild(Func<Element, bool> condition = null) {
Element rightmost = null;
foreach (var child in this.Children) {
if (condition != null && !condition(child))
continue;
if (child.Anchor < Anchor.AutoLeft && child.Anchor != Anchor.TopLeft && child.Anchor != Anchor.CenterLeft && child.Anchor != Anchor.BottomLeft)
continue;
if (rightmost == null || child.UnscrolledArea.Right >= rightmost.UnscrolledArea.Right)
rightmost = child;
}
return rightmost;
}
/// <summary>
/// Returns this element's lowest sibling that is also older (lower in its parent's <see cref="Children"/> list) than this element that also matches the given condition.
/// The returned element's <see cref="Parent"/> will always be equal to this element's <see cref="Parent"/>.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <returns>The lowest older sibling of this element, or null if no such element exists</returns>
public Element GetLowestOlderSibling(Func<Element, bool> condition = null) {
if (this.Parent == null)
return null;
Element lowest = null;
foreach (var child in this.Parent.Children) {
if (child == this)
break;
if (condition != null && !condition(child))
continue;
if (lowest == null || child.UnscrolledArea.Bottom >= lowest.UnscrolledArea.Bottom)
lowest = child;
}
return lowest;
}
/// <summary>
/// Returns this element's first older sibling that matches the given condition.
/// The returned element's <see cref="Parent"/> will always be equal to this element's <see cref="Parent"/>.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <returns>The older sibling, or null if no such element exists</returns>
public Element GetOlderSibling(Func<Element, bool> condition = null) {
if (this.Parent == null)
return null;
Element older = null;
foreach (var child in this.Parent.Children) {
if (child == this)
break;
if (condition != null && !condition(child))
continue;
older = child;
}
return older;
}
/// <summary>
/// Returns all of this element's siblings that match the given condition.
/// Siblings are elements that have the same <see cref="Parent"/> as this element.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <returns>This element's siblings</returns>
public IEnumerable<Element> GetSiblings(Func<Element, bool> condition = null) {
if (this.Parent == null)
yield break;
foreach (var child in this.Parent.Children) {
if (condition != null && !condition(child))
continue;
if (child != this)
yield return child;
}
}
/// <summary>
/// Returns all of this element's children of the given type that match the given condition.
/// Optionally, the entire tree of children (grandchildren) can be searched.
/// </summary>
/// <param name="condition">The condition to match</param>
/// <param name="regardGrandchildren">If this value is true, children of children of this element are also searched</param>
/// <param name="ignoreFalseGrandchildren">If this value is true, children for which the condition does not match will not have their children searched</param>
/// <typeparam name="T">The type of children to search for</typeparam>
/// <returns>All children that match the condition</returns>
public IEnumerable<T> GetChildren<T>(Func<T, bool> condition = null, bool regardGrandchildren = false, bool ignoreFalseGrandchildren = false) where T : Element {
foreach (var child in this.Children) {
var applies = child is T t && (condition == null || condition(t));
if (applies)
yield return (T) child;
if (regardGrandchildren && (!ignoreFalseGrandchildren || applies)) {
foreach (var cc in child.GetChildren(condition, true, ignoreFalseGrandchildren))
yield return cc;
}
}
}
/// <inheritdoc cref="GetChildren{T}"/>
public IEnumerable<Element> GetChildren(Func<Element, bool> condition = null, bool regardGrandchildren = false, bool ignoreFalseGrandchildren = false) {
return this.GetChildren<Element>(condition, regardGrandchildren, ignoreFalseGrandchildren);
}
/// <summary>
/// Returns the parent tree of this element.
/// The parent tree is this element's <see cref="Parent"/>, followed by its parent, and so on, up until the <see cref="RootElement"/>'s <see cref="RootElement.Element"/>.
/// </summary>
/// <returns>This element's parent tree</returns>
public IEnumerable<Element> GetParentTree() {
if (this.Parent == null)
yield break;
yield return this.Parent;
foreach (var parent in this.Parent.GetParentTree())
yield return parent;
}
/// <summary>
/// Returns a subset of <see cref="Children"/> that are currently relevant in terms of drawing and input querying.
/// A <see cref="Panel"/> only returns elements that are currently in view here.
/// </summary>
/// <returns>This element's relevant children</returns>
protected virtual List<Element> GetRelevantChildren() {
return this.SortedChildren;
}
/// <summary>
/// Updates this element and all of its <see cref="GetRelevantChildren"/>
/// </summary>
/// <param name="time">The game's time</param>
public virtual void Update(GameTime time) {
this.System.OnElementUpdated?.Invoke(this, time);
foreach (var child in this.GetRelevantChildren())
if (child.System != null)
child.Update(time);
}
/// <summary>
/// Draws this element by calling <see cref="Draw"/> internally.
/// If <see cref="Transform"/> or <see cref="BeginImpl"/> is set, a new <see cref="SpriteBatch.Begin"/> call is also started.
/// </summary>
/// <param name="time">The game's time</param>
/// <param name="batch">The sprite batch to use for drawing</param>
/// <param name="alpha">The alpha to draw this element and its children with</param>
/// <param name="blendState">The blend state that is used for drawing</param>
/// <param name="samplerState">The sampler state that is used for drawing</param>
/// <param name="matrix">The transformation matrix that is used for drawing</param>
public void DrawTransformed(GameTime time, SpriteBatch batch, float alpha, BlendState blendState, SamplerState samplerState, Matrix matrix) {
var customDraw = this.BeginImpl != null || this.Transform != Matrix.Identity;
var mat = this.Transform * matrix;
if (customDraw) {
// end the usual draw so that we can begin our own
batch.End();
// begin our own draw call
if (this.BeginImpl != null) {
this.BeginImpl(this, time, batch, alpha, blendState, samplerState, mat);
} else {
batch.Begin(SpriteSortMode.Deferred, blendState, samplerState, null, null, null, mat);
}
}
// draw content in custom begin call
this.Draw(time, batch, alpha, blendState, samplerState, mat);
if (customDraw) {
// end our draw
batch.End();
// begin the usual draw again for other elements
batch.Begin(SpriteSortMode.Deferred, blendState, samplerState, null, null, null, matrix);
}
}
/// <summary>
/// Draws this element and all of its children. Override this method to draw the content of custom elements.
/// Note that, when this is called, <see cref="SpriteBatch.Begin"/> has already been called with custom <see cref="Transform"/> etc. applied.
/// </summary>
/// <param name="time">The game's time</param>
/// <param name="batch">The sprite batch to use for drawing</param>
/// <param name="alpha">The alpha to draw this element and its children with</param>
/// <param name="blendState">The blend state that is used for drawing</param>
/// <param name="samplerState">The sampler state that is used for drawing</param>
/// <param name="matrix">The transformation matrix that is used for drawing</param>
public virtual void Draw(GameTime time, SpriteBatch batch, float alpha, BlendState blendState, SamplerState samplerState, Matrix matrix) {
this.System.OnElementDrawn?.Invoke(this, time, batch, alpha);
if (this.IsSelected)
this.System.OnSelectedElementDrawn?.Invoke(this, time, batch, alpha);
foreach (var child in this.GetRelevantChildren()) {
if (!child.IsHidden)
child.DrawTransformed(time, batch, alpha * child.DrawAlpha, blendState, samplerState, matrix);
}
}
/// <summary>
/// Draws this element and all of its <see cref="GetRelevantChildren"/> early.
/// Drawing early involves drawing onto <see cref="RenderTarget2D"/> instances rather than onto the screen.
/// Note that, when this is called, <see cref="SpriteBatch.Begin"/> has not yet been called.
/// </summary>
/// <param name="time">The game's time</param>
/// <param name="batch">The sprite batch to use for drawing</param>
/// <param name="alpha">The alpha to draw this element and its children with</param>
/// <param name="blendState">The blend state that is used for drawing</param>
/// <param name="samplerState">The sampler state that is used for drawing</param>
/// <param name="matrix">The transformation matrix that is used for drawing</param>
public virtual void DrawEarly(GameTime time, SpriteBatch batch, float alpha, BlendState blendState, SamplerState samplerState, Matrix matrix) {
foreach (var child in this.GetRelevantChildren()) {
if (!child.IsHidden)
child.DrawEarly(time, batch, alpha * child.DrawAlpha, blendState, samplerState, matrix);
}
}
/// <summary>
/// Returns the element under the given position, searching the current element and all of its <see cref="GetRelevantChildren"/>.
/// </summary>
/// <param name="position">The position to query</param>
/// <returns>The element under the position, or null if no such element exists</returns>
public virtual Element GetElementUnderPos(Vector2 position) {
if (this.IsHidden)
return null;
if (this.Transform != Matrix.Identity)
position = Vector2.Transform(position, Matrix.Invert(this.Transform));
var children = this.GetRelevantChildren();
for (var i = children.Count - 1; i >= 0; i--) {
var element = children[i].GetElementUnderPos(position);
if (element != null)
return element;
}
return this.CanBeMoused && this.DisplayArea.Contains(position) ? this : null;
}
/// <summary>
/// Performs the specified action on this element and all of its <see cref="Children"/>
/// </summary>
/// <param name="action">The action to perform</param>
public void AndChildren(Action<Element> action) {
action(this);
foreach (var child in this.Children)
child.AndChildren(action);
}
/// <summary>
/// Sorts this element's <see cref="Children"/> using the given comparison.
/// </summary>
/// <param name="comparison">The comparison to sort by</param>
public void ReorderChildren(Comparison<Element> comparison) {
this.Children.Sort(comparison);
}
/// <summary>
/// Reverses this element's <see cref="Children"/> list in the given range.
/// </summary>
/// <param name="index">The index to start reversing at</param>
/// <param name="count">The amount of elements to reverse</param>
public void ReverseChildren(int index = 0, int? count = null) {
this.Children.Reverse(index, count ?? this.Children.Count);
}
/// <summary>
/// Scales this element's <see cref="Transform"/> matrix based on the given scale and origin.
/// </summary>
/// <param name="scale">The scale to use</param>
/// <param name="origin">The origin to use for scaling, or null to use this element's center point</param>
public void ScaleTransform(float scale, Vector2? origin = null) {
this.Transform = Matrix.CreateScale(scale, scale, 1) * Matrix.CreateTranslation(new Vector3((1 - scale) * (origin ?? this.DisplayArea.Center), 0));
}
/// <summary>
/// Initializes this element's <see cref="StyleProp{T}"/> instances using the ui system's <see cref="UiStyle"/>.
/// </summary>
/// <param name="style">The new style</param>
protected virtual void InitStyle(UiStyle style) {
this.SelectionIndicator.SetFromStyle(style.SelectionIndicator);
this.ActionSound.SetFromStyle(style.ActionSound);
this.SecondActionSound.SetFromStyle(style.ActionSound);
}
/// <summary>
/// A delegate used for the <see cref="Element.OnTextInput"/> event.
/// </summary>
/// <param name="element">The current element</param>
/// <param name="key">The key that was pressed</param>
/// <param name="character">The character that was input</param>
public delegate void TextInputCallback(Element element, Keys key, char character);
/// <summary>
/// A generic element-specific delegate.
/// </summary>
/// <param name="element">The current element</param>
public delegate void GenericCallback(Element element);
/// <summary>
/// A generic element-specific delegate that includes a second element.
/// </summary>
/// <param name="thisElement">The current element</param>
/// <param name="otherElement">The other element</param>
public delegate void OtherElementCallback(Element thisElement, Element otherElement);
/// <summary>
/// A delegate used inside of <see cref="Element.Draw"/>
/// </summary>
/// <param name="element">The element that is being drawn</param>
/// <param name="time">The game's time</param>
/// <param name="batch">The sprite batch used for drawing</param>
/// <param name="alpha">The alpha this element is drawn with</param>
public delegate void DrawCallback(Element element, GameTime time, SpriteBatch batch, float alpha);
/// <summary>
/// A generic delegate used inside of <see cref="Element.Update"/>
/// </summary>
/// <param name="element">The current element</param>
/// <param name="time">The game's time</param>
public delegate void TimeCallback(Element element, GameTime time);
/// <summary>
/// A delegate used by <see cref="Element.GetTabNextElement"/>.
/// </summary>
/// <param name="backward">If this value is true, <see cref="ModifierKey.Shift"/> is being held</param>
/// <param name="usualNext">The element that is considered to be the next element by default</param>
public delegate Element TabNextElementCallback(bool backward, Element usualNext);
/// <summary>
/// A delegate used by <see cref="Element.GetGamepadNextElement"/>.
/// </summary>
/// <param name="dir">The direction of the gamepad button that was pressed</param>
/// <param name="usualNext">The element that is considered to be the next element by default</param>
public delegate Element GamepadNextElementCallback(Direction2 dir, Element usualNext);
/// <summary>
/// A delegate method used for <see cref="BeginImpl"/>
/// </summary>
/// <param name="element">The custom draw group</param>
/// <param name="time">The game's time</param>
/// <param name="batch">The sprite batch used for drawing</param>
/// <param name="alpha">This element's draw alpha</param>
/// <param name="blendState">The blend state used for drawing</param>
/// <param name="samplerState">The sampler state used for drawing</param>
/// <param name="matrix">The transform matrix used for drawing</param>
public delegate void BeginDelegate(Element element, GameTime time, SpriteBatch batch, float alpha, BlendState blendState, SamplerState samplerState, Matrix matrix);
}
}