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#nullable disable
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Linq;
using Microsoft.Maui.Controls.Internals;
using Microsoft.Maui.Graphics;
namespace Microsoft.Maui.Controls
{
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="Type[@FullName='Microsoft.Maui.Controls.Label']/Docs/*" />
[ContentProperty(nameof(Text))]
public partial class Label : View, IFontElement, ITextElement, ITextAlignmentElement, ILineHeightElement, IElementConfiguration<Label>, IDecorableTextElement, IPaddingElement, ILabel
{
/// <summary>Bindable property for <see cref="HorizontalTextAlignment"/>.</summary>
public static readonly BindableProperty HorizontalTextAlignmentProperty = TextAlignmentElement.HorizontalTextAlignmentProperty;
/// <summary>Bindable property for <see cref="VerticalTextAlignment"/>.</summary>
public static readonly BindableProperty VerticalTextAlignmentProperty = BindableProperty.Create(nameof(VerticalTextAlignment), typeof(TextAlignment), typeof(Label), TextAlignment.Start);
/// <summary>Bindable property for <see cref="TextColor"/>.</summary>
public static readonly BindableProperty TextColorProperty = TextElement.TextColorProperty;
/// <summary>Bindable property for <see cref="CharacterSpacing"/>.</summary>
public static readonly BindableProperty CharacterSpacingProperty = TextElement.CharacterSpacingProperty;
/// <summary>Bindable property for <see cref="Text"/>.</summary>
public static readonly BindableProperty TextProperty = BindableProperty.Create(nameof(Text), typeof(string), typeof(Label), default(string), propertyChanged: OnTextPropertyChanged);
/// <summary>Bindable property for <see cref="FontFamily"/>.</summary>
public static readonly BindableProperty FontFamilyProperty = FontElement.FontFamilyProperty;
/// <summary>Bindable property for <see cref="FontSize"/>.</summary>
public static readonly BindableProperty FontSizeProperty = FontElement.FontSizeProperty;
/// <summary>Bindable property for <see cref="FontAttributes"/>.</summary>
public static readonly BindableProperty FontAttributesProperty = FontElement.FontAttributesProperty;
/// <summary>Bindable property for <see cref="FontAutoScalingEnabled"/>.</summary>
public static readonly BindableProperty FontAutoScalingEnabledProperty = FontElement.FontAutoScalingEnabledProperty;
/// <summary>Bindable property for <see cref="TextTransform"/>.</summary>
public static readonly BindableProperty TextTransformProperty = TextElement.TextTransformProperty;
/// <summary>Bindable property for <see cref="TextDecorations"/>.</summary>
public static readonly BindableProperty TextDecorationsProperty = DecorableTextElement.TextDecorationsProperty;
/// <summary>Bindable property for <see cref="FormattedText"/>.</summary>
public static readonly BindableProperty FormattedTextProperty = BindableProperty.Create(nameof(FormattedText), typeof(FormattedString), typeof(Label), default(FormattedString),
propertyChanging: (bindable, oldvalue, newvalue) =>
{
if (oldvalue != null)
{
var formattedString = ((FormattedString)oldvalue);
var label = ((Label)bindable);
formattedString.SpansCollectionChanged -= label.Span_CollectionChanged;
formattedString.PropertyChanged -= label.OnFormattedTextChanged;
formattedString.PropertyChanging -= label.OnFormattedTextChanging;
formattedString.Parent = null;
label.RemoveSpans(formattedString.Spans);
}
},
propertyChanged: (bindable, oldvalue, newvalue) =>
{
var label = ((Label)bindable);
if (newvalue != null)
{
var formattedString = (FormattedString)newvalue;
formattedString.Parent = label;
formattedString.PropertyChanging += label.OnFormattedTextChanging;
formattedString.PropertyChanged += label.OnFormattedTextChanged;
formattedString.SpansCollectionChanged += label.Span_CollectionChanged;
label.SetupSpans(formattedString.Spans);
}
label.InvalidateMeasureIfLabelSizeable();
if (newvalue != null)
label.Text = null;
});
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='TextTransform']/Docs/*" />
public TextTransform TextTransform
{
get { return (TextTransform)GetValue(TextTransformProperty); }
set { SetValue(TextTransformProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='UpdateFormsText']/Docs/*" />
public virtual string UpdateFormsText(string source, TextTransform textTransform)
=> TextTransformUtilites.GetTransformedText(source, textTransform);
/// <summary>Bindable property for <see cref="LineBreakMode"/>.</summary>
public static readonly BindableProperty LineBreakModeProperty = BindableProperty.Create(nameof(LineBreakMode), typeof(LineBreakMode), typeof(Label), LineBreakMode.WordWrap,
propertyChanged: (bindable, oldvalue, newvalue) => ((Label)bindable).InvalidateMeasureIfLabelSizeable());
/// <summary>Bindable property for <see cref="LineHeight"/>.</summary>
public static readonly BindableProperty LineHeightProperty = LineHeightElement.LineHeightProperty;
/// <summary>Bindable property for <see cref="MaxLines"/>.</summary>
public static readonly BindableProperty MaxLinesProperty = BindableProperty.Create(nameof(MaxLines), typeof(int), typeof(Label), -1,
propertyChanged: (bindable, oldvalue, newvalue) => ((Label)bindable).InvalidateMeasureIfLabelSizeable());
/// <summary>Bindable property for <see cref="Padding"/>.</summary>
public static readonly BindableProperty PaddingProperty = PaddingElement.PaddingProperty;
/// <summary>Bindable property for <see cref="TextType"/>.</summary>
public static readonly BindableProperty TextTypeProperty = BindableProperty.Create(nameof(TextType), typeof(TextType), typeof(Label), TextType.Text,
propertyChanged: (bindable, oldvalue, newvalue) => ((Label)bindable).InvalidateMeasureIfLabelSizeable());
readonly Lazy<PlatformConfigurationRegistry<Label>> _platformConfigurationRegistry;
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='.ctor']/Docs/*" />
public Label()
{
_platformConfigurationRegistry = new Lazy<PlatformConfigurationRegistry<Label>>(() => new PlatformConfigurationRegistry<Label>(this));
}
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
if (FormattedText != null)
SetInheritedBindingContext(FormattedText, this.BindingContext);
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='FormattedText']/Docs/*" />
public FormattedString FormattedText
{
get { return (FormattedString)GetValue(FormattedTextProperty); }
set { SetValue(FormattedTextProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='HorizontalTextAlignment']/Docs/*" />
public TextAlignment HorizontalTextAlignment
{
get { return (TextAlignment)GetValue(TextAlignmentElement.HorizontalTextAlignmentProperty); }
set { SetValue(TextAlignmentElement.HorizontalTextAlignmentProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='LineBreakMode']/Docs/*" />
public LineBreakMode LineBreakMode
{
get { return (LineBreakMode)GetValue(LineBreakModeProperty); }
set { SetValue(LineBreakModeProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='Text']/Docs/*" />
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='TextColor']/Docs/*" />
public Color TextColor
{
get { return (Color)GetValue(TextElement.TextColorProperty); }
set { SetValue(TextElement.TextColorProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='CharacterSpacing']/Docs/*" />
public double CharacterSpacing
{
get { return (double)GetValue(TextElement.CharacterSpacingProperty); }
set { SetValue(TextElement.CharacterSpacingProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='VerticalTextAlignment']/Docs/*" />
public TextAlignment VerticalTextAlignment
{
get { return (TextAlignment)GetValue(VerticalTextAlignmentProperty); }
set { SetValue(VerticalTextAlignmentProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='FontAttributes']/Docs/*" />
public FontAttributes FontAttributes
{
get { return (FontAttributes)GetValue(FontAttributesProperty); }
set { SetValue(FontAttributesProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='TextDecorations']/Docs/*" />
public TextDecorations TextDecorations
{
get { return (TextDecorations)GetValue(TextDecorationsProperty); }
set { SetValue(TextDecorationsProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='FontFamily']/Docs/*" />
public string FontFamily
{
get { return (string)GetValue(FontFamilyProperty); }
set { SetValue(FontFamilyProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='FontSize']/Docs/*" />
[System.ComponentModel.TypeConverter(typeof(FontSizeConverter))]
public double FontSize
{
get { return (double)GetValue(FontSizeProperty); }
set { SetValue(FontSizeProperty, value); }
}
public bool FontAutoScalingEnabled
{
get => (bool)GetValue(FontAutoScalingEnabledProperty);
set => SetValue(FontAutoScalingEnabledProperty, value);
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='LineHeight']/Docs/*" />
public double LineHeight
{
get { return (double)GetValue(LineHeightProperty); }
set { SetValue(LineHeightProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='MaxLines']/Docs/*" />
public int MaxLines
{
get => (int)GetValue(MaxLinesProperty);
set => SetValue(MaxLinesProperty, value);
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='Padding']/Docs/*" />
public Thickness Padding
{
get { return (Thickness)GetValue(PaddingProperty); }
set { SetValue(PaddingProperty, value); }
}
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='TextType']/Docs/*" />
public TextType TextType
{
get => (TextType)GetValue(TextTypeProperty);
set => SetValue(TextTypeProperty, value);
}
double IFontElement.FontSizeDefaultValueCreator() =>
this.GetDefaultFontSize();
void IFontElement.OnFontAttributesChanged(FontAttributes oldValue, FontAttributes newValue) =>
HandleFontChanged();
void IFontElement.OnFontFamilyChanged(string oldValue, string newValue) =>
HandleFontChanged();
void IFontElement.OnFontSizeChanged(double oldValue, double newValue) =>
HandleFontChanged();
void IFontElement.OnFontAutoScalingEnabledChanged(bool oldValue, bool newValue) =>
HandleFontChanged();
void HandleFontChanged()
{
Handler?.UpdateValue(nameof(ITextStyle.Font));
InvalidateMeasureIfLabelSizeable();
}
void ILineHeightElement.OnLineHeightChanged(double oldValue, double newValue) =>
InvalidateMeasureIfLabelSizeable();
void ITextElement.OnTextTransformChanged(TextTransform oldValue, TextTransform newValue) =>
InvalidateMeasureIfLabelSizeable();
void OnFormattedTextChanging(object sender, PropertyChangingEventArgs e) =>
OnPropertyChanging(nameof(FormattedText));
void OnFormattedTextChanged(object sender, PropertyChangedEventArgs e)
{
OnPropertyChanged(nameof(FormattedText));
InvalidateMeasureIfLabelSizeable();
}
void SetupSpans(IEnumerable spans)
{
foreach (Span span in spans)
{
span.GestureRecognizersCollectionChanged += Span_GestureRecognizer_CollectionChanged;
SetupSpanGestureRecognizers(span.GestureRecognizers);
}
}
void SetupSpanGestureRecognizers(IEnumerable gestureRecognizers)
{
foreach (GestureRecognizer gestureRecognizer in gestureRecognizers)
GestureController.CompositeGestureRecognizers.Add(new ChildGestureRecognizer() { GestureRecognizer = gestureRecognizer });
}
void RemoveSpans(IEnumerable spans)
{
foreach (Span span in spans)
{
RemoveSpanGestureRecognizers(span.GestureRecognizers);
span.GestureRecognizersCollectionChanged -= Span_GestureRecognizer_CollectionChanged;
}
}
void RemoveSpanGestureRecognizers(IEnumerable gestureRecognizers)
{
foreach (GestureRecognizer gestureRecognizer in gestureRecognizers)
foreach (var spanRecognizer in GestureController.CompositeGestureRecognizers.ToList())
if (spanRecognizer is ChildGestureRecognizer childGestureRecognizer && childGestureRecognizer.GestureRecognizer == gestureRecognizer)
GestureController.CompositeGestureRecognizers.Remove(spanRecognizer);
}
void Span_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
SetupSpans(e.NewItems);
break;
case NotifyCollectionChangedAction.Remove:
RemoveSpans(e.OldItems);
break;
case NotifyCollectionChangedAction.Replace:
RemoveSpans(e.OldItems);
SetupSpans(e.NewItems);
break;
case NotifyCollectionChangedAction.Reset:
// Is never called, because the clear command is overridden.
break;
}
}
void Span_GestureRecognizer_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
SetupSpanGestureRecognizers(e.NewItems);
break;
case NotifyCollectionChangedAction.Remove:
RemoveSpanGestureRecognizers(e.OldItems);
break;
case NotifyCollectionChangedAction.Replace:
RemoveSpanGestureRecognizers(e.OldItems);
SetupSpanGestureRecognizers(e.NewItems);
break;
case NotifyCollectionChangedAction.Reset:
// is never called, because the clear command is overridden.
break;
}
}
void ITextAlignmentElement.OnHorizontalTextAlignmentPropertyChanged(TextAlignment oldValue, TextAlignment newValue)
{
// This is a no-op since the horizontal text alignment does not affect bounds or
// any other property that would require a measure invalidation.
}
static void OnTextPropertyChanged(BindableObject bindable, object oldvalue, object newvalue)
{
var label = (Label)bindable;
if (TextChangedShouldInvalidateMeasure(label))
label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
if (newvalue != null)
label.FormattedText = null;
}
/// <inheritdoc/>
public IPlatformElementConfiguration<T, Label> On<T>() where T : IConfigPlatform
{
return _platformConfigurationRegistry.Value.On<T>();
}
void ITextElement.OnTextColorPropertyChanged(Color oldValue, Color newValue)
{
// This is a no-op since the text color does not affect bounds or
// any other property that would require a measure invalidation.
}
void ITextElement.OnCharacterSpacingPropertyChanged(double oldValue, double newValue) =>
InvalidateMeasureIfLabelSizeable();
internal bool HasFormattedTextSpans
=> (FormattedText?.Spans?.Count ?? 0) > 0;
/// <include file="../../docs/Microsoft.Maui.Controls/Label.xml" path="//Member[@MemberName='GetChildElements']/Docs/*" />
public override IList<GestureElement> GetChildElements(Point point)
{
if (FormattedText?.Spans == null || FormattedText?.Spans.Count == 0)
return null;
var spans = new List<GestureElement>();
for (int i = 0; i < FormattedText.Spans.Count; i++)
{
Span span = FormattedText.Spans[i];
if (span.GestureRecognizers.Count > 0 && (((ISpatialElement)span).Region.Contains(point) || point.IsEmpty))
spans.Add(span);
}
if (!point.IsEmpty && spans.Count > 1) // More than 2 elements overlapping, deflate to see which one is actually hit.
for (var i = spans.Count - 1; i >= 0; i--)
if (!((ISpatialElement)spans[i]).Region.Deflate().Contains(point))
spans.RemoveAt(i);
return spans;
}
Thickness IPaddingElement.PaddingDefaultValueCreator() => default;
void IPaddingElement.OnPaddingPropertyChanged(Thickness oldValue, Thickness newValue) =>
InvalidateMeasureIfLabelSizeable();
Font ITextStyle.Font => this.ToFont();
/// <summary>
/// This method prevents unnecessary measure invalidations when the label is not
/// sizeable. If the label has a fixed width and height, then no matter what the
/// text is, the label will never change size.
/// </summary>
void InvalidateMeasureIfLabelSizeable()
{
if (!IsLabelSizeable(this))
return;
InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
}
/// <summary>
/// Determines if the label can grow in any direction based on the constraints. If the
/// label cannot grow in any direction, then we usually don't need to do anything.
/// </summary>
internal static bool IsLabelSizeable(Label label)
{
// Determine in which direction the label can grow/shrink.
var constraint = label.Constraint;
var isVerticallySizeable = (constraint & LayoutConstraint.VerticallyFixed) == 0;
var isHorizontallySizeable = (constraint & LayoutConstraint.HorizontallyFixed) == 0;
var isSizeable = isVerticallySizeable || isHorizontallySizeable;
// If the label cannot grow in any direction, then we usually don't need to do anything.
if (!isSizeable)
return false;
// The label may grow/shrink based on the constraints, so we may need to invalidate.
return true;
}
/// <summary>
/// Determines if the text has changed in a way that would require a measure invalidation.
/// Unlike FormattedText changes, Text changes may not always require invalidation because
/// the text size and spacing is all uniform. Formatted text may have a case where even
/// though the label is a single line, the font size of a span may cause the label to grow
/// vertically.
/// </summary>
internal static bool TextChangedShouldInvalidateMeasure(Label label)
{
// If the label cannot grow in any direction, then we don't need to invalidate.
var isSizeable = IsLabelSizeable(label);
if (!isSizeable)
return false;
// Determine if the label can grow vertically (wrapping means it may grow vertically).
var constraint = label.Constraint;
var breakMode = label.LineBreakMode;
var isHorizontallySizeable = (constraint & LayoutConstraint.HorizontallyFixed) == 0;
var isMultiline = breakMode == LineBreakMode.CharacterWrap || breakMode == LineBreakMode.WordWrap;
var isSingleLine = !isMultiline;
// If the label cannot grow horizontally and is only single line,
// then we don't need to invalidate since the only direction it can grow in
// is vertically but it never will.
if (!isHorizontallySizeable && isSingleLine)
return false;
// The label may grow/shrink based on the constraints, so we need to invalidate.
return true;
}
}
}
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