maui-linux/Xamarin.Forms.Platform.UAP/LabelRenderer.cs

372 строки
10 KiB
C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Automation.Peers;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Documents;
using Xamarin.Forms.PlatformConfiguration.WindowsSpecific;
using Specifics = Xamarin.Forms.PlatformConfiguration.WindowsSpecific.Label;
namespace Xamarin.Forms.Platform.UWP
{
public static class FormattedStringExtensions
{
public static Run ToRun(this Span span)
{
var run = new Run { Text = span.Text ?? string.Empty };
if (span.TextColor != Color.Default)
run.Foreground = span.TextColor.ToBrush();
if (!span.IsDefault())
#pragma warning disable 618
run.ApplyFont(span.Font);
#pragma warning restore 618
if (span.IsSet(Span.TextDecorationsProperty))
run.TextDecorations = (Windows.UI.Text.TextDecorations)span.TextDecorations;
return run;
}
}
public class LabelRenderer : ViewRenderer<Label, TextBlock>
{
bool _fontApplied;
bool _isInitiallyDefault;
SizeRequest _perfectSize;
bool _perfectSizeValid;
IList<double> _inlineHeights = new List<double>();
//TODO: We need to revisit this later when we complete the UI Tests for UWP.
// Changing the AutomationPeer here prevents the Narrator from functioning properly.
// Oddly, it affects more than just the TextBlocks. It seems to break the entire scan mode.
//protected override AutomationPeer OnCreateAutomationPeer()
//{
// // We need an automation peer so we can interact with this in automated tests
// if (Control == null)
// {
// return new FrameworkElementAutomationPeer(this);
// }
// return new TextBlockAutomationPeer(Control);
//}
protected override Windows.Foundation.Size ArrangeOverride(Windows.Foundation.Size finalSize)
{
if (Element == null)
return finalSize;
double childHeight = Math.Max(0, Math.Min(Element.Height, Control.DesiredSize.Height));
var rect = new Rect();
switch (Element.VerticalTextAlignment)
{
case TextAlignment.Start:
break;
default:
case TextAlignment.Center:
rect.Y = (int)((finalSize.Height - childHeight) / 2);
break;
case TextAlignment.End:
rect.Y = finalSize.Height - childHeight;
break;
}
rect.Height = childHeight;
rect.Width = finalSize.Width;
Control.Arrange(rect);
Control.RecalculateSpanPositions(Element, _inlineHeights);
return finalSize;
}
public override SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
{
if (!_perfectSizeValid)
{
_perfectSize = base.GetDesiredSize(double.PositiveInfinity, double.PositiveInfinity);
_perfectSize.Minimum = new Size(Math.Min(10, _perfectSize.Request.Width), _perfectSize.Request.Height);
_perfectSizeValid = true;
}
var widthFits = widthConstraint >= _perfectSize.Request.Width;
var heightFits = heightConstraint >= _perfectSize.Request.Height;
if (widthFits && heightFits)
return _perfectSize;
var result = base.GetDesiredSize(widthConstraint, heightConstraint);
var tinyWidth = Math.Min(10, result.Request.Width);
result.Minimum = new Size(tinyWidth, result.Request.Height);
if (widthFits || Element.LineBreakMode == LineBreakMode.NoWrap)
return result;
bool containerIsNotInfinitelyWide = !double.IsInfinity(widthConstraint);
if (containerIsNotInfinitelyWide)
{
bool textCouldHaveWrapped = Element.LineBreakMode == LineBreakMode.WordWrap || Element.LineBreakMode == LineBreakMode.CharacterWrap;
bool textExceedsContainer = result.Request.Width > widthConstraint;
if (textExceedsContainer || textCouldHaveWrapped)
{
var expandedWidth = Math.Max(tinyWidth, widthConstraint);
result.Request = new Size(expandedWidth, result.Request.Height);
}
}
return result;
}
protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
if (Control == null)
{
SetNativeControl(new TextBlock());
}
_isInitiallyDefault = Element.IsDefault();
UpdateText(Control);
UpdateTextDecorations(Control);
UpdateColor(Control);
UpdateAlign(Control);
UpdateFont(Control);
UpdateLineBreakMode(Control);
UpdateMaxLines(Control);
UpdateDetectReadingOrderFromContent(Control);
UpdateLineHeight(Control);
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == Label.TextProperty.PropertyName || e.PropertyName == Label.FormattedTextProperty.PropertyName)
UpdateText(Control);
else if (e.PropertyName == Label.TextColorProperty.PropertyName)
UpdateColor(Control);
else if (e.PropertyName == Label.HorizontalTextAlignmentProperty.PropertyName || e.PropertyName == Label.VerticalTextAlignmentProperty.PropertyName)
UpdateAlign(Control);
else if (e.PropertyName == Label.FontProperty.PropertyName)
UpdateFont(Control);
else if (e.PropertyName == Label.TextDecorationsProperty.PropertyName)
UpdateTextDecorations(Control);
else if (e.PropertyName == Label.LineBreakModeProperty.PropertyName)
UpdateLineBreakMode(Control);
else if (e.PropertyName == VisualElement.FlowDirectionProperty.PropertyName)
UpdateAlign(Control);
else if (e.PropertyName == Specifics.DetectReadingOrderFromContentProperty.PropertyName)
UpdateDetectReadingOrderFromContent(Control);
else if (e.PropertyName == Label.LineHeightProperty.PropertyName)
UpdateLineHeight(Control);
else if (e.PropertyName == Label.MaxLinesProperty.PropertyName)
UpdateMaxLines(Control);
base.OnElementPropertyChanged(sender, e);
}
void UpdateTextDecorations(TextBlock textBlock)
{
if (!Element.IsSet(Label.TextDecorationsProperty))
return;
var elementTextDecorations = Element.TextDecorations;
if ((elementTextDecorations & TextDecorations.Underline) == 0)
textBlock.TextDecorations &= ~Windows.UI.Text.TextDecorations.Underline;
else
textBlock.TextDecorations |= Windows.UI.Text.TextDecorations.Underline;
if ((elementTextDecorations & TextDecorations.Strikethrough) == 0)
textBlock.TextDecorations &= ~Windows.UI.Text.TextDecorations.Strikethrough;
else
textBlock.TextDecorations |= Windows.UI.Text.TextDecorations.Strikethrough;
//TextDecorations are not updated in the UI until the text changes
if (textBlock.Inlines != null && textBlock.Inlines.Count > 0)
{
for (var i = 0; i < textBlock.Inlines.Count; i++)
{
var run = (Run)textBlock.Inlines[i];
run.Text = run.Text;
}
}
else
{
textBlock.Text = textBlock.Text;
}
}
void UpdateAlign(TextBlock textBlock)
{
_perfectSizeValid = false;
if (textBlock == null)
return;
Label label = Element;
if (label == null)
return;
textBlock.TextAlignment = label.HorizontalTextAlignment.ToNativeTextAlignment(((IVisualElementController)Element).EffectiveFlowDirection);
textBlock.VerticalAlignment = label.VerticalTextAlignment.ToNativeVerticalAlignment();
}
void UpdateColor(TextBlock textBlock)
{
if (textBlock == null)
return;
Label label = Element;
if (label != null && label.TextColor != Color.Default)
{
textBlock.Foreground = label.TextColor.ToBrush();
}
else
{
textBlock.ClearValue(TextBlock.ForegroundProperty);
}
}
void UpdateFont(TextBlock textBlock)
{
_perfectSizeValid = false;
if (textBlock == null)
return;
Label label = Element;
if (label == null || (label.IsDefault() && !_fontApplied))
return;
#pragma warning disable 618
Font fontToApply = label.IsDefault() && _isInitiallyDefault ? Font.SystemFontOfSize(NamedSize.Medium) : label.Font;
#pragma warning restore 618
textBlock.ApplyFont(fontToApply);
_fontApplied = true;
}
void UpdateLineBreakMode(TextBlock textBlock)
{
_perfectSizeValid = false;
if (textBlock == null)
return;
switch (Element.LineBreakMode)
{
case LineBreakMode.NoWrap:
textBlock.TextTrimming = TextTrimming.Clip;
textBlock.TextWrapping = TextWrapping.NoWrap;
break;
case LineBreakMode.WordWrap:
textBlock.TextTrimming = TextTrimming.None;
textBlock.TextWrapping = TextWrapping.Wrap;
break;
case LineBreakMode.CharacterWrap:
textBlock.TextTrimming = TextTrimming.WordEllipsis;
textBlock.TextWrapping = TextWrapping.Wrap;
break;
case LineBreakMode.HeadTruncation:
// TODO: This truncates at the end.
textBlock.TextTrimming = TextTrimming.WordEllipsis;
textBlock.TextWrapping = TextWrapping.NoWrap;
break;
case LineBreakMode.TailTruncation:
textBlock.TextTrimming = TextTrimming.CharacterEllipsis;
textBlock.TextWrapping = TextWrapping.NoWrap;
break;
case LineBreakMode.MiddleTruncation:
// TODO: This truncates at the end.
textBlock.TextTrimming = TextTrimming.WordEllipsis;
textBlock.TextWrapping = TextWrapping.NoWrap;
break;
default:
throw new ArgumentOutOfRangeException();
}
}
void UpdateText(TextBlock textBlock)
{
_perfectSizeValid = false;
if (textBlock == null)
return;
Label label = Element;
if (label != null)
{
FormattedString formatted = label.FormattedText;
if (formatted == null)
{
textBlock.Text = label.Text ?? string.Empty;
}
else
{
textBlock.Inlines.Clear();
// Have to implement a measure here, otherwise inline.ContentStart and ContentEnd will be null, when used in RecalculatePositions
textBlock.Measure(new Windows.Foundation.Size(double.MaxValue, double.MaxValue));
var heights = new List<double>();
for (var i = 0; i < formatted.Spans.Count; i++)
{
var span = formatted.Spans[i];
var run = span.ToRun();
heights.Add(Control.FindDefaultLineHeight(run));
textBlock.Inlines.Add(run);
}
_inlineHeights = heights;
}
}
}
void UpdateDetectReadingOrderFromContent(TextBlock textBlock)
{
if (Element.IsSet(Specifics.DetectReadingOrderFromContentProperty))
{
if (Element.OnThisPlatform().GetDetectReadingOrderFromContent())
{
textBlock.TextReadingOrder = TextReadingOrder.DetectFromContent;
}
else
{
textBlock.TextReadingOrder = TextReadingOrder.UseFlowDirection;
}
}
}
void UpdateLineHeight(TextBlock textBlock)
{
if (textBlock == null)
return;
if (Element.LineHeight >= 0)
{
textBlock.LineHeight = Element.LineHeight * textBlock.FontSize;
}
}
void UpdateMaxLines(TextBlock textBlock)
{
if (Element.MaxLines >= 0)
{
textBlock.MaxLines = Element.MaxLines;
}
else
{
textBlock.MaxLines = 0;
}
}
}
}