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Make emoji:TextBlock inherit from TextBlock.
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@samhocevar
samhocevar committed May 13, 2018
1 parent 0d7ed3a commit 892dd5b
Showing 1 changed file with 83 additions and 82 deletions.
165 changes: 83 additions & 82 deletions Emoji.Wpf/TextBlock.cs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
//
// Emoji.Wpf — Emoji support for WPF
//
// Copyright © 2017 Sam Hocevar <sam@hocevar.net>
// Copyright © 2017—2018 Sam Hocevar <sam@hocevar.net>
//
// This library is free software. It comes without any warranty, to
// the extent permitted by applicable law. You can redistribute it
Expand All @@ -11,7 +11,10 @@
//

using System;
using System.ComponentModel;
using System.Threading;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Media;
using Typography.TextLayout;

Expand All @@ -27,19 +30,89 @@ public class Image : TextBlock { }
/// <summary>
/// A simple WPF Control that renders an emoji. It can be resized.
/// </summary>
public class TextBlock : Controls.Canvas
public class TextBlock : Controls.TextBlock
{
public TextBlock()
{
SnapsToDevicePixels = true;

//m_base_dp.AddValueChanged(this, OnBaseTextChanged);
//Unloaded += (o, e) =>
// m_base_dp.RemoveValueChanged(this, OnBaseTextChanged);
}

public TextBlock(string text)
/// <summary>
/// Override System.Windows.Controls.TextBox.Text
/// </summary>
public new string Text
{
SnapsToDevicePixels = true;
Text = text;
get => m_text_dp.GetValue(this) as string;
set => m_text_dp.SetValue(this, value);
}

/// <summary>
/// Override System.Windows.Controls.TextBox.TextProperty
/// </summary>
public static new readonly DependencyProperty TextProperty = DependencyProperty.Register(
nameof(Text), typeof(string), typeof(TextBlock),
new FrameworkPropertyMetadata("", TextChangedCallback));

private static void TextChangedCallback(DependencyObject o, DependencyPropertyChangedEventArgs e)
=> (o as TextBlock).OnTextChanged(o, new EventArgs());

private void OnTextChanged(object sender, EventArgs args)
{
base.Text = Text;
if (Inlines.FirstInline != m_inline)
{
Inlines.Clear();
Inlines.Add(m_inline);
}
m_canvas.Reset(Text, FontSize);
}

/// <summary>
/// Guard against recursive calls to OnTextChanged
/// </summary>
private bool m_updating = false;

private EmojiCanvas m_canvas = new EmojiCanvas();
private InlineUIContainer m_inline = new InlineUIContainer(m_canvas);

private static DependencyPropertyDescriptor m_text_dp =
DependencyPropertyDescriptor.FromProperty(TextProperty, typeof(TextBlock));
//private static DependencyPropertyDescriptor m_base_dp =
// DependencyPropertyDescriptor.FromProperty(Controls.TextBlock.TextProperty, typeof(TextBlock));
}

public class EmojiCanvas : Controls.Canvas
{
public void Reset(string text, double fontsize)
{
if (text == m_text && fontsize == m_fontsize)
return;

m_text = text;
m_fontsize = fontsize;

m_glyphplanlist = m_font.StringToGlyphPlanList(m_text, m_fontsize);

// Check whether the Emoji font knows about all codepoints;
// otherwise, set Invalid to true.
Invalid = false;
for (int i = 0; i < m_glyphplanlist.Count; ++i)
if (m_glyphplanlist[i].glyphIndex == 0)
Invalid = true;

// Try to compute our own widget size
// FIXME: I am not sure why the math below works
Height = m_fontsize / 0.75; // 1 pixel = 0.75pt
Width = m_glyphplanlist.AccumAdvanceX * 0.75;
InvalidateVisual();
}

public bool Invalid { get; private set; }

protected override void OnRender(DrawingContext dc)
{
if (m_glyphplanlist.Count > 0 && ActualWidth > 0 && ActualHeight > 0)
Expand All @@ -53,9 +126,9 @@ protected override void OnRender(DrawingContext dc)
// Compute font size in pixels
double total_width = m_glyphplanlist.AccumAdvanceX;
double font_size = Math.Min(ActualWidth / total_width,
ActualHeight / FontSize);
ActualHeight / m_fontsize);
double startx = 0;
double starty = FontSize * m_font.Baseline;
double starty = m_fontsize * m_font.Baseline;

// Debug the glyph bounding box
//dc.DrawRectangle(Brushes.LightYellow, new Pen(Brushes.Orange, 1.0), new Rect(startx, 0, total_width * font_size, m_font.Height * font_size));
Expand All @@ -65,87 +138,15 @@ protected override void OnRender(DrawingContext dc)
var g = m_glyphplanlist[i];
var origin = new Point(Math.Round(startx + g.ExactX * 0.75),
Math.Round(starty + g.ExactY * 0.75));
m_font.RenderGlyph(dc, g.glyphIndex, origin, FontSize);
m_font.RenderGlyph(dc, g.glyphIndex, origin, m_fontsize);
}
}
}

private static void TextChangedCallback(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
(o as TextBlock).OnTextChanged((string)e.NewValue);
}

private void OnTextChanged(string str)
{
m_glyphplanlist = m_font.StringToGlyphPlanList(str, FontSize);

// Check whether the Emoji font knows about this codepoint;
// otherwise, fall back to a simple TextBlock.
for (int i = 0; i < m_glyphplanlist.Count; ++i)
{
var g = m_glyphplanlist[i];
if (g.glyphIndex == 0)
{
m_glyphplanlist.Clear();
m_textblock.Text = str;
if (Width >= 0)
m_textblock.Width = Width;
if (Height >= 0)
m_textblock.FontSize = Height * 0.75;
if (Children.Count == 0)
Children.Add(m_textblock);
break;
}
}

// If the glyph list is valid, hide our TextBlock child
// and try to compute our own widget size
if (m_glyphplanlist.Count > 0)
{
Children.Clear();
// FIXME: I am not sure why the math below works
Height = FontSize / 0.75; // 1 pixel = 0.75pt
Width = m_glyphplanlist.AccumAdvanceX * 0.75;
InvalidateVisual();
}
}

public Brush Foreground
{
get => m_textblock.Foreground;
set => m_textblock.Foreground = value;
}

public double FontSize
{
get => m_textblock.FontSize;
set { m_textblock.FontSize = value; OnTextChanged(Text); }
}

public FontFamily FontFamily
{
get => m_textblock.FontFamily;
set => m_textblock.FontFamily = value;
}

public TextAlignment TextAlignment
{
get => m_textblock.TextAlignment;
set => m_textblock.TextAlignment = value;
}

public string Text
{
get => (string)GetValue(TextProperty);
set => SetValue(TextProperty, value);
}

public static readonly DependencyProperty TextProperty = DependencyProperty.Register(
nameof(Text), typeof(string), typeof(TextBlock), new FrameworkPropertyMetadata("", TextChangedCallback));
private string m_text;
private double m_fontsize;

private GlyphPlanList m_glyphplanlist = new GlyphPlanList();
private Controls.TextBlock m_textblock = new Controls.TextBlock();

private static EmojiTypeface m_font = new EmojiTypeface();
}
}
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