private bool TryUpdateVisualElementsOnThemeChanged(Brainf_ckTheme theme)
{
if (_SelectionHighlightBorder is null)
{
return(false);
}
UpdateVisualElementsOnThemeChanged(theme);
return(true);
}
private void UpdateVisualElementsOnThemeChanged(Brainf_ckTheme theme)
{
switch (theme.LineHighlightStyle)
{
case LineHighlightStyle.Outline:
_SelectionHighlightBorder !.BorderThickness = new Thickness(2);
_SelectionHighlightBorder.BorderBrush = new SolidColorBrush(theme.LineHighlightColor);
_SelectionHighlightBorder.Background = null;
break;
case LineHighlightStyle.Fill:
_SelectionHighlightBorder !.BorderThickness = default;
_SelectionHighlightBorder.BorderBrush = null;
_SelectionHighlightBorder.Background = new SolidColorBrush(theme.LineHighlightColor);
break;
default:
ThrowHelper.ThrowArgumentException("Invalid line highlight style");
break;
}
}
/// <summary>
/// Updates the UI when <see cref="SourceProperty"/> changes
/// </summary>
/// <param name="d">The source <see cref="DependencyObject"/> instance</param>
/// <param name="e">The <see cref="DependencyPropertyChangedEventArgs"/> info for the current update</param>
private static void OnSourcePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
// Unpack the arguments
Span @this = (Span)d;
string
oldValue = (string)e.OldValue,
newValue = (string)e.NewValue;
// Skip if the input code is empty
if (string.IsNullOrEmpty(newValue))
{
@this.Inlines.Clear();
return;
}
// When the new value is a prefix of the previous value,
// it means that the user has deleted one or more characters
// from the previous string. In this case we just need to traverse
// the current inlines collection backwards and remove as many
// runs or characters as needed. This will avoid having to recompute
// the entire syntax highlight from scratch for the new text.
if (oldValue.Length > newValue.Length && oldValue.StartsWith(newValue))
{
// The difference is doubled because each character has an additional
// zero width space character next to it, for better line wrapping
int difference = (oldValue.Length - newValue.Length) * 2;
do
{
// Get the last inline, remove it entirely if needed
Run run = (Run)@this.Inlines.LastOrDefault();
if (run.Text.Length <= difference)
{
@this.Inlines.RemoveLast();
difference -= run.Text.Length;
}
else
{
// Inline too long, only remove the exceeding characters
run.Text = run.Text.Substring(0, run.Text.Length - difference);
break;
}
} while (difference > 0);
return;
}
// Reuse the existing inlines when the new code is an extension of the previous code
int start = 0, end = newValue.Length;
if (newValue.Length > oldValue.Length && newValue.StartsWith(oldValue))
{
// Move the initial offset ahead to skip the prefix characters.
// Using a moving starting index saves an entire substring creation.
start = oldValue.Length;
if (@this.Inlines.LastOrDefault() is Run run)
{
// Check how many characters can be inserted into the last existing run
int i = start;
while (i < end && Brainf_ckTheme.HaveSameColor(run.Text[0], newValue[i]))
{
i++;
}
// If the entire prefix fit in the last run, just concat the string
if (i == end)
{
run.Text += newValue.AsSpan(start, end - start).InterleaveWithCharacter(ZeroWidthSpace);
return;
}
// If at least one character has been moved, insert those
if (i > start)
{
run.Text += newValue.AsSpan(start, i).InterleaveWithCharacter(ZeroWidthSpace);
}
}
}
else
{
@this.Inlines.Clear();
}
Brainf_ckTheme theme = SettingsService.GetValue <IdeTheme>(SettingsKeys.IdeTheme).AsBrainf_ckTheme();
// Parse and render the remaining text with new runs
while (start < end)
{
char c = newValue[start];
int i = start + 1;
// Aggregate as many characters as possible into a single run
while (i < end && Brainf_ckTheme.HaveSameColor(c, newValue[i]))
{
i++;
}
// Create and display the new run
@this.Inlines.Add(new Run
{
Text = newValue.AsSpan(start, i - start).InterleaveWithCharacter(ZeroWidthSpace),
Foreground = theme.GetBrush(c)
});
start = i;
}
}
