Remove all instances of HasFlag

[JimBobSquarePants]

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Description

See #425 (reply in thread)

HasFlags sometimes still boxes (in tier 0 compilation) if JIT does not optimize it away.

@nolife99 I profiled a couple of unit tests and saw a reduction however it would be useful if you could give this a try by referencing the code directly and report back.

Copilot reviewed 5 out of 7 changed files in this pull request and generated no suggestions.

Files not reviewed (2)

• src/SixLabors.Fonts/Font.cs: Evaluated as low risk
• src/SixLabors.Fonts/FontDescription.cs: Evaluated as low risk

[nolife99]

I did implement this myself yesterday (exactly the same as you did), and it showed a pretty good improvement in memory usage and GC performance

[JimBobSquarePants]

@nolife99 You wouldn't have any screenshots you can share or some sample code I can use to reproduce would you?

[nolife99]

    public Image<Rgba32> CreateBitmap(string text,
        string fontName,
        float fontSize,
        Vector2 padding,
        out Vector2 textureSize)
    {
        if (string.IsNullOrEmpty(text)) text = " ";

        const float dpi = 72f; 

        // replace below with a Font instance, '96 * fontSize / dpi' is the font size
        var font = getFont(fontName, 96 * fontSize / dpi, FontStyle.Regular);

        var foundMetrics = font.Family.TryGetMetrics(FontStyle.Regular, out var metrics);
        RichTextOptions options = new(font)
        {
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Center,
            LineSpacing = foundMetrics ? Math.Max(metrics.VerticalMetrics.LineHeight * .001f, 1) : 1,
            Dpi = dpi
        };

        var measuredSize = TextMeasurer.MeasureAdvance(text, options);
        var width = (int)(measuredSize.Width + padding.X * 2 + 1);
        var height = (int)(measuredSize.Height + padding.Y * 2 + 1);

        textureSize = new(width, height);

        Image<Rgba32> bitmap = new(width, height);
        bitmap.Mutate(b =>
        {
            RichTextOptions drawOptions = new(font) { Origin = padding };
            b.DrawText(new(drawOptions) { Origin = padding + Vector2.One }, text, Color.White).DrawText(drawOptions, text, Color.FromRgba(0, 0, 0, 220));
        });

        return bitmap;
    }

    Image<Rgba32> generateGlyph(char c)
    {
        return CreateBitmap(c.ToString(), name, size, default, out measuredSize);
    }

This is a snippet of code from one of my projects, basically generateGlyph() is called for each character in a string
Sorry if there are any errors, I extracted this in a rush

To add one more thing, Rider's DPA no longer generates a ton of SOH allocation warnings