how to get correct metrics identical to DrawText() ?

[iperov]

var family = fc.Add(q);
var font = family.CreateFont(16);

TextOptions options = new(font);

string text = "000";
var met = font.FontMetrics;

var text_size = TextMeasurer.MeasureAdvance(text, options);

var img = new Image<Rgba32>( (int)text_size.Width, (int)text_size.Height, Color.Black);
img.Mutate((x) => x.DrawText(text, font, Color.White, new PointF(0, 0)));
img.SaveAsPng("D:\\test.png");

var ascender = (metrics.VerticalMetrics.Ascender * font.Size * options.Dpi) / metrics.ScaleFactor;
var decender = (metrics.VerticalMetrics.Descender * font.Size * options.Dpi) / metrics.ScaleFactor;
var LineGap = (metrics.VerticalMetrics.LineGap * font.Size * options.Dpi) / metrics.ScaleFactor;
var LineHeight = (metrics.VerticalMetrics.LineHeight * font.Size * options.Dpi) / metrics.ScaleFactor;    

metrics don't match rendered text

[iperov]

I can't figure out what values are output from metrics and what is drawn.

[iperov]

var family = fc.Add(q);
var font = family.CreateFont(20);

string text = "00";// 0,00";
var metrics = font.FontMetrics;

new DrawingOptions()
{
    GraphicsOptions = new GraphicsOptions(),
    ShapeOptions = new ShapeOptions()
};

var rich_text_options = new RichTextOptions(font)
{
    Origin = new System.Numerics.Vector2(0,0),
};

var ascender = (metrics.HorizontalMetrics.Ascender * font.Size * rich_text_options.Dpi) / (metrics.ScaleFactor);
var decender = (metrics.HorizontalMetrics.Descender * font.Size * rich_text_options.Dpi) / (metrics.ScaleFactor);
var LineGap = (metrics.HorizontalMetrics.LineGap * font.Size * rich_text_options.Dpi) / (metrics.ScaleFactor);
var LineHeight = (metrics.HorizontalMetrics.LineHeight * font.Size * rich_text_options.Dpi) / (metrics.ScaleFactor);
Console.WriteLine($"ascender {ascender}");
Console.WriteLine($"decender {decender}");
Console.WriteLine($"LineHeight {LineHeight}");

var text_size = TextMeasurer.MeasureAdvance(text, rich_text_options);

var img = new Image<Rgba32>((int)text_size.Width, (int)text_size.Height, Color.Black);
img.Mutate((x) => x.DrawText(rich_text_options, text, Color.White));
img.SaveAsPng("D:\\test.png");

[iperov]

NotoSans-Regular.ttf

[iperov]

so how to get exact baseline in box of MeasureAdvance and DrawText ?

[JimBobSquarePants]

It doesn’t look to me like you are using the correct formula to calculate the metrics.

see SixLabors/ImageSharp.Drawing#353