GlyphRun and the exact position of the cursor (WPF) - wpf

Question

I would like to draw a text exactly in the place of the mouse cursor.
Because I need very high performance, I would like to use GlyphRun.
Everything works almost well, but unfortunately my text is slightly below the cursor.
Can someone help me modify this method to eliminate this vertical shift?
Now it looks like this
My expectation (the text touches the cursor)
My code:
void MyDrawer_MouseMove(object sender, MouseEventArgs e)
{
Test1();
}
void Test1()
{
MyDrawer.DeleteVisual(Dv);
MyDrawer.Cursor = Cursors.Cross;
string text = "Hello Word";
double size = 40;
Dv = new DrawingVisual();
using (var dc = Dv.RenderOpen())
{
Typeface typeface = new Typeface("Arial");
if (typeface.TryGetGlyphTypeface(out GlyphTypeface glyphTypeface))
{
ushort[] glyphIndexes = new ushort[text.Length];
double[] advanceWidths = new double[text.Length];
for (int i = 0; i < text.Length; i++)
{
ushort glyphIndex = glyphTypeface.CharacterToGlyphMap[text[i]];
glyphIndexes[i] = glyphIndex;
double width = glyphTypeface.AdvanceWidths[glyphIndex] * size;
advanceWidths[i] = width;
}
Point origin = Mouse.GetPosition(MyDrawer);
//Move text belowe the cursor
origin = new Point { X = origin.X, Y = origin.Y + (glyphTypeface.Baseline * size) };
GlyphRun glyphRun = new GlyphRun(glyphTypeface, 0, false, size,
glyphIndexes, origin, advanceWidths, null, null, null, null,
null, null);
dc.DrawGlyphRun(Brushes.Red, glyphRun);
MyDrawer.AddVisual(Dv);
}
}
}
Of course, this is only a test, in practice it will not affect the cursor, but the indicated point and text will be much more than in this example.

Answer 1

I bumped into this question in search for the same issue.
Glyph content (GlyphRun for that matter) is wrapped in a black-box.
The black-box contain a bit of padding on the top.
Like so : Rought skecth of the glyph run
// To get the box size
var blackBoxHeight = glyphTypeface.Height * fontSize;
// To get the actual character height
var characterHeight = glyphTypeface.Baseline * fontSize;
// To get the padding inside the black box
var blackBoxPadding = blackBoxHeight - characterHeight;
// set the point to draw a little bit up (skip the padding)
origin.Y -= blackBoxPadding;
// Create the glyph
var run = new GlyphRun
(
glyphTypeface: glyphTypeface,
bidiLevel: 0,
isSideways: false,
renderingEmSize: fontSize,
pixelsPerDip: 1.0f,
glyphIndices: indices,
baselineOrigin: origin, /* The point containing the padding offset */
advanceWidths: widths,
glyphOffsets: null,
characters: null,
deviceFontName: null,
clusterMap: null,
caretStops: null,
language: null
);

Answer 2

The other answer lacks of some details.
There is actually no magic or unreasoned paddings. The picture shows relations of glyphTypeface height parameters to the displayed GlyphRun.
The code that calculates corresponding line vertical positions based on the GlyphRun origin Y is shown below:
var baseLine = origin.Y;
var boxTop = baseLine - glyphTypeface.Baseline * FontSize;
var boxBottom = boxTop + glyphTypeface.Height * FontSize;
var capsHeight = baseLine - glyphTypeface.CapsHeight * FontSize;
var lowHeight = baseLine - glyphTypeface.XHeight * FontSize;