PDFsharp & MigraDoc Foundation

XGraphics.MeasureString() uses a FormattedText object to measure string width. This is expensive because the FormattedText creates a drawing context underneath the scenes, for any unique text string that gets drawn. A better method is to use the GlyphTypeface method, such a what this blog entry does:

http://incrediblejourneysintotheknown.b ... forth.html

When rendering many pages, this performance is improved significantly by using the following code fix in XGraphics.cs (3213):

#if WPF && !GDI
/* OLD CODE:

FormattedText formattedText = new FormattedText(text, new CultureInfo("en-us"),
FlowDirection.LeftToRight, font.typeface, font.Height, System.Windows.Media.Brushes.Black);
return new XSize(formattedText.WidthIncludingTrailingWhitespace, formattedText.Height);
* */

GlyphTypeface gTypeface;
if (!font.typeface.TryGetGlyphTypeface(out gTypeface))
throw new InvalidOperationException("No glyphtypeface found");
ushort[] glyphIndexes = new ushort[text.Length];
double[] advanceWidths = new double[text.Length];
double totalWidth = 0;
for (int n = 0; n < text.Length; n++)
{
ushort glyphIndex = gTypeface.CharacterToGlyphMap[text[n]];
glyphIndexes[n] = glyphIndex;

double width = gTypeface.AdvanceWidths[glyphIndex] * font.Size;
advanceWidths[n] = width;
totalWidth += width;
}
return new XSize(totalWidth, gTypeface.Height * font.Size);
#endif

Also - the glyph typeface code is the key to implementing custom kerning...

Thank you for the feedback.

This is not my area of expertise, but I put it on the internal TODO list for the next release.

_________________
Regards
Thomas Hoevel
PDFsharp Team

I looked at the latest version of PdfSharp, and this fix is still not in the code. What can we do to put this fix into the source?

As of PDFsharp 1.50 beta 2, XGraphics.MeasureString() no longer uses a FormattedText object to measure strings.

_________________
Regards
Thomas Hoevel
PDFsharp Team