Why does textheight not return the double when you double the printer
resolution?
Example: i:= printer.canvas.textheight("xyz")
         i is 64 (with 300 dpi printer resolution)
     but i is 113 (with 600 dpi printer res)
     why not 128?
This cause problem with line spacing. The lines of a text in 300 dpi is
closer than the lines of a 600 dpi text.
How can i ensure that the line space is always the same?

Thanks for any hints
Daniel

I would advise you to use millimeters or inches and not pixels
when you deal with printing. Call SetMapMode() with MM_LOMETRIC or
MM_LOENGLISH.

I wrote a CAD plotting engine with print preview using 100% GDI calls,
because I don't trust Delphi's Canvas implementation. I used
DrawText() with the option that calculates the text rectangle and
had no problems whatsoever ...

Look up the SetMapMode() and DrawText() functions in Windows API Help.

Good Luck
Peter