public static extern IntPtr SendMessage(IntPtr hWnd, uint msg, IntPtr wp, ref FORMATRANGE lp);
// send the EM_FORMATRANGE message to the RichTextBox to render or measure
// a range of the document into a target specified by a FORMATRANGE structure.
int FormatRange(RichTextBox rtb, bool render, ref FORMATRANGE fmt)
{
// render
int nextChar = SendMessageFormatRange(
rtb.Handle,
EM_FORMATRANGE,
render ? 1 : 0,
ref fmt);
// reset
SendMessage(rtb.Handle, EM_FORMATRANGE, 0, 0);
// return next character to print
return nextChar;
}
// build a FORMATRANGE structure with the proper page size and hdc
// (the hdc must be released after the FORMATRANGE is used)
FORMATRANGE GetFormatRange(PrintPageEventArgs e, int firstChar)
{
// get page rectangle in twips
var rc = e.MarginBounds;
rc.X = (int)(rc.X * 14.4 + .5);
rc.Y = (int)(rc.Y * 14.4 + .5);
rc.Width = (int)(rc.Width * 14.4 + .5);
rc.Height = (int)(rc.Height * 14.40 + .5);
// set up FORMATRANGE structure
var hdc = e.Graphics.GetHdc();
var fmt = new FORMATRANGE();
fmt.hdc = fmt.hdcTarget = hdc;
fmt.rc.SetRect(rc);
fmt.rcPage = fmt.rc;
fmt.cpMin = firstChar;
fmt.cpMax = -1;
// done
return fmt;
}
static extern int SendMessageFormatRange(IntPtr hWnd, uint wMsg, int wParam, ref FORMATRANGE lParam);
