public void FormatRange(Graphics g, int startChar, int endChar)
{
STRUCT_CHARRANGE chrg = default(STRUCT_CHARRANGE);
chrg.cpMin = startChar;
chrg.cpMax = endChar;
STRUCT_RECT rc = default(STRUCT_RECT);
rc.top = 0;
rc.bottom = ToTwips(MasterControl.ClientSize.Height + 40);
rc.left = 0;
if (MasterControl.Size.Width - MasterControl.ClientSize.Width == 20)
{
rc.right = ToTwips((float)MasterControl.ClientSize.Width + (float)MasterControl.ClientSize.Width / 80f + 4f);
}
else
{
rc.right = ToTwips((float)MasterControl.ClientSize.Width + (float)MasterControl.ClientSize.Width / 100f + 5f);
}
STRUCT_RECT rcPage = default(STRUCT_RECT);
rcPage.top = 0;
rcPage.bottom = ToTwips(MasterControl.Size.Height);
rcPage.left = 0;
rcPage.right = ToTwips(MasterControl.Size.Width);
IntPtr hdc = g.GetHdc();
STRUCT_FORMATRANGE structure = default(STRUCT_FORMATRANGE);
structure.chrg = chrg;
structure.hdc = hdc;
structure.hdcTarget = hdc;
structure.rc = rc;
structure.rcPage = rcPage;
IntPtr intPtr = Marshal.AllocCoTaskMem(Marshal.SizeOf(structure));
Marshal.StructureToPtr(structure, intPtr, fDeleteOld: false);
SendMessageToMaster(EM_FORMATRANGE, (IntPtr)1, intPtr, 1);
SendMessageToMaster(EM_FORMATRANGE, IntPtr.Zero, IntPtr.Zero, -1);
Marshal.FreeCoTaskMem(intPtr);
g.ReleaseHdc(hdc);
}
/// <summary>
/// Calculate or render the contents of our RichTextBox for printing
/// </summary>
/// <param name="measureOnly">If true, only the calculation is performed, otherwise the text is rendered as well</param>
/// <param name="e">The PrintPageEventArgs object from the PrintPage event</param>
/// <param name="charFrom">Index of first character to be printed</param>
/// <param name="charTo">Index of last character to be printed</param>
/// <returns> (Index of last character that fitted on the page) + 1</returns>
public int FormatRange(bool measureOnly, PrintPageEventArgs e, int charFrom, int charTo)
{
// Specify which characters to print
STRUCT_CHARRANGE cr = default(STRUCT_CHARRANGE);
cr.cpMin = charFrom;
cr.cpMax = charTo;
// Specify the area inside page margins
STRUCT_RECT rc = default(STRUCT_RECT);
rc.top = HundredthInchToTwips(e.MarginBounds.Top);
rc.bottom = HundredthInchToTwips(e.MarginBounds.Bottom);
rc.left = HundredthInchToTwips(e.MarginBounds.Left);
rc.right = HundredthInchToTwips(e.MarginBounds.Right);
// Specify the page area
STRUCT_RECT rcPage = default(STRUCT_RECT);
rcPage.top = HundredthInchToTwips(e.PageBounds.Top);
rcPage.bottom = HundredthInchToTwips(e.PageBounds.Bottom);
rcPage.left = HundredthInchToTwips(e.PageBounds.Left);
rcPage.right = HundredthInchToTwips(e.PageBounds.Right);
// Get device context of output device
IntPtr hdc = default(IntPtr);
hdc = e.Graphics.GetHdc();
// Fill in the FORMATRANGE structure
STRUCT_FORMATRANGE fr = default(STRUCT_FORMATRANGE);
fr.chrg = cr;
fr.hdc = hdc;
fr.hdcTarget = hdc;
fr.rc = rc;
fr.rcPage = rcPage;
// Non-Zero wParam means render, Zero means measure
Int32 wParam = default(Int32);
if (measureOnly)
{
wParam = 0;
}
else
{
wParam = 1;
}
// Allocate memory for the FORMATRANGE struct and
// copy the contents of our struct to this memory
IntPtr lParam = default(IntPtr);
lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(fr));
Marshal.StructureToPtr(fr, lParam, false);
// Send the actual Win32 message
int res = 0;
res = SendMessage(Handle, EM_FORMATRANGE, wParam, lParam);
// Free allocated memory
Marshal.FreeCoTaskMem(lParam);
// and release the device context
e.Graphics.ReleaseHdc(hdc);
return(res);
}