Supporting copy is usually straightforward for most applications. It usually requires 10-20 lines of code. But like many features of MFC, the implementation is simple. However, finding the information needed to create the implementation is tedious and time consuming. To save you many hours of reading documentation, I have included several common methods for placing data on the clipboard.
Copying a Bitmap of the Client Area
The following bit of code renders the client area using OnDraw()
into a bitmap. The bitmap is placed on the clipboard as a CF_BITMAP
that is recognizable by most applications that accept bitmaps. This code will work will all mapping modes provided that mapping mode is set in the OnPrepareDC()
function.
void CXStitchView::OnEditCopy()
{
CRect rect;
CClientDC dc(this);
CDC memDC;
CBitmap bitmap;
GetClientRect(&rect);
memDC.CreateCompatibleDC(&dc);
bitmap.CreateCompatibleBitmap(&dc, rect.Width(), rect.Height());
CBitmap* pOldBitmap = memDC.SelectObject(&bitmap);
memDC.FillSolidRect(rect, dc.GetBkColor());
OnPrepareDC(&memDC);
OnDraw(&memDC);
OpenClipboard();
EmptyClipboard();
SetClipboardData(CF_BITMAP, bitmap.GetSafeHandle());
CloseClipboard();
memDC.SelectObject(pOldBitmap);
bitmap.Detach();
}
Copying a Table of Data to the Clipboard
Placing a table of data on the clipboard is easy. It is simply a string of text. Tabs separate columns, new lines separate rows. Here's some example source.
#include <afxpriv.h>
void CClipExamView::OnEditCopy()
{
CSharedFile sf(GMEM_MOVEABLE | GMEM_SHARE | GMEM_ZEROINIT);
RenderTableData(sf);
if (sf.GetLength() > 0) {
OpenClipboard();
EmptyClipboard();
SetClipboardData(CF_TEXT, sf.Detach());
CloseClipboard();
}
}
void CClipExamView::RenderTableData(CFile &file)
{
CString buffer = "1\t2\t3\n4\t5\t6\n";
file.Write(buffer, buffer.GetLength());
}
Copying Formatted Data to the Clipboard
Formatted text can support bold, italic or any other formatting that can be done in a word processor. Formatted text is usually placed on the clipboard as RTF (Rich Text Format).
The Rich Text Format is intended as an interchange format for Word-processing applications. Because of that, it is a rather large and feature rich file format. Fortunately, it is possible to describe a minimal RTF command set for creating simple formatted documents.
Basic RTF commands:
\par - Starts a new paragraph.
\tab - A tab.
\b - Enable Bold (scoped within a group)
\i - Enable Italics (scoped within a group)
\ul - Enable Underline (scoped within a group)
For example, the RTF string:
{\rtf1 {1 \tab 2 \tab 3 \par 4 \tab {\b\i 5} \tab 6}}
Source
#include <afxpriv.h>
void CClipExamView::OnEditCopy()
{
CSharedFile sf(GMEM_MOVEABLE | GMEM_SHARE | GMEM_ZEROINIT);
RenderFormattedData(sf);
if (sf.GetLength() > 0) {
OpenClipboard();
EmptyClipboard();
SetClipboardData(::RegisterClipboardFormat(CF_RTF), sf.Detach());
CloseClipboard();
}
}
void CClipExamView::RenderFormattedData(CFile &file)
{
CString buffer = "{\\rtf1 {1 \\tab 2 \\tab 3"
" \\par 4 \\tab {\\b\\i 5} \\tab 6}}";
file.Write(buffer, buffer.GetLength());
}
Getting More Info on RTF
Most books on file format address RTF in some form. You can find the RTF specification here.
Virtually all word processors can save RTF files. This is usually a good place to start when building an RTF template.
I work at Tektronix in Beaverton OR. I've been programming for fun since 1975 (I started while in a Computer Explorer Scout group in Spokane WA). I've been programming in C since 1979 and I've been working professionally since 1983.
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