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Hi,
I'm working on WinUI3 desktop app in c++. I want to print the current UI (content of an window) to PDF without should any print UI.
I was able to print without showing the UI with Win32 API's (but I had to draw the whole UI myself),
HDC pdfDC = CreateDC(L"WINSPOOL", L"Microsoft Print to PDF", NULL, NULL);
if (StartDoc(pdfDC, &di) > 0) {
StartPage(pdfDC);
// Perform printing operations here
}
But I want print the current UI to PDF without showing Print UI with WinUI3/CppWinrt interfaces. Is it possible to do so? I read about PrintDocument class but I did not find any good examples. I found one example in C# for UWP app but there is was not able to print to PDF without showing the UI. Can you help me with how to print the current UI(Content of Window) to PDF without showing the UI? Thank you.
I was able to print without showing the UI with Win32 API's (but I had to draw the whole UI myself),
You can use PrintWindow I tested on Windows 10, with PW_RENDERFULLCONTENT flag
Thank you for the response @Castorix31 . I tried using this API like this to print to PDF (For winui3 desktop application and XAML island) -
void PrintPDF(HWND pHwnd) {
HWND hwndTarget = pHwnd;
DOCINFO di = { sizeof(DOCINFO), "MyPDFDocument", NULL, NULL, 0 };
HDC hdcTarget = CreateDC("WINSPOOL", "Microsoft Print to PDF", NULL, NULL);
if (!hwndTarget && !hdcTarget) {
return;
}
if (StartDoc(hdcTarget, &di) > 0) {
StartPage(hdcTarget);
// Perform printing operations here
if (!PrintWindow(hwndTarget, hdcTarget, PW_CLIENTONLY)) {
// Handle error: PrintWindow failed
DeleteObject(hdcTarget);
ReleaseDC(hwndTarget, hdcTarget);
MessageBox(NULL, "Error", "Print Failed", 0);
return;
}
EndPage(hdcTarget);
EndDoc(hdcTarget);
}
}
But this printed an empty PDF. Where did i go wrong?
I used a memory DC I can only test in C# (too long to compile in C++/WinRT), but it is the same code in C++ =>
{
IntPtr hPrinterDC = CreateDC("WINSPOOL", "Microsoft Print to PDF", null, IntPtr.Zero);
if (hPrinterDC != IntPtr.Zero)
{
int nWidth = GetDeviceCaps(hPrinterDC, HORZRES);
int nHeight = GetDeviceCaps(hPrinterDC, VERTRES);
IntPtr hDC = GetDC(IntPtr.Zero);
IntPtr hBitmap = Create32BPPDIBSection(hDC, _apw.Size.Width, _apw.Size.Height);
IntPtr hMemoryDC = CreateCompatibleDC(hDC);
IntPtr hBitmapOld = SelectObject(hMemoryDC, hBitmap);
bool bRet = PrintWindow(hWndMain, hMemoryDC, PW_RENDERFULLCONTENT);
DOCINFO di = new DOCINFO();
di.cbSize = Marshal.SizeOf(typeof(DOCINFO));
di.lpszDocName = "Print Window";
di.lpszOutput = "E:\\temp\\testprint.pdf";
if (StartDoc(hPrinterDC, di) > 0)
{
if (StartPage(hPrinterDC) > 0)
{
DIBSECTION ds = new DIBSECTION();
GetObject(hBitmap, Marshal.SizeOf(typeof(DIBSECTION)), ref ds);
double nRatio = (double)nWidth / (double)_apw.Size.Width;
nHeight = (int)(_apw.Size.Height * nRatio);
StretchDIBits(hPrinterDC, 0, 0, nWidth, nHeight, 0, 0, _apw.Size.Width, _apw.Size.Height, ds.dsBm.bmBits, ref ds.dsBmih, DIB_RGB_COLORS, SRCCOPY);
EndPage(hPrinterDC);
}
EndDoc(hPrinterDC);
}
SelectObject(hMemoryDC, hBitmapOld);
DeleteDC(hMemoryDC);
DeleteObject(hBitmap);
ReleaseDC(IntPtr.Zero, hDC);
DeleteDC(hPrinterDC);
}
}
public IntPtr Create32BPPDIBSection(IntPtr hDC, int iWidth, int iHeight)
{
IntPtr hBitmap = IntPtr.Zero;
IntPtr pBits = IntPtr.Zero;
BITMAPINFO bmi = new BITMAPINFO();
bmi.bmiHeader.biSize = Marshal.SizeOf(typeof(BITMAPINFOHEADER));
bmi.bmiHeader.biWidth = iWidth;
bmi.bmiHeader.biHeight = iHeight;
bmi.bmiHeader.biPlanes = 1;
bmi.bmiHeader.biBitCount = 32;
bmi.bmiHeader.biCompression = BI_RGB;
hBitmap = CreateDIBSection(hDC, ref bmi, DIB_RGB_COLORS, ref pBits, IntPtr.Zero, 0);
return hBitmap;
}
At beginning (to get window dimensions from AppWindow, GetWindowRect can also be used) :
private IntPtr hWndMain = IntPtr.Zero;
private Microsoft.UI.Windowing.AppWindow _apw;
hWndMain = WinRT.Interop.WindowNative.GetWindowHandle(this);
Microsoft.UI.WindowId myWndId = Microsoft.UI.Win32Interop.GetWindowIdFromWindow(hWndMain);
_apw = Microsoft.UI.Windowing.AppWindow.GetFromWindowId(myWndId);
Thank you this was very helpful. I was able to print to PDF with this
But I want to remove the title and border. I tried using PW_CLIENTONLY flag for PrintWindow, but it did not work.
I got the output like this -
How to fix this?
It works for me with both flags : PW_RENDERFULLCONTENT | PW_CLIENTONLY
Yea it worked for me with PW_RENDERFULLCONTENT | PW_CLIENTONLY. But im still getting the black border
If you only print client area, you must reduce the width/height (caption height , DWMWA_EXTENDED_FRAME_BOUNDS for borders, or GetClientRect...)
Okay thank you
@Castorix31 , This only works if the windows is visible. Is there any way print the invisible windows content?
There is an article on CodeProject for minimized windows, but I did not test : https://www.codeproject.com/Articles/20651/Capturing-Minimized-Window-A-Kid-s-Trick