I want to draw water mark on some documents like JPG, DOCX, PNG and PDF when printing. for this purpose, I Hook EndPage() function and use GDI+ DrawString to Draw Some Text. My code works well for Docx and JPG but the when I print PDF or PNG the water mark is not drawn. Any body know why this happened?
this my code:
I get water mark info trough RPC I check RPC the info received correctly in all formats
int EndPageHook::hookFunction(HDC hdc)
{
//Intialize GdiplusStartupInput and Graphics
Gdiplus::GdiplusStartupInput gdiplusStartupInput;
Gdiplus::GdiplusStartup(&m_gdiplusToken, &gdiplusStartupInput, NULL);
Graphics graphic_Obj(hdc);
//Get Watermark Information Throught RPC
WatermarkParameters = WaterMarkRPCClient::GetWaterMarkInfo(status, printInfo);
//Get Watermark Information and set in local variables
string s = std::to_string(WatermarkParameters.transparency);
s = std::to_string(WatermarkParameters.positions);
s = std::to_string(WatermarkParameters.font);
//Concatenation Text + User + Ip + Date
wcsncat_s(finalsenetce, WatermarkParameters._text, 512);
if (WatermarkParameters.Has_UserName)
{
wcsncat_s(finalsenetce, WatermarkParameters._username, 256);
}
if (WatermarkParameters.Has_Client)
{
wcsncat_s(finalsenetce, WatermarkParameters._client, 256);
}
if (WatermarkParameters.Has_Date)
{
wcsncat_s(finalsenetce, WatermarkParameters._date, 256);
}
{
//Set watermark position
StringAlignment WMLocation{};
StringFormat stringFormat;
switch (WatermarkParameters.positions)
{
case 1:
stringFormat.SetAlignment(StringAlignment::StringAlignmentNear);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentNear);
break;
case 2:
stringFormat.SetAlignment(StringAlignment::StringAlignmentCenter);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentCenter);
break;
case 3:
stringFormat.SetAlignment(StringAlignment::StringAlignmentFar);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentFar);
break;
default:
stringFormat.SetAlignment(StringAlignment::StringAlignmentCenter);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentCenter);
break;
}
// Claculate Page Size
double WidthsPixels = GetDeviceCaps(hdc, VERTRES);
double HeightsPixels = GetDeviceCaps(hdc, HORZRES);
double WidthsPixelsPerInch = GetDeviceCaps(hdc, LOGPIXELSX);
double HeightsPixelsPeInch = GetDeviceCaps(hdc, LOGPIXELSY);
////----------------------------------------------------------------------------------------------------------------
Gdiplus::FontFamily nameFontFamily(L"Arial");
Gdiplus::Font font(&nameFontFamily, WatermarkParameters.font, Gdiplus::FontStyleBold, Gdiplus::UnitPoint);
Gdiplus::RectF rectF(0, 0, 20, 20);
Gdiplus::SolidBrush solidBrush(Gdiplus::Color(WatermarkParameters.transparency, 250, 0, 250));
rectF.Width = (HeightsPixels / HeightsPixelsPeInch)* Screendpi;
rectF.Height = (WidthsPixels / WidthsPixelsPerInch)* Screendpi;
graphic_Obj.DrawString(finalsenetce, -1, &font, rectF, &stringFormat, &solidBrush);
}
GdiplusShutdown(m_gdiplusToken);
return getOriginalFunction()(hdc);```
}
I finally find the solution...
First I must return 1; instead of return getOriginalFunction()(hdc);.
Second I must add Scope { before Graphics graphic_Obj(hdc); and close it
after GdiplusShutdown(m_gdiplusToken); here is the correct code
int EndPageHook::hookFunction(HDC hdc)
{
//Intialize GdiplusStartupInput and Graphics
Gdiplus::GdiplusStartupInput gdiplusStartupInput;
Gdiplus::GdiplusStartup(&m_gdiplusToken, &gdiplusStartupInput, NULL);
{
Graphics graphic_Obj(hdc);
//Get Watermark Information Throught RPC
WatermarkParameters = WaterMarkRPCClient::GetWaterMarkInfo(status, printInfo);
//Get Watermark Information and set in local variables
string s = std::to_string(WatermarkParameters.transparency);
s = std::to_string(WatermarkParameters.positions);
s = std::to_string(WatermarkParameters.font);
//Concatenation Text + User + Ip + Date
wcsncat_s(finalsenetce, WatermarkParameters._text, 512);
if (WatermarkParameters.Has_UserName)
{
wcsncat_s(finalsenetce, WatermarkParameters._username, 256);
}
if (WatermarkParameters.Has_Client)
{
wcsncat_s(finalsenetce, WatermarkParameters._client, 256);
}
if (WatermarkParameters.Has_Date)
{
wcsncat_s(finalsenetce, WatermarkParameters._date, 256);
}
//Set watermark position
StringAlignment WMLocation{};
StringFormat stringFormat;
switch (WatermarkParameters.positions)
{
case 1:
stringFormat.SetAlignment(StringAlignment::StringAlignmentNear);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentNear);
break;
case 2:
stringFormat.SetAlignment(StringAlignment::StringAlignmentCenter);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentCenter);
break;
case 3:
stringFormat.SetAlignment(StringAlignment::StringAlignmentFar);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentFar);
break;
default:
stringFormat.SetAlignment(StringAlignment::StringAlignmentCenter);
stringFormat.SetLineAlignment(StringAlignment::StringAlignmentCenter);
break;
}
// Claculate Page Size
double WidthsPixels = GetDeviceCaps(hdc, VERTRES); // Get Device WIDTH
double HeightsPixels = GetDeviceCaps(hdc, HORZRES);//Get Device HEIGHT
double WidthsPixelsPerInch = GetDeviceCaps(hdc, LOGPIXELSX);// Get Document Pixel Per Inch in WIDTH of Screen
double HeightsPixelsPeInch = GetDeviceCaps(hdc, LOGPIXELSY);// Get Document Pixel Per Inch in HEIGHT of Screen
////----------------------------------------------------------------------------------------------------------------
Gdiplus::FontFamily nameFontFamily(L"Arial");
Gdiplus::Font font(&nameFontFamily, WatermarkParameters.font, Gdiplus::FontStyleBold, Gdiplus::UnitPoint);
Gdiplus::RectF rectF(0, 0, 200, 200);
Gdiplus::SolidBrush solidBrush(Gdiplus::Color(WatermarkParameters.transparency, 250, 0, 250));
rectF.Width = (HeightsPixels / HeightsPixelsPeInch)* Screendpi;
rectF.Height = (WidthsPixels / WidthsPixelsPerInch)* Screendpi;
graphic_Obj.DrawString(finalsenetce, -1, &font, rectF, &stringFormat, &solidBrush);
}
GdiplusShutdown(m_gdiplusToken);
return 1;
}