gecko-dev/gfx/thebes/PrintTargetPDF.cpp

86 строки
2.6 KiB
C++

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "PrintTargetPDF.h"
#include "cairo.h"
#include "cairo-pdf.h"
namespace mozilla {
namespace gfx {
static cairo_status_t
write_func(void *closure, const unsigned char *data, unsigned int length)
{
nsCOMPtr<nsIOutputStream> out = reinterpret_cast<nsIOutputStream*>(closure);
do {
uint32_t wrote = 0;
if (NS_FAILED(out->Write((const char*)data, length, &wrote))) {
break;
}
data += wrote; length -= wrote;
} while (length > 0);
NS_ASSERTION(length == 0, "not everything was written to the file");
return CAIRO_STATUS_SUCCESS;
}
PrintTargetPDF::PrintTargetPDF(cairo_surface_t* aCairoSurface,
const IntSize& aSize,
nsIOutputStream *aStream)
: PrintTarget(aCairoSurface, aSize)
, mStream(aStream)
{
}
PrintTargetPDF::~PrintTargetPDF()
{
// We get called first, then PrintTarget's dtor. That means that mStream
// is destroyed before PrintTarget's dtor calls cairo_surface_destroy. This
// can be a problem if Finish() hasn't been called on us, since
// cairo_surface_destroy will then call cairo_surface_finish and that will
// end up invoking write_func above with the by now dangling pointer mStream
// that mCairoSurface stored. To prevent that from happening we must call
// Flush here before mStream is deleted.
Finish();
}
/* static */ already_AddRefed<PrintTargetPDF>
PrintTargetPDF::CreateOrNull(nsIOutputStream *aStream,
const IntSize& aSizeInPoints)
{
cairo_surface_t* surface =
cairo_pdf_surface_create_for_stream(write_func, (void*)aStream,
aSizeInPoints.width,
aSizeInPoints.height);
if (cairo_surface_status(surface)) {
return nullptr;
}
// The new object takes ownership of our surface reference.
RefPtr<PrintTargetPDF> target = new PrintTargetPDF(surface, aSizeInPoints,
aStream);
return target.forget();
}
nsresult
PrintTargetPDF::EndPage()
{
cairo_surface_show_page(mCairoSurface);
return PrintTarget::EndPage();
}
void
PrintTargetPDF::Finish()
{
if (mIsFinished) {
return; // We don't want to call Close() on mStream more than once
}
PrintTarget::Finish();
mStream->Close();
}
} // namespace gfx
} // namespace mozilla