gecko-dev/dom/base/AutoPrintEventDispatcher.h

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4.3 KiB
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#ifndef mozilla_dom_AutoPrintEventDispatcher_h
#define mozilla_dom_AutoPrintEventDispatcher_h
#include "mozilla/dom/Document.h"
#include "mozilla/dom/DocumentInlines.h"
#include "nsContentUtils.h"
#include "nsIPrintSettings.h"
namespace mozilla::dom {
class AutoPrintEventDispatcher {
// NOTE(emilio): For fission iframes, we dispatch this event in
// RecvCloneDocumentTreeIntoSelf.
static void CollectInProcessSubdocuments(
Document& aDoc, nsTArray<std::pair<nsCOMPtr<Document>, bool>>& aDocs) {
auto recurse = [&aDocs](Document& aSubDoc) {
aDocs.AppendElement(std::make_pair(&aSubDoc, false));
CollectInProcessSubdocuments(aSubDoc, aDocs);
return CallState::Continue;
};
aDoc.EnumerateSubDocuments(recurse);
}
MOZ_CAN_RUN_SCRIPT void DispatchEvent(bool aBefore) {
for (auto& [doc, isTop] : mDocuments) {
nsContentUtils::DispatchTrustedEvent(
doc, doc->GetWindow(), aBefore ? u"beforeprint"_ns : u"afterprint"_ns,
CanBubble::eNo, Cancelable::eNo, nullptr);
if (RefPtr<nsPresContext> presContext = doc->GetPresContext()) {
presContext->EmulateMedium(aBefore ? nsGkAtoms::print : nullptr);
bool needResizeEvent = false;
if (isTop) {
// NOTE(emilio): Having this code here means that we only fire the
// resize on the initial document clone, not on any further print
// settings changes. This is an intentional trade-off.
//
// On a continuously changing document, we don't want to keep
// re-cloning every time the user changes the print settings, as it
// changes what you're printing.
if (aBefore) {
mVisibleAreaToRestore = presContext->GetVisibleArea();
presContext->SetVisibleArea(
nsRect(mVisibleAreaToRestore.TopLeft(), mPageSize));
needResizeEvent = mVisibleAreaToRestore.Size() != mPageSize;
} else {
if (presContext->GetVisibleArea().Size() == mPageSize) {
presContext->SetVisibleArea(mVisibleAreaToRestore);
needResizeEvent = mVisibleAreaToRestore.Size() != mPageSize;
} else {
// This shouldn't happen, but can if used by privileged script,
// like in test_printpreview.xhtml. It's ok to do nothing here
// tho, we just need to make sure that the mPageSize viewport size
// doesn't persist.
NS_WARNING(
"Something changed our viewport size between firing "
"before/afterprint?");
}
}
}
// Ensure media query listeners fire.
doc->FlushPendingNotifications(FlushType::Style);
if (needResizeEvent) {
if (RefPtr ps = presContext->GetPresShell()) {
ps->FireResizeEventSync();
}
}
}
}
}
static nsSize ComputePrintPageSize(nsIPrintSettings* aPrintSettings) {
double pageWidth = 0;
double pageHeight = 0;
aPrintSettings->GetEffectivePageSize(&pageWidth, &pageHeight);
return nsSize(nsPresContext::CSSTwipsToAppUnits(NSToIntFloor(pageWidth)),
nsPresContext::CSSTwipsToAppUnits(NSToIntFloor(pageHeight)));
}
public:
MOZ_CAN_RUN_SCRIPT AutoPrintEventDispatcher(Document& aDoc,
nsIPrintSettings* aPrintSettings,
bool aIsTop)
: mPageSize(ComputePrintPageSize(aPrintSettings)) {
if (!aDoc.IsStaticDocument()) {
mDocuments.AppendElement(std::make_pair(&aDoc, aIsTop));
CollectInProcessSubdocuments(aDoc, mDocuments);
}
DispatchEvent(true);
}
MOZ_CAN_RUN_SCRIPT ~AutoPrintEventDispatcher() { DispatchEvent(false); }
// The bool represents whether this is the top-level paginated document.
AutoTArray<std::pair<nsCOMPtr<Document>, bool>, 8> mDocuments;
const nsSize mPageSize;
nsRect mVisibleAreaToRestore;
};
} // namespace mozilla::dom
#endif