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2024-06-29 11:52:32 +06:00
// vim: set tabstop=4 shiftwidth=4 expandtab:
/*
Gwenview: an image viewer
Copyright 2008 Aurélien Gâteau <agateau@kde.org>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Cambridge, MA 02110-1301, USA.
*/
// Self
#include "preloader.h"
// Qt
// KF
// Local
#include "gwenview_app_debug.h"
#include <lib/document/documentfactory.h>
namespace Gwenview
{
#undef ENABLE_LOG
#undef LOG
// #define ENABLE_LOG
#ifdef ENABLE_LOG
#define LOG(x) qCDebug(GWENVIEW_APP_LOG) << x
#else
#define LOG(x) ;
#endif
struct PreloaderPrivate {
Preloader *q = nullptr;
Document::Ptr mDocument;
QSize mSize;
void forgetDocument()
{
// Forget about the document. Keeping a reference to it would prevent it
// from being garbage collected.
QObject::disconnect(mDocument.data(), nullptr, q, nullptr);
mDocument = nullptr;
}
};
Preloader::Preloader(QObject *parent)
: QObject(parent)
, d(new PreloaderPrivate)
{
d->q = this;
}
Preloader::~Preloader()
{
delete d;
}
void Preloader::preload(const QUrl &url, const QSize &size)
{
LOG("url=" << url);
if (d->mDocument) {
disconnect(d->mDocument.data(), nullptr, this, nullptr);
}
d->mDocument = DocumentFactory::instance()->load(url);
d->mSize = size;
connect(d->mDocument.data(), &Document::metaInfoUpdated, this, &Preloader::doPreload);
if (d->mDocument->size().isValid()) {
LOG("size is already available");
doPreload();
}
}
void Preloader::doPreload()
{
if (!d->mDocument) {
return;
}
if (d->mDocument->loadingState() == Document::LoadingFailed) {
LOG("loading failed");
d->forgetDocument();
return;
}
if (!d->mDocument->size().isValid()) {
LOG("size not available yet");
return;
}
qreal zoom = qMin(d->mSize.width() / qreal(d->mDocument->width()), d->mSize.height() / qreal(d->mDocument->height()));
if (zoom < Document::maxDownSampledZoom()) {
LOG("preloading down sampled, zoom=" << zoom);
d->mDocument->prepareDownSampledImageForZoom(zoom);
} else {
LOG("preloading full image");
d->mDocument->startLoadingFullImage();
}
d->forgetDocument();
}
} // namespace
#include "moc_preloader.cpp"