git.iko.soy/unity8
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unity8/plugins/ImageCache/ImageCache.cpp
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1/*
2 * Copyright (C) 2016 Canonical, Ltd.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 3.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program. If not, see <http://www.gnu.org/licenses/>.
15 */
17#include <QDateTime>
18#include <QDebug>
19#include <QDir>
20#include <QImageReader>
21#include <QUrlQuery>
23#include "ImageCache.h"
25ImageCache::ImageCache()
26 : QQuickImageProvider(QQmlImageProviderBase::Image,
27 QQmlImageProviderBase::ForceAsynchronousImageLoading)
31QString ImageCache::imageCacheRoot()
33 QString xdgCache(qgetenv("XDG_CACHE_HOME"));
34 if (xdgCache.isEmpty()) {
35 xdgCache = QDir::homePath() + QStringLiteral("/.cache");
36 }
38 return QDir::cleanPath(xdgCache) + QStringLiteral("/unity8/imagecache");
41QFileInfo ImageCache::imagePath(const QUrl &image)
43 QUrlQuery query(image);
45 auto name = query.queryItemValue(QStringLiteral("name"));
46 if (name.isEmpty()) {
47 name = QStringLiteral("/paths") + image.toLocalFile();
48 } else {
49 name = QStringLiteral("/names/") + name;
50 }
52 return QFileInfo(imageCacheRoot() + name);
55bool ImageCache::needsUpdate(const QUrl &image, const QFileInfo &cachePath, const QSize &requestedSize, QSize &finalSize)
57 if (!cachePath.exists())
58 return true;
60 QFileInfo imageInfo(image.toLocalFile());
61 if (imageInfo.lastModified() > cachePath.lastModified())
62 return true;
64 QSize cacheSize(QImageReader(cachePath.filePath()).size());
65 QSize imageSize(QImageReader(imageInfo.filePath()).size());
66 finalSize = calculateSize(imageSize, requestedSize);
67 if (finalSize.isValid() && cacheSize != finalSize)
68 return true;
70 return false;
73QSize ImageCache::calculateSize(const QSize &imageSize, const QSize &requestedSize)
75 QSize finalSize(requestedSize);
77 if (finalSize.width() == 0) {
78 finalSize.setWidth(imageSize.width() * (((double)finalSize.height()) / imageSize.height()));
79 } else if (finalSize.height() == 0) {
80 finalSize.setHeight(imageSize.height() * (((double)finalSize.width()) / imageSize.width()));
81 }
83 return finalSize;
86QImage ImageCache::loadAndCacheImage(const QUrl &image, const QFileInfo &cachePath, const QSize &finalSize)
88 QImageReader reader(image.toLocalFile());
89 reader.setQuality(100);
90 reader.setScaledSize(finalSize);
91 auto format = reader.format(); // can't get this after reading
93 QImage loadedImage(reader.read());
94 if (loadedImage.isNull()) {
95 qWarning() << "ImageCache could not read image" << image.path();
96 return QImage();
97 }
99 cachePath.dir().mkpath(QStringLiteral("."));
100 loadedImage.save(cachePath.filePath(), format, 100);
102 return loadedImage;
105QImage ImageCache::requestImage(const QString &id, QSize *size, const QSize &requestedSize)
107 QUrl image(id);
108 QSize imageSize(QImageReader(image.toLocalFile()).size());
109 QImage result;
111 // Early exit here, with no sourceSize, scaled-up sourceSize, or bad source image
112 if ((requestedSize.width() <= 0 && requestedSize.height() <= 0) ||
113 imageSize.isEmpty() ||
114 requestedSize.height() >= imageSize.height() ||
115 requestedSize.width() >= imageSize.width()) {
116 // We're only interested in scaling down, not up.
117 result = QImage(image.toLocalFile());
118 *size = result.size();
119 return result;
120 }
122 auto cachePath = imagePath(image);
123 QSize finalSize;
125 if (needsUpdate(image, cachePath, requestedSize, finalSize)) {
126 if (finalSize.isEmpty()) {
127 finalSize = calculateSize(imageSize, requestedSize);
128 }
129 result = loadAndCacheImage(image, cachePath, finalSize);
130 } else {
131 result = QImage(cachePath.filePath());
132 }
134 *size = result.size();
135 return result;