1 files changed, 258 insertions, 0 deletions
diff --git a/src/libs/threadimageio/previewtask.cpp b/src/libs/threadimageio/previewtask.cpp
new file mode 100644
index 00000000..5f277481
--- /dev/null
+++ b/src/libs/threadimageio/previewtask.cpp
@@ -0,0 +1,258 @@
+/* ============================================================
+ *
+ * This file is a part of digiKam project
+ * http://www.digikam.org
+ *
+ * Date        : 2006-12-26
+ * Description : Multithreaded loader for previews
+ *
+ * Copyright (C) 2006-2007 by Marcel Wiesweg <marcel.wiesweg@gmx.de>
+ * Copyright (C) 2006-2008 by Gilles Caulier <caulier dot gilles at gmail dot com>
+ *
+ * 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, 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.
+ *
+ * ============================================================ */
+
+// C++ includes.
+
+#include <cmath>
+
+// TQt includes.
+
+#include <tqapplication.h>
+#include <tqimage.h>
+#include <tqvariant.h>
+#include <tqwmatrix.h>
+
+// LibKDcraw includes.
+
+#include <libkdcraw/kdcraw.h>
+
+// Local includes.
+
+#include "ddebug.h"
+#include "dmetadata.h"
+#include "jpegutils.h"
+#include "previewloadthread.h"
+#include "previewtask.h"
+
+namespace Digikam
+{
+
+void PreviewLoadingTask::execute()
+{
+    if (m_loadingTaskStatus == LoadingTaskStatusStopping)
+        return;
+
+    LoadingCache *cache = LoadingCache::cache();
+    {
+        LoadingCache::CacheLock lock(cache);
+
+        // find possible cached images
+        DImg *cachedImg = 0;
+        TQStringList lookupKeys = m_loadingDescription.lookupCacheKeys();
+        // lookupCacheKeys returns "best first". Prepend the cache key to make the list "fastest first":
+        // Scaling a full version takes longer!
+        lookupKeys.push_front(m_loadingDescription.cacheKey());
+        for ( TQStringList::Iterator it = lookupKeys.begin(); it != lookupKeys.end(); ++it ) {
+            if ( (cachedImg = cache->retrieveImage(*it)) )
+                break;
+        }
+
+        if (cachedImg)
+        {
+            // image is found in image cache, loading is successful
+
+            DImg img(*cachedImg);
+
+            // rotate if needed - images are unrotated in the cache,
+            // except for RAW images, which are already rotated by dcraw.
+            if (m_loadingDescription.previewParameters.exifRotate)
+            {
+                img = img.copy();
+                LoadSaveThread::exifRotate(img, m_loadingDescription.filePath);
+            }
+
+            TQApplication::postEvent(m_thread, new LoadedEvent(m_loadingDescription.filePath, img));
+            return;
+        }
+        else
+        {
+            // find possible running loading process
+            m_usedProcess = 0;
+            for ( TQStringList::Iterator it = lookupKeys.begin(); it != lookupKeys.end(); ++it ) {
+                if ( (m_usedProcess = cache->retrieveLoadingProcess(*it)) )
+                {
+                    break;
+                }
+            }
+            // do not wait on other loading processes?
+            //m_usedProcess = cache->retrieveLoadingProcess(m_loadingDescription.cacheKey());
+
+            if (m_usedProcess)
+            {
+                // Other process is right now loading this image.
+                // Add this task to the list of listeners and
+                // attach this thread to the other thread, wait until loading
+                // has finished.
+                m_usedProcess->addListener(this);
+                // break loop when either the loading has completed, or this task is being stopped
+                while ( !m_usedProcess->completed() && m_loadingTaskStatus != LoadingTaskStatusStopping )
+                    lock.timedWait();
+                // remove listener from process
+                m_usedProcess->removeListener(this);
+                // wake up the process which is waiting until all listeners have removed themselves
+                lock.wakeAll();
+                // set to 0, as checked in setStatus
+                m_usedProcess = 0;
+                return;
+            }
+            else
+            {
+                // Neither in cache, nor currently loading in different thread.
+                // Load it here and now, add this LoadingProcess to cache list.
+                cache->addLoadingProcess(this);
+                // Add this to the list of listeners
+                addListener(this);
+                // for use in setStatus
+                m_usedProcess = this;
+                // Notify other processes that we are now loading this image.
+                // They might be interested - see notifyNewLoadingProcess below
+                cache->notifyNewLoadingProcess(this, m_loadingDescription);
+            }
+        }
+    }
+
+    // load image
+    int  size = m_loadingDescription.previewParameters.size;
+
+    DImg img;
+    TQImage qimage;
+    bool fromEmbeddedPreview = false;
+
+    // -- Get the image preview --------------------------------
+
+    // First the TQImage-dependent loading methods
+    // Trying to load with dcraw: RAW files.
+    if (KDcrawIface::KDcraw::loadEmbeddedPreview(qimage, m_loadingDescription.filePath))
+        fromEmbeddedPreview = true;
+
+    if (qimage.isNull())
+    {
+        //TODO: Use DImg based loader instead?
+        KDcrawIface::KDcraw::loadHalfPreview(qimage, m_loadingDescription.filePath);
+    }
+
+    // Try to extract Exif/Iptc preview.
+    if (qimage.isNull())
+    {
+        loadImagePreview(qimage, m_loadingDescription.filePath);
+    }
+
+    if (!qimage.isNull())
+    {
+        // convert from TQImage
+        img = DImg(qimage);
+        // mark as embedded preview (for exif rotation)
+        if (fromEmbeddedPreview)
+            img.setAttribute("fromRawEmbeddedPreview", true);
+        // free memory
+        qimage = TQImage();
+    }
+
+    // DImg-dependent loading methods
+    if (img.isNull())
+    {
+        // Set a hint to try to load a JPEG with the fast scale-before-decoding method
+        img.setAttribute("jpegScaledLoadingSize", size);
+        img.load(m_loadingDescription.filePath, this, m_loadingDescription.rawDecodingSettings);
+    }
+
+    if (img.isNull())
+    {
+        DWarning() << "Cannot extract preview for " << m_loadingDescription.filePath << endl;
+    }
+
+    img.convertToEightBit();
+
+    // Reduce size of image:
+    // - only scale down if size is considerably larger
+    // - only scale down, do not scale up
+    TQSize scaledSize = img.size();
+    if (needToScale(scaledSize, size))
+    {
+        scaledSize.scale(size, size, TQSize::ScaleMin);
+        img = img.smoothScale(scaledSize.width(), scaledSize.height());
+    }
+
+    // Scale if hinted, Store previews rotated in the cache (?)
+    if (m_loadingDescription.previewParameters.exifRotate)
+        LoadSaveThread::exifRotate(img, m_loadingDescription.filePath);
+
+    {
+        LoadingCache::CacheLock lock(cache);
+        // put (valid) image into cache of loaded images
+        if (!img.isNull())
+            cache->putImage(m_loadingDescription.cacheKey(), new DImg(img), m_loadingDescription.filePath);
+        // remove this from the list of loading processes in cache
+        cache->removeLoadingProcess(this);
+    }
+
+    // following the golden rule to avoid deadlocks, do this when CacheLock is not held
+    m_thread->taskHasFinished();
+
+    {
+        LoadingCache::CacheLock lock(cache);
+        // indicate that loading has finished so that listeners can stop waiting
+        m_completed = true;
+
+        // dispatch image to all listeners, including this
+        for (LoadingProcessListener *l = m_listeners.first(); l; l = m_listeners.next())
+        {
+            TQApplication::postEvent(l->eventReceiver(), new LoadedEvent(m_loadingDescription, img));
+        }
+
+        // remove myself from list of listeners
+        removeListener(this);
+        // wake all listeners waiting on cache condVar, so that they remove themselves
+        lock.wakeAll();
+        // wait until all listeners have removed themselves
+        while (m_listeners.count() != 0)
+            lock.timedWait();
+        // set to 0, as checked in setStatus
+        m_usedProcess = 0;
+    }
+}
+
+bool PreviewLoadingTask::needToScale(const TQSize &imageSize, int previewSize)
+{
+    int maxSize = imageSize.width() > imageSize.height() ? imageSize.width() : imageSize.height();
+    int acceptableUpperSize = lround(1.25 * (double)previewSize);
+    return  maxSize >= acceptableUpperSize;
+}
+
+// -- Exif/IPTC preview extraction using Exiv2 --------------------------------------------------------
+
+bool PreviewLoadingTask::loadImagePreview(TQImage& image, const TQString& path)
+{
+    DMetadata metadata(path);
+    if (metadata.getImagePreview(image))
+    {
+        DDebug() << "Use Exif/Iptc preview extraction. Size of image: "
+                  << image.width() << "x" << image.height() << endl;
+        return true;
+    }
+
+    return false;
+}
+
+} // namespace Digikam