Preview (thumbnail) extraction.

Read-only at the moment.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/exiv2wrapper.cpp b/src/exiv2wrapper.cpp
index 914657a..3dbd8b2 100644
--- a/src/exiv2wrapper.cpp
+++ b/src/exiv2wrapper.cpp
@@ -398,6 +398,24 @@ void Image::deleteXmpTag(std::string key)
         throw Exiv2::Error(KEY_NOT_FOUND, key);
 }
 
+boost::python::list Image::previews()
+{
+    CHECK_METADATA_READ
+
+    boost::python::list previews;
+    Exiv2::PreviewManager pm(*_image);
+    Exiv2::PreviewPropertiesList props = pm.getPreviewProperties();
+    for (Exiv2::PreviewPropertiesList::const_iterator i = props.begin();
+         i != props.end();
+         ++i)
+    {
+        previews.append(Preview(pm.getPreviewImage(*i)));
+    }
+
+    return previews;
+}
+
+
 /*
 boost::python::tuple Image::getThumbnailData()
 {
@@ -774,6 +792,29 @@ const boost::python::dict XmpTag::getLangAltValue()
 }
 
 
+Preview::Preview(const Exiv2::PreviewImage& previewImage)
+{
+    _mimeType = previewImage.mimeType();
+    _extension = previewImage.extension();
+    _size = previewImage.size();
+    _dimensions = boost::python::make_tuple(previewImage.width(),
+                                            previewImage.height());
+    // Copy the data buffer in a string. Since the data buffer can contain null
+    // characters ('\x00'), the string cannot be simply constructed like that:
+    //     _data = std::string((char*) previewImage.pData());
+    // because it would be truncated after the first occurence of a null
+    // character. Therefore, it has to be copied character by character.
+    const Exiv2::byte* pData = previewImage.pData();
+    // First allocate the memory for the whole string...
+    _data = std::string(_size, ' ');
+    // ... then fill it with the raw data.
+    for(unsigned int i = 0; i < _size; ++i)
+    {
+        _data[i] = pData[i];
+    }
+}
+
+
 // TODO: update the errors code to reflect changes from src/error.cpp in libexiv2
 void translateExiv2Error(Exiv2::Error const& error)
 {