imagedata: report if file is DNG

rtengine/imagedata.cc

@@ -565,6 +565,8 @@ FramesData::FramesData(const Glib::ustring &fname, time_t ts) :
 
         meta.getDimensions(w_, h_);
 
+        isDNG = find_exif_tag("Exif.Image.DNGVersion");
+
         // -----------------------
         // Special file type detection (HDR, PixelShift)
         // ------------------------
@@ -778,6 +780,11 @@ bool FramesData::getHDR() const
     return isHDR;
 }
 
+bool FramesData::getDNG() const
+{
+    return isDNG;
+}
+
 std::string FramesData::getImageType() const
 {
     return isPixelShift ? "PS" : isHDR ? "HDR" : "STD";

rtengine/imagedata.h

@@ -59,6 +59,7 @@ private:
     time_t modTimeStamp;
     bool isPixelShift;
     bool isHDR;
+    bool isDNG;
     int w_;
     int h_;
 
@@ -69,6 +70,7 @@ public:
     unsigned int getFrameCount() const override;
     bool getPixelShift() const override;
     bool getHDR() const override;
+    bool getDNG() const override;
     std::string getImageType() const override;
     IIOSampleFormat getSampleFormat() const override;
     bool hasExif() const override;

rtengine/rtengine.h

@@ -130,6 +130,8 @@ public:
     virtual bool getPixelShift () const = 0;
     /** @return false: not an HDR file ; true: single or multi-frame HDR file (e.g. Pentax HDR raw file or 32 bit float DNG file or Log compressed) */
     virtual bool getHDR() const = 0;
+    /** @return true if the file is a DNG file */
+    virtual bool getDNG() const = 0;
 
     /** @return false: not an HDR file ; true: single or multi-frame HDR file (e.g. Pentax HDR raw file or 32 bit float DNG file or Log compressed) */
     virtual std::string getImageType() const = 0;