metadata: make sure to include XResolution and YResolution when writing TIFFs

This is mandatory (according to http://dpfmanager.org), and in fact needed for
Photoshop compatibility

(cherry picked from commit 5d281810cc7a7f7dc563dde030cf90c78dbf55d0)

rtengine/imageio.cc

@@ -1098,6 +1098,7 @@ int ImageIO::saveJPEG (const Glib::ustring &fname, int quality, int subSamp) con
     return IMIO_SUCCESS;
 }
 
+
 int ImageIO::saveTIFF (const Glib::ustring &fname, int bps, bool isFloat, bool uncompressed) const
 {
     if (getWidth() < 1 || getHeight() < 1) {
@@ -1168,6 +1169,31 @@ int ImageIO::saveTIFF (const Glib::ustring &fname, int bps, bool isFloat, bool u
         }
     }();*/
 
+    // somehow Exiv2 (tested with 0.27.3) doesn't seem to be able to update
+    // XResolution and YResolution, so we do it ourselves here....
+    constexpr float default_resolution = 300.f;
+    float x_res = default_resolution;
+    float y_res = default_resolution;
+    int res_unit = RESUNIT_INCH;
+    if (!metadataInfo.filename().empty()) {
+        auto exif = metadataInfo.getOutputExifData();
+        auto it = exif.findKey(Exiv2::ExifKey("Exif.Image.XResolution"));
+        if (it != exif.end()) {
+            x_res = it->toFloat();
+        }
+        it = exif.findKey(Exiv2::ExifKey("Exif.Image.YResolution"));
+        if (it != exif.end()) {
+            y_res = it->toFloat();
+        }
+        it = exif.findKey(Exiv2::ExifKey("Exif.Image.ResolutionUnit"));
+        if (it != exif.end()) {
+            res_unit = it->toLong();
+        }
+    }
+    TIFFSetField(out, TIFFTAG_XRESOLUTION, x_res);
+    TIFFSetField(out, TIFFTAG_YRESOLUTION, y_res);
+    TIFFSetField(out, TIFFTAG_RESOLUTIONUNIT, res_unit);
+
     if (!uncompressed) {
         TIFFSetField (out, TIFFTAG_PREDICTOR, (bps == 16 || bps == 32) && isFloat ? PREDICTOR_FLOATINGPOINT : PREDICTOR_HORIZONTAL);
     }

rtengine/metadata.cc

@@ -390,7 +390,12 @@ void Exiv2Metadata::import_exif_pairs(Exiv2::ExifData &out) const
     for (auto &p : *exif_) {
         try {
             out[p.first] = p.second;
-        } catch (std::exception &exc) {}
+        } catch (std::exception &exc) {
+            if (settings->verbose) {
+                std::cout << "Error setting " << p.first << " to " << p.second
+                          << ": " << exc.what() << std::endl;
+            }
+        }
     }
 }
 
@@ -408,7 +413,12 @@ void Exiv2Metadata::import_iptc_pairs(Exiv2::IptcData &out) const
                     out.add(d);
                 }
             }
-        } catch (std::exception &exc) {}
+        } catch (std::exception &exc) {
+            if (settings->verbose) {
+                std::cout << "Error setting " << p.first
+                          << ": " << exc.what() << std::endl;
+            }
+        }
     }
 }
 
@@ -515,4 +525,30 @@ void Exiv2Metadata::cleanup()
     Exiv2::XmpParser::terminate();
 }
 
+
+Exiv2::ExifData Exiv2Metadata::getOutputExifData() const
+{
+    Exiv2::ExifData exif = exifData();
+    try {
+        auto xmp = getXmpSidecar(src_);
+        Exiv2::moveXmpToExif(xmp, exif);
+    } catch (std::exception &exc) {
+        if (settings->verbose) {
+            std::cerr << "Error loading metadata from XMP sidecar: "
+                      << exc.what() << std::endl;
+        }
+    }
+    remove_unwanted(exif);
+    import_exif_pairs(exif);
+    for (auto it = exif.begin(); it != exif.end(); ) {
+        if (it->count() > 0) {
+            ++it;
+        } else {
+            it = exif.erase(it);
+        }
+    }
+    return exif;
+}
+
+
 } // namespace rtengine

rtengine/metadata.h

@@ -60,6 +60,8 @@ public:
 
     void getDimensions(int &w, int &h) const;
 
+    Exiv2::ExifData getOutputExifData() const;
+
     static Glib::ustring xmpSidecarPath(const Glib::ustring& path);
     static Exiv2::XmpData getXmpSidecar(const Glib::ustring& path);