Allow EXIF metadata to be set/update #650

src/common.cc

@@ -36,6 +36,9 @@ namespace sharp {
   std::string AttrAsStr(Napi::Object obj, std::string attr) {
     return obj.Get(attr).As<Napi::String>();
   }
+  std::string AttrAsStr(Napi::Object obj, unsigned int const attr) {
+    return obj.Get(attr).As<Napi::String>();
+  }
   uint32_t AttrAsUint32(Napi::Object obj, std::string attr) {
     return obj.Get(attr).As<Napi::Number>().Uint32Value();
   }

src/common.h

@@ -95,6 +95,7 @@ namespace sharp {
   // Convenience methods to access the attributes of a Napi::Object
   bool HasAttr(Napi::Object obj, std::string attr);
   std::string AttrAsStr(Napi::Object obj, std::string attr);
+  std::string AttrAsStr(Napi::Object obj, unsigned int const attr);
   uint32_t AttrAsUint32(Napi::Object obj, std::string attr);
   int32_t AttrAsInt32(Napi::Object obj, std::string attr);
   int32_t AttrAsInt32(Napi::Object obj, unsigned int const attr);

src/pipeline.cc

@@ -717,11 +717,17 @@ class PipelineWorker : public Napi::AsyncWorker {
             ->set("input_profile", "srgb")
             ->set("intent", VIPS_INTENT_PERCEPTUAL));
       }
-
       // Override EXIF Orientation tag
       if (baton->withMetadata && baton->withMetadataOrientation != -1) {
         image = sharp::SetExifOrientation(image, baton->withMetadataOrientation);
       }
+      // Metadata key/value pairs, e.g. EXIF
+      if (!baton->withMetadataStrs.empty()) {
+        image = image.copy();
+        for (const auto& s : baton->withMetadataStrs) {
+          image.set(s.first.data(), s.second.data());
+        }
+      }
 
       // Number of channels used in output image
       baton->channels = image.bands();
@@ -1379,6 +1385,12 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   baton->withMetadata = sharp::AttrAsBool(options, "withMetadata");
   baton->withMetadataOrientation = sharp::AttrAsUint32(options, "withMetadataOrientation");
   baton->withMetadataIcc = sharp::AttrAsStr(options, "withMetadataIcc");
+  Napi::Object mdStrs = options.Get("withMetadataStrs").As<Napi::Object>();
+  Napi::Array mdStrKeys = mdStrs.GetPropertyNames();
+  for (unsigned int i = 0; i < mdStrKeys.Length(); i++) {
+    std::string k = sharp::AttrAsStr(mdStrKeys, i);
+    baton->withMetadataStrs.insert(std::make_pair(k, sharp::AttrAsStr(mdStrs, k)));
+  }
   // Format-specific
   baton->jpegQuality = sharp::AttrAsUint32(options, "jpegQuality");
   baton->jpegProgressive = sharp::AttrAsBool(options, "jpegProgressive");

src/pipeline.h

@@ -18,6 +18,7 @@
 #include <memory>
 #include <string>
 #include <vector>
+#include <unordered_map>
 
 #include <napi.h>
 #include <vips/vips8>
@@ -168,6 +169,7 @@ struct PipelineBaton {
   bool withMetadata;
   int withMetadataOrientation;
   std::string withMetadataIcc;
+  std::unordered_map<std::string, std::string> withMetadataStrs;
   std::unique_ptr<double[]> convKernel;
   int convKernelWidth;
   int convKernelHeight;