implemented import_image function

src/gfx/generated_image.cpp

@@ -14,6 +14,7 @@
 #include <data/field/symbol.hpp>
 #include <render/symbol/filter.hpp>
 #include <gui/util.hpp> // load_resource_image
+#include <wx/wfstream.h>
 
 // ----------------------------------------------------------------------------- : GeneratedImage
 
@@ -515,3 +516,50 @@ bool ImageValueToImage::operator == (const GeneratedImage& that) const {
   return that2 && filename == that2->filename
                && age      == that2->age;
 }
+
+// ----------------------------------------------------------------------------- : ExternalImage
+
+Image ExternalImage::generate(const Options& opt) const {
+  wxFileName fname(filepath, wxPATH_UNIX);
+
+  // does the file pointed to by filepath exist?
+  if (!fname.FileExists()) {
+    String filePathString = fname.GetAbsolutePath().ToStdString();
+    throw ScriptError(format_string(_("The file '%s' was not found."),filePathString));
+  }
+
+  String fileExt = fname.GetExt();
+  wxBitmapType bitmapType;
+  if (fileExt == _("png"))
+    bitmapType = wxBITMAP_TYPE_PNG;
+  else if (fileExt == _("jpg"))
+    bitmapType = wxBITMAP_TYPE_JPEG;
+  else
+    bitmapType = wxBITMAP_TYPE_BMP;
+
+  // does the file exist in the package?
+  String fileNameNoExtension = fname.GetName();
+  if (!opt.local_package->existsIn(fileNameNoExtension)) {
+    auto outStream = opt.local_package->openOut(fileNameNoExtension);
+    wxFileInputStream inStream = wxFileInputStream(filepath.ToStdString());
+    if (!inStream.IsOk()) throw ScriptError("Failed to create file stream.");
+    outStream->Write(inStream);
+    if (!outStream->IsOk()) throw ScriptError("Failed to write image to set.");
+    outStream->Close();
+  }
+
+  // save the package with the new image
+  opt.local_package->saveAs(opt.local_package->relativeFilename(), false, false);
+
+  auto imageInputStream = opt.local_package->openIn(fileNameNoExtension);
+  Image img(*imageInputStream.get(), bitmapType);
+
+  if (!img.IsOk()) throw ScriptError("The image could not be created.");
+
+  return img;
+}
+
+bool ExternalImage::operator == (const GeneratedImage& that) const {
+  const ExternalImage* that2 = dynamic_cast<const ExternalImage*>(&that);
+  return that2 && that2->filepath == filepath;
+}