.. _program_listing_file_dx2_scan.cxx:

Program Listing for File scan.cxx
=================================

|exhale_lsh| :ref:`Return to documentation for file <file_dx2_scan.cxx>` (``dx2/scan.cxx``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   
   #include "dx2/scan.hpp"
   
   Scan::Scan(std::array<int, 2> image_range, std::array<double, 2> oscillation)
       : image_range_{image_range} {
     num_images_ = image_range_[1] - image_range_[0] + 1;
     oscillation_start_ = oscillation[0];
     oscillation_width_ = oscillation[1];
   }
   
   Scan::Scan(json scan_data) {
     // minimal required keys are image range and ["properties"]:"oscillation"
     std::vector<std::string> required_keys = {"image_range", "properties"};
     for (const auto &key : required_keys) {
       if (scan_data.find(key) == scan_data.end()) {
         throw std::invalid_argument("Key " + key +
                                     " is missing from the input scan JSON");
       }
     }
     image_range_ = scan_data["image_range"];
     num_images_ = image_range_[1] - image_range_[0] + 1;
     if (scan_data["properties"].find("oscillation") ==
         scan_data["properties"].end()) {
       throw std::invalid_argument(
           "Key oscillation is missing from the input scan['properties'] JSON");
     }
     std::vector<double> oscillation;
     json osc_array = scan_data["properties"]["oscillation"];
     // Just read the first two oscillation values as that is all that is needed
     if (osc_array.size() < 1) {
       // Unlikely to happen but check anyway for safety.
       throw std::invalid_argument(
           "scan['properties']['oscillation'] has no values in the scan JSON");
     } else if (osc_array.size() == 1) {
       // SSX scans just have a single oscillation value (the start angle, usually
       // 0). Therefore by convention the oscillation width is 0. The dials/dxtbx
       // output should probably be changed to have two oscillation values both of
       // zero as a consistent model.
       oscillation.push_back(osc_array[0]);
       oscillation_start_ = oscillation[0];
       oscillation_width_ = 0;
     } else {
       // Typical rotation scan.
       for (json::iterator it = osc_array.begin(); it != osc_array.begin() + 2;
            ++it) {
         oscillation.push_back(*it);
       }
       oscillation_start_ = oscillation[0];
       oscillation_width_ = oscillation[1] - oscillation[0];
     }
   }
   
   json Scan::to_json() const {
     json scan_data;
     scan_data["image_range"] = image_range_;
     scan_data["batch_offset"] = 0; // We MUST NOT use batch offsets in dx2,
                                    // written out here for compatibility
     std::vector<double> oscillation_array(num_images_);
     for (int i = 0; i < num_images_; i++) {
       oscillation_array[i] = oscillation_start_ + oscillation_width_ * i;
     }
     json properties;
     properties["oscillation"] = oscillation_array;
     if (oscillation_array.size() == 1) {
       properties["oscillation_width"] = 0;
     }
     scan_data["properties"] = properties;
     // FIXME for dials compatibility, do we need exposure times and epochs arrays,
     // also valid_image_ranges empty dict?
     return scan_data;
   }
   
   std::array<int, 2> Scan::get_image_range() const { return image_range_; }
   
   std::array<double, 2> Scan::get_oscillation() const {
     return {oscillation_start_, oscillation_width_};
   }