genesys: Adjust host side calibration by shading pixel offset

backend/genesys/low.cpp

@@ -921,6 +921,8 @@ void compute_session(const Genesys_Device* dev, ScanSession& s, const Genesys_Se
     s.buffer_size_read = s.output_line_bytes_raw * 64;
     compute_session_pixel_offsets(dev, s, sensor);
 
+    s.shading_pixel_offset = sensor.shading_pixel_offset;
+
     if (dev->model->asic_type == AsicType::GL124 ||
         dev->model->asic_type == AsicType::GL845 ||
         dev->model->asic_type == AsicType::GL846)
@@ -1071,10 +1073,10 @@ ImagePipelineStack build_image_pipeline(const Genesys_Device& dev, const ScanSes
         !has_flag(dev.model->flags, ModelFlag::DISABLE_SHADING_CALIBRATION) &&
         !has_flag(session.params.flags, ScanFlag::DISABLE_SHADING))
     {
+        unsigned offset_pixels = session.params.startx + dev.calib_session.shading_pixel_offset;
+        unsigned offset_bytes = offset_pixels * dev.calib_session.params.channels;
         pipeline.push_node<ImagePipelineNodeCalibrate>(dev.dark_average_data,
-                                                            dev.white_average_data,
-                                                            session.params.startx *
-                                                                dev.calib_session.params.channels);
+                                                       dev.white_average_data, offset_bytes);
 
         if (log_image_data) {
             pipeline.push_node<ImagePipelineNodeDebug>(debug_prefix + "_9_after_calibrate.tiff");

backend/genesys/sensor.h

@@ -286,7 +286,8 @@ struct Genesys_Sensor {
     // How many real pixels correspond to one shading pixel that is sent to the scanner
     unsigned shading_factor = 1;
 
-    // How many pixels the shading data is offset from the acquired data
+    // How many pixels the shading data is offset to the right from the acquired data. Calculated
+    // in shading resolution.
     int shading_pixel_offset = 0;
 
     // This defines the ratio between logical pixel coordinates and the pixel coordinates sent to

backend/genesys/settings.cpp

@@ -126,6 +126,7 @@ bool ScanSession::operator==(const ScanSession& other) const
         conseq_pixel_dist == other.conseq_pixel_dist &&
         output_segment_pixel_group_count == other.output_segment_pixel_group_count &&
         output_segment_start_offset == other.output_segment_start_offset &&
+        shading_pixel_offset == other.shading_pixel_offset &&
         buffer_size_read == other.buffer_size_read &&
         enable_ledadd == other.enable_ledadd &&
         use_host_side_calib == other.use_host_side_calib;
@@ -161,6 +162,7 @@ std::ostream& operator<<(std::ostream& out, const ScanSession& session)
         << "    conseq_pixel_dist: " << session.conseq_pixel_dist << '\n'
         << "    output_segment_pixel_group_count: "
             << session.output_segment_pixel_group_count << '\n'
+        << "    shading_pixel_offset: " << session.shading_pixel_offset << '\n'
         << "    buffer_size_read: " << session.buffer_size_read << '\n'
         << "    enable_ledadd: " << session.enable_ledadd << '\n'
         << "    use_host_side_calib: " << session.use_host_side_calib << '\n'

backend/genesys/settings.h

@@ -306,6 +306,10 @@ struct ScanSession {
     // Currently it's always zero.
     unsigned output_segment_start_offset = 0;
 
+    // How many pixels the shading data is offset to the right from the acquired data. Calculated
+    // in shading resolution.
+    int shading_pixel_offset = 0;
+
     // the size of the read buffer.
     size_t buffer_size_read = 0;
 
@@ -362,6 +366,7 @@ void serialize(Stream& str, ScanSession& x)
     serialize(str, x.conseq_pixel_dist);
     serialize(str, x.output_segment_pixel_group_count);
     serialize(str, x.output_segment_start_offset);
+    serialize(str, x.shading_pixel_offset);
     serialize(str, x.buffer_size_read);
     serialize(str, x.enable_ledadd);
     serialize(str, x.use_host_side_calib);