genesys: Deduplicate calculation of scan line count

backend/genesys/gl124.cpp

@@ -885,8 +885,7 @@ void CommandSetGl124::init_regs_for_scan_session(Genesys_Device* dev, const Gene
         mflags |= MotorFlag::REVERSE;
     }
     gl124_init_motor_regs_scan(dev, sensor, reg, motor_profile, exposure_time, slope_dpi,
-                               dev->model->is_cis ? session.output_line_count * session.params.channels :
-                                                    session.output_line_count,
+                               session.optical_line_count,
                                dummy, move, session.params.scan_mode, mflags);
 
   /*** prepares data reordering ***/

backend/genesys/gl841.cpp

@@ -1603,16 +1603,13 @@ dummy \ scanned lines
     DBG(DBG_info, "%s: move=%d steps\n", __func__, move);*/
 
     if (has_flag(session.params.flags, ScanFlag::SINGLE_LINE)) {
-        gl841_init_motor_regs_off(reg, dev->model->is_cis ? session.output_line_count * session.params.channels
-                                                          : session.output_line_count);
+        gl841_init_motor_regs_off(reg, session.optical_line_count);
     } else {
         auto motor_flag = has_flag(session.params.flags, ScanFlag::DISABLE_BUFFER_FULL_MOVE) ?
                               MotorFlag::DISABLE_BUFFER_FULL_MOVE : MotorFlag::NONE;
 
         gl841_init_motor_regs_scan(dev, sensor, reg, exposure_time, slope_dpi, scan_step_type,
-                                   dev->model->is_cis ? session.output_line_count * session.params.channels
-                                                      : session.output_line_count,
-                                   dummy, move, motor_flag);
+                                   session.optical_line_count, dummy, move, motor_flag);
   }
 
     dev->read_buffer.clear();

backend/genesys/gl843.cpp

@@ -1196,11 +1196,8 @@ void CommandSetGl843::init_regs_for_scan_session(Genesys_Device* dev, const Gene
         mflags |= MotorFlag::REVERSE;
     }
 
-    unsigned scan_lines = dev->model->is_cis ? session.output_line_count * session.params.channels
-                                             : session.output_line_count;
-
     gl843_init_motor_regs_scan(dev, sensor, reg, motor_profile, exposure, slope_dpi,
-                               scan_lines, dummy, session.params.starty, mflags);
+                               session.optical_line_count, dummy, session.params.starty, mflags);
 
     dev->read_buffer.clear();
     dev->read_buffer.alloc(session.buffer_size_read);

backend/genesys/gl846.cpp

@@ -736,9 +736,7 @@ void CommandSetGl846::init_regs_for_scan_session(Genesys_Device* dev, const Gene
     }
 
     gl846_init_motor_regs_scan(dev, sensor, reg, motor_profile, exposure_time, slope_dpi,
-                               dev->model->is_cis ? session.output_line_count * session.params.channels
-                                                  : session.output_line_count,
-                               dummy, move, mflags);
+                               session.optical_line_count, dummy, move, mflags);
 
   /*** prepares data reordering ***/
 

backend/genesys/gl847.cpp

@@ -740,9 +740,7 @@ void CommandSetGl847::init_regs_for_scan_session(Genesys_Device* dev, const Gene
     }
 
     gl847_init_motor_regs_scan(dev, sensor, reg, motor_profile, exposure_time, slope_dpi,
-                               dev->model->is_cis ? session.output_line_count * session.params.channels
-                                                  : session.output_line_count,
-                               dummy, move, mflags);
+                               session.optical_line_count, dummy, move, mflags);
 
     dev->read_buffer.clear();
     dev->read_buffer.alloc(session.buffer_size_read);

backend/genesys/low.cpp

@@ -516,7 +516,7 @@ Image read_unshuffled_image_from_scanner(Genesys_Device* dev, const ScanSession&
                                       dev->model->line_mode_color_order);
 
     auto width = get_pixels_from_row_bytes(format, session.output_line_bytes_raw);
-    auto height = session.output_line_count * (dev->model->is_cis ? session.params.channels : 1);
+    auto height = session.optical_line_count;
 
     Image image(width, height, format);
 
@@ -1103,6 +1103,8 @@ void compute_session(const Genesys_Device* dev, ScanSession& s, const Genesys_Se
     }
 
     s.output_line_count = s.params.lines + s.max_color_shift_lines + s.num_staggered_lines;
+    s.optical_line_count = dev->model->is_cis ? s.output_line_count * s.params.channels
+                                              : s.output_line_count;
 
     s.output_channel_bytes = multiply_by_depth_ceil(s.output_pixels, s.params.depth);
     s.output_line_bytes = s.output_channel_bytes * s.params.channels;
@@ -1261,7 +1263,7 @@ void build_image_pipeline(Genesys_Device* dev, const ScanSession& session)
         return true;
     };
 
-    auto lines = session.output_line_count * (dev->model->is_cis ? session.params.channels : 1);
+    auto lines = session.optical_line_count;
 
     dev->pipeline.clear();
 

backend/genesys/settings.cpp

@@ -96,6 +96,7 @@ std::ostream& operator<<(std::ostream& out, const ScanSession& session)
         << "    optical_resolution: " << session.optical_resolution << '\n'
         << "    optical_pixels: " << session.optical_pixels << '\n'
         << "    optical_pixels_raw: " << session.optical_pixels_raw << '\n'
+        << "    optical_line_count: " << session.optical_line_count << '\n'
         << "    output_resolution: " << session.output_resolution << '\n'
         << "    output_pixels: " << session.output_pixels << '\n'
         << "    output_line_bytes: " << session.output_line_bytes << '\n'

backend/genesys/settings.h

@@ -228,6 +228,9 @@ struct ScanSession {
     // only on gl846, g847
     unsigned optical_pixels_raw = 0;
 
+    // the number of optical scan lines. Equal to output_line_count on CCD scanners.
+    unsigned optical_line_count = 0;
+
     // the resolution of the output data.
     // gl843-only
     unsigned output_resolution = 0;