genesys: Use separate settings for dark-white calibration area geometry

backend/genesys/device.h

@@ -137,12 +137,19 @@ struct Genesys_Model
     // Size of scan area in mm
     float y_size = 0;
 
-    // Start of white strip in mm
+    // Start of white strip in mm for scanners that use separate dark and white shading calibration.
     float y_offset_calib_white = 0;
 
     // The size of the scan area that is used to acquire shading data in mm
     float y_size_calib_mm = 0;
 
+    // Start of the black/white strip in mm for scanners that use unified dark and white shading
+    // calibration.
+    float y_offset_calib_dark_white_mm = 0;
+
+    // The size of the scan area that is used to acquire dark/white shading data in mm
+    float y_size_calib_dark_white_mm = 0;
+
     // Start of black mark in mm
     float x_offset_calib_black = 0;
 

backend/genesys/gl841.cpp

@@ -2396,21 +2396,6 @@ void CommandSetGl841::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
                                             Genesys_Register_Set& regs) const
 {
     DBG_HELPER(dbg);
-    unsigned starty = 0;
-
-    if (dev->model->motor_id == MotorId::CANON_LIDE_80) {
-      /* get over extra dark area for this model.
-	 It looks like different devices have dark areas of different width
-	 due to manufacturing variability. The initial value of starty was 140,
-	 but it moves the sensor almost past the dark area completely in places
-	 on certain devices.
-
-	 On a particular device the black area starts at roughly position
-	 160 to 230 depending on location (the dark area is not completely
-	 parallel to the frame).
-      */
-      starty = 70;
-    }
 
     unsigned channels = 3;
 
@@ -2421,7 +2406,9 @@ void CommandSetGl841::init_regs_for_shading(Genesys_Device* dev, const Genesys_S
                                                          dev->settings.scan_method);
 
     unsigned calib_lines =
-            static_cast<unsigned>(dev->model->y_size_calib_mm * resolution / MM_PER_INCH);
+            static_cast<unsigned>(dev->model->y_size_calib_dark_white_mm * resolution / MM_PER_INCH);
+    unsigned starty =
+            static_cast<unsigned>(dev->model->y_offset_calib_dark_white_mm * dev->motor.base_ydpi / MM_PER_INCH);
     ScanSession session;
     session.params.xres = resolution;
     session.params.yres = resolution;

backend/genesys/tables_model.cpp

@@ -88,6 +88,12 @@ void genesys_init_usb_device_tables()
         model.y_offset_sensor_to_ta = 0.0;
         model.y_offset_calib_white_ta = 0.0;
         model.y_size_calib_ta_mm = 0.0;
+
+        If the scanner does not have ModelFlag::DARK_WHITE_CALIBRATION, then the following
+        properties are optional:
+
+        model.y_offset_calib_dark_white_mm = 0.0;
+        model.y_size_calib_dark_white_mm = 0.0;
     */
 
     s_usb_devices.init();
@@ -165,6 +171,8 @@ void genesys_init_usb_device_tables()
 
     model.y_offset_calib_white = 3.0;
     model.y_size_calib_mm = 3.0;
+    model.y_offset_calib_dark_white_mm = 1.0;
+    model.y_size_calib_dark_white_mm = 6.0;
     model.x_offset_calib_black = 0.0;
 
     model.post_scan = 0.0;
@@ -1083,6 +1091,8 @@ void genesys_init_usb_device_tables()
 
     model.y_offset_calib_white = 3.0;
     model.y_size_calib_mm = 3.0;
+    model.y_offset_calib_dark_white_mm = 1.0;
+    model.y_size_calib_dark_white_mm = 6.0;
     model.x_offset_calib_black = 0.0;
 
     model.post_scan = 0.0;
@@ -1136,6 +1146,8 @@ void genesys_init_usb_device_tables()
 
     model.y_offset_calib_white = 4.5;
     model.y_size_calib_mm = 3.0;
+    model.y_offset_calib_dark_white_mm = 1.0;
+    model.y_size_calib_dark_white_mm = 6.0;
     model.x_offset_calib_black = 0.0;
 
     model.post_scan = 0.0;