Merge branch 'genesys-override-dpi' into 'master'

genesys: Add a way to override logical dpi and physical pixel counts

See merge request sane-project/backends!187

backend/genesys_low.cc

@@ -1336,6 +1336,9 @@ void compute_session_pixel_offsets(const Genesys_Device* dev, ScanSession& s,
             s.pixel_endx = 0;
         }
     }
+
+    s.pixel_startx *= sensor.pixel_count_multiplier;
+    s.pixel_endx *= sensor.pixel_count_multiplier;
 }
 
 void compute_session(Genesys_Device* dev, ScanSession& s, const Genesys_Sensor& sensor)
@@ -1858,8 +1861,8 @@ void sanei_genesys_set_dpihw(Genesys_Register_Set& regs, const Genesys_Sensor& s
     const uint8_t REG05_DPIHW_2400 = 0x80;
     const uint8_t REG05_DPIHW_4800 = 0xc0;
 
-    if (sensor.dpihw_override != 0) {
-        dpihw = sensor.dpihw_override;
+    if (sensor.register_dpihw_override != 0) {
+        dpihw = sensor.register_dpihw_override;
     }
 
     uint8_t dpihw_setting;

backend/genesys_sensor.h

@@ -277,7 +277,11 @@ struct Genesys_Sensor {
 
     // The scanner may be setup to use a custom dpihw that does not correspond to any actual
     // resolution. The value zero does not set the override.
-    unsigned dpihw_override = 0;
+    unsigned register_dpihw_override = 0;
+
+    // The scanner may be setup to use a custom logical dpihw that does not correspond to any actual
+    // resolution. The value zero does not set the override.
+    unsigned logical_dpihw_override = 0;
 
     // The scanner may be setup to use a custom dpiset value that does not correspond to any actual
     // resolution. The value zero does not set the override.
@@ -286,6 +290,9 @@ struct Genesys_Sensor {
     // CCD may present itself as half or quarter-size CCD on certain resolutions
     int ccd_size_divisor = 1;
 
+    // Some scanners need an additional multiplier over the scan coordinates
+    int pixel_count_multiplier = 1;
+
     int black_pixels = 0;
     // value of the dummy register
     int dummy_pixel = 0;

backend/genesys_tables_sensor.cc

@@ -47,6 +47,9 @@
 
 inline unsigned default_get_logical_hwdpi(const Genesys_Sensor& sensor, unsigned xres)
 {
+    if (sensor.logical_dpihw_override)
+        return sensor.logical_dpihw_override;
+
     // can't be below 600 dpi
     if (xres <= 600) {
         return 600;