wb: Split find_temperature_from_raw_coeffs, renamed to find_temperature_from_as_shot_coeffs; factored out find_temperature_from_wb_coeffs

Author: kofa73

src/common/illuminants.h

@@ -216,9 +216,11 @@ static inline void illuminant_CCT_to_RGB(const float t, dt_aligned_pixel_t RGB)
   illuminant_xy_to_RGB(x, y, RGB);
 }
 
+static inline gboolean find_temperature_from_wb_coeffs(const dt_image_t *img, const dt_aligned_pixel_t wb_coeffs,
+                                            float *chroma_x, float *chroma_y);
 
 // Fetch image from pipeline and read EXIF for camera RAW WB coeffs
-static inline gboolean find_temperature_from_raw_coeffs(const dt_image_t *img, const dt_aligned_pixel_t custom_wb,
+static inline gboolean find_temperature_from_as_shot_coeffs(const dt_image_t *img, const dt_aligned_pixel_t custom_wb,
                                                    float *chroma_x, float *chroma_y);
 
 
@@ -301,13 +303,13 @@ static inline int illuminant_to_xy(const dt_illuminant_t illuminant, // primary
     {
       // Detect WB from RAW EXIF
       if(img)
-        if(find_temperature_from_raw_coeffs(img, custom_wb, &x, &y)) break;
+        if(find_temperature_from_as_shot_coeffs(img, custom_wb, &x, &y)) break;
     }
     case DT_ILLUMINANT_FROM_WB:
     { // FIXME copy-paste
       // Detect WB from RAW EXIF
       if(img)
-        if(find_temperature_from_raw_coeffs(img, custom_wb, &x, &y)) break;
+        if(find_temperature_from_as_shot_coeffs(img, custom_wb, &x, &y)) break;
     }
     case DT_ILLUMINANT_CUSTOM: // leave x and y as-is
     case DT_ILLUMINANT_DETECT_EDGES:
@@ -392,31 +394,11 @@ static inline void matrice_pseudoinverse(float (*in)[3], float (*out)[3], int si
     }
 }
 
-
-static gboolean find_temperature_from_raw_coeffs(const dt_image_t *img, const dt_aligned_pixel_t custom_wb,
-                                            float *chroma_x, float *chroma_y)
+// returns TRUE is OK, FALSE if failed
+static gboolean get_CAM_to_XYZ(const dt_image_t * img, float(* CAM_to_XYZ)[3])
 {
-  if(img == NULL) return FALSE;
-  if(!dt_image_is_matrix_correction_supported(img)) return FALSE;
-
-  gboolean has_valid_coeffs = TRUE;
-  const int num_coeffs = (img->flags & DT_IMAGE_4BAYER) ? 4 : 3;
-
-  // Check coeffs
-  for(int k = 0; has_valid_coeffs && k < num_coeffs; k++)
-    if(!dt_isnormal(img->wb_coeffs[k]) || img->wb_coeffs[k] == 0.0f) has_valid_coeffs = FALSE;
-
-  if(!has_valid_coeffs) return FALSE;
-
-  // Get white balance camera factors
-  dt_aligned_pixel_t WB = { img->wb_coeffs[0], img->wb_coeffs[1], img->wb_coeffs[2], img->wb_coeffs[3] };
-
-  // Adapt the camera coeffs with custom white balance if provided
-  // this can deal with WB coeffs that don't use the input matrix reference
-  if(custom_wb)
-    for(size_t k = 0; k < 4; k++) WB[k] *= custom_wb[k];
-
-  // Get the camera input profile (matrice of primaries)
+  if (img == NULL || CAM_to_XYZ == NULL) return FALSE;
+  // Get the camera input profile (matrice of primaries) - embedded or raw library DB
   float XYZ_to_CAM[4][3];
   dt_mark_colormatrix_invalid(&XYZ_to_CAM[0][0]);
 
@@ -445,21 +427,61 @@ static gboolean find_temperature_from_raw_coeffs(const dt_image_t *img, const dt
 
   if(!dt_is_valid_colormatrix(XYZ_to_CAM[0][0])) return FALSE;
 
-  // Bloody input matrices define XYZ -> CAM transform, as if we often needed camera profiles to output
-  // So we need to invert them. Here go your CPU cycles again.
-  float CAM_to_XYZ[4][3];
   dt_mark_colormatrix_invalid(&CAM_to_XYZ[0][0]);
   matrice_pseudoinverse(XYZ_to_CAM, CAM_to_XYZ, 3);
-  if(!dt_is_valid_colormatrix(CAM_to_XYZ[0][0])) return FALSE;
+  return dt_is_valid_colormatrix(CAM_to_XYZ[0][0]);
+}
+
+// returns FALSE if failed; TRUE if successful
+static gboolean find_temperature_from_wb_coeffs(const dt_image_t *img, const dt_aligned_pixel_t wb_coeffs,
+                                            float *chroma_x, float *chroma_y)
+{
+  if(img == NULL || wb_coeffs == NULL) return FALSE;
+  if(!dt_image_is_matrix_correction_supported(img)) return FALSE;
+
+  float CAM_to_XYZ[4][3];
+  if (!get_CAM_to_XYZ(img, CAM_to_XYZ)) {
+    return FALSE;
+  }
 
   float x, y;
-  WB_coeffs_to_illuminant_xy(CAM_to_XYZ, WB, &x, &y);
+  WB_coeffs_to_illuminant_xy(CAM_to_XYZ, wb_coeffs, &x, &y);
   *chroma_x = x;
   *chroma_y = y;
 
   return TRUE;
 }
 
+// returns FALSE if failed; TRUE if successful
+static gboolean find_temperature_from_as_shot_coeffs(const dt_image_t *img, const dt_aligned_pixel_t custom_wb,
+                                            float *chroma_x, float *chroma_y)
+{
+  if(img == NULL) return FALSE;
+
+  gboolean has_valid_coeffs = TRUE;
+  const int num_coeffs = (img->flags & DT_IMAGE_4BAYER) ? 4 : 3;
+
+  // Check coeffs
+  for(int k = 0; has_valid_coeffs && k < num_coeffs; k++)
+    if(!dt_isnormal(img->wb_coeffs[k]) || img->wb_coeffs[k] == 0.0f) has_valid_coeffs = FALSE;
+
+  if(!has_valid_coeffs) return FALSE;
+
+  // Get as-shot white balance camera factors (from raw)
+  // component wise raw-RGB * wb_coeffs should provide R=G=B for a neutral patch under
+  // the scene illuminant
+  dt_aligned_pixel_t WB = { img->wb_coeffs[0], img->wb_coeffs[1], img->wb_coeffs[2], img->wb_coeffs[3] };
+
+  // Adapt the camera coeffs with custom D65 coefficients if provided ('caveats' workaround)
+  // this can deal with WB coeffs that don't use the input matrix reference
+  // adaptation_ratios[k] = chr->D65coeffs[k] / chr->wb_coeffs[k]
+  if(custom_wb)
+    for(size_t k = 0; k < 4; k++) WB[k] *= custom_wb[k];
+  // for a neutral surface, raw RGB * img->wb_coeffs would produce neutral R=G=B
+
+  return find_temperature_from_wb_coeffs(img, WB, chroma_x, chroma_y);
+}
+
 
 DT_OMP_DECLARE_SIMD()
 static inline float planckian_normal(const float x, const float t)

src/iop/channelmixerrgb.c

@@ -2209,7 +2209,7 @@ void process(dt_iop_module_t *self,
     dt_aligned_pixel_t custom_wb;
     _get_white_balance_coeff(self, custom_wb);
 
-    if(find_temperature_from_raw_coeffs(&(self->dev->image_storage), custom_wb, &(x), &(y)))
+    if(find_temperature_from_as_shot_coeffs(&(self->dev->image_storage), custom_wb, &(x), &(y)))
     {
       // Convert illuminant from xyY to XYZ
       dt_aligned_pixel_t XYZ;
@@ -2320,7 +2320,7 @@ int process_cl(dt_iop_module_t *self,
     dt_aligned_pixel_t custom_wb;
     _get_white_balance_coeff(self, custom_wb);
 
-    if(find_temperature_from_raw_coeffs(&(self->dev->image_storage), custom_wb, &(x), &(y)))
+    if(find_temperature_from_as_shot_coeffs(&(self->dev->image_storage), custom_wb, &(x), &(y)))
     {
       // Convert illuminant from xyY to XYZ
       dt_aligned_pixel_t XYZ;
@@ -3897,7 +3897,7 @@ void reload_defaults(dt_iop_module_t *self)
     dt_aligned_pixel_t custom_wb;
     if(!_get_white_balance_coeff(self, custom_wb))
     {
-      if(find_temperature_from_raw_coeffs(img, custom_wb, &(d->x), &(d->y)))
+      if(find_temperature_from_as_shot_coeffs(img, custom_wb, &(d->x), &(d->y)))
         d->illuminant = DT_ILLUMINANT_CAMERA;
       _check_if_close_to_daylight(d->x, d->y,
                                   &(d->temperature), &(d->illuminant), &(d->adaptation));
@@ -4000,7 +4000,7 @@ void gui_changed(dt_iop_module_t *self,
         // illuminant is changed.
         dt_aligned_pixel_t custom_wb;
         _get_white_balance_coeff(self, custom_wb);
-        find_temperature_from_raw_coeffs(&(self->dev->image_storage), custom_wb,
+        find_temperature_from_as_shot_coeffs(&(self->dev->image_storage), custom_wb,
                                          &(p->x), &(p->y));
         _check_if_close_to_daylight(p->x, p->y, &(p->temperature), NULL, &(p->adaptation));
       }
@@ -4017,7 +4017,7 @@ void gui_changed(dt_iop_module_t *self,
       // Get camera WB and update illuminant
       dt_aligned_pixel_t custom_wb;
       _get_white_balance_coeff(self, custom_wb);
-      const gboolean found = find_temperature_from_raw_coeffs(&(self->dev->image_storage),
+      const gboolean found = find_temperature_from_as_shot_coeffs(&(self->dev->image_storage),
                                                          custom_wb, &(p->x), &(p->y));
       _check_if_close_to_daylight(p->x, p->y, &(p->temperature), NULL, &(p->adaptation));