Two subtle demosaicer fixes

1. In case of a very small roi_in area we only fall back to a safe demosaicer if we are not using any of the
   passthru demosaicers
2. In preview pipe we can and should avoid dual demosaicing as we do for the fast pipe.

While being here some code readability cleanups, also for the log info about output writing -d verbose is good enough.

Author: jenshannoschwalm

src/iop/demosaic.c

@@ -137,7 +137,7 @@ typedef struct dt_iop_demosaic_gui_data_t
   GtkWidget *demosaic_method_bayerfour;
   GtkWidget *dual_thrs;
   GtkWidget *lmmse_refine;
-  gboolean visual_mask;
+  gboolean dual_mask;
 } dt_iop_demosaic_gui_data_t;
 
 typedef struct dt_iop_demosaic_global_data_t
@@ -476,7 +476,7 @@ void tiling_callback(dt_iop_module_t *self,
   dt_iop_demosaic_data_t *d = piece->data;
 
   const float ioratio = (float)roi_out->width * roi_out->height / ((float)roi_in->width * roi_in->height);
-  const float smooth = d->color_smoothing ? ioratio : 0.0f;
+  const float smooth = d->color_smoothing != DT_DEMOSAIC_SMOOTH_OFF ? ioratio : 0.0f;
   const gboolean is_xtrans = piece->pipe->dsc.filters == 9u;
   const float greeneq = (!is_xtrans && (d->green_eq != DT_IOP_GREEN_EQ_NO)) ? 0.25f : 0.0f;
   const dt_iop_demosaic_method_t demosaicing_method = d->demosaicing_method & ~DT_DEMOSAIC_DUAL;
@@ -600,6 +600,7 @@ void process(dt_iop_module_t *self,
 
   const gboolean run_fast = pipe->type & DT_DEV_PIXELPIPE_FAST;
   const gboolean fullpipe = pipe->type & DT_DEV_PIXELPIPE_FULL;
+  const gboolean previewpipe = pipe->type & DT_DEV_PIXELPIPE_PREVIEW;
 
   const uint8_t(*const xtrans)[6] = (const uint8_t(*const)[6])pipe->dsc.xtrans;
 
@@ -616,13 +617,15 @@ void process(dt_iop_module_t *self,
   const int width = roi_in->width;
   const int height = roi_in->height;
 
-  if(width < 16 || height < 16)
+  if((width < 16 || height < 16)
+        &&  (demosaicing_method != DT_IOP_DEMOSAIC_PASSTHROUGH_MONOCHROME
+          && demosaicing_method != DT_IOP_DEMOSAIC_PASSTHROUGH_COLOR))
     demosaicing_method = is_xtrans ? DT_IOP_DEMOSAIC_VNG : DT_IOP_DEMOSAIC_VNG4;
 
   gboolean showmask = FALSE;
   if(self->dev->gui_attached && fullpipe)
   {
-    if(g->visual_mask)
+    if(g->dual_mask)
     {
       showmask = TRUE;
       pipe->mask_display = DT_DEV_PIXELPIPE_DISPLAY_MASK;
@@ -649,7 +652,7 @@ void process(dt_iop_module_t *self,
   }
 
   const int base_demosaicing_method = demosaicing_method & ~DT_DEMOSAIC_DUAL;
-  const gboolean dual = (demosaicing_method & DT_DEMOSAIC_DUAL) && !run_fast;
+  const gboolean dual = (demosaicing_method & DT_DEMOSAIC_DUAL) && !run_fast && !previewpipe;
 
   const gboolean direct = roi_out->width == width && roi_out->height == height && feqf(roi_in->scale, roi_out->scale, 1e-8f);
 
@@ -724,10 +727,10 @@ void process(dt_iop_module_t *self,
 
   if((float *)i != in) dt_free_align(in);
 
-  if(d->color_smoothing)
+  if(d->color_smoothing != DT_DEMOSAIC_SMOOTH_OFF)
     color_smoothing(out, roi_in, d->color_smoothing);
 
-  dt_print_pipe(DT_DEBUG_PIPE, direct ? "demosaic inplace" : "demosaic clip_and_zoom", pipe, self, DT_DEVICE_CPU, roi_in, roi_out);
+  dt_print_pipe(DT_DEBUG_VERBOSE, direct ? "demosaic inplace" : "demosaic clip_and_zoom", pipe, self, DT_DEVICE_CPU, roi_in, roi_out);
   if(!direct)
   {
     dt_iop_roi_t roo = *roi_out;
@@ -751,6 +754,7 @@ int process_cl(dt_iop_module_t *self,
   dt_dev_pixelpipe_t *const pipe = piece->pipe;
   const gboolean run_fast = pipe->type & DT_DEV_PIXELPIPE_FAST;
   const gboolean fullpipe = pipe->type & DT_DEV_PIXELPIPE_FULL;
+  const gboolean previewpipe = pipe->type & DT_DEV_PIXELPIPE_PREVIEW;
   const int qual_flags = demosaic_qual_flags(piece, img, roi_out);
   const gboolean fullscale = qual_flags & DT_DEMOSAIC_FULL_SCALE;
   const gboolean is_xtrans = pipe->dsc.filters == 9u;
@@ -773,13 +777,15 @@ int process_cl(dt_iop_module_t *self,
   const int width = roi_in->width;
   const int height = roi_in->height;
 
-  if(width < 16 || height < 16)
+  if((width < 16 || height < 16)
+    &&  (demosaicing_method != DT_IOP_DEMOSAIC_PASSTHROUGH_MONOCHROME
+      && demosaicing_method != DT_IOP_DEMOSAIC_PASSTHROUGH_COLOR))
     demosaicing_method = is_xtrans ? DT_IOP_DEMOSAIC_VNG : DT_IOP_DEMOSAIC_VNG4;
 
   gboolean showmask = FALSE;
   if(self->dev->gui_attached && fullpipe)
   {
-    if(g->visual_mask)
+    if(g->dual_mask)
     {
       showmask = TRUE;
       pipe->mask_display = DT_DEV_PIXELPIPE_DISPLAY_MASK;
@@ -822,7 +828,7 @@ int process_cl(dt_iop_module_t *self,
 
   const gboolean direct = roi_out->width == width && roi_out->height == height && feqf(roi_in->scale, roi_out->scale, 1e-8f);
   const int base_demosaicing_method = demosaicing_method & ~DT_DEMOSAIC_DUAL;
-  const gboolean dual = (demosaicing_method & DT_DEMOSAIC_DUAL) && !run_fast;
+  const gboolean dual = (demosaicing_method & DT_DEMOSAIC_DUAL) && !run_fast && !previewpipe;
 
   cl_mem out_image = direct ? dev_out : dt_opencl_alloc_device(devid, width, height, sizeof(float) * 4);
   cl_mem in_image = dev_in;
@@ -902,13 +908,13 @@ int process_cl(dt_iop_module_t *self,
     in_image = NULL;
   }
 
-  if(d->color_smoothing)
+  if(d->color_smoothing != DT_DEMOSAIC_SMOOTH_OFF)
   {
     err = color_smoothing_cl(self, piece, out_image, out_image, roi_in, d->color_smoothing);
     if(err != CL_SUCCESS) goto finish;
   }
 
-  dt_print_pipe(DT_DEBUG_PIPE, direct ? "demosaic inplace" : "demosaic clip_and_zoom", pipe, self, devid, roi_in, roi_out);
+  dt_print_pipe(DT_DEBUG_VERBOSE, direct ? "demosaic inplace" : "demosaic clip_and_zoom", pipe, self, devid, roi_in, roi_out);
   if(!direct)
     err = dt_iop_clip_and_zoom_roi_cl(devid, dev_out, out_image, roi_out, roi_in);
 
@@ -1151,8 +1157,8 @@ void commit_params(dt_iop_module_t *self,
 
   // green-equilibrate over full image excludes tiling
   // The details mask calculation required for dual demosaicing does not allow tiling.
-  if((d->green_eq == DT_IOP_GREEN_EQ_FULL
-      || d->green_eq == DT_IOP_GREEN_EQ_BOTH)
+  if(    d->green_eq == DT_IOP_GREEN_EQ_FULL
+      || d->green_eq == DT_IOP_GREEN_EQ_BOTH
       || use_method & DT_DEMOSAIC_DUAL
       || piece->pipe->want_detail_mask)
   {
@@ -1278,7 +1284,7 @@ void gui_changed(dt_iop_module_t *self, GtkWidget *w, void *previous)
   if(!w || w != g->dual_thrs)
   {
     dt_bauhaus_widget_set_quad_active(g->dual_thrs, FALSE);
-    g->visual_mask = FALSE;
+    g->dual_mask = FALSE;
   }
 
   // as the dual modes change behaviour for previous pipeline modules we do a reprocess
@@ -1297,7 +1303,7 @@ static void _visualize_callback(GtkWidget *quad, dt_iop_module_t *self)
   if(darktable.gui->reset) return;
   dt_iop_demosaic_gui_data_t *g = self->gui_data;
 
-  g->visual_mask = dt_bauhaus_widget_get_quad_active(quad);
+  g->dual_mask = dt_bauhaus_widget_get_quad_active(quad);
   dt_dev_reprocess_center(self->dev);
 }
 
@@ -1306,9 +1312,9 @@ void gui_focus(dt_iop_module_t *self, gboolean in)
   dt_iop_demosaic_gui_data_t *g = self->gui_data;
   if(!in)
   {
-    const gboolean was_dualmask = g->visual_mask;
+    const gboolean was_dualmask = g->dual_mask;
     dt_bauhaus_widget_set_quad_active(g->dual_thrs, FALSE);
-    g->visual_mask = FALSE;
+    g->dual_mask = FALSE;
     if(was_dualmask) dt_dev_reprocess_center(self->dev);
   }
 }