Redesign pixelpipe input scaling

Analysis: With current pixelpipe and cache design we must reprocess the full pipe whenever we zoom in/out or
drag around, as we select another area and thus the hash won't match.

Solution:
1. Decouple crop&scale from demosaic module and introduce a "pipescale" module that presents the currently
   chosen roi.
2. Make sure modules before pipescale always process full image data.
3. By doing so we will have a 100% cache hit rate for the pipescale modulule if there are no changed parameters
   in any of the modules before.
   As those modules before pipescale could include very performance costly algorithms the UI will now be far more
   responsive.
4. The default pipescale position is now right after demosaicing, the current implementation allows dragging
   it's position further up the pipe so it could also include costly stuff like denoising or even notorious
   modules like dehaze as that loves to be processed with full image data.
5. As we now always have full image data available before and including demosaicing all raw-only modules can
   use simplified code reducing code and complexity.
   It will also be possible to provide details mask while demosaic tiling.
6. The scale module is also available for non-raw files allowing crop&scale to be done **after** colorin.
   (One problem here so far: the preview pipe scaling is not fixed so far)
7. The low quality demosaicers are gone as we always have full data to be processed.

Author: jenshannoschwalm

src/common/iop_order.c

@@ -88,6 +88,7 @@ const dt_iop_order_entry_t legacy_order[] = {
   { { 6.0f }, "hotpixels", 0},
   { { 7.0f }, "rawdenoise", 0},
   { { 8.0f }, "demosaic", 0},
+  { { 8.5f }, "pipescale", 0},
   { { 9.0f }, "mask_manager", 0},
   { {10.0f }, "denoiseprofile", 0},
   { {11.0f }, "tonemap", 0},
@@ -184,6 +185,7 @@ const dt_iop_order_entry_t v30_order[] = {
   { { 6.0f }, "hotpixels", 0},
   { { 7.0f }, "rawdenoise", 0},
   { { 8.0f }, "demosaic", 0},
+  { { 8.5f }, "pipescale", 0},
   { { 9.0f }, "denoiseprofile", 0},
   { {10.0f }, "bilateral", 0},
   { {11.0f }, "rotatepixels", 0},
@@ -301,6 +303,7 @@ const dt_iop_order_entry_t v50_order[] = {
   { { 6.0f }, "hotpixels", 0},
   { { 7.0f }, "rawdenoise", 0},
   { { 8.0f }, "demosaic", 0},
+  { { 8.5f }, "pipescale", 0},
   { { 9.0f }, "denoiseprofile", 0},
   { {10.0f }, "bilateral", 0},
   { {11.0f }, "rotatepixels", 0},
@@ -420,6 +423,7 @@ const dt_iop_order_entry_t v30_jpg_order[] = {
   { { 6.0f }, "hotpixels", 0 },
   { { 7.0f }, "rawdenoise", 0 },
   { { 8.0f }, "demosaic", 0 },
+  { { 8.5f }, "pipescale", 0},
   // all the modules between [8; 28] expect linear RGB, so they need to be moved after colorin
   { { 28.0f }, "colorin", 0 },
   // moved modules : (copy-pasted in the same order)
@@ -540,6 +544,7 @@ const dt_iop_order_entry_t v50_jpg_order[] = {
   { { 6.0f }, "hotpixels", 0 },
   { { 7.0f }, "rawdenoise", 0 },
   { { 8.0f }, "demosaic", 0 },
+  { { 8.5f }, "pipescale", 0},
   // all the modules between [8; 28] expect linear RGB, so they need to be moved after colorin
   { { 28.0f }, "colorin", 0 },
   // moved modules : (copy-pasted in the same order)
@@ -1179,6 +1184,7 @@ GList *dt_ioppr_get_iop_order_list(const dt_imgid_t imgid,
           _insert_before(iop_order_list, "filmicrgb", "sigmoid");
           _insert_before(iop_order_list, "colorbalancergb", "colorequal");
           _insert_before(iop_order_list, "highlights", "rasterfile");
+          _insert_before(iop_order_list, "denoiseprofile", "pipescale"); // ????
         }
       }
       else if(version >= DT_IOP_ORDER_LEGACY

src/develop/pixelpipe_hb.c

@@ -1737,9 +1737,6 @@ static gboolean _dev_pixelpipe_process_rec(dt_dev_pixelpipe_t *pipe,
   // 3b) recurse and obtain output array in &input
 
   // get region of interest which is needed in input
-  if(dt_pipe_shutdown(pipe))
-    return TRUE;
-
   module->modify_roi_in(module, piece, roi_out, &roi_in);
   if((darktable.unmuted & DT_DEBUG_PIPE) && memcmp(roi_out, &roi_in, sizeof(dt_iop_roi_t)))
   {
@@ -1775,18 +1772,11 @@ static gboolean _dev_pixelpipe_process_rec(dt_dev_pixelpipe_t *pipe,
   const size_t out_bpp = dt_iop_buffer_dsc_to_bpp(*out_format);
 
   // reserve new cache line: output
-  if(dt_pipe_shutdown(pipe))
-    return TRUE;
-
   const gboolean important = module
       && (pipe->mask_display == DT_DEV_PIXELPIPE_DISPLAY_NONE)
-      && (((pipe->type & DT_DEV_PIXELPIPE_PREVIEW)
-           && dt_iop_module_is(module->so, "colorout"))
-       || ((pipe->type & DT_DEV_PIXELPIPE_FULL)
-           && dt_iop_module_is(module->so, "gamma")));
+      && dt_iop_module_is(module->so, "pipescale");
 
-  dt_dev_pixelpipe_cache_get(pipe, hash, bufsize,
-                             output, out_format, module, important);
+  dt_dev_pixelpipe_cache_get(pipe, hash, bufsize, output, out_format, module, important);
 
   if(dt_pipe_shutdown(pipe))
     return TRUE;
@@ -2546,8 +2536,8 @@ static gboolean _dev_pixelpipe_process_rec(dt_dev_pixelpipe_t *pipe,
            && dev->gui_attached
            && ((module == dt_dev_gui_module())
                 || darktable.develop->history_last_module == module
-                || dt_iop_module_is(module->so, "colorout")
-                || dt_iop_module_is(module->so, "finalscale"));
+                || dt_iop_module_is(module->so, "finalscale")
+                || dt_iop_module_is(module->so, "pipescale"));
 
         if(important_cl)
         {

src/iop/CMakeLists.txt

@@ -155,6 +155,7 @@ add_iop(sigmoid "sigmoid.c")
 add_iop(primaries "primaries.c")
 add_iop(colorequal "colorequal.c")
 add_iop(rasterfile "rasterfile.c")
+add_iop(pipescale "pipescale.c")
 
 if(Rsvg2_FOUND)
   add_iop(watermark "watermark.c")

src/iop/cacorrect.c

@@ -1215,37 +1215,6 @@ DT_OMP_PRAGMA(barrier)
 /*==================================================================================
  * end raw therapee code
  *==================================================================================*/
-void modify_roi_out(dt_iop_module_t *self,
-                    dt_dev_pixelpipe_iop_t *piece,
-                    dt_iop_roi_t *roi_out,
-                    const dt_iop_roi_t *const roi_in)
-{
-  *roi_out = *roi_in;
-  roi_out->x = MAX(0, roi_in->x);
-  roi_out->y = MAX(0, roi_in->y);
-}
-void modify_roi_in(dt_iop_module_t *self,
-                   dt_dev_pixelpipe_iop_t *piece,
-                   const dt_iop_roi_t *const roi_out,
-                   dt_iop_roi_t *roi_in)
-{
-  *roi_in = *roi_out;
-  roi_in->x = 0;
-  roi_in->y = 0;
-  roi_in->width = piece->buf_in.width;
-  roi_in->height = piece->buf_in.height;
-  roi_in->scale = 1.0f;
-}
-
-void distort_mask(dt_iop_module_t *self,
-                  dt_dev_pixelpipe_iop_t *piece,
-                  const float *const in,
-                  float *const out,
-                  const dt_iop_roi_t *const roi_in,
-                  const dt_iop_roi_t *const roi_out)
-{
-  dt_iop_copy_image_roi(out, in, 1, roi_in, roi_out);
-}
 
 void reload_defaults(dt_iop_module_t *self)
 {