IOP Color EQ : Add interactive editing mode for color adjustments in image

src/CMakeLists.txt

@@ -130,6 +130,7 @@ FILE(GLOB SOURCE_FILES
   "develop/masks/masks.c"
   "develop/masks/path.c"
   "develop/pixelpipe.c"
+  "develop/preview_data.c"
   "develop/tiling.c"
   "dtgtk/button.c"
   "dtgtk/culling.c"

src/develop/preview_data.c

@@ -0,0 +1,235 @@
+/*
+    This file is part of darktable,
+    Copyright (C) 2026 darktable developers.
+
+    darktable is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    darktable is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "develop/preview_data.h"
+
+#include "common/darktable.h"
+#include "develop/develop.h"
+#include "develop/imageop.h"
+#include "develop/pixelpipe_hb.h"
+
+void dt_preview_data_alloc(dt_preview_data_t *pd,
+                           const dt_iop_module_t *module)
+{
+  pd->buf = NULL;
+  pd->width = 0;
+  pd->height = 0;
+  pd->components = 1;
+  pd->hash = DT_INVALID_HASH;
+  pd->module = module;
+}
+
+void dt_preview_data_free(dt_preview_data_t *pd)
+{
+  if(pd->buf)
+  {
+    dt_free_align(pd->buf);
+    pd->buf = NULL;
+  }
+  pd->width = 0;
+  pd->height = 0;
+  pd->hash = DT_INVALID_HASH;
+  pd->module = NULL;
+}
+
+void dt_preview_data_store(dt_preview_data_t *pd,
+                           const size_t width,
+                           const size_t height,
+                           const dt_dev_pixelpipe_iop_t *piece,
+                           dt_preview_data_fill_t fill,
+                           void *const user_data)
+{
+  if(!pd || !pd->module || !fill || !piece) return;
+
+  // resize, fill and hash commit all happen under the same GUI lock so
+  // that the GUI thread can never observe a resized but not-yet-filled
+  // buffer (a window the earlier ensure()/fill/set_hash split exposed).
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+
+  const size_t nelems = width * height * pd->components;
+  gboolean can_fill = TRUE;
+  if(pd->width != width || pd->height != height)
+  {
+    float *const new_buf = dt_alloc_align_float(nelems);
+    if(new_buf)
+    {
+      dt_free_align(pd->buf);
+      pd->buf = new_buf;
+      pd->width = width;
+      pd->height = height;
+    }
+    else
+    {
+      pd->hash = DT_INVALID_HASH;
+      can_fill = FALSE;
+    }
+  }
+
+  if(can_fill && pd->buf)
+  {
+    fill(user_data, pd->buf, nelems);
+    pd->hash = dt_dev_pixelpipe_piece_hash((dt_dev_pixelpipe_iop_t *)piece,
+                                           &piece->processed_roi_out, TRUE);
+  }
+
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+}
+
+float *dt_preview_data_resize(dt_preview_data_t *pd,
+                              const size_t width,
+                              const size_t height,
+                              dt_preview_data_resize_cb_t resize_cb,
+                              void *const user_data)
+{
+  if(!pd || !pd->module) return NULL;
+
+  // The resize and the caller's invalidation callback run under the same
+  // GUI lock so that the module can atomically mark its dependent state
+  // stale together with the buffer reallocation.
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+
+  gboolean ok = TRUE;
+  if(pd->width != width || pd->height != height)
+  {
+    float *const new_buf = dt_alloc_align_float(width * height * pd->components);
+    if(new_buf)
+    {
+      dt_free_align(pd->buf);
+      pd->buf = new_buf;
+      pd->width = width;
+      pd->height = height;
+    }
+    else
+    {
+      pd->hash = DT_INVALID_HASH;
+      ok = FALSE;
+    }
+    if(resize_cb) resize_cb(user_data);
+  }
+
+  float *const buf = ok ? pd->buf : NULL;
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+
+  return buf;
+}
+
+void dt_preview_data_set_hash(dt_preview_data_t *pd,
+                              const dt_dev_pixelpipe_iop_t *piece)
+{
+  if(!pd || !pd->module) return;
+
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+  pd->hash = dt_dev_pixelpipe_piece_hash((dt_dev_pixelpipe_iop_t *)piece,
+                                         &piece->processed_roi_out, TRUE);
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+}
+
+gboolean dt_preview_data_get(dt_preview_data_t *pd,
+                             const size_t x,
+                             const size_t y,
+                             const size_t comp,
+                             float *value)
+{
+  if(!pd || !pd->module || !value) return FALSE;
+
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+
+  gboolean ok = FALSE;
+  float v = 0.f;
+  // The bounds check and the buffer read must both happen under the
+  // GUI lock: the pipe thread may resize pd->buf between the two.
+  if(pd->buf && x < pd->width && y < pd->height && comp < pd->components)
+  {
+    const size_t idx = (((size_t)y * pd->width + (size_t)x) * pd->components) + comp;
+    v = pd->buf[idx];
+    ok = TRUE;
+  }
+
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+
+  *value = v;
+  return ok;
+}
+
+gboolean dt_preview_data_is_fresh(dt_preview_data_t *pd)
+{
+  if(!pd || !pd->module || !pd->buf) return FALSE;
+
+  const dt_iop_module_t *const module = pd->module;
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)module);
+
+  // No value stored yet, or the stored data has been invalidated.
+  const dt_hash_t stored_hash = pd->hash;
+  gboolean fresh = (stored_hash != DT_INVALID_HASH);
+
+  if(fresh)
+  {
+    const dt_develop_t *const dev = module->dev;
+    if(!dev || !dev->preview_pipe)
+      fresh = FALSE;
+    else
+    {
+      dt_dev_pixelpipe_iop_t *piece = NULL;
+      for(GList *iter = dev->preview_pipe->nodes; iter; iter = g_list_next(iter))
+      {
+        dt_dev_pixelpipe_iop_t *const p = (dt_dev_pixelpipe_iop_t *)iter->data;
+        if(p->module == module)
+        {
+          piece = p;
+          break;
+        }
+      }
+      if(!piece)
+        fresh = FALSE;
+      else
+      {
+        const dt_hash_t cur_hash = dt_dev_pixelpipe_piece_hash(piece, &piece->processed_roi_out, TRUE);
+        fresh = (cur_hash == stored_hash);
+      }
+    }
+  }
+
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)module);
+  return fresh;
+}
+
+dt_hash_t dt_preview_data_get_hash(dt_preview_data_t *pd)
+{
+  if(!pd || !pd->module) return DT_INVALID_HASH;
+
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+  const dt_hash_t hash = pd->hash;
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+
+  return hash;
+}
+
+void dt_preview_data_invalidate(dt_preview_data_t *pd)
+{
+  if(!pd || !pd->module) return;
+
+  dt_iop_gui_enter_critical_section((dt_iop_module_t *)pd->module);
+  pd->hash = DT_INVALID_HASH;
+  dt_iop_gui_leave_critical_section((dt_iop_module_t *)pd->module);
+}
+
+// clang-format off
+// modelines: These editor modelines have been set for all relevant files by tools/update_modelines.py
+// vim: shiftwidth=2 expandtab tabstop=2 cindent
+// kate: tab-indents: off; indent-width 2; replace-tabs on; indent-mode cstyle; remove-trailing-spaces modified;
+// clang-format on