agx: don't activate the pivot pickers until the user starts dragging the mouse

src/gui/color_picker_proxy.c

@@ -73,6 +73,11 @@ gboolean dt_iop_color_picker_is_visible(const dt_develop_t *dev)
   return module_picker || primary_picker;
 }
 
+gboolean dt_iop_color_picker_is_area_empty(const dt_pickerbox_t box)
+{
+  return (fabsf(box[2] - box[0]) < 1e-3f || fabsf(box[3] - box[1]) < 1e-3f);
+}
+
 static gboolean _record_point_area(dt_iop_color_picker_t *self)
 {
   const dt_colorpicker_sample_t *const sample =
@@ -204,8 +209,16 @@ static gboolean _color_picker_callback_button_press(GtkWidget *button,
       if(   self->pick_box[0] == 0.0f && self->pick_box[1] == 0.0f
          && self->pick_box[2] == 1.0f && self->pick_box[3] == 1.0f)
       {
-        dt_boundingbox_t reset = { 0.02f, 0.02f, 0.98f, 0.98f };
-        dt_color_picker_backtransform_box(darktable.develop, 2, reset, self->pick_box);
+        if(flags & DT_COLOR_PICKER_NO_AUTO)
+        {
+          // reset coordinates to 0.0f to create a zero-area box,
+          // requiring the user to drag-select manually
+          memset(self->pick_box, 0, sizeof(self->pick_box));
+        }
+        else {
+          dt_boundingbox_t reset = { 0.02f, 0.02f, 0.98f, 0.98f };
+          dt_color_picker_backtransform_box(darktable.develop, 2, reset, self->pick_box);
+        }
       }
       dt_lib_colorpicker_set_box_area(darktable.lib, self->pick_box);
     }
@@ -317,6 +330,13 @@ static void _iop_color_picker_pickerdata_ready_callback(gpointer instance,
   // iops only need new picker data if the pointer has moved
   if(_record_point_area(picker))
   {
+    // in Area mode, ignore updates where the area is empty (e.g. when using DT_COLOR_PICKER_NO_AUTO
+    // and the user has not started dragging yet)
+    if((picker->flags & DT_COLOR_PICKER_AREA) && dt_iop_color_picker_is_area_empty(picker->pick_box))
+    {
+      return;
+    }
+
     if(!module->blend_data || !blend_color_picker_apply(module, picker->colorpick, pipe))
     {
       if(module->color_picker_apply)

src/gui/color_picker_proxy.h

@@ -40,7 +40,9 @@ typedef enum _iop_color_picker_flags_t
   // only works with 4-channel images
   DT_COLOR_PICKER_DENOISE = 1 << 2,
   // all pickers sample input, only ones with this flag set sample output
-  DT_COLOR_PICKER_IO = 1 << 3
+  DT_COLOR_PICKER_IO = 1 << 3,
+  // don't auto-expand the area, wait for user selection via dragging
+  DT_COLOR_PICKER_NO_AUTO = 1 << 4
 } dt_iop_color_picker_flags_t;
 
 typedef struct dt_iop_color_picker_t
@@ -71,6 +73,8 @@ typedef struct dt_iop_color_picker_t
 
 gboolean dt_iop_color_picker_is_visible(const dt_develop_t *dev);
 
+gboolean dt_iop_color_picker_is_area_empty(const dt_pickerbox_t box);
+
 //* reset current color picker if not keep-active or not keep */
 void dt_iop_color_picker_reset(dt_iop_module_t *module,
                                const gboolean keep);

src/iop/agx.c

@@ -1170,6 +1170,12 @@ static void _read_exposure_params_callback(GtkWidget *widget,
 // move only the pivot's relative (input) exposure, and recalculate its output based on mid-gray
 static void _apply_auto_pivot_xy(dt_iop_module_t *self, const dt_iop_order_iccprofile_info_t *profile)
 {
+  printf("_apply_auto_pivot_xy, %d\n", darktable.control->button_down);
+  // don't update while the user is dragging the mouse
+  if (darktable.control->button_down) {
+    return;
+  }
+
   dt_iop_agx_params_t *p = self->params;
   const dt_iop_agx_gui_data_t *g = self->gui_data;
 
@@ -1824,7 +1830,7 @@ static GtkWidget* _create_basic_curve_controls_box(dt_iop_module_t *self,
                                                "used to set the pivot relative to mid-gray"));
 
   // curve_pivot_y_linear
-  slider = dt_color_picker_new(self, DT_COLOR_PICKER_AREA | DT_COLOR_PICKER_DENOISE, dt_bauhaus_slider_from_params(section, "curve_pivot_y_linear_output"));
+  slider = dt_color_picker_new(self, DT_COLOR_PICKER_AREA | DT_COLOR_PICKER_DENOISE | DT_COLOR_PICKER_NO_AUTO, dt_bauhaus_slider_from_params(section, "curve_pivot_y_linear_output"));
   controls->curve_pivot_y_linear = slider;
   dt_bauhaus_slider_set_format(slider, "%");
   dt_bauhaus_slider_set_digits(slider, 2);

src/views/darkroom.c

@@ -310,6 +310,10 @@ static void _darkroom_pickers_draw(dt_view_t *self,
     // overlays are aligned with pixels for a clean look
     if(sample->size == DT_LIB_COLORPICKER_SIZE_BOX)
     {
+      // do not draw if the area is empty
+      if(dt_iop_color_picker_is_area_empty(sample->box))
+        continue;
+
       dt_boundingbox_t fbox;
       dt_color_picker_transform_box(dev, 2, sample->box, fbox, FALSE);
       x = fbox[0];
@@ -3442,6 +3446,10 @@ int button_released(dt_view_t *self,
   int handled = 0;
   if(dt_iop_color_picker_is_visible(dev) && which == GDK_BUTTON_PRIMARY)
   {
+    // force an update on release so modules can detect the finish event
+    if(darktable.lib->proxy.colorpicker.picker_proxy)
+      darktable.lib->proxy.colorpicker.picker_proxy->changed = TRUE;
+
     // only sample box picker at end, for speed
     if(darktable.lib->proxy.colorpicker.primary_sample->size == DT_LIB_COLORPICKER_SIZE_BOX)
     {