UI Code Quality: Use derived struct for curve profile buttons

Continuing the work from rB49f088e2d093.

Differential Revision: https://developer.blender.org/D8561

source/blender/editors/interface/interface.c

@@ -3797,6 +3797,10 @@ static void ui_but_alloc_info(const eButType type,
       alloc_size = sizeof(uiButHSVCube);
       alloc_str = "uiButHSVCube";
       break;
+    case UI_BTYPE_CURVEPROFILE:
+      alloc_size = sizeof(uiButCurveProfile);
+      alloc_str = "uiButCurveProfile";
+      break;
     default:
       alloc_size = sizeof(uiBut);
       alloc_str = "uiBut";

source/blender/editors/interface/interface_draw.c

@@ -2179,13 +2179,10 @@ void ui_draw_but_CURVEPROFILE(ARegion *region,
 {
   uint i;
   float fx, fy;
-  CurveProfile *profile;
-  if (but->editprofile) {
-    profile = but->editprofile;
-  }
-  else {
-    profile = (CurveProfile *)but->poin;
-  }
+
+  uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+  CurveProfile *profile = (but_profile->edit_profile == NULL) ? (CurveProfile *)but->poin :
+                                                                but_profile->edit_profile;
 
   /* Calculate offset and zoom. */
   float zoomx = (BLI_rcti_size_x(rect) - 2.0f) / BLI_rctf_size_x(&profile->view_rect);

source/blender/editors/interface/interface_handlers.c

@@ -2088,13 +2088,19 @@ static void ui_apply_but(
   editvec = but->editvec;
   editcoba = but->editcoba;
   editcumap = but->editcumap;
-  editprofile = but->editprofile;
+  if (but->type == UI_BTYPE_CURVEPROFILE) {
+    uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+    editprofile = but_profile->edit_profile;
+  }
   but->editstr = NULL;
   but->editval = NULL;
   but->editvec = NULL;
   but->editcoba = NULL;
   but->editcumap = NULL;
-  but->editprofile = NULL;
+  if (but->type == UI_BTYPE_CURVEPROFILE) {
+    uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+    but_profile->edit_profile = NULL;
+  }
 
   /* handle different types */
   switch (but->type) {
@@ -2205,7 +2211,10 @@ static void ui_apply_but(
   but->editvec = editvec;
   but->editcoba = editcoba;
   but->editcumap = editcumap;
-  but->editprofile = editprofile;
+  if (but->type == UI_BTYPE_CURVEPROFILE) {
+    uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+    but_profile->edit_profile = editprofile;
+  }
 }
 
 /** \} */
@@ -3851,7 +3860,8 @@ static void ui_numedit_begin(uiBut *but, uiHandleButtonData *data)
     but->editcumap = (CurveMapping *)but->poin;
   }
   if (but->type == UI_BTYPE_CURVEPROFILE) {
-    but->editprofile = (CurveProfile *)but->poin;
+    uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+    but_profile->edit_profile = (CurveProfile *)but->poin;
   }
   else if (but->type == UI_BTYPE_COLORBAND) {
     data->coba = (ColorBand *)but->poin;
@@ -3943,8 +3953,10 @@ static void ui_numedit_end(uiBut *but, uiHandleButtonData *data)
   but->editvec = NULL;
   but->editcoba = NULL;
   but->editcumap = NULL;
-  but->editprofile = NULL;
-
+  if (but->type == UI_BTYPE_CURVEPROFILE) {
+    uiButCurveProfile *but_profile = (uiButCurveProfile *)but;
+    but_profile->edit_profile = NULL;
+  }
   data->dragstartx = 0;
   data->draglastx = 0;
   data->dragchange = false;

source/blender/editors/interface/interface_intern.h

@@ -33,6 +33,7 @@
 
 struct AnimationEvalContext;
 struct ARegion;
+struct CurveProfile;
 struct ID;
 struct ImBuf;
 struct Scene;
@@ -268,7 +269,6 @@ struct uiBut {
   float *editvec;
   void *editcoba;
   void *editcumap;
-  void *editprofile;
 
   uiButPushedStateFunc pushed_state_func;
   void *pushed_state_arg;
@@ -320,6 +320,7 @@ typedef struct uiButDecorator {
   int rnaindex;
 } uiButDecorator;
 
+/** Derived struct for #UI_BTYPE_PROGRESS_BAR. */
 typedef struct uiButProgressbar {
   uiBut but;
 
@@ -327,12 +328,20 @@ typedef struct uiButProgressbar {
   float progress;
 } uiButProgressbar;
 
+/** Derived struct for #UI_BTYPE_HSVCUBE. */
 typedef struct uiButHSVCube {
   uiBut but;
 
   eButGradientType gradient_type;
 } uiButHSVCube;
 
+/** Derived struct for #UI_BTYPE_CURVEPROFILE. */
+typedef struct uiButCurveProfile {
+  uiBut but;
+
+  struct CurveProfile *edit_profile;
+} uiButCurveProfile;
+
 /**
  * Additional, superimposed icon for a button, invoking an operator.
  */