GPencil: Merge GSoC curve edit mode

Differential Revision: https://developer.blender.org/D8660

This patch is the result of the GSoC 2020 "Editing Grease Pencil Strokes
Using Curves" project. It adds a submode to greasepencil edit mode that
allows for the transformation of greasepencil strokes using bezier
curves. More information about the project can be found
here: https://wiki.blender.org/wiki/User:Filedescriptor/GSoC_2020.

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/editors/transform/transform_mode_gpopacity.c b/source/blender/editors/transform/transform_mode_gpopacity.c
index 103eb17c273..e67c6c03481 100644
--- a/source/blender/editors/transform/transform_mode_gpopacity.c
+++ b/source/blender/editors/transform/transform_mode_gpopacity.c
@@ -29,6 +29,8 @@
 #include "BKE_context.h"
 #include "BKE_unit.h"
 
+#include "DNA_gpencil_types.h"
+
 #include "ED_screen.h"
 
 #include "UI_interface.h"
@@ -68,8 +70,16 @@ static void applyGPOpacity(TransInfo *t, const int UNUSED(mval[2]))
     BLI_snprintf(str, sizeof(str), TIP_("Opacity: %3f"), ratio);
   }
 
+  bool recalc = false;
   FOREACH_TRANS_DATA_CONTAINER (t, tc) {
     TransData *td = tc->data;
+    bGPdata *gpd = td->ob->data;
+    const bool is_curve_edit = (bool)GPENCIL_CURVE_EDIT_SESSIONS_ON(gpd);
+    /* Only recalculate data when in curve edit mode. */
+    if (is_curve_edit) {
+      recalc = true;
+    }
+
     for (i = 0; i < tc->data_len; i++, td++) {
       if (td->flag & TD_SKIP) {
         continue;
@@ -84,6 +94,10 @@ static void applyGPOpacity(TransInfo *t, const int UNUSED(mval[2]))
     }
   }
 
+  if (recalc) {
+    recalcData(t);
+  }
+
   ED_area_status_text(t->area, str);
 }