UI: ShaderFx Drag and Drop, Layout Updates

This patch implements the list panel system D7490 for grease pencil
shader effects. It also moves their drawing to a callback in
ShaderFxTypeInfo in line with the extensible architecture refactoring
goal T75724.

The implementation is basically exactly the same as for the modifier
patch (9b099c86123fc82).

Thanks to Matias Mendiola (@mendio) for helping to develop the layout
changes.

Differential Revision: https://developer.blender.org/D7985

1 files changed, 3 insertions, 2 deletions

diff --git a/source/blender/makesdna/DNA_shader_fx_types.h b/source/blender/makesdna/DNA_shader_fx_types.h
index 18a4e8655a3..2ccff2da993 100644
--- a/source/blender/makesdna/DNA_shader_fx_types.h
+++ b/source/blender/makesdna/DNA_shader_fx_types.h
@@ -50,7 +50,7 @@ typedef enum ShaderFxMode {
   eShaderFxMode_Realtime = (1 << 0),
   eShaderFxMode_Render = (1 << 1),
   eShaderFxMode_Editmode = (1 << 2),
-  eShaderFxMode_Expanded = (1 << 3),
+  eShaderFxMode_Expanded_DEPRECATED = (1 << 3),
 } ShaderFxMode;
 
 typedef enum {
@@ -64,7 +64,8 @@ typedef struct ShaderFxData {
   int type, mode;
   int stackindex;
   short flag;
-  char _pad[2];
+  /* Expansion for shader effect panels and subpanels. */
+  short ui_expand_flag;
   /** MAX_NAME. */
   char name[64];