Grease Pencil - Storyboarding Features (merge from GPencil_EditStrokes branch)

This merge-commit brings in a number of new features and workflow/UI improvements for
working with Grease Pencil. While these were originally targetted at improving
the workflow for creating 3D storyboards in Blender using the Grease Pencil,
many of these changes should also prove useful in other workflows too.

The main highlights here are:
1) It is now possible to edit Grease Pencil strokes
   - Use D Tab, or toggle the "Enable Editing" toggles in the Toolbar/Properties regions
     to enter "Stroke Edit Mode". In this mode, many common editing tools will
     operate on Grease Pencil stroke points instead.
   - Tools implemented include Select, Select All/Border/Circle/Linked/More/Less,
     Grab, Rotate, Scale, Bend, Shear, To Sphere, Mirror, Duplicate, Delete.
   - Proportional Editing works when using the transform tools

2) Grease Pencil stroke settings can now be animated
   NOTE: Currently drivers don't work, but if time allows, this may still be
         added before the release.

3) Strokes can be drawn with "filled" interiors, using a separate set of
   colour/opacity settings to the ones used for the lines themselves.

   This makes use of OpenGL filled polys, which has the limitation of only
   being able to fill convex shapes. Some artifacts may be visible on concave
   shapes (e.g. pacman's mouth will be overdrawn)

4) "Volumetric Strokes" - An alternative drawing technique for stroke drawing
   has been added which draws strokes as a series of screen-aligned discs.

   While this was originally a partial experimental technique at getting better
   quality 3D lines, the effects possible using this technique were interesting
   enough to warrant making this a dedicated feature. Best results when partial
   opacity and large stroke widths are used.

5) Improved Onion Skinning Support
   - Different colours can be selected for the before/after ghosts. To do so,
     enable the "colour wheel" toggle beside the Onion Skinning toggle, and set
     the colours accordingly.
   - Different numbers of ghosts can be shown before/after the current frame

6) Grease Pencil datablocks are now attached to the scene by default instead of
   the active object.
   - For a long time, the object-attachment has proved to be quite problematic
     for users to keep track of. Now that this is done at scene level, it is
     easier for most users to use.
   - An exception for old files (and for any addons which may benefit from object
     attachment instead), is that if the active object has a Grease Pencil datablock,
     that will be used instead.
   - It is not currently possible to choose object-attachment from the UI, but
     it is simple to do this from the console instead, by doing:
     context.active_object.grease_pencil = bpy.data.grease_pencil["blah"]

7) Various UI Cleanups
   - The layers UI has been cleaned up to use a list instead of the nested-panels
     design. Apart from saving space, this is also much nicer to look at now.

   - The UI code is now all defined in Python. To support this, it has been necessary
     to add some new context properties to make it easier to access these settings.
     e.g. "gpencil_data" for the datablock
          "active_gpencil_layer" and "active_gpencil_frame" for active data,
          "editable_gpencil_strokes" for the strokes that can be edited

   - The "stroke placement/alignment" settings (previously "Drawing Settings" at the
     bottom of the Grease Pencil panel in the Properties Region) is now located in
     the toolbar. These were more toolsettings than properties for how GPencil got drawn.

   - "Use Sketching Sessions" has been renamed "Continuous Drawing", as per a
     suggestion for an earlier discussion on developer.blender.org

   - By default, the painting operator will wait for a mouse button to be pressed
     before it starts creating the stroke. This is to make it easier to include
     this operator in various toolbars/menus/etc.   To get it immediately starting
     (as when you hold down DKEy to draw), set "wait_for_input" to False.

   - GPencil Layers can be rearranged in the "Grease Pencil" mode of the Action Editor

   - Toolbar panels have been added to all the other editors which support these.

8) Pie menus for quick-access to tools
   A set of experimental pie menus has been included for quick access to many
   tools and settings. It is not necessary to use these to get things done,
   but they have been designed to help make certain common tasks easier.

   - Ctrl-D = The main pie menu. Reveals tools in a context sensitive and
              spatially stable manner.
   - D Q    = "Quick Settings" pie. This allows quick access to the active
              layer's settings. Notably, colours, thickness, and turning
              onion skinning on/off.

1 files changed, 75 insertions, 35 deletions

diff --git a/source/blender/makesdna/DNA_gpencil_types.h b/source/blender/makesdna/DNA_gpencil_types.h
index 2bf874d3a85..3fb047ebbe7 100644
--- a/source/blender/makesdna/DNA_gpencil_types.h
+++ b/source/blender/makesdna/DNA_gpencil_types.h
@@ -33,6 +33,9 @@
 #include "DNA_listBase.h"
 #include "DNA_ID.h"
 
+struct AnimData;
+
+
 /* Grease-Pencil Annotations - 'Stroke Point'
  *	-> Coordinates may either be 2d or 3d depending on settings at the time
  * 	-> Coordinates of point on stroke, in proportions of window size
@@ -42,8 +45,15 @@ typedef struct bGPDspoint {
 	float x, y, z;			/* co-ordinates of point (usually 2d, but can be 3d as well) */
 	float pressure;			/* pressure of input device (from 0 to 1) at this point */
 	float time;				/* seconds since start of stroke */
+	int flag;				/* additional options (NOTE: can shrink this field down later if needed) */
 } bGPDspoint;
 
+/* bGPDspoint->flag */
+typedef enum eGPDspoint_Flag {
+	/* stroke point is selected (for editing) */
+	GP_SPOINT_SELECT	= (1 << 0)
+} eGPSPoint_Flag;
+
 /* Grease-Pencil Annotations - 'Stroke'
  * 	-> A stroke represents a (simplified version) of the curve
  *	   drawn by the user in one 'mousedown'->'mouseup' operation
@@ -61,15 +71,18 @@ typedef struct bGPDstroke {
 } bGPDstroke;
 
 /* bGPDstroke->flag */
+typedef enum eGPDstroke_Flag {
 	/* stroke is in 3d-space */
-#define GP_STROKE_3DSPACE		(1<<0)
+	GP_STROKE_3DSPACE		= (1 << 0),
 	/* stroke is in 2d-space */
-#define GP_STROKE_2DSPACE		(1<<1)
+	GP_STROKE_2DSPACE		= (1 << 1),
 	/* stroke is in 2d-space (but with special 'image' scaling) */
-#define GP_STROKE_2DIMAGE		(1<<2)
+	GP_STROKE_2DIMAGE		= (1 << 2),
+	/* stroke is selected */
+	GP_STROKE_SELECT		= (1 << 3),
 	/* only for use with stroke-buffer (while drawing eraser) */
-#define GP_STROKE_ERASER		(1<<15)
-
+	GP_STROKE_ERASER		= (1 << 15)
+} eGPDstroke_Flag;
 
 /* Grease-Pencil Annotations - 'Frame'
  *	-> Acts as storage for the 'image' formed by strokes
@@ -80,15 +93,18 @@ typedef struct bGPDframe {
 	ListBase strokes;	/* list of the simplified 'strokes' that make up the frame's data */
 	
 	int framenum;		/* frame number of this frame */
-	int flag;			/* temp settings */
+	
+	short flag;			/* temp settings */
+	short key_type;		/* keyframe type (eBezTriple_KeyframeType) */
 } bGPDframe;
 
-/* bGPDframe->flag */	
+/* bGPDframe->flag */
+typedef enum eGPDframe_Flag {
 	/* frame is being painted on */
-#define GP_FRAME_PAINT		(1<<0)
+	GP_FRAME_PAINT		= (1 << 0),
 	/* for editing in Action Editor */
-#define GP_FRAME_SELECT		(1<<1)
-
+	GP_FRAME_SELECT		= (1 << 1)
+} eGPDframe_Flag;
 
 /* Grease-Pencil Annotations - 'Layer' */
 typedef struct bGPDlayer {
@@ -97,38 +113,52 @@ typedef struct bGPDlayer {
 	ListBase frames;		/* list of annotations to display for frames (bGPDframe list) */
 	bGPDframe *actframe;	/* active frame (should be the frame that is currently being displayed) */
 	
-	int flag;				/* settings for layer */
+	short flag;				/* settings for layer */
 	short thickness;		/* current thickness to apply to strokes */
-	short gstep;			/* max number of frames between active and ghost to show (0=only those on either side) */
+	
+	short gstep;			/* Ghosts Before: max number of ghost frames to show between active frame and the one before it (0 = only the ghost itself) */
+	short gstep_next;		/* Ghosts After:  max number of ghost frames to show after active frame and the following it    (0 = only the ghost itself) */
+	
+	float gcolor_prev[3];	/* optional color for ghosts before the active frame */
+	float gcolor_next[3];	/* optional color for ghosts after the active frame */
 	
 	float color[4];			/* color that should be used to draw all the strokes in this layer */
+	float fill[4];			/* color that should be used for drawing "fills" for strokes */
 	
 	char info[128];			/* optional reference info about this layer (i.e. "director's comments, 12/3")
 							 * this is used for the name of the layer  too and kept unique. */
 } bGPDlayer;
 
 /* bGPDlayer->flag */
+typedef enum eGPDlayer_Flag {
 	/* don't display layer */
-#define GP_LAYER_HIDE		(1<<0)
+	GP_LAYER_HIDE			= (1 << 0),
 	/* protected from further editing */
-#define GP_LAYER_LOCKED		(1<<1)	
+	GP_LAYER_LOCKED			= (1 << 1),
 	/* layer is 'active' layer being edited */
-#define GP_LAYER_ACTIVE		(1<<2)
+	GP_LAYER_ACTIVE			= (1 << 2),
 	/* draw points of stroke for debugging purposes */
-#define GP_LAYER_DRAWDEBUG 	(1<<3)
-	/* do onionskinning */
-#define GP_LAYER_ONIONSKIN	(1<<4)
+	GP_LAYER_DRAWDEBUG 		= (1 << 3),
+	/* do onion skinning */
+	GP_LAYER_ONIONSKIN		= (1 << 4),
 	/* for editing in Action Editor */
-#define GP_LAYER_SELECT		(1<<5)
+	GP_LAYER_SELECT			= (1 << 5),
 	/* current frame for layer can't be changed */
-#define GP_LAYER_FRAMELOCK	(1<<6)
+	GP_LAYER_FRAMELOCK		= (1 << 6),
 	/* don't render xray (which is default) */
-#define GP_LAYER_NO_XRAY	(1<<7)
-
+	GP_LAYER_NO_XRAY		= (1 << 7),
+	/* use custom color for ghosts before current frame */
+	GP_LAYER_GHOST_PREVCOL	= (1 << 8),
+	/* use custom color for ghosts after current frame */
+	GP_LAYER_GHOST_NEXTCOL	= (1 << 9),
+	/* "volumetric" strokes (i.e. GLU Quadric discs in 3D) */
+	GP_LAYER_VOLUMETRIC		= (1 << 10),
+} eGPDlayer_Flag;
 
 /* Grease-Pencil Annotations - 'DataBlock' */
 typedef struct bGPdata {
-	ID id;					/* Grease Pencil data is */
+	ID id;					/* Grease Pencil data is a datablock */
+	struct AnimData *adt;   /* animation data - for animating draw settings */
 	
 	/* saved Grease-Pencil data */
 	ListBase layers;		/* bGPDlayers */
@@ -144,23 +174,33 @@ typedef struct bGPdata {
 } bGPdata;
 
 /* bGPdata->flag */
-// XXX many of these flags should be deprecated for more general ideas in 2.5
+/* NOTE: A few flags have been deprecated since early 2.5,
+ *       since they have been made redundant by interaction
+ *       changes made during the porting process.
+ */
+typedef enum eGPdata_Flag {
 	/* don't allow painting to occur at all */
-	// XXX is deprecated - not well understood
-// #define GP_DATA_LMBPLOCK	(1<<0)
+	/* GP_DATA_LMBPLOCK  = (1 << 0), */
+	
 	/* show debugging info in viewport (i.e. status print) */
-#define GP_DATA_DISPINFO	(1<<1)
+	GP_DATA_DISPINFO	= (1 << 1),
 	/* in Action Editor, show as expanded channel */
-#define GP_DATA_EXPAND		(1<<2)
+	GP_DATA_EXPAND		= (1 << 2),
+	
 	/* is the block overriding all clicks? */
-	// XXX is deprecated - nasty old concept
-// #define GP_DATA_EDITPAINT	(1<<3)
+ 	/* GP_DATA_EDITPAINT = (1 << 3), */
+	
 	/* new strokes are added in viewport space */
-#define GP_DATA_VIEWALIGN	(1<<4)
-	/* Project into the screens Z values */
-#define GP_DATA_DEPTH_VIEW	(1<<5)
-#define GP_DATA_DEPTH_STROKE (1<<6)
+	GP_DATA_VIEWALIGN	= (1 << 4),
+	
+	/* Project into the screen's Z values */
+	GP_DATA_DEPTH_VIEW	= (1 << 5),
+	GP_DATA_DEPTH_STROKE = (1 << 6),
 
-#define GP_DATA_DEPTH_STROKE_ENDPOINTS (1<<7)
+	GP_DATA_DEPTH_STROKE_ENDPOINTS = (1 << 7),
+	
+	/* Stroke Editing Mode - Toggle to enable alternative keymap for easier editing of stroke points */
+	GP_DATA_STROKE_EDITMODE	= (1 << 8)
+} eGPdata_Flag;
 
 #endif /*  __DNA_GPENCIL_TYPES_H__ */