[Bf-blender-cvs] [97b0d23] master: GPencil: Add option to draw new strokes on back of layer

[Antonioya]

Commit: 97b0d23357b1f48f30d45f2f328707a7bdc40695
Author: Antonioya
Date:   Fri Aug 5 23:03:51 2016 +0200
Branches: master
https://developer.blender.org/rB97b0d23357b1f48f30d45f2f328707a7bdc40695

GPencil: Add option to draw new strokes on back of layer

For artist point of view is very useful to have an option to draw by
default the new strokes on back of all strokes in the layer.

===================================================================

M	release/scripts/startup/bl_ui/properties_grease_pencil_common.py
M	source/blender/editors/gpencil/gpencil_paint.c
M	source/blender/makesdna/DNA_scene_types.h
M	source/blender/makesrna/intern/rna_scene.c

===================================================================

diff --git a/release/scripts/startup/bl_ui/properties_grease_pencil_common.py b/release/scripts/startup/bl_ui/properties_grease_pencil_common.py
index c80c5ca..cabcd49 100644
--- a/release/scripts/startup/bl_ui/properties_grease_pencil_common.py
+++ b/release/scripts/startup/bl_ui/properties_grease_pencil_common.py
@@ -80,6 +80,7 @@ class GreasePencilDrawingToolsPanel:
         sub = col.column(align=True)
         sub.prop(context.tool_settings, "use_gpencil_additive_drawing", text="Additive Drawing")
         sub.prop(context.tool_settings, "use_gpencil_continuous_drawing", text="Continuous Drawing")
+        sub.prop(context.tool_settings, "use_gpencil_draw_onback", text="Draw on Back")
 
         col.separator()
         col.separator()
diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index d637aff..cebcbfe 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -692,6 +692,7 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
 	bGPDspoint *pt;
 	tGPspoint *ptc;
 	bGPDbrush *brush = p->brush;
+	ToolSettings *ts = p->scene->toolsettings;
 	
 	int i, totelem;
 	/* since strokes are so fine, when using their depth we need a margin otherwise they might get missed */
@@ -925,8 +926,16 @@ static void gp_stroke_newfrombuffer(tGPsdata *p)
 	gps->palcolor = palcolor;
 	strcpy(gps->colorname, palcolor->info);
 
-	/* add stroke to frame */
-	BLI_addtail(&p->gpf->strokes, gps);
+	/* add stroke to frame, usually on tail of the listbase, but if on back is enabled the stroke is added on listbase head 
+	* because the drawing order is inverse and the head stroke is the first to draw. This is very useful for artist
+	* when drawing the background
+	*/
+	if (ts->gpencil_flags & GP_TOOL_FLAG_PAINT_ONBACK) {
+		BLI_addhead(&p->gpf->strokes, gps);
+	}
+	else {
+		BLI_addtail(&p->gpf->strokes, gps);
+	}
 	gp_stroke_added_enable(p);
 }
 
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 90e8d8b..a4934cc 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -2088,6 +2088,8 @@ typedef enum eGPencil_Flags {
 	GP_TOOL_FLAG_PAINTSESSIONS_ON       = (1 << 0),
 	/* When creating new frames, the last frame gets used as the basis for the new one */
 	GP_TOOL_FLAG_RETAIN_LAST            = (1 << 1),
+	/* Add the strokes below all strokes in the layer */
+	GP_TOOL_FLAG_PAINT_ONBACK = (1 << 2)
 } eGPencil_Flags;
 
 /* toolsettings->gpencil_src */
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index abac6b9..156c327 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -2612,6 +2612,12 @@ static void rna_def_tool_settings(BlenderRNA  *brna)
 	                         "are included as the basis for the new one");
 	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
 	
+	prop = RNA_def_property(srna, "use_gpencil_draw_onback", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "gpencil_flags", GP_TOOL_FLAG_PAINT_ONBACK);
+	RNA_def_property_ui_text(prop, "Draw Strokes on Back",
+		"When draw new strokes, the new stroke is drawn below of all strokes in the layer");
+	RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL);
+
 	prop = RNA_def_property(srna, "grease_pencil_source", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_bitflag_sdna(prop, NULL, "gpencil_src");
 	RNA_def_property_enum_items(prop, gpencil_source_3d_items);