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.

4 files changed, 64 insertions, 2 deletions

diff --git a/release/scripts/modules/bl_keymap_utils/keymap_hierarchy.py b/release/scripts/modules/bl_keymap_utils/keymap_hierarchy.py
index 52b9f1601d5..f92a478fb66 100644
--- a/release/scripts/modules/bl_keymap_utils/keymap_hierarchy.py
+++ b/release/scripts/modules/bl_keymap_utils/keymap_hierarchy.py
@@ -191,6 +191,7 @@ _km_hierarchy = [
     ]),
 
     ('Grease Pencil', 'EMPTY', 'WINDOW', [  # grease pencil stuff (per region)
+        ('Grease Pencil Stroke Curve Edit Mode', 'EMPTY', 'WINDOW', []),
         ('Grease Pencil Stroke Edit Mode', 'EMPTY', 'WINDOW', []),
         ('Grease Pencil Stroke Paint (Draw brush)', 'EMPTY', 'WINDOW', []),
         ('Grease Pencil Stroke Paint (Fill)', 'EMPTY', 'WINDOW', []),
diff --git a/release/scripts/presets/keyconfig/keymap_data/blender_default.py b/release/scripts/presets/keyconfig/keymap_data/blender_default.py
index 174ab6fd28b..d66d7c45dd4 100644
--- a/release/scripts/presets/keyconfig/keymap_data/blender_default.py
+++ b/release/scripts/presets/keyconfig/keymap_data/blender_default.py
@@ -3226,6 +3226,9 @@ def km_grease_pencil_stroke_edit_mode(params):
          {"properties": [("mode", 'GPENCIL_OPACITY')]}),
         # Proportional editing.
         *_template_items_proportional_editing(connected=True),
+        # Curve edit mode toggle.
+        ("wm.context_toggle", {"type": 'U', "value": 'PRESS'},
+         {"properties": [("data_path", 'gpencil_data.use_curve_edit')]}),
         # Add menu
         ("object.gpencil_add", {"type": 'A', "value": 'PRESS', "shift": True}, None),
         # Vertex group menu
@@ -3253,6 +3256,20 @@ def km_grease_pencil_stroke_edit_mode(params):
 
     return keymap
 
+def km_grease_pencil_stroke_curve_edit_mode(params):
+    items = []
+    keymap = (
+        "Grease Pencil Stroke Curve Edit Mode",
+        {"space_type": 'EMPTY', "region_type": 'WINDOW'},
+        {"items": items},
+    )
+
+    items.extend([
+        # Set handle type
+        ("gpencil.stroke_editcurve_set_handle_type", {"type": 'V', "value": 'PRESS'}, None),
+    ])
+
+    return keymap
 
 def km_grease_pencil_stroke_paint_mode(params):
     items = []
@@ -6890,6 +6907,7 @@ def generate_keymaps(params=None):
 
         # Modes.
         km_grease_pencil(params),
+        km_grease_pencil_stroke_curve_edit_mode(params),
         km_grease_pencil_stroke_edit_mode(params),
         km_grease_pencil_stroke_paint_mode(params),
         km_grease_pencil_stroke_paint_draw_brush(params),
diff --git a/release/scripts/startup/bl_ui/properties_data_gpencil.py b/release/scripts/startup/bl_ui/properties_data_gpencil.py
index affdba6f693..398bf60c493 100644
--- a/release/scripts/startup/bl_ui/properties_data_gpencil.py
+++ b/release/scripts/startup/bl_ui/properties_data_gpencil.py
@@ -369,6 +369,8 @@ class DATA_PT_gpencil_strokes(DataButtonsPanel, Panel):
         sub.active = gpd.stroke_thickness_space == 'WORLDSPACE'
         sub.prop(gpd, "pixel_factor", text="Thickness Scale")
 
+        col.prop(gpd, "edit_curve_resolution")
+
 
 class DATA_PT_gpencil_display(DataButtonsPanel, Panel):
     bl_label = "Viewport Display"
diff --git a/release/scripts/startup/bl_ui/space_view3d.py b/release/scripts/startup/bl_ui/space_view3d.py
index 1b5a7da61b0..9dbb56e7e45 100644
--- a/release/scripts/startup/bl_ui/space_view3d.py
+++ b/release/scripts/startup/bl_ui/space_view3d.py
@@ -661,7 +661,23 @@ class VIEW3D_HT_header(Header):
             # Select mode for Editing
             if gpd.use_stroke_edit_mode:
                 row = layout.row(align=True)
-                row.prop(tool_settings, "gpencil_selectmode_edit", text="", expand=True)
+                row.prop_enum(tool_settings, "gpencil_selectmode_edit", text="", value='POINT')
+                row.prop_enum(tool_settings, "gpencil_selectmode_edit", text="", value='STROKE')
+
+                subrow = row.row(align=True)
+                subrow.enabled = not gpd.use_curve_edit
+                subrow.prop_enum(tool_settings, "gpencil_selectmode_edit", text="", value='SEGMENT')
+
+                # Curve edit submode
+                row = layout.row(align=True)
+                row.prop(gpd, "use_curve_edit", text="",
+                         icon='IPO_BEZIER')
+                sub = row.row(align=True)
+                sub.active = gpd.use_curve_edit
+                sub.popover(
+                    panel="VIEW3D_PT_gpencil_curve_edit",
+                    text="Curve Editing",
+                )
 
             # Select mode for Sculpt
             if gpd.is_stroke_sculpt_mode:
@@ -687,7 +703,7 @@ class VIEW3D_HT_header(Header):
                 row.prop(gpd, "use_multiedit", text="", icon='GP_MULTIFRAME_EDITING')
 
                 sub = row.row(align=True)
-                sub.active = gpd.use_multiedit
+                sub.enabled = gpd.use_multiedit
                 sub.popover(
                     panel="VIEW3D_PT_gpencil_multi_frame",
                     text="Multiframe",
@@ -6802,6 +6818,12 @@ class VIEW3D_PT_overlay_gpencil_options(Panel):
 
             layout.prop(overlay, "vertex_opacity", text="Vertex Opacity", slider=True)
 
+            # Handles for Curve Edit
+            if context.object.mode == 'EDIT_GPENCIL':
+                gpd = context.object.data
+                if gpd.use_curve_edit:
+                    layout.prop(overlay, "display_handle", text="Handles")
+
         if context.object.mode in {'PAINT_GPENCIL', 'VERTEX_GPENCIL'}:
             layout.label(text="Vertex Paint")
             row = layout.row()
@@ -6965,6 +6987,24 @@ class VIEW3D_PT_gpencil_multi_frame(Panel):
             layout.template_curve_mapping(settings, "multiframe_falloff_curve", brush=True)
 
 
+# Grease Pencil Object - Curve Editing tools
+class VIEW3D_PT_gpencil_curve_edit(Panel):
+    bl_space_type = 'VIEW_3D'
+    bl_region_type = 'HEADER'
+    bl_label = "Curve Editing"
+
+    def draw(self, context):
+        gpd = context.gpencil_data
+        settings = context.tool_settings.gpencil_sculpt
+
+        layout = self.layout
+        col = layout.column(align=True)
+        col.prop(gpd, "edit_curve_resolution")
+        col.prop(gpd, "curve_edit_threshold")
+        col.prop(gpd, "curve_edit_corner_angle")
+        col.prop(gpd, "use_adaptive_curve_resolution")
+
+
 class VIEW3D_MT_gpencil_edit_context_menu(Menu):
     bl_label = ""
 
@@ -7606,6 +7646,7 @@ classes = (
     VIEW3D_PT_grease_pencil,
     VIEW3D_PT_annotation_onion,
     VIEW3D_PT_gpencil_multi_frame,
+    VIEW3D_PT_gpencil_curve_edit,
     VIEW3D_PT_quad_view,
     VIEW3D_PT_view3d_stereo,
     VIEW3D_PT_shading,