Properties Editor: Grease Pencil and pinning fixes

The UI was trying to use screen_context.c for its poll and draw
functions. So the active object and active object data and active layer
was used in the UI, instead of the context one.

Besides, for the material, the wrong context path was used altogether
when the active object was a greasepencil.

This would lead to all sort of pinning problems:

* A Mesh panel is pinned, but the active object is a grease pencil, the
grease pencil panels would show.

* If a Grease Pencil (data) panel is pinned, but the active object is not
the one pinned, nothing would show.

* Material panels and pinning were totally broken, showing the material
context for pinned mesh data panels even.

I also sanitized the name of the panels, their inheritance and poll
functions.

Reviewers: antoniov, brecht

Subscribers: billrey

Differential Revision: https://developer.blender.org/D4470

1 files changed, 53 insertions, 70 deletions

diff --git a/release/scripts/startup/bl_ui/properties_material_gpencil.py b/release/scripts/startup/bl_ui/properties_material_gpencil.py
index 282f8d77515..c8691d15cc4 100644
--- a/release/scripts/startup/bl_ui/properties_material_gpencil.py
+++ b/release/scripts/startup/bl_ui/properties_material_gpencil.py
@@ -81,10 +81,8 @@ class GPMaterialButtonsPanel:
 
     @classmethod
     def poll(cls, context):
-        ob = context.object
-        return (ob and ob.type == 'GPENCIL' and
-                ob.active_material and
-                ob.active_material.grease_pencil)
+        ma = context.material
+        return ma and ma.grease_pencil
 
 
 class MATERIAL_PT_gpencil_slots(GreasePencilMaterialsPanel, Panel):
@@ -99,18 +97,6 @@ class MATERIAL_PT_gpencil_slots(GreasePencilMaterialsPanel, Panel):
 class MATERIAL_PT_gpencil_surface(GPMaterialButtonsPanel, Panel):
     bl_label = "Surface"
 
-    @classmethod
-    def poll(cls, context):
-        ob = context.object
-        if not (ob and ob.type == 'GPENCIL'):
-            return False
-
-        ma = ob.active_material
-        if not (ma and ma.grease_pencil):
-            return False
-
-        return True
-
     def draw_header_preset(self, context):
         MATERIAL_PT_gpencil_material_presets.draw_panel_header(self.layout)
 
@@ -125,7 +111,7 @@ class MATERIAL_PT_gpencil_strokecolor(GPMaterialButtonsPanel, Panel):
     bl_parent_id = 'MATERIAL_PT_gpencil_surface'
 
     def draw_header(self, context):
-        ma = context.object.active_material
+        ma = context.material
         if ma is not None and ma.grease_pencil is not None:
             gpcolor = ma.grease_pencil
             self.layout.prop(gpcolor, "show_stroke", text="")
@@ -135,7 +121,7 @@ class MATERIAL_PT_gpencil_strokecolor(GPMaterialButtonsPanel, Panel):
         layout = self.layout
         layout.use_property_split = True
 
-        ma = context.object.active_material
+        ma = context.material
         if ma is not None and ma.grease_pencil is not None:
             gpcolor = ma.grease_pencil
 
@@ -163,73 +149,71 @@ class MATERIAL_PT_gpencil_fillcolor(GPMaterialButtonsPanel, Panel):
     bl_parent_id = 'MATERIAL_PT_gpencil_surface'
 
     def draw_header(self, context):
-        ma = context.object.active_material
-        if ma is not None and ma.grease_pencil is not None:
-            gpcolor = ma.grease_pencil
-            self.layout.prop(gpcolor, "show_fill", text="")
+        ma = context.material
+        gpcolor = ma.grease_pencil
+        self.layout.prop(gpcolor, "show_fill", text="")
 
     @staticmethod
     def draw(self, context):
         layout = self.layout
         layout.use_property_split = True
 
-        ma = context.object.active_material
-        if ma is not None and ma.grease_pencil:
-            gpcolor = ma.grease_pencil
+        ma = context.material
+        gpcolor = ma.grease_pencil
 
-            # color settings
-            col = layout.column()
-            col.active = not gpcolor.lock
-            col.prop(gpcolor, "fill_style", text="Style")
+        # color settings
+        col = layout.column()
+        col.active = not gpcolor.lock
+        col.prop(gpcolor, "fill_style", text="Style")
 
-            if gpcolor.fill_style == 'GRADIENT':
-                col.prop(gpcolor, "gradient_type")
+        if gpcolor.fill_style == 'GRADIENT':
+            col.prop(gpcolor, "gradient_type")
 
-            if gpcolor.fill_style != 'TEXTURE':
-                col.prop(gpcolor, "fill_color", text="Color")
+        if gpcolor.fill_style != 'TEXTURE':
+            col.prop(gpcolor, "fill_color", text="Color")
 
-                if gpcolor.fill_style in {'GRADIENT', 'CHESSBOARD'}:
-                    col.prop(gpcolor, "mix_color", text="Secondary Color")
+            if gpcolor.fill_style in {'GRADIENT', 'CHESSBOARD'}:
+                col.prop(gpcolor, "mix_color", text="Secondary Color")
 
-                if gpcolor.fill_style == 'GRADIENT':
-                    col.prop(gpcolor, "mix_factor", text="Mix Factor", slider=True)
+            if gpcolor.fill_style == 'GRADIENT':
+                col.prop(gpcolor, "mix_factor", text="Mix Factor", slider=True)
 
-                if gpcolor.fill_style in {'GRADIENT', 'CHESSBOARD'}:
-                    col.prop(gpcolor, "flip", text="Flip Colors")
+            if gpcolor.fill_style in {'GRADIENT', 'CHESSBOARD'}:
+                col.prop(gpcolor, "flip", text="Flip Colors")
 
-                    col.prop(gpcolor, "pattern_shift", text="Location")
-                    col.prop(gpcolor, "pattern_scale", text="Scale")
+                col.prop(gpcolor, "pattern_shift", text="Location")
+                col.prop(gpcolor, "pattern_scale", text="Scale")
 
-                if gpcolor.gradient_type == 'RADIAL' and gpcolor.fill_style not in {'SOLID', 'CHESSBOARD'}:
-                    col.prop(gpcolor, "pattern_radius", text="Radius")
-                else:
-                    if gpcolor.fill_style != 'SOLID':
-                        col.prop(gpcolor, "pattern_angle", text="Angle")
+            if gpcolor.gradient_type == 'RADIAL' and gpcolor.fill_style not in {'SOLID', 'CHESSBOARD'}:
+                col.prop(gpcolor, "pattern_radius", text="Radius")
+            else:
+                if gpcolor.fill_style != 'SOLID':
+                    col.prop(gpcolor, "pattern_angle", text="Angle")
 
-                if gpcolor.fill_style == 'CHESSBOARD':
-                    col.prop(gpcolor, "pattern_gridsize", text="Box Size")
+            if gpcolor.fill_style == 'CHESSBOARD':
+                col.prop(gpcolor, "pattern_gridsize", text="Box Size")
 
-            # Texture
-            if gpcolor.fill_style == 'TEXTURE' or (gpcolor.texture_mix is True and gpcolor.fill_style == 'SOLID'):
-                col.template_ID(gpcolor, "fill_image", open="image.open")
+        # Texture
+        if gpcolor.fill_style == 'TEXTURE' or (gpcolor.texture_mix is True and gpcolor.fill_style == 'SOLID'):
+            col.template_ID(gpcolor, "fill_image", open="image.open")
 
-                if gpcolor.fill_style == 'TEXTURE':
-                    col.prop(gpcolor, "use_fill_pattern", text="Use As Pattern")
-                    if gpcolor.use_fill_pattern is True:
-                        col.prop(gpcolor, "fill_color", text="Color")
+            if gpcolor.fill_style == 'TEXTURE':
+                col.prop(gpcolor, "use_fill_pattern", text="Use As Pattern")
+                if gpcolor.use_fill_pattern is True:
+                    col.prop(gpcolor, "fill_color", text="Color")
 
-                col.prop(gpcolor, "texture_offset", text="Offset")
-                col.prop(gpcolor, "texture_scale", text="Scale")
-                col.prop(gpcolor, "texture_angle")
-                col.prop(gpcolor, "texture_opacity")
-                col.prop(gpcolor, "texture_clamp", text="Clip Image")
+            col.prop(gpcolor, "texture_offset", text="Offset")
+            col.prop(gpcolor, "texture_scale", text="Scale")
+            col.prop(gpcolor, "texture_angle")
+            col.prop(gpcolor, "texture_opacity")
+            col.prop(gpcolor, "texture_clamp", text="Clip Image")
 
-                if gpcolor.use_fill_pattern is False:
-                    col.prop(gpcolor, "texture_mix", text="Mix With Color")
+            if gpcolor.use_fill_pattern is False:
+                col.prop(gpcolor, "texture_mix", text="Mix With Color")
 
-                    if gpcolor.texture_mix is True:
-                        col.prop(gpcolor, "fill_color", text="Mix Color")
-                        col.prop(gpcolor, "mix_factor", text="Mix Factor", slider=True)
+                if gpcolor.texture_mix is True:
+                    col.prop(gpcolor, "fill_color", text="Mix Color")
+                    col.prop(gpcolor, "mix_factor", text="Mix Factor", slider=True)
 
 
 class MATERIAL_PT_gpencil_preview(GPMaterialButtonsPanel, Panel):
@@ -238,7 +222,7 @@ class MATERIAL_PT_gpencil_preview(GPMaterialButtonsPanel, Panel):
     bl_options = {'DEFAULT_CLOSED'}
 
     def draw(self, context):
-        ma = context.object.active_material
+        ma = context.material
         self.layout.label(text=ma.name)
         self.layout.template_preview(ma)
 
@@ -258,10 +242,9 @@ class MATERIAL_PT_gpencil_options(GPMaterialButtonsPanel, Panel):
         layout = self.layout
         layout.use_property_split = True
 
-        ma = context.object.active_material
-        if ma is not None and ma.grease_pencil is not None:
-            gpcolor = ma.grease_pencil
-            layout.prop(gpcolor, "pass_index")
+        ma = context.material
+        gpcolor = ma.grease_pencil
+        layout.prop(gpcolor, "pass_index")
 
 
 class MATERIAL_PT_gpencil_material_presets(PresetMenu):