Grease Pencil: Add layer channel color property

This adds a `channel_color` property to layers.
The color is stored in the tree nodes.
It's currently used by the dopesheet for the channel colors.

Resolves #130370.

Pull Request: https://projects.blender.org/blender/blender/pulls/130512

scripts/startup/bl_ui/properties_data_grease_pencil.py

@@ -146,6 +146,19 @@ class GreasePencil_LayerRelationsPanel:
         col.prop(layer, "use_viewlayer_masks")
 
 
+class GreasePencil_LayerDisplayPanel:
+    bl_label = "Display"
+
+    def draw(self, context):
+        layout = self.layout
+        layout.use_property_split = True
+
+        grease_pencil = context.grease_pencil
+        layer = grease_pencil.layers.active
+
+        layout.prop(layer, "channel_color", text="Channel Color")
+
+
 class GREASE_PENCIL_MT_layer_mask_add(Menu):
     bl_label = "Add Mask"
 
@@ -315,6 +328,12 @@ class DATA_PT_grease_pencil_layer_relations(LayerDataButtonsPanel, GreasePencil_
     bl_options = {'DEFAULT_CLOSED'}
 
 
+class DATA_PT_grease_pencil_layer_display(LayerDataButtonsPanel, GreasePencil_LayerDisplayPanel, Panel):
+    bl_label = "Display"
+    bl_parent_id = "DATA_PT_grease_pencil_layers"
+    bl_options = {'DEFAULT_CLOSED'}
+
+
 class DATA_PT_grease_pencil_onion_skinning(DataButtonsPanel, Panel):
     bl_label = "Onion Skinning"
 
@@ -473,6 +492,7 @@ classes = (
     DATA_PT_grease_pencil_layer_transform,
     DATA_PT_grease_pencil_layer_adjustments,
     DATA_PT_grease_pencil_layer_relations,
+    DATA_PT_grease_pencil_layer_display,
     DATA_PT_grease_pencil_onion_skinning,
     DATA_PT_grease_pencil_onion_skinning_custom_colors,
     DATA_PT_grease_pencil_onion_skinning_display,

scripts/startup/bl_ui/space_dopesheet.py

@@ -14,6 +14,7 @@ from bl_ui.properties_data_grease_pencil import (
     GreasePencil_LayerTransformPanel,
     GreasePencil_LayerRelationsPanel,
     GreasePencil_LayerAdjustmentsPanel,
+    GreasePencil_LayerDisplayPanel,
 )
 
 from rna_prop_ui import PropertyPanel
@@ -965,6 +966,15 @@ class DOPESHEET_PT_grease_pencil_layer_adjustments(
     bl_options = {'DEFAULT_CLOSED'}
 
 
+class DOPESHEET_PT_grease_pencil_layer_display(
+        GreasePencilLayersDopeSheetPanel,
+        GreasePencil_LayerDisplayPanel,
+        Panel):
+    bl_label = "Display"
+    bl_parent_id = "DOPESHEET_PT_grease_pencil_mode"
+    bl_options = {'DEFAULT_CLOSED'}
+
+
 classes = (
     DOPESHEET_HT_header,
     DOPESHEET_PT_proportional_edit,
@@ -992,6 +1002,7 @@ classes = (
     DOPESHEET_PT_grease_pencil_layer_transform,
     DOPESHEET_PT_grease_pencil_layer_adjustments,
     DOPESHEET_PT_grease_pencil_layer_relations,
+    DOPESHEET_PT_grease_pencil_layer_display,
 )
 
 if __name__ == "__main__":  # only for live edit.

source/blender/blenkernel/intern/grease_pencil.cc

@@ -959,7 +959,7 @@ TreeNode::TreeNode(const TreeNode &other) : TreeNode(GreasePencilLayerTreeNodeTy
 {
   this->GreasePencilLayerTreeNode::name = BLI_strdup_null(other.GreasePencilLayerTreeNode::name);
   this->flag = other.flag;
-  copy_v3_v3_uchar(this->color, other.color);
+  copy_v3_v3(this->color, other.color);
 }
 
 TreeNode::~TreeNode()
@@ -1946,7 +1946,7 @@ void BKE_grease_pencil_copy_layer_parameters(const blender::bke::greasepencil::L
 {
   using namespace blender::bke::greasepencil;
   dst.as_node().flag = src.as_node().flag;
-  copy_v3_v3_uchar(dst.as_node().color, src.as_node().color);
+  copy_v3_v3(dst.as_node().color, src.as_node().color);
 
   dst.blend_mode = src.blend_mode;
   dst.opacity = src.opacity;
@@ -1973,7 +1973,7 @@ void BKE_grease_pencil_copy_layer_group_parameters(
 {
   using namespace blender::bke::greasepencil;
   dst.as_node().flag = src.as_node().flag;
-  copy_v3_v3_uchar(dst.as_node().color, src.as_node().color);
+  copy_v3_v3(dst.as_node().color, src.as_node().color);
   dst.color_tag = src.color_tag;
 }
 

source/blender/editors/animation/anim_channels_defines.cc

@@ -3903,6 +3903,14 @@ static void *layer_setting_ptr(bAnimListElem *ale,
   return GET_ACF_FLAG_PTR(layer->base.flag, r_type);
 }
 
+static bool layer_channel_color(const bAnimListElem *ale, uint8_t r_color[3])
+{
+  using namespace bke::greasepencil;
+  GreasePencilLayerTreeNode &layer = *static_cast<GreasePencilLayerTreeNode *>(ale->data);
+  rgb_float_to_uchar(r_color, layer.color);
+  return true;
+}
+
 static int layer_group_icon(bAnimListElem *ale)
 {
   using namespace bke::greasepencil;
@@ -3985,7 +3993,7 @@ static bAnimChannelType ACF_GPL = {
     /*channel_role*/ ACHANNEL_ROLE_CHANNEL,
 
     /*get_backdrop_color*/ acf_generic_channel_color,
-    /*get_channel_color*/ nullptr,
+    /*get_channel_color*/ greasepencil::layer_channel_color,
     /*draw_backdrop*/ acf_generic_channel_backdrop,
     /*get_indent_level*/ acf_generic_indentation_flexible,
     /*get_offset*/ greasepencil::layer_offset,

source/blender/makesdna/DNA_grease_pencil_types.h

@@ -259,10 +259,11 @@ typedef struct GreasePencilLayerTreeNode {
    * Indicates the type of struct this element is.
    */
   int8_t type;
+  char _pad[7];
   /**
-   * Color tag.
+   * Channel color for dopesheet.
    */
-  uint8_t color[3];
+  float color[3];
   /**
    * Flag. Used to set e.g. the selection, visibility, ... status.
    * See `GreasePencilLayerTreeNodeFlag`.

source/blender/makesrna/intern/rna_grease_pencil.cc

@@ -1097,6 +1097,11 @@ static void rna_def_grease_pencil_layer(BlenderRNA *brna)
   RNA_def_property_ui_text(
       prop, "Parent Layer Group", "The parent layer group this layer is part of");
 
+  prop = RNA_def_property(srna, "channel_color", PROP_FLOAT, PROP_COLOR);
+  RNA_def_property_float_sdna(prop, "GreasePencilLayerTreeNode", "color");
+  RNA_def_property_array(prop, 3);
+  RNA_def_property_update(prop, NC_GPENCIL | NA_EDITED, nullptr);
+
   RNA_api_grease_pencil_layer(srna);
 }