Blender插件之操作器(Operator)实战

前言

在Blender中, 操作器(Operator)是它的核心. 用户通过各种操作器来创建和操作场景中的物体.

操作器对象继承自 class bpy.types.Operator(bpy_struct)

下面通过代码实例来学习它, 以下代码来源于https://docs.blender.org/api/2.79/bpy.types.Operator.html

#### 1 最简单的Operator

简单的信息打印

import bpy

class HelloWorldOperator(bpy.types.Operator):

    bl_idname = "yy.hello_world"

    bl_label = "Minimal Operator"

    def execute(self, context):

        print("Hello World!")

        return {'FINISHED'}

bpy.utils.register_class(HelloWorldOperator)

# test call to the newly defined operator

bpy.ops.yy.hello_world()

#### 2 Invoke

Operator.invoke用于在调用operator时从上下文初始化operator。

Operator.invoke is used to initialize the operator from the context at the moment the operator is called.

import bpy

class SimpleMouseOperator(bpy.types.Operator):

    """ This operator shows the mouse location,

        this string is used for the tooltip and API docs

    """

    bl_idname = "wm.mouse_position"

    bl_label = "Invoke Mouse Operator"

    x = bpy.props.IntProperty()

    y = bpy.props.IntProperty()

    def execute(self, context):

        # rather than printing, use the report function,

        # this way the message appears in the header,

        self.report({'INFO'}, "Mouse coords are %d %d" % (self.x, self.y))

        return {'FINISHED'}

    def invoke(self, context, event):

        self.x = event.mouse_x

        self.y = event.mouse_y

        return self.execute(context)

bpy.utils.register_class(SimpleMouseOperator)

# Test call to the newly defined operator.

# Here we call the operator and invoke it, meaning that the settings are taken

# from the mouse.

bpy.ops.wm.mouse_position('INVOKE_DEFAULT')

# Another test call, this time call execute() directly with pre-defined settings.

bpy.ops.wm.mouse_position('EXEC_DEFAULT', x=20, y=66)

#### 3 调用文件选择器

Opens a file selector with an operator. The string properties ‘filepath’, ‘filename’, ‘directory’ and a ‘files’ collection are assigned

when present in the operator Notice the invoke function calls a window manager method and returns {'RUNNING_MODAL'},

this means the file selector stays open and the operator does not exit immediately after invoke finishes.

import bpy

class ExportSomeData(bpy.types.Operator):

    """Test exporter which just writes hello world"""

    bl_idname = "export.some_data"

    bl_label = "Export Some Data"

    filepath = bpy.props.StringProperty(subtype="FILE_PATH")

    @classmethod

    def poll(cls, context):

        return context.object is not None

    def execute(self, context):

        file = open(self.filepath, 'r')

        print(file.read())

        file.close()

        #file.write("Hello World " + context.object.name)

        return {'FINISHED'}

    def invoke(self, context, event):

        context.window_manager.fileselect_add(self)

        return {'RUNNING_MODAL'}

# Only needed if you want to add into a dynamic menu

def menu_func(self, context):

    self.layout.operator_context = 'INVOKE_DEFAULT'

    self.layout.operator(ExportSomeData.bl_idname, text="Text Export Operator")

# Register and add to the file selector

bpy.utils.register_class(ExportSomeData)

bpy.types.INFO_MT_file_export.append(menu_func)

# test call

bpy.ops.export.some_data('INVOKE_DEFAULT')

#### 4 对话框

import bpy

class DialogOperator(bpy.types.Operator):

    bl_idname = "object.dialog_operator"

    bl_label = "Simple Dialog Operator"

    my_float = bpy.props.FloatProperty(name="Some Floating Point")

    my_bool = bpy.props.BoolProperty(name="Toggle Option")

    my_string = bpy.props.StringProperty(name="String Value")

    def execute(self, context):

        message = "Popup Values: %f, %d, '%s'" % \

            (self.my_float, self.my_bool, self.my_string)

        self.report({'INFO'}, message)

        return {'FINISHED'}

    def invoke(self, context, event):

        wm = context.window_manager

        return wm.invoke_props_dialog(self)

bpy.utils.register_class(DialogOperator)

# test call

bpy.ops.object.dialog_operator('INVOKE_DEFAULT')

#### 5 自定义绘图

By default operator properties use an automatic user interface layout. If you need more control you can create your own layout with a Operator.draw function.

import bpy

class CustomDrawOperator(bpy.types.Operator):

    bl_idname = "object.custom_draw"

    bl_label = "Simple Modal Operator"

    filepath = bpy.props.StringProperty(subtype="FILE_PATH")

    my_float = bpy.props.FloatProperty(name="Float")

    my_bool = bpy.props.BoolProperty(name="Toggle Option")

    my_string = bpy.props.StringProperty(name="String Value")

    def execute(self, context):

        print("Test", self)

        return {'FINISHED'}

    def invoke(self, context, event):

        wm = context.window_manager

        return wm.invoke_props_dialog(self)

    def draw(self, context):

        layout = self.layout

        col = layout.column()

        col.label(text="Custom Interface!")

        row = col.row()

        row.prop(self, "my_float")

        row.prop(self, "my_bool")

        col.prop(self, "my_string")

bpy.utils.register_class(CustomDrawOperator)

# test call

bpy.ops.object.custom_draw('INVOKE_DEFAULT')

#### 6 Modal执行

This operator defines a Operator.modal function that will keep being run to handle events until it returns {'FINISHED'} or {'CANCELLED'}.

import bpy

class ModalOperator(bpy.types.Operator):

    bl_idname = "object.modal_operator"

    bl_label = "Simple Modal Operator"

    def __init__(self):

        print("Start")

    def __del__(self):

        print("End")

    def execute(self, context):

        context.object.location.x = self.value / 100.0

        return {'FINISHED'}

    def modal(self, context, event):

        if event.type == 'MOUSEMOVE':  # Apply

            self.value = event.mouse_x

            self.execute(context)

        elif event.type == 'LEFTMOUSE':  # Confirm

            return {'FINISHED'}

        elif event.type in {'RIGHTMOUSE', 'ESC'}:  # Cancel

            context.object.location.x = self.init_loc_x

            return {'CANCELLED'}

        return {'RUNNING_MODAL'}

    def invoke(self, context, event):

        self.init_loc_x = context.object.location.x

        self.value = event.mouse_x

        self.execute(context)

        context.window_manager.modal_handler_add(self)

        return {'RUNNING_MODAL'}

bpy.utils.register_class(ModalOperator)

# test call

bpy.ops.object.modal_operator('INVOKE_DEFAULT')

巴特西

Blender插件之操作器(Operator)实战

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