Edit keyframes of selected armature bones to each match their first keyframes.

FixCyclicKeyframes.py

bl_info = {
    "name": "Fix Seams of Cyclic Keyframes",
    "description": "Edit keyframes of selected armature bones to each match their first keyframes.",
    "author": "Ferdinand Joseph Fernandez",
    "version": (1, 3),
    "location": "Dopesheet > Key > Fix Seams of Cyclic Keyframes",
    "support": "TESTING",
    "category": "Animation",
}

#
# I am putting the MIT license notice right inside this file because this add-on
# is just one file at the moment. --Ferdinand
#
# ----------------------
#
# Copyright (c) 2017 Ferdinand Joseph Fernandez
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#



import bpy, bgl, blf, math
from bpy.props import *

class FixSeamsOfCyclicKeyframes(bpy.types.Operator):
    """Fix Seams of Cyclic Keyframes"""
    bl_idname = "animation.fix_end_of_cyclic_keyframes"
    bl_label = "Fix Seams of Cyclic Keyframes"
    bl_options = {'REGISTER', 'UNDO'}
    
#    def __init__(self):
#        self.text_display = ""

    
    def execute(self, context):
        if (bpy.context.selected_pose_bones is None or len(bpy.context.selected_pose_bones) == 0):
            # no bone selected
            self.report({'WARNING'}, "No bone selected.")
            return {'CANCELLED'}
        
        bone_names = [b.name for b in bpy.context.selected_pose_bones]
        fcurves = bpy.context.active_object.animation_data.action.fcurves

        #print("start")

        for curve in fcurves:
            #print (curve.data_path)
            
            # if this curve belongs to the currently selected bone
            if curve.data_path.split('"')[1] in bone_names:
                
                keyframePoints = curve.keyframe_points
                
                if len(keyframePoints) > 0:
                    #for keyframe in keyframePoints:
                    #    print(keyframe.co)
                    
                    firstKeyframeCo = keyframePoints[0].co
                    lastKeyframeCo = keyframePoints[len(keyframePoints)-1].co
                    #print("last keyframe: %s" % lastKeyframeCo)
                    
                    deltaY = firstKeyframeCo[1] - lastKeyframeCo[1]
                    
                    if (abs(deltaY) > 0.0001):
                        #print("deltaY for %s: %s" % (curve.data_path, deltaY))
                        
                        for idx in range(len(keyframePoints)):
                            #print(idx)
                            
                            if (idx > 0):
                                keyframePoints[idx].co[1] += deltaY
                                keyframePoints[idx].handle_left[1] += deltaY
                                keyframePoints[idx].handle_right[1] += deltaY
                                
        return {'FINISHED'}


def menu_separator(self, context):
    self.layout.separator()
    
def fix_cyclic_keyframes_menu(self, context):
    self.layout.operator(FixSeamsOfCyclicKeyframes.bl_idname)


# keymaps are stored here so they can be accessed after registration
addon_keymaps = []

def register():
    bpy.utils.register_module(__name__)
    
    # menu registration
    bpy.types.DOPESHEET_MT_key.prepend(menu_separator)
    bpy.types.DOPESHEET_MT_key.prepend(fix_cyclic_keyframes_menu)
    
#    # hotkey registration
#    wm = bpy.context.window_manager
#    kc = wm.keyconfigs.addon

#    if kc:
#        keymap = kc.keymaps.new(name='Dopesheet', space_type='DOPESHEET_EDITOR')
#        keymap_item = keymap.keymap_items.new(GetSelectedKeyframesLength.bl_idname, 'Q', 'PRESS')
#        
#        # add to list so we can unregister afterwards
#        addon_keymaps.append((keymap, keymap_item))
    
    
def unregister():
    
#    # unregister hotkey
#    wm = bpy.context.window_manager
#    kc = wm.keyconfigs.addon
#    if kc:
#        for km, kmi in addon_keymaps:
#            km.keymap_items.remove(kmi)
#            
#    addon_keymaps.clear()
    
    bpy.utils.unregister_module(__name__)
    
    # unregister menu
    bpy.types.DOPESHEET_MT_key.remove(fix_cyclic_keyframes_menu)
    bpy.types.DOPESHEET_MT_key.remove(menu_separator)
    
    
if __name__ == "__main__":
    register()