GIMP plugin that slices a Minecraft animated texture into layers; used for converting them to GIFs

slice-minecraft-animation.py

#!/usr/bin/env python

import json
from gimpfu import *


def copy_frame(img, layer, sprite_size, index):
    pdb.gimp_image_select_rectangle(img, CHANNEL_OP_REPLACE, 0, index * sprite_size,
                                    sprite_size, sprite_size)
    pdb.gimp_edit_copy(layer)


def paste_frame(img, layer, sprite_size):
    pdb.gimp_image_select_rectangle(img, CHANNEL_OP_REPLACE, 0, 0,
                                    sprite_size, sprite_size)
    floating_selection = pdb.gimp_edit_paste(layer, FALSE)
    pdb.gimp_floating_sel_anchor(floating_selection)


def slice_minecraft_animation(img, layer, frametime=1, frames='', interpolate=False):
    gimp.progress_init('Slicing layer...')
    pdb.gimp_image_undo_group_start(img)

    try:
        sprite_size = layer.width

        if interpolate:
            frame_ms = 50
            frames_between = frametime - 1
        else:
            frame_ms = int(frametime / 20.0 * 1000.0)
            frames_between = 0

        if len(frames) > 0:
            indices = json.loads(frames)
        else:
            indices = range(int(layer.height / sprite_size))

        total_frames = len(indices) + (len(indices) * frames_between)
        frame_counter = 0

        for i, frame_index in enumerate(indices):
            copy_frame(img, layer, sprite_size, frame_index)

            layer_name = 'Frame {} ({}ms) (replace)'.format(frame_counter, frame_ms)
            frame_layer = gimp.Layer(img, layer_name, sprite_size, sprite_size,
                                     RGBA_IMAGE, 100, NORMAL_MODE)
            img.add_layer(frame_layer, 0)

            paste_frame(img, frame_layer, sprite_size)

            gimp.progress_update(float(frame_counter + 1) / float(total_frames))

            frame_counter += 1

            for between_index in range(0, frames_between):
                opacity = (between_index + 1.0) / (frames_between + 1.0) * 100.0

                layer_name = 'Frame {} (interpolated) ({}ms) (replace)'\
                             .format(frame_counter, frame_ms)
                between_layer = gimp.Layer(img, layer_name, sprite_size,
                                           sprite_size, RGBA_IMAGE, 100,
                                           NORMAL_MODE)
                between_layer_overlay = gimp.Layer(img, 'Temp', sprite_size,
                                                   sprite_size, RGBA_IMAGE,
                                                   opacity,  NORMAL_MODE)

                img.add_layer(between_layer, 0)
                img.add_layer(between_layer_overlay, 0)

                copy_frame(img, layer, sprite_size, frame_index)
                paste_frame(img, between_layer, sprite_size)

                try:
                    next_frame_index = indices[i + 1]
                except IndexError:
                    next_frame_index = indices[0]

                copy_frame(img, layer, sprite_size, next_frame_index)
                paste_frame(img, between_layer_overlay, sprite_size)
                pdb.gimp_image_merge_down(img, between_layer_overlay,
                                          CLIP_TO_BOTTOM_LAYER)

                frame_counter += 1
                gimp.progress_update(float(frame_counter + 1) / float(total_frames))

        img.remove_layer(layer)
        img.resize(sprite_size, sprite_size, 0, 0)

    except Exception as err:
        gimp.message('Unexpected error: {}'.format(str(err)))

    pdb.gimp_image_undo_group_end(img)
    pdb.gimp_progress_end()


register(
    'python_fu_slice_minecraft_animation',
    'Slice Minecraft animation',
    'Slices a Minecraft animated sprite into layers.',
    'Ton Broekhuizen',
    '',
    '2017',
    '<Image>/Filters/Minecraft/Slice animation',
    'RGB*',
    [
        (PF_INT, 'frametime', 'Frame time (from .mcmeta)', 1),
        (PF_STRING, 'frames', 'Frames array (from .mcmeta)', ''),
        (PF_BOOL, 'interpolate', 'Interpolate', False)
    ],
    [],
    slice_minecraft_animation
)

main()