#!/usr/bin/env python
# encoding: utf-8
# api: inkscape
##type: effect
# category: export
# title: GIF slideshow
# description: Export and combine layers as animation via ImageMagick/Pillow
# id: org.include-once.inkscape.export-gif
# license: MITL
# version: 1.1
# state: stable
# depends: bin:inkscape (>= 1.1), bin:convert, python (>= 3.6)
# suggests: python:svgelements >= 1.8
# pylint: disable=line-too-long, missing-module-docstring, bad-whitespace
# config:
#    { name: file, type: file, mode: file, value: "~/anim.gif", description: "Target GIF filename", help: "Output filename should end in .gif for actual results. Alternatively can be `APNG:dir/filename.apng` with ImageMagick 7." }
#    { name: mode, type: select, select: "PNG→ImageMagick (better quality)|SVG→ImageMagick (simple drawings)|PNG→Pillow (builtin - a bit faster)|JavaScript→SVG (embed anim code)", value: PNG+ImageMagick, description: Conversion mode, help: "There's different backends to assemble the GIF. Pillow also works on Windows without convert.exe installed. The JavaScript mode embeds some code, does not actually generate a GIF output file." }
#    { name: delay, type: float, value: 0.35, min: 0.01, max: 20, precision: 2, description: "Delay between slides (seconds)", "Can be overriden on a per-slide basis with [--delay=2.5]. Note that convert(1) usually uses »ticks« (*10ms), but this export_gif option is really in seconds." }
#    { name: loop, type: int, value: 0, description: "Loop limit (0 for endless)" }
#    [ hidden: 1, disabled: save_as, type: str, value: "0", description: used in saveas_gif.inx, note: "have to use `str` here, cause .inx `false` is not recognized for hidden attributes" ]
#    { xml: <image width="505" height="50">export_gif.svg</image> }
#    { name: notebook, type: notebook, value: system, description: "Additional flags and help" }
#    { category: ImageMagick, name: fuzz, type: select, select: "0%|5%|10%|20%|30%|50%", value: "10%", description: "Fuzzing/dither", help: "Detect similar colors for optimization" }
#    { category: ImageMagick, name: layers, type: select, select: "optimize|coalesce|compare-any|compare-clear|compare-overlay|composite|dispose|flatten|merge|mosaic|optimize-frame|optimize-plus|optimize-transparency|remove-dups|remove-zero|trim-bounds", value: "optimize", description: "Accumulation/combination of -layers", help: "Can influence optimization or layer combination. Specifically coalesce/merge are pre-interpreted by export_gif to produce accumulating slides." }
#    { category: ImageMagick, name: extra, type: select, select: "-quiet|-optimize|-size 640x360|-alpha background|-auto-gamma|-auto-level|-coalesce|-colors 64|-dither FloydSteinberg|-limit disk 1MB|-reverse|-monochrome|-transparent white", value: "", description: "Extra args", help: "Some default convert -args." }
#    { category: ImageMagick, name: extra2, type: str, value: "", description: "Custom args", help: "Specify additional convert(1) options." }
#    { category: ImageMagick, name: background, type: color, appearance: colorbutton, value: "0", description: "Background color for transparent layers", help: "Only works for SVG→ImageMagick option." }
#    { category: System, name: preview, type: bool, value: 0, description: "Preview result file", help: "Should bring up default image viewer on resulting GIF (via xdg-open, or start… on Windows)" }
#    { category: System, name: keep_tmp, type: bool, value: 0, description: "Keep temporary files", help: "Will retain the frame PNGs in the fixed directory /tmp/inkscape.export_gif/" }
#    { category: System, name: reload_svg, type: bool, value: 0, description: "Reload SVG in Inkscape", help: "Averts the warning popup of lacking result data. But is quite redundant for this tool. And should only be enabled if it's becoming too obnoxious." }
#    { category: System, name: export_background, type: bool, value: 0, description: "Force background application in PNG export", help: "Uses --export-background for generating PNG slides prior assembly. (See ImageMagick for color tab.)" }
#    { category: System, name: default_merge, type: bool, value: 0, description: "Default all layers to [merge] - not implemented yet", help: "Requires to annotate actual slides with [background] or [export], because it defaults everything else to down-grouping [merge]" }
#    { category: Animation, name: subframes, type: int, value: 5, description: "Subframes per ❮animation❯ slide", help: "Can be overridden per [animate=25] or [steps=25] in layer label." }
#    { category: Animation, name: a_rotate, type: bool, value: 1, description: "Use simpler rotate() handler", help: "Actually works better than tweening, and allows for >90° rotations without collapsing the matrix. OTOH the inkex method might handle positioning better." }
#    { category: Animation, name: all_anim, type: bool, value: 0, description: "Engage whenever SVG animate instructions are present", help: "Makes [animate] tags redundant, at the expense of longer processing times; and repeat runs for background layers." }
#    { category: Animation, name: all_pace, type: bool, value: 0, description: "Honor timing information for all slides", help: "Honor begin=, dur=, and some calcMode= settings, for pacing or delayed timing. Otherwise individual layers can be marked with [pace] or [smooth] in addition to [animate]. Else animations run/stretch across the alloted delay time for a slide." }
#    { category: Help, label: "Layer labels (Ctrl+Shift+L, double click) can specify additional options:" }
#    { category: Help, label: " 🞂 [fixed] for very permanent foreground layer" }
#    { category: Help, label: " 🞂 [background] for sticky background images" }
#    { category: Help, label: " 🞂 [merge] enjoins partial layers; and [exclude] skips them" }
#    { category: Help, label: " 🞂 [animate=10] generates ❮animate*❯ subframes, flag: [pace] timing" }
#    { category: Help, label: " 🞂 [--delay=2.5] resets ImageMagick option (delay also for Pillow)",
#    { category: Help, label: $help, appearance: url }
# inx-export: .gif, image/gif, GIF slideshow (*.gif), Graphics Interchange Format 98a
# architecture: all
# pack: export_gif.py, *.inx, pmd2inks, animate_yo.py, svgelements.py, export_gif.svg, LICENSE=/usr/share/doc/inkscape-export-gif/copyright


# permissive: 0.5
# format: off
# author: mario#include-once:org
# url: https://inkscape.org/~culturaljuice/★export_gif
# help: https://fossil.include-once.org/scripts/wiki/inkscape
# orig: https://github.com/jespino/inkscape-export-layers
#
# Generates a GIF slideshow from image layers ☰  (Shift+Ctrl+L). The menu
# entry Extensions➜Export➔GIF-slideshow… iterates over layers to generate
# animation slides. They get merged from bottom to top. Depending on shape
# overlap or layer transparency, there's different usage modes:
#
#  🞂 With a solid background in each layer, there's no accumulation to
#    take care of.
#  🞂 Alternatively elect layers can be labeled as [background] to stick,
#    or [fixed] as permanent foreground, or [merge] for down-grouping.
#  🞂 If the -layers option is composite/coalesce/merge then all lower
#    layers remain visible until the current frame.
#  🞂 Any [animate] layers get interpolated as is, layer transparency
#    preserved.
#
# Requires ImageMagick installed; fit for standard Linux setups. But might

#    labels for more refined combinations.
#  🞂 Can't run two instances in parallel, due to fixed /tmp/inkscape… dir
#  🞂 It's also available as File > Save As... option (fewer options).
#  🞂 Tested on Inkscape 1.2 (2022-05-xx) and 1.3-dev (2022-09-xx)
#
# Might require some experimentation, and heavily utilizing the preview
# option. Potential error popups become informative at the very end.
# The save as dialog ".gif" option provides fewer options, but effectively
# same behaviours for layer flags.
#
# Code is derived from Xavi's "Export Layers Redux For Inkscape 1.1+".
# <https://inkscape.org/~VagabondArcade/%E2%98%85export-layers-redux-for-inkscape-11>
#
# ZIP contains the `pmd2inks` command-line tool to ease extending the
# options dialog (using the <https://pypi.org/project/pluginconf/> format).

import math
import inkex
from inkex.utils import strargs
from inkex.tween import StyleInterpolator, TransformInterpolator
from inkex.transforms import Transform


class GIFExport(inkex.EffectExtension):#, inkex.OutputExtension (for export pane):#, inkex.RasterOutputExtension (only works for static PNG conversion)
    """ doubles as effect and save-as extension """
    multi_inx = True

    def __init__(self):
        """ init the effect library """
        self.tempdir = None
        self.index = 0 # current slide

        pars.add_argument("--extra", type=str, dest="extra", default="", help="Extra args")
        pars.add_argument("--extra2", type=str, dest="extra2", default="", help="Custom args")
        pars.add_argument("--background", type=inkex.Color, dest="background", default="0", help="Background color for transparent layers")
        pars.add_argument("--preview", type=inkex.Boolean, dest="preview", default=False, help="Preview result file")
        pars.add_argument("--keep_tmp", type=inkex.Boolean, dest="keep_tmp", default=False, help="Keep temporary files")
        pars.add_argument("--reload_svg", type=inkex.Boolean, dest="reload_svg", default=False, help="Reload SVG in Inkscape")
        pars.add_argument("--export_background", type=inkex.Boolean, dest="export_background", default=False, help="Force background application in PNG export")
        pars.add_argument("--default_merge", type=inkex.Boolean, dest="default_merge", default=False, help="Default all layers to [merge] - not implemented yet")
        pars.add_argument("--subframes", type=int, dest="subframes", default=5, help="Subframes per ❮animation❯ slide")
        pars.add_argument("--a_rotate", type=inkex.Boolean, dest="a_rotate", default=True, help="Use simpler rotate() handler")
        pars.add_argument("--all_anim", type=inkex.Boolean, dest="all_anim", default=False, help="Engage whenever SVG animate instructions are present")
        pars.add_argument("--all_pace", type=inkex.Boolean, dest="all_pace", default=False, help="Honor timing information for all slides")
        # only used in saveas_gif.inx (but not export_gif.inx, else hidden argument would be populated from preferences.xml history)
        pars.add_argument("--save_as", type=bool, dest="save_as", default=False, help="used in saveas_gif.inx")

        up_until_mode = re.search("merge|compo|coal|plus", self.options.layers)
        preconvert_png = re.search("PNG", self.options.mode, re.I)
        img_ext = "png" if preconvert_png else "svg"

        # traverse layers, iteratively slicing for individual .svg/.png frames
        for self.index, layer in enumerate(layers):

            if layer.no_frame: # [fixed], [exclude]
                continue

            if layer.is_sticky or up_until_mode:
                fixed_layers.append(layer.id)
            merge_layers = [
                follow.id for follow in layers[self.index+1:] if follow.do_merge
            ]

            if layer.animate or self.is_animatable(layer):
                # produces multiple subframe .pngs
                anim = AnimationSteps(
                    parent = self, layer = layer,
                    svg = self.export_layers(dest="", show=[layer.id] + fixed_layers + merge_layers)
                )
                temp_files_args.extend(list(anim.export()))
            else:
                # current frame into .svg/.png

    def get_layers(self):
        """ Per default all layers are exported, label tags [bg], [exclude], [merge] yield special treatment """
        for layer in self.svg.xpath('./svg:g[@inkscape:groupmode="layer"][@inkscape:label]'):

            label = layer.attrib["{http://www.inkscape.org/namespaces/inkscape}label"]
            animate = re.findall(r"\[(?:steps|animate)(?:=(\d+))?\]", label)
            
            # all-merge mode?
            is_export = bool(re.search(r"background|fixed|\[(bg|export|foreground)\]", label)),
            # no_frame = … or self.options.default_merge
            # do_merge = self.options.default_merge and not is_export

            yield Namespace(
                id = layer.attrib["id"],
                label = re.sub(r"\W+", "_", label),
                is_fixed = bool(re.search(r"fixed|\[(is_?fixe?d?|foreground)\]", label)),
                is_sticky = bool(re.search(r"background|\[(bg)\]", label)),
                no_frame = bool(re.search(r"fixed|\[(merge|no_frame|exclude)\]", label)),

        )
        # return modified SVG tree
        inkex.base.SvgOutputMixin.save(self, self.options.output)

def animate_with_values(func):
    """
    Decorator: unpacks values=1;2;3 into to= invocation of chained apply() steps.
    The time= parameter is evenly split across partial applicators - the assumption
    being that pace() already coralls keyTimes= into linear intervals.

    """
    @functools.wraps(func)
    def wrapped(self, anim, **attrib):
        if "values" not in attrib:
            return func(self, anim, **attrib)

        # prepare multiple applicators, with keyTimes pre-mapped into indexable range