GIMP+Python-Fuでcairo(pycairo)を使って描画するスクリプト、の雛形

cairo_draw_example.py

#!/usr/bin/env python
# -*- mode: python; Encoding: utf-8; coding: utf-8 -*-
# Last updated: <2017/04/21 18:35:47 +0900>

u"""
Python-Fu cairo draw example

usage: Filter -> Python-Fu -> Cairo draw example

Author : mieki256
License : CC0 / Public Domain

testing environment :
* GIMP 2.8.20 Portable + Windows10 x64
* GIMP 2.8.16 + Ubuntu Linux 16.04 LTS

"""

from gimpfu import *
import cairo
import struct
import random


def get_rgba_str(src):
    """convert cairo surface data to RGBA."""
    rgba_buf = ""
    l = len(src)
    for i in range(l / 4):
        i0 = i * 4
        i1 = i0 + 4
        bgra = struct.unpack('=L', src[i0: i1])[0]
        a = (bgra >> 24) & 0x0ff
        r = (bgra >> 16) & 0x0ff
        g = (bgra >> 8) & 0x0ff
        b = bgra & 0x0ff
        rgba = struct.pack('4B', r, g, b, a)
        rgba_buf += rgba
    return rgba_buf


def draw_by_cairo(surface, w, h):
    """draw by cairo."""
    ctx = cairo.Context(surface)

    ctx.set_antialias(cairo.ANTIALIAS_NONE)
    ctx.set_line_width(1.0)
    ctx.set_line_join(cairo.LINE_JOIN_MITER)
    ctx.set_line_cap(cairo.LINE_CAP_SQUARE)

    l = random.randint(16, 64)
    for i in range(l):
        r = random.random()
        g = random.random()
        b = random.random()
        ctx.set_source_rgb(r, g, b)

        rx = random.randint(0, w / 2)
        ry = random.randint(0, h / 2)
        rw = random.randint(1, w / 2)
        rh = random.randint(1, h / 2)
        ctx.rectangle(rx, ry, rw, rh)
        ctx.fill_preserve()

        ctx.set_source_rgb(0, 0, 0)
        ctx.stroke()

    return surface


def python_fu_cairo_draw_example_main(img, layer, w, h,
                                      createtype, layername, rnd_on, seed):
    """main func."""
    w = int(w)
    h = int(h)

    if rnd_on:
        random.seed()
    else:
        random.seed(int(seed))

    if createtype == "Image":
        img = gimp.Image(w, h, RGB)
        gimp.Display(img)

    layer = gimp.Layer(img, layername, w, h, RGBA_IMAGE, 100, NORMAL_MODE)
    layer.fill(TRANSPARENT_FILL)
    img.add_layer(layer, 0)

    # draw cairo
    surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
    draw_by_cairo(surface, w, h)

    # transfer gimp layer
    src = surface.get_data()
    dst = get_rgba_str(src)
    rgn = layer.get_pixel_rgn(0, 0, w, h, True, True)
    rgn[0:w, 0:h] = str(dst)

    layer.flush()
    layer.merge_shadow()
    layer.update(0, 0, w, h)
    pdb.gimp_displays_flush()

    # gimp.message("Done.")

register(
    "python_fu_cairo_draw_example",
    "cairo draw example",
    "cairo draw example by Python-Fu",
    "Your name",
    "Your name",
    "2017/04/21",
    "Cairo draw example",  # menu name
    "RGB*",      # Alternately use RGB, RGB*, GRAY*, INDEXED etc.
    # params
    [
        # (type, name, description, default [, extra])
        (PF_IMAGE, "timg", "Input image", None),
        (PF_DRAWABLE, "tdrawable", "Input drawable", None),
        (PF_SPINNER, "width", "Width", 512, (8, 8192, 1)),
        (PF_SPINNER, "height", "Height", 512, (8, 8192, 1)),
        (PF_RADIO, "createtype", "Create", "Image",
            (("Image", "Image"), ("Layer", "Layer"))),
        (PF_STRING, "layername", "Layer name", 'cairo_draw_layer'),
        (PF_TOGGLE, "randomize", "Randomize:", 1),
        (PF_INT, "seed", "Random seed", 0)
    ],
    # return vals
    [],
    python_fu_cairo_draw_example_main,  # function name
    menu="<Image>/Filters/Languages/Python-Fu"
)

main()