kivy/kivy/atlas.py

398 lines
13 KiB
Python

'''
Atlas
=====
.. versionadded:: 1.1.0
Atlas is a class for managing textures atlases: packing multiple texture into
one. With it, you are reducing the number of image to load and speedup the
application loading.
An Atlas is composed of:
- a json file (.atlas) that contain all the information about the image
contained inside the atlas.
- one or multiple atlas image associated to the atlas definition.
Definition of .atlas
--------------------
A file with ``<basename>.atlas`` is a json file formatted like this::
{
"<basename>-<index>.png": {
"id1": [ <x>, <y>, <width>, <height> ],
"id2": [ <x>, <y>, <width>, <height> ],
# ...
},
# ...
}
Example of the Kivy ``defaulttheme.atlas``::
{
"defaulttheme-0.png": {
"progressbar_background": [431, 224, 59, 24],
"image-missing": [253, 344, 48, 48],
"filechooser_selected": [1, 207, 118, 118],
"bubble_btn": [83, 174, 32, 32],
# ... and more ...
}
}
How to create an atlas
----------------------
.. warning::
The atlas creation require Imaging/PIL. This will be removed in the future
when Kivy core Image will be able to support loading / blitting / save
operation.
You can directly use this module to create atlas file with this command::
$ python -m kivy.atlas <basename> <size> <list of images...>
Let's say you have a list of image that you want to put into an Atlas. The
directory is named ``images`` with lot of png::
$ ls
images
$ cd images
$ ls
bubble.png bubble-red.png button.png button-down.png
You can combine all the png into one, and generate the atlas file with::
$ python -m kivy.atlas myatlas 256 *.png
Atlas created at myatlas.atlas
1 image have been created
$ ls
bubble.png bubble-red.png button.png button-down.png myatlas.atlas
myatlas-0.png
As you can see, we got 2 new files: ``myatlas.atlas`` and ``myatlas-0.png``.
.. note::
When using this script, the ids referenced in the atlas is the base name of
the image, without the extension. So if you are going to give a file name
``../images/button.png``, the id for this image will be ``button``.
If you need path information included, you must include ``use_path`` like
this::
$ python -m kivy.atlas use_path myatlas 256 *.png
In which case the id for ``../images/button.png`` will be ``images_button``
How to use an atlas
-------------------
Usually, you are doing something like this::
a = Button(background_normal='images/button.png',
background_down='images/button_down.png')
In our previous example, we have created the atlas containing both of them, and
put it in ``images/myatlas.atlas``. You can use the url notation to reference
them::
atlas://path/to/myatlas/id
# will search for the ``path/to/myatlas.atlas``, and get the image ``id``
In our case, it will be::
atlas://images/myatlas/button
.. note::
In the atlas url, their is no need to put the ``.atlas`` extension, it will
be automatically append to the filename.
Manual usage of the Atlas
-------------------------
::
>>> from kivy.atlas import Atlas
>>> atlas = Atlas('path/to/myatlas.atlas')
>>> print(atlas.textures.keys())
['bubble', 'bubble-red', 'button', 'button-down']
>>> print(atlas['button'])
<kivy.graphics.texture.TextureRegion object at 0x2404d10>
'''
__all__ = ('Atlas', )
import json
from os.path import basename, dirname, join, splitext
from kivy.event import EventDispatcher
from kivy.logger import Logger
from kivy.properties import AliasProperty, DictProperty
import os
# late import to prevent recursion
CoreImage = None
class Atlas(EventDispatcher):
'''Manage texture atlas. See module documentation for more information.
'''
textures = DictProperty({})
'''List of available textures within the atlas.
:data:`textures` is a :class:`~kivy.properties.DictProperty`, default to {}
'''
def _get_filename(self):
return self._filename
filename = AliasProperty(_get_filename, None)
'''Filename of the current Atlas
:data:`filename` is a :class:`~kivy.properties.AliasProperty`, default to
None
'''
def __init__(self, filename):
self._filename = filename
super(Atlas, self).__init__()
self._load()
def __getitem__(self, key):
return self.textures[key]
def _load(self):
# late import to prevent recursive import.
global CoreImage
if CoreImage is None:
from kivy.core.image import Image as CoreImage
# must be a name finished by .atlas ?
filename = self._filename
assert(filename.endswith('.atlas'))
filename = filename.replace('/', os.sep)
Logger.debug('Atlas: Load <%s>' % filename)
with open(filename, 'r') as fd:
meta = json.load(fd)
Logger.debug('Atlas: Need to load %d images' % len(meta))
d = dirname(filename)
textures = {}
for subfilename, ids in meta.items():
subfilename = join(d, subfilename)
Logger.debug('Atlas: Load <%s>' % subfilename)
# load the image
ci = CoreImage(subfilename)
# for all the uid, load the image, get the region, and put it in our
# dict.
for meta_id, meta_coords in ids.items():
x, y, w, h = meta_coords
textures[meta_id] = ci.texture.get_region(*meta_coords)
self.textures = textures
@staticmethod
def create(outname, filenames, size, padding=2, use_path=False):
'''This method can be used to create manually an atlas from a set of
images.
:Parameters:
`outname`: str
Basename to use for ``.atlas`` creation and ``-<idx>.png``
associated images.
`filenames`: list
List of filename to put in the atlas
`size`: int
Size of an atlas image
`padding`: int, default to 2
Padding to put around each image.
Be careful. If you're using a padding < 2, you might get issues
with border of the images. Because of the OpenGL linearization,
it might take the pixels of the adjacent image.
If you're using a padding >= 2, we'll automatically generate a
"border" of 1px of your image, around the image. If you look at
the result, don't be scared if the image inside it are not
exactly the same as yours :).
`use_path`: bool, if true, the relative path of the source png
file names will be included in their atlas ids, rather
that just the file name. Leading dots and slashes will be
excluded and all other slashes in the path will be replaced
with underscores, so for example, if the path and file name is
``../data/tiles/green_grass.png`` then the id will be
``green_grass`` if use_path is False, and it will be
``data_tiles_green_grass`` if use_path is True
.. versionchanged:: 1.8.0
Parameter use_path added
'''
# Thanks to
# omnisaurusgames.com/2011/06/texture-atlas-generation-using-python/
# for its initial implementation.
try:
from PIL import Image
except ImportError:
Logger.critical('Atlas: Imaging/PIL are missing')
raise
size = int(size)
# open all of the images
ims = [(f, Image.open(f)) for f in filenames]
# sort by image area
ims = sorted(ims, key=lambda im: im[1].size[0] * im[1].size[1],
reverse=True)
# free boxes are empty space in our output image set
# the freebox tuple format is: outidx, x, y, w, h
freeboxes = [(0, 0, 0, size, size)]
numoutimages = 1
# full boxes are areas where we have placed images in the atlas
# the full box tuple format is: image, outidx, x, y, w, h, filename
fullboxes = []
# do the actual atlasing by sticking the largest images we can have into
# the smallest valid free boxes
for imageinfo in ims:
im = imageinfo[1]
imw, imh = im.size
imw += padding
imh += padding
if imw > size or imh > size:
Logger.error('Atlas: image %s is larger than the atlas size!' %
imageinfo[0])
return
inserted = False
while not inserted:
for idx, fb in enumerate(freeboxes):
# find the smallest free box that will contain this image
if fb[3] >= imw and fb[4] >= imh:
# we found a valid spot! Remove the current freebox, and
# split the leftover space into (up to) two new
# freeboxes
del freeboxes[idx]
if fb[3] > imw:
freeboxes.append((
fb[0], fb[1] + imw, fb[2],
fb[3] - imw, imh))
if fb[4] > imh:
freeboxes.append((
fb[0], fb[1], fb[2] + imh,
fb[3], fb[4] - imh))
# keep this sorted!
freeboxes = sorted(freeboxes,
key=lambda fb: fb[3] * fb[4])
fullboxes.append((im,
fb[0], fb[1] + padding,
fb[2] + padding, imw - padding,
imh - padding, imageinfo[0]))
inserted = True
break
if not inserted:
# oh crap - there isn't room in any of our free boxes, so we
# have to add a new output image
freeboxes.append((numoutimages, 0, 0, size, size))
numoutimages += 1
# now that we've figured out where everything goes, make the output
# images and blit the source images to the approriate locations
Logger.info('Atlas: create an {0}x{0} rgba image'.format(size))
outimages = [Image.new('RGBA', (size, size))
for i in range(0, int(numoutimages))]
for fb in fullboxes:
x, y = fb[2], fb[3]
out = outimages[fb[1]]
out.paste(fb[0], (fb[2], fb[3]))
w, h = fb[0].size
if padding > 1:
out.paste(fb[0].crop((0, 0, w, 1)), (x, y - 1))
out.paste(fb[0].crop((0, h - 1, w, h)), (x, y + h))
out.paste(fb[0].crop((0, 0, 1, h)), (x - 1, y))
out.paste(fb[0].crop((w - 1, 0, w, h)), (x + w, y))
# save the output images
for idx, outimage in enumerate(outimages):
outimage.save('%s-%d.png' % (outname, idx))
# write out an json file that says where everything ended up
meta = {}
for fb in fullboxes:
fn = '%s-%d.png' % (basename(outname), fb[1])
if fn not in meta:
d = meta[fn] = {}
else:
d = meta[fn]
# fb[6] contain the filename
if use_path:
# use the path with separators replaced by _
# example '../data/tiles/green_grass.png' becomes
# 'data_tiles_green_grass'
uid = splitext(fb[6])[0]
# remove leading dots and slashes
uid = uid.lstrip('./\\')
# replace remaining slashes with _
uid = uid.replace('/', '_').replace('\\', '_')
else:
# for example, '../data/tiles/green_grass.png'
# just get only 'green_grass' as the uniq id.
uid = splitext(basename(fb[6]))[0]
x, y, w, h = fb[2:6]
d[uid] = x, size - y - h, w, h
outfn = '%s.atlas' % outname
with open(outfn, 'w') as fd:
json.dump(meta, fd)
return outfn, meta
if __name__ == '__main__':
import sys
argv = sys.argv[1:]
if len(argv) < 3:
print('Usage: python -m kivy.atlas [use_path] <outname>' +
' <size> <img1.png> [<img2.png>, ...]')
sys.exit(1)
if argv[0] == 'use_path':
argv = argv[1:]
use_path = True
else:
use_path = False
outname = argv[0]
try:
size = int(argv[1])
except ValueError:
print('Error: size must be an integer')
sys.exit(1)
filenames = argv[2:]
ret = Atlas.create(outname, filenames, size, use_path=use_path)
if not ret:
print('Error while creating atlas!')
sys.exit(1)
fn, meta = ret
print('Atlas created at', fn)
print('%d image%s have been created' % (len(meta),
's' if len(meta) > 1 else ''))