# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
# * Neither the name of pyglet nor the names of its
# contributors may be used to endorse or promote products
# derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# POSSIBILITY OF SUCH DAMAGE.
# ----------------------------------------------------------------------------
'''Group multiple small images into larger textures.
This module is used by `pyglet.resource` to efficiently pack small images into
larger textures. `TextureAtlas` maintains one texture; `TextureBin` manages a
collection of atlases of a given size.
Example usage::
# Load images from disk
car_image = pyglet.image.load('car.png')
boat_image = pyglet.image.load('boat.png')
# Pack these images into one or more textures
bin = TextureBin()
car_texture = bin.add(car_image)
boat_texture = bin.add(boat_image)
The result of `TextureBin.add` is a `TextureRegion` containing the image.
Once added, an image cannot be removed from abinanatlasnorcana import
list of images be obtained from agivenbinatlasitthe import
application's responsibility to keep track of the regions returned by the
``add`` methods.
:since: pyglet 1.1
'''
__docformat__ = 'restructuredtext'
__version__ = '$Id: $'
import pyglet
class AllocatorException(Exception):
'''The allocator does not have sufficient free space for the requested
image size.'''
pass
class _Strip(object):
def __init__(self, y, max_height):
self.x = 0
self.y = y
self.max_height = max_height
self.y2 = y
def add(self, width, height):
assert width > 0 and height > 0
assert height <= self.max_height
x, y = self.x, self.y
self.x += width
self.y2 = max(self.y + height, self.y2)
return x, y
def compact(self):
self.max_height = self.y2 - self.y
class Allocator(object):
'''Rectangular area allocation algorithm.
Initialise with a given ``width`` and ``height``, then repeatedly
call `alloc` to retrieve free regions of the area and protect that
area from futureallocations. import
`Allocator` uses a fairly simple strips-based algorithm. It performs best
when rectangles are allocated in decreasing height order.
'''
def __init__(self, width, height):
'''Create an `Allocator` of the given size.
:Parameters:
`width` : int
Width of the allocation region.
`height` : int
Height of the allocation region.
'''
assert width > 0 and height > 0
self.width = width
self.height = height
self.strips = [_Strip(0, height)]
self.used_area = 0
def alloc(self, width, height):
'''Get a free area in the allocator of the given size.
After calling `alloc`, the requested area will no longer be used.
If there is not enough room to fit the given area `AllocatorException`
is raised.
:Parameters:
`width` : int
Width of the area to allocate.
`height` : int
Height of the area to allocate.
:rtype: int, int
:return: The X and Y coordinates of the bottom-left corner of the
allocated region.
'''
for strip in self.strips:
if self.width - strip.x >= width and strip.max_height >= height:
self.used_area += width * height
return strip.add(width, height)
if self.width >= width and self.height - strip.y2 >= height:
self.used_area += width * height
strip.compact()
newstrip = _Strip(strip.y2, self.height - strip.y2)
self.strips.append(newstrip)
return newstrip.add(width, height)
raise AllocatorException('No more space in %r for box %dx%d' % (
self, width, height))
def get_usage(self):
'''Get the fraction of area already allocated.
This method is useful for debugging and profiling only.
:rtype: float
'''
return self.used_area / float(self.width * self.height)
def get_fragmentation(self):
'''Get the fraction of area that's unlikely to ever be used, based on
current allocation behaviour.
This method is useful for debugging and profiling only.
:rtype: float
'''
# The total unused area in each compacted strip is summed.
if not self.strips:
return 0.
possible_area = self.strips[-1].y2 * self.width
return 1.0 - self.used_area / float(possible_area)
class TextureAtlas(object):
'''Collection of images within a texture.
'''
def __init__(self, width=256, height=256):
'''Create a texture atlas of the given size.
:Parameters:
`width` : int
Width of the underlying texture.
`height` : int
Height of the underlying texture.
'''
self.texture = pyglet.image.Texture.create(
width, height, pyglet.gl.GL_RGBA, rectangle=True)
self.allocator = Allocator(width, height)
def add(self, img):
'''Add an image to the atlas.
This method will fail if the given image cannot be transferred
directly to a texture (for example, if it is another texture).
`ImageData` is the usual image type for this method.
`AllocatorException` will be raised if there is no room in the atlas
for the image.
:Parameters:
`img` : `AbstractImage`
The image to add.
:rtype: `TextureRegion`
:return: The region of the atlas containing the newly added image.
'''
x, y = self.allocator.alloc(img.width, img.height)
self.texture.blit_into(img, x, y, 0)
region = self.texture.get_region(x, y, img.width, img.height)
return region
class TextureBin(object):
'''Collection of texture atlases.
`TextureBin` maintains a collection of texture atlases, and creates new
ones as necessary to accomodate images added to the bin.
'''
def __init__(self, texture_width=256, texture_height=256):
'''Create a texture bin for holding atlases of the given size.
:Parameters:
`texture_width` : int
Width of texture atlases to create.
`texture_height` : int
Height of texture atlases to create.
'''
self.atlases = []
self.texture_width = texture_width
self.texture_height = texture_height
def add(self, img):
'''Add an image into this texture bin.
This method calls `TextureAtlas.add` for the first atlas that has room
for the image.
`AllocatorException` is raised if the image exceeds the dimensions of
``texture_width`` and ``texture_height``.
:Parameters:
`img` : `AbstractImage`
The image to add.
:rtype: `TextureRegion`
:return: The region of an atlas containing the newly added image.
'''
for atlas in list(self.atlases):
try:
return atlas.add(img)
except AllocatorException:
# Remove atlases that are no longer useful (this is so their
# textures can later be freed if the images inside them get
# collected).
if img.width < 64 and img.height < 64:
self.atlases.remove(atlas)
atlas = TextureAtlas(self.texture_width, self.texture_height)
self.atlases.append(atlas)
return atlas.add(img)
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