Spaces:
Runtime error
Runtime error
File size: 8,237 Bytes
d82cf6a |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 |
"""Group multiple small images into larger textures.
This module is used by :py:mod:`pyglet.resource` to efficiently pack small
images into larger textures. :py:class:`~pyglet.image.atlas.TextureAtlas` maintains one texture;
:py:class:`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 :py:meth:`TextureBin.add` is a :py:class:`TextureRegion`
containing the image. Once added, an image cannot be removed from a bin (or an
atlas); nor can a list of images be obtained from a given bin or atlas -- it is
the application's responsibility to keep track of the regions returned by the
``add`` methods.
.. versionadded:: 1.1
"""
import pyglet
class AllocatorException(Exception):
"""The allocator does not have sufficient free space for the requested
image size."""
pass
class _Strip:
__slots__ = 'x', 'y', 'max_height', 'y2'
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:
"""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 future allocations.
`Allocator` uses a fairly simple strips-based algorithm. It performs best
when rectangles are allocated in decreasing height order.
"""
__slots__ = 'width', 'height', 'strips', 'used_area'
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 0.0
possible_area = self.strips[-1].y2 * self.width
return 1.0 - self.used_area / float(possible_area)
class TextureAtlas:
"""Collection of images within a texture."""
def __init__(self, width=2048, height=2048):
"""Create a texture atlas of the given size.
:Parameters:
`width` : int
Width of the underlying texture.
`height` : int
Height of the underlying texture.
"""
max_texture_size = pyglet.image.get_max_texture_size()
width = min(width, max_texture_size)
height = min(height, max_texture_size)
self.texture = pyglet.image.Texture.create(width, height)
self.allocator = Allocator(width, height)
def add(self, img, border=0):
"""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).
:py:class:`~pyglet.image.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` : `~pyglet.image.AbstractImage`
The image to add.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlas.
:rtype: :py:class:`~pyglet.image.TextureRegion`
:return: The region of the atlas containing the newly added image.
"""
x, y = self.allocator.alloc(img.width + border*2, img.height + border*2)
self.texture.blit_into(img, x+border, y+border, 0)
return self.texture.get_region(x+border, y+border, img.width, img.height)
class TextureBin:
"""Collection of texture atlases.
:py:class:`~pyglet.image.atlas.TextureBin` maintains a collection of texture atlases, and creates new
ones as necessary to accommodate images added to the bin.
"""
def __init__(self, texture_width=2048, texture_height=2048):
"""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.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlases.
"""
max_texture_size = pyglet.image.get_max_texture_size()
self.texture_width = min(texture_width, max_texture_size)
self.texture_height = min(texture_height, max_texture_size)
self.atlases = []
def add(self, img, border=0):
"""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` : `~pyglet.image.AbstractImage`
The image to add.
`border` : int
Leaves specified pixels of blank space around
each image added to the Atlas.
:rtype: :py:class:`~pyglet.image.TextureRegion`
:return: The region of an atlas containing the newly added image.
"""
for atlas in list(self.atlases):
try:
return atlas.add(img, border)
except AllocatorException:
# Remove atlases that are no longer useful (so that 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, border)
|