from libc.errno cimport (
errno,
)
from libc.string cimport (
strerror,
memset,
memcpy,
)
from libc.stdio cimport (
FILE,
)
from libc.stdlib cimport (
free,
)
from cpython.string cimport (
PyString_FromStringAndSize,
)
from pypngtile cimport *
cdef extern from "Python.h" :
int PyFile_Check (object p)
FILE* PyFile_AsFile (object p)
## constants
# Image()
OPEN_READ = PT_OPEN_READ
OPEN_UPDATE = PT_OPEN_UPDATE
# Image.status -> ...
CACHE_FRESH = PT_CACHE_FRESH
CACHE_NONE = PT_CACHE_NONE
CACHE_STALE = PT_CACHE_STALE
CACHE_INCOMPAT = PT_CACHE_INCOMPAT
import datetime
class Error (Exception) :
"""
Base class for errors raised by pypngtile.
"""
def __init__ (self, func, err) :
super(Error, self).__init__("%s: %s: %s" % (func, pt_strerror(err), strerror(errno)))
cdef class Image :
"""
An image file on disk (.png) and an associated .cache file.
Open the .png file at the given path using the given mode.
path - filesystem path to .png file
mode - mode to operate cache in
OPEN_READ - read-only access to cache
OPEN_UPDATE - allow .update()
"""
cdef pt_image *image
# XXX: should really be a pt_image property...
cdef readonly object path
# open the pt_image
def __cinit__ (self, char *path, int mode = 0) :
cdef int err
# store
self.path = path
# open
with nogil :
# XXX: I hope use of path doesn't break...
err = pt_image_open(&self.image, NULL, path, mode)
if err :
raise Error("pt_image_open", err)
def info (self) :
"""
Return a dictionary containing various information about the image.
img_width - pixel dimensions of the source image
img_height only available if the cache was opened
img_bpp - bits per pixel for the source image
image_mtime - last modification timestamp for source image
image_bytes - size of source image file in bytes
cache_version - version of cache file available
cache_mtime - last modification timestamp for cache file
cache_bytes - size of cache file in bytes
cache_blocks - size of cache file in disk blocks - 512 bytes / block
"""
cdef const_image_info_ptr infop
cdef int err
with nogil :
err = pt_image_info_(self.image, &infop)
if err :
raise Error("pt_image_info", err)
# return as a struct
return infop[0]
def cache_mtime (self) :
"""
Return cache's mtime as an UTC datetime.
"""
info = self.info()
return datetime.datetime.utcfromtimestamp(info['cache_mtime'])
def status (self) :
"""
Return a code describing the status of the underlying cache file.
CACHE_FRESH - the cache file exists and is up-to-date
CACHE_NONE - the cache file does not exist
CACHE_STALE - the cache file exists, but is older than the source image
CACHE_INCOMPAT - the cache file exists, but is incompatible with this version of the library
"""
cdef int ret
with nogil :
ret = pt_image_status(self.image)
if ret :
raise Error("pt_image_status", ret)
return ret
def open (self) :
"""
Open the underlying cache file for reading, if available.
"""
cdef int err
with nogil :
err = pt_image_load(self.image)
if err :
raise Error("pt_image_load", err)
def update (self, background_color = None) :
"""
Update the underlying cache file from the source image.
background_color - skip consecutive pixels that match this byte pattern in output
Requires that the Image was opened using OPEN_UPDATE.
"""
cdef pt_image_params params
cdef char *bgcolor
cdef int err
memset(¶ms, 0, sizeof(params))
# params
if background_color :
# cast
bgcolor = <char *>background_color
if 0 >= len(bgcolor) > 4 :
raise ValueError("background_color must be a str of between 1 and 4 bytes")
# decode
memcpy(params.background_color, bgcolor, len(bgcolor))
# run update
with nogil :
err = pt_image_update(self.image, ¶ms)
if err :
raise Error("pt_image_update", err)
def tile_file (self, size_t width, size_t height, size_t x, size_t y, int zoom, object out) :
"""
Render a region of the source image as a PNG tile to the given output file.
width - dimensions of the output tile in px
height
x - coordinates in the source file
y
zoom - zoom level: out = 2**(-zoom) * in
out - output file
Note that the given file object MUST be a *real* FILE*, not a fake Python object.
"""
cdef FILE *outf
cdef pt_tile_info ti
cdef int err
memset(&ti, 0, sizeof(ti))
# convert to FILE
if not PyFile_Check(out) :
raise TypeError("out: must be a file object")
outf = PyFile_AsFile(out)
if not outf :
raise TypeError("out: must have a FILE*")
# pack params
ti.width = width
ti.height = height
ti.x = x
ti.y = y
ti.zoom = zoom
# render
with nogil :
err = pt_image_tile_file(self.image, &ti, outf)
if err :
raise Error("pt_image_tile_file", err)
def tile_mem (self, size_t width, size_t height, size_t x, size_t y, int zoom) :
"""
Render a region of the source image as a PNG tile, and return the PNG data a a string.
width - dimensions of the output tile in px
height
x - coordinates in the source file
y
zoom - zoom level: out = 2**(-zoom) * in
"""
cdef pt_tile_info ti
cdef char *buf
cdef size_t len
cdef int err
memset(&ti, 0, sizeof(ti))
# pack params
ti.width = width
ti.height = height
ti.x = x
ti.y = y
ti.zoom = zoom
# render and return via buf/len
with nogil :
err = pt_image_tile_mem(self.image, &ti, &buf, &len)
if err :
raise Error("pt_image_tile_mem", err)
# copy buffer as str...
data = PyString_FromStringAndSize(buf, len)
# drop buffer...
free(buf)
return data
# release the pt_image
def __dealloc__ (self) :
if self.image :
pt_image_destroy(self.image)
self.image = NULL