cdef extern from "errno.h" :
extern int errno
cdef extern from "string.h" :
char* strerror (int err)
void* memset (void *, int, size_t)
void* memcpy (void *, void *, size_t)
cimport stdio
cimport stdlib
cimport python_string
cdef extern from "Python.h" :
int PyFile_Check (object p)
stdio.FILE* PyFile_AsFile (object p)
void PyFile_IncUseCount (object p)
void PyFile_DecUseCount (object p)
cdef extern from "pngtile.h" :
struct pt_ctx :
pass
struct pt_image :
pass
enum pt_open_mode :
PT_OPEN_READ # 0
PT_OPEN_UPDATE
enum pt_cache_status :
PT_CACHE_ERROR # -1
PT_CACHE_FRESH
PT_CACHE_NONE
PT_CACHE_STALE
PT_CACHE_INCOMPAT
struct pt_image_info :
size_t img_width, img_height, img_bpp
int image_mtime, cache_mtime, cache_version
size_t image_bytes, cache_bytes
size_t cache_blocks
struct pt_image_params :
int background_color[4]
struct pt_tile_info :
size_t width, height
size_t x, y
int zoom
## functions
int pt_image_open (pt_image **image_ptr, pt_ctx *ctx, char *png_path, int cache_mode)
int pt_image_info_ "pt_image_info" (pt_image *image, pt_image_info **info_ptr)
int pt_image_status (pt_image *image)
int pt_image_load (pt_image *image)
int pt_image_update (pt_image *image, pt_image_params *params)
int pt_image_tile_file (pt_image *image, pt_tile_info *info, stdio.FILE *out)
int pt_image_tile_mem (pt_image *image, pt_tile_info *info, char **buf_ptr, size_t *len_ptr)
void pt_image_destroy (pt_image *image)
# error code -> name
char* pt_strerror (int err)
## 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
class Error (BaseException) :
pass
# raise Error if the given return value is <0
cdef int trap_err (char *op, int ret) except -1 :
if ret < 0 :
raise Error("%s: %s: %s" % (op, pt_strerror(ret), strerror(errno)))
else :
return ret
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
# open the pt_image
def __cinit__ (self, char *path, int mode = 0) :
trap_err("pt_image_open",
pt_image_open(&self.image, NULL, path, mode)
)
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 pt_image_info *info
trap_err("pt_image_info",
pt_image_info_(self.image, &info)
)
# return as a struct
return info[0]
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
"""
return trap_err("pt_image_status",
pt_image_status(self.image)
)
def open (self) :
"""
Open the underlying cache file for reading, if available.
"""
return trap_err("pt_image_load",
pt_image_load(self.image)
)
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
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
trap_err("pt_image_update",
pt_image_update(self.image, ¶ms)
)
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* stdio FILE*, not a fake Python object.
"""
cdef stdio.FILE *outf
cdef pt_tile_info ti
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
trap_err("pt_image_tile_file",
pt_image_tile_file(self.image, &ti, outf)
)
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
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
trap_err("pt_image_tile_mem",
pt_image_tile_mem(self.image, &ti, &buf, &len)
)
# copy buffer as str...
data = python_string.PyString_FromStringAndSize(buf, len)
# drop buffer...
stdlib.free(buf)
return data
# release the pt_image
def __dealloc__ (self) :
if self.image :
pt_image_destroy(self.image)
self.image = NULL