Source code for PIL.PyAccess

#
# The Python Imaging Library
# Pillow fork
#
# Python implementation of the PixelAccess Object
#
# Copyright (c) 1997-2009 by Secret Labs AB.  All rights reserved.
# Copyright (c) 1995-2009 by Fredrik Lundh.
# Copyright (c) 2013 Eric Soroos
#
# See the README file for information on usage and redistribution
#

# Notes:
#
#  * Implements the pixel access object following Access.
#  * Does not implement the line functions, as they don't appear to be used
#  * Taking only the tuple form, which is used from python.
#    * Fill.c uses the integer form, but it's still going to use the old
#      Access.c implementation.
#

import logging
import sys

try:
    from cffi import FFI

    defs = """
    struct Pixel_RGBA {
        unsigned char r,g,b,a;
    };
    struct Pixel_I16 {
        unsigned char l,r;
    };
    """
    ffi = FFI()
    ffi.cdef(defs)
except ImportError as ex:
    # Allow error import for doc purposes, but error out when accessing
    # anything in core.
    from ._util import deferred_error

    FFI = ffi = deferred_error(ex)

logger = logging.getLogger(__name__)


[docs]class PyAccess: def __init__(self, img, readonly=False): vals = dict(img.im.unsafe_ptrs) self.readonly = readonly self.image8 = ffi.cast("unsigned char **", vals["image8"]) self.image32 = ffi.cast("int **", vals["image32"]) self.image = ffi.cast("unsigned char **", vals["image"]) self.xsize, self.ysize = img.im.size # Keep pointer to im object to prevent dereferencing. self._im = img.im if self._im.mode == "P": self._palette = img.palette # Debugging is polluting test traces, only useful here # when hacking on PyAccess # logger.debug("%s", vals) self._post_init() def _post_init(self): pass def __setitem__(self, xy, color): """ Modifies the pixel at x,y. The color is given as a single numerical value for single band images, and a tuple for multi-band images :param xy: The pixel coordinate, given as (x, y). See :ref:`coordinate-system`. :param color: The pixel value. """ if self.readonly: raise ValueError("Attempt to putpixel a read only image") (x, y) = xy if x < 0: x = self.xsize + x if y < 0: y = self.ysize + y (x, y) = self.check_xy((x, y)) if ( self._im.mode == "P" and isinstance(color, (list, tuple)) and len(color) in [3, 4] ): # RGB or RGBA value for a P image color = self._palette.getcolor(color) return self.set_pixel(x, y, color) def __getitem__(self, xy): """ Returns the pixel at x,y. The pixel is returned as a single value for single band images or a tuple for multiple band images :param xy: The pixel coordinate, given as (x, y). See :ref:`coordinate-system`. :returns: a pixel value for single band images, a tuple of pixel values for multiband images. """ (x, y) = xy if x < 0: x = self.xsize + x if y < 0: y = self.ysize + y (x, y) = self.check_xy((x, y)) return self.get_pixel(x, y) putpixel = __setitem__ getpixel = __getitem__ def check_xy(self, xy): (x, y) = xy if not (0 <= x < self.xsize and 0 <= y < self.ysize): raise ValueError("pixel location out of range") return xy
class _PyAccess32_2(PyAccess): """ PA, LA, stored in first and last bytes of a 32 bit word """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("struct Pixel_RGBA **", self.image32) def get_pixel(self, x, y): pixel = self.pixels[y][x] return (pixel.r, pixel.a) def set_pixel(self, x, y, color): pixel = self.pixels[y][x] # tuple pixel.r = min(color[0], 255) pixel.a = min(color[1], 255) class _PyAccess32_3(PyAccess): """ RGB and friends, stored in the first three bytes of a 32 bit word """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("struct Pixel_RGBA **", self.image32) def get_pixel(self, x, y): pixel = self.pixels[y][x] return (pixel.r, pixel.g, pixel.b) def set_pixel(self, x, y, color): pixel = self.pixels[y][x] # tuple pixel.r = min(color[0], 255) pixel.g = min(color[1], 255) pixel.b = min(color[2], 255) pixel.a = 255 class _PyAccess32_4(PyAccess): """ RGBA etc, all 4 bytes of a 32 bit word """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("struct Pixel_RGBA **", self.image32) def get_pixel(self, x, y): pixel = self.pixels[y][x] return (pixel.r, pixel.g, pixel.b, pixel.a) def set_pixel(self, x, y, color): pixel = self.pixels[y][x] # tuple pixel.r = min(color[0], 255) pixel.g = min(color[1], 255) pixel.b = min(color[2], 255) pixel.a = min(color[3], 255) class _PyAccess8(PyAccess): """ 1, L, P, 8 bit images stored as uint8 """ def _post_init(self, *args, **kwargs): self.pixels = self.image8 def get_pixel(self, x, y): return self.pixels[y][x] def set_pixel(self, x, y, color): try: # integer self.pixels[y][x] = min(color, 255) except TypeError: # tuple self.pixels[y][x] = min(color[0], 255) class _PyAccessI16_N(PyAccess): """ I;16 access, native bitendian without conversion """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("unsigned short **", self.image) def get_pixel(self, x, y): return self.pixels[y][x] def set_pixel(self, x, y, color): try: # integer self.pixels[y][x] = min(color, 65535) except TypeError: # tuple self.pixels[y][x] = min(color[0], 65535) class _PyAccessI16_L(PyAccess): """ I;16L access, with conversion """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("struct Pixel_I16 **", self.image) def get_pixel(self, x, y): pixel = self.pixels[y][x] return pixel.l + pixel.r * 256 def set_pixel(self, x, y, color): pixel = self.pixels[y][x] try: color = min(color, 65535) except TypeError: color = min(color[0], 65535) pixel.l = color & 0xFF # noqa: E741 pixel.r = color >> 8 class _PyAccessI16_B(PyAccess): """ I;16B access, with conversion """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("struct Pixel_I16 **", self.image) def get_pixel(self, x, y): pixel = self.pixels[y][x] return pixel.l * 256 + pixel.r def set_pixel(self, x, y, color): pixel = self.pixels[y][x] try: color = min(color, 65535) except Exception: color = min(color[0], 65535) pixel.l = color >> 8 # noqa: E741 pixel.r = color & 0xFF class _PyAccessI32_N(PyAccess): """ Signed Int32 access, native endian """ def _post_init(self, *args, **kwargs): self.pixels = self.image32 def get_pixel(self, x, y): return self.pixels[y][x] def set_pixel(self, x, y, color): self.pixels[y][x] = color class _PyAccessI32_Swap(PyAccess): """ I;32L/B access, with byteswapping conversion """ def _post_init(self, *args, **kwargs): self.pixels = self.image32 def reverse(self, i): orig = ffi.new("int *", i) chars = ffi.cast("unsigned char *", orig) chars[0], chars[1], chars[2], chars[3] = chars[3], chars[2], chars[1], chars[0] return ffi.cast("int *", chars)[0] def get_pixel(self, x, y): return self.reverse(self.pixels[y][x]) def set_pixel(self, x, y, color): self.pixels[y][x] = self.reverse(color) class _PyAccessF(PyAccess): """ 32 bit float access """ def _post_init(self, *args, **kwargs): self.pixels = ffi.cast("float **", self.image32) def get_pixel(self, x, y): return self.pixels[y][x] def set_pixel(self, x, y, color): try: # not a tuple self.pixels[y][x] = color except TypeError: # tuple self.pixels[y][x] = color[0] mode_map = { "1": _PyAccess8, "L": _PyAccess8, "P": _PyAccess8, "LA": _PyAccess32_2, "La": _PyAccess32_2, "PA": _PyAccess32_2, "RGB": _PyAccess32_3, "LAB": _PyAccess32_3, "HSV": _PyAccess32_3, "YCbCr": _PyAccess32_3, "RGBA": _PyAccess32_4, "RGBa": _PyAccess32_4, "RGBX": _PyAccess32_4, "CMYK": _PyAccess32_4, "F": _PyAccessF, "I": _PyAccessI32_N, } if sys.byteorder == "little": mode_map["I;16"] = _PyAccessI16_N mode_map["I;16L"] = _PyAccessI16_N mode_map["I;16B"] = _PyAccessI16_B mode_map["I;32L"] = _PyAccessI32_N mode_map["I;32B"] = _PyAccessI32_Swap else: mode_map["I;16"] = _PyAccessI16_L mode_map["I;16L"] = _PyAccessI16_L mode_map["I;16B"] = _PyAccessI16_N mode_map["I;32L"] = _PyAccessI32_Swap mode_map["I;32B"] = _PyAccessI32_N def new(img, readonly=False): access_type = mode_map.get(img.mode, None) if not access_type: logger.debug("PyAccess Not Implemented: %s", img.mode) return None return access_type(img, readonly)