我们从Python开源项目中，提取了以下50个代码示例，用于说明如何使用PIL.ImageFile._safe_read()。
def DQT(self, marker): # # Define quantization table. Support baseline 8-bit tables # only. Note that there might be more than one table in # each marker. # FIXME: The quantization tables can be used to estimate the # compression quality. n = i16(self.fp.read(2))-2 s = ImageFile._safe_read(self.fp, n) while len(s): if len(s) < 65: raise SyntaxError("bad quantization table marker") v = i8(s[0]) if v//16 == 0: self.quantization[v & 15] = array.array("b", s[1:65]) s = s[65:] else: return # FIXME: add code to read 16-bit tables! # raise SyntaxError, "bad quantization table element size" # # JPEG marker table
def chunk_tRNS(self, pos, length): # transparency s = ImageFile._safe_read(self.fp, length) if self.im_mode == "P": if _simple_palette.match(s): i = s.find(b"\0") if i >= 0: self.im_info["transparency"] = i elif _null_palette.match(s): self.im_info["transparency"] = 0 else: self.im_info["transparency"] = s elif self.im_mode == "L": self.im_info["transparency"] = i16(s) elif self.im_mode == "RGB": self.im_info["transparency"] = i16(s), i16(s[2:]), i16(s[4:]) return s
def DQT(self, marker): # # Define quantization table. Support baseline 8-bit tables # only. Note that there might be more than one table in # each marker. # FIXME: The quantization tables can be used to estimate the # compression quality. n = i16(self.fp.read(2))-2 s = ImageFile._safe_read(self.fp, n) while len(s): if len(s) < 65: raise SyntaxError("bad quantization table marker") v = i8(s[0]) if v//16 == 0: self.quantization[v & 15] = array.array("B", s[1:65]) s = s[65:] else: return # FIXME: add code to read 16-bit tables! # raise SyntaxError, "bad quantization table element size" # # JPEG marker table
def verify(self, endchunk=b"IEND"): # Simple approach; just calculate checksum for all remaining # blocks. Must be called directly after open. cids = [] while True: try: cid, pos, length = self.read() except struct.error: raise IOError("truncated PNG file") if cid == endchunk: break self.crc(cid, ImageFile._safe_read(self.fp, length)) cids.append(cid) return cids
def chunk_tRNS(self, pos, length): # transparency s = ImageFile._safe_read(self.fp, length) if self.im_mode == "P": if _simple_palette.match(s): # tRNS contains only one full-transparent entry, # other entries are full opaque i = s.find(b"\0") if i >= 0: self.im_info["transparency"] = i else: # otherwise, we have a byte string with one alpha value # for each palette entry self.im_info["transparency"] = s elif self.im_mode == "L": self.im_info["transparency"] = i16(s) elif self.im_mode == "RGB": self.im_info["transparency"] = i16(s), i16(s[2:]), i16(s[4:]) return s
def chunk_tEXt(self, pos, length): # text s = ImageFile._safe_read(self.fp, length) try: k, v = s.split(b"\0", 1) except ValueError: # fallback for broken tEXt tags k = s v = b"" if k: if bytes is not str: k = k.decode('latin-1', 'strict') v = v.decode('latin-1', 'replace') self.im_info[k] = self.im_text[k] = v self.check_text_memory(len(v)) return s
def Skip(self, marker): n = i16(self.fp.read(2))-2 ImageFile._safe_read(self.fp, n)
def COM(self, marker): # # Comment marker. Store these in the APP dictionary. n = i16(self.fp.read(2))-2 s = ImageFile._safe_read(self.fp, n) self.app["COM"] = s # compatibility self.applist.append(("COM", s))
def verify(self, endchunk=b"IEND"): # Simple approach; just calculate checksum for all remaining # blocks. Must be called directly after open. cids = [] while True: cid, pos, length = self.read() if cid == endchunk: break self.crc(cid, ImageFile._safe_read(self.fp, length)) cids.append(cid) return cids
def chunk_IHDR(self, pos, length): # image header s = ImageFile._safe_read(self.fp, length) self.im_size = i32(s), i32(s[4:]) try: self.im_mode, self.im_rawmode = _MODES[(i8(s[8]), i8(s[9]))] except: pass if i8(s[12]): self.im_info["interlace"] = 1 if i8(s[11]): raise SyntaxError("unknown filter category") return s
def chunk_PLTE(self, pos, length): # palette s = ImageFile._safe_read(self.fp, length) if self.im_mode == "P": self.im_palette = "RGB", s return s
def chunk_gAMA(self, pos, length): # gamma setting s = ImageFile._safe_read(self.fp, length) self.im_info["gamma"] = i32(s) / 100000.0 return s
def chunk_pHYs(self, pos, length): # pixels per unit s = ImageFile._safe_read(self.fp, length) px, py = i32(s), i32(s[4:]) unit = i8(s[8]) if unit == 1: # meter dpi = int(px * 0.0254 + 0.5), int(py * 0.0254 + 0.5) self.im_info["dpi"] = dpi elif unit == 0: self.im_info["aspect"] = px, py return s
def chunk_zTXt(self, pos, length): # compressed text s = ImageFile._safe_read(self.fp, length) try: k, v = s.split(b"\0", 1) except ValueError: k = s v = b"" if v: comp_method = i8(v[0]) else: comp_method = 0 if comp_method != 0: raise SyntaxError("Unknown compression method %s in zTXt chunk" % comp_method) try: v = _safe_zlib_decompress(v[1:]) except zlib.error: v = b"" if k: if bytes is not str: k = k.decode('latin-1', 'strict') v = v.decode('latin-1', 'replace') self.im_info[k] = self.im_text[k] = v self.check_text_memory(len(v)) return s
def chunk_iTXt(self, pos, length): # international text r = s = ImageFile._safe_read(self.fp, length) try: k, r = r.split(b"\0", 1) except ValueError: return s if len(r) < 2: return s cf, cm, r = i8(r[0]), i8(r[1]), r[2:] try: lang, tk, v = r.split(b"\0", 2) except ValueError: return s if cf != 0: if cm == 0: try: v = _safe_zlib_decompress(v) except zlib.error: return s else: return s if bytes is not str: try: k = k.decode("latin-1", "strict") lang = lang.decode("utf-8", "strict") tk = tk.decode("utf-8", "strict") v = v.decode("utf-8", "strict") except UnicodeError: return s self.im_info[k] = self.im_text[k] = iTXt(v, lang, tk) self.check_text_memory(len(v)) return s # -------------------------------------------------------------------- # PNG reader
def chunk_zTXt(self, pos, length): # compressed text s = ImageFile._safe_read(self.fp, length) try: k, v = s.split(b"\0", 1) except ValueError: k = s v = b"" if v: comp_method = i8(v[0]) else: comp_method = 0 if comp_method != 0: raise SyntaxError("Unknown compression method %s in zTXt chunk" % comp_method) try: v = _safe_zlib_decompress(v[1:]) except ValueError: if ImageFile.LOAD_TRUNCATED_IMAGES: v = b"" else: raise except zlib.error: v = b"" if k: if bytes is not str: k = k.decode('latin-1', 'strict') v = v.decode('latin-1', 'replace') self.im_info[k] = self.im_text[k] = v self.check_text_memory(len(v)) return s
