import os
import fitz
from PIL import Image
from io import BytesIO
# 页面保存为png图片参数
ZOOM_X_1 = ZOOM_Y_1 = 1.0
ZOOM_X_2 = ZOOM_Y_2 = 2.0
trans_1 = fitz.Matrix(ZOOM_X_1, ZOOM_X_1).preRotate(0) # zoom factor 1 in each dimension
trans_2 = fitz.Matrix(ZOOM_X_2, ZOOM_X_2).preRotate(0) # zoom factor 2 in each dimension
# 特殊filter处理
ADOBE_FILTER_SET = {'FlateDecode', 'JPXDecode', 'JBIG2Decode'}
# 宽高阈值组合
WH_COUPLE_1 = (500, 500)
WH_COUPLE_2 = (700, 647)
WH_COUPLE_3 = (100, 100)
WH_COUPLE_4 = (100, 300)
WH_COUPLE_5 = (100, 200)
class PDFHandler:
def __init__(self, path, img_dir_path):
self.path = path
self.img_dir_path = img_dir_path
self.img_path_list = []
self.xref_set = set()
def get_img_save_path(self, pno, img_index=0, ext='png'):
return os.path.join(self.img_dir_path, 'page_{0}_img_{1}.{2}'.format(pno, img_index, ext))
def page_to_png(self, page):
if page.MediaBoxSize.x > 1500 or page.MediaBoxSize.y > 1500:
pm = page.getPixmap(matrix=trans_1, alpha=False)
else:
pm = page.getPixmap(matrix=trans_2, alpha=False)
img_save_path = self.get_img_save_path(page.number)
pm.writePNG(img_save_path)
self.img_path_list.append(img_save_path)
@staticmethod
def getimage(pix):
# RGB
if pix.colorspace.n != 4:
return pix
# GRAY/CMYK
tpix = fitz.Pixmap(fitz.csRGB, pix)
return tpix
def recover_pix(self, doc, xref, smask, colorspace):
if smask != 0:
# we need to reconstruct the alpha channel with the smask
pix1 = fitz.Pixmap(doc, xref)
pix2 = fitz.Pixmap(doc, smask) # create pixmap of the /SMask entry
# sanity check
if not (pix1.irect == pix2.irect and pix1.alpha == pix2.alpha == 0 and pix2.n == 1):
pix2 = None
return self.getimage(pix1)
pix = fitz.Pixmap(pix1) # copy of pix1, alpha channel added
pix.setAlpha(pix2.samples) # treat pix2.samples as alpha value
pix1 = pix2 = None # free temp pixmaps
return self.getimage(pix)
elif colorspace in {'Separation', 'DeviceCMYK'}:
pix = fitz.Pixmap(doc, xref)
tpix = fitz.Pixmap(fitz.csRGB, pix)
return tpix
else:
return doc.extractImage(xref)
@staticmethod
def get_img_data(pix):
if type(pix) is dict: # we got a raw image
ext = pix["ext"]
img_data = pix["image"]
else: # we got a pixmap
ext = 'png'
img_data = pix.getPNGData()
return ext, img_data
def extract_single_image(self, pdf, xref, smask, colorspace, pno, img_index=0):
pix = self.recover_pix(pdf, xref, smask, colorspace)
ext, img_data = self.get_img_data(pix)
if ext == 'jpx':
img_save_path = self.get_img_save_path(pno, img_index=img_index, ext='jpeg')
jpx_pix = fitz.Pixmap(img_data)
jpx_pix.writeImage(img_save_path)
jpx_pix = None
else:
img_save_path = self.get_img_save_path(pno, img_index=img_index, ext=ext)
with open(img_save_path, "wb") as f:
f.write(img_data)
self.xref_set.add(xref)
self.img_path_list.append(img_save_path)
@staticmethod
def split_il(il):
broken_il = []
start = 0
length = len(il)
page_to_png = None
for i in range(length):
# 当图片对象含有特殊filter时，特殊处理：整个页面保存为png图片
if il[i][-1] in ADOBE_FILTER_SET:
page_to_png = True
break
else:
for i in range(length):
# 当图片对象够大时，不作碎图合并处理，而是单纯提取
if il[i][2] >= WH_COUPLE_2[0] and il[i][3] >= WH_COUPLE_2[1]:
break
if i == start:
if i == length - 1:
broken_il.append(il[start: length])
continue
elif i == length - 1:
if il[i][2] == il[i - 1][2]:
broken_il.append(il[start: length])
else:
broken_il.append(il[start: i])
broken_il.append(il[i: length])
continue
if il[i][2] != il[i - 1][2]:
broken_il.append(il[start: i])
start = i
elif il[i][3] != il[i - 1][3]:
broken_il.append(il[start: i + 1])
start = i + 1
else:
# 碎图分组结果
return broken_il
return page_to_png
def merge_il(self, pdf, pno, il):
# 尝试碎图合并前的分组
il.sort(key=lambda x: x[0])
broken_il = self.split_il(il)
page_to_png = True
# 3.1 当图片对象够大时，不作碎图合并处理，而是单纯提取
if broken_il is None:
page_to_png = False
for img_index, img in enumerate(il):
xref, smask, width, height, _, colorspace, _, _, adobe_filter = img
if width < WH_COUPLE_3[0] or height < WH_COUPLE_3[1]: # 过滤小图(如二维码)
continue
elif xref not in self.xref_set:
self.extract_single_image(pdf, xref, smask, colorspace, pno, img_index)
# 3.2 碎图按照分组合并
elif isinstance(broken_il, list) and len(broken_il) <= 2:
for img_index, img_il in enumerate(broken_il):
# 3.2.1 仅一张碎图，过滤或直接提取
if len(img_il) == 1:
xref, smask, width, height, _, colorspace, _, _, adobe_filter = img_il[0]
# 过滤小图(如二维码)
if width < WH_COUPLE_4[0] or height < WH_COUPLE_4[1] or \
(width < WH_COUPLE_1[0] and height < WH_COUPLE_1[1]):
continue
elif xref not in self.xref_set:
self.extract_single_image(pdf, xref, smask, colorspace, pno, img_index)
page_to_png = False
# 3.2.2 多张碎图，竖向拼接
else:
height_sum = sum([img[3] for img in img_il])
width = img_il[0][2]
# 过滤小图和不常规大图
if width < WH_COUPLE_5[0] or height_sum < WH_COUPLE_5[1] or \
(width > 1000 and height_sum > width * 3):
continue
im_list = []
for img in img_il:
xref, smask, _, height, _, colorspace, _, _, adobe_filter = img
pix = self.recover_pix(pdf, xref, smask, colorspace)
ext, img_data = self.get_img_data(pix)
im = Image.open(BytesIO(img_data))
im_list.append((height, im, ext))
new_img = Image.new(im_list[0][1].mode, (width, height_sum))
h_now = 0
for h, m, _ in im_list:
new_img.paste(m, box=(0, h_now))
h_now += h
img_save_path = self.get_img_save_path(pno, img_index, im_list[0][2])
new_img.save(img_save_path)
page_to_png = False
self.img_path_list.append(img_save_path)
# 3.3 碎图分组大于2、全过滤、含特殊filter，特殊处理：整个页面保存为png图片
if page_to_png:
page = pdf.loadPage(pno)
self.page_to_png(page)
def extract_image(self):
self.img_path_list = []
self.xref_set = set()
os.makedirs(self.img_dir_path, exist_ok=True)
with fitz.Document(self.path) as pdf:
for pno in range(pdf.pageCount):
il = pdf.getPageImageList(pno) # 获取页面图片对象
# (xref, smask, width, height, bpc, colorspace, alt.colorspace, name, filter, invoker)
# 1.页面图片对象数目为0时，保存整个页面为png图片
if len(il) == 0:
page = pdf.loadPage(pno)
self.page_to_png(page)
# 2.页面图片对象数目为1时：
# 小图(如电子账单的盖章)：保存整个页面为png图片
# 大图：提取图片对象
elif len(il) == 1:
xref, smask, width, height, _, colorspace, _, _, _ = il[0]
# 小图
if width < WH_COUPLE_1[0] and height < WH_COUPLE_1[1]:
page = pdf.loadPage(pno)
self.page_to_png(page)
# 大图
elif xref not in self.xref_set:
self.extract_single_image(pdf, xref, smask, colorspace, pno)
# 3.页面图片对象数目大于1时，特殊处理
else:
self.merge_il(pdf, pno, il)