1 """

     2     Use of PIL to render the image formatting stuff

     3 """

     4 

     5 from PIL import Image, ImageDraw, ImageFont

     6 

     7 from cStringIO import StringIO

     8 

     9 class PILImageFormatter (object) :

    10     """

    11         Mixin for LogFormatter that implements the basic image-rendering operations on top of format_txt

    12     """

    13     

    14     # the font we load

    15     font = None

    16 

    17     # line spacing in pixels

    18     LINE_SPACING = 1

    19 

    20     def _load_font (self) :

    21         """

    22             Use the configured img_ttf_path for a TrueType font, or a default one

    23         """

    24 

    25         if self.font :

    26             pass

    27         

    28         elif self.img_ttf_path :

    29             # load truetype with configured size

    30             self.font = ImageFont.truetype(self.img_ttf_path, self.img_font_size)

    31 

    32         else :

    33             # default

    34             self.font = ImageFont.load_default()

    35 

    36         return self.font

    37 

    38     def format_png (self, lines, **kwargs) :

    39         """

    40             Build and return a PNG image of the given lines, using format_txt

    41         """

    42 

    43         # load font

    44         font = self._load_font()

    45 

    46         # build list of plain-text line data

    47         lines = list(data for line, data in self.format_txt(lines, **kwargs))

    48         

    49         # lines sizes

    50         line_sizes = [font.getsize(line) for line in lines]

    51 

    52         # figure out how wide/high the image will be

    53         width = max(width for width, height in line_sizes)

    54         height = sum(height + self.LINE_SPACING for width, height in line_sizes)

    55 

    56         # create new B/W image

    57         img = Image.new('L', (width, height), 0xff)

    58 

    59         # drawer

    60         draw = ImageDraw.Draw(img)

    61         

    62         # starting offset

    63         offset_y = 0

    64 

    65         # draw the lines

    66         for line, (width, height) in zip(lines, line_sizes) :

    67             # draw

    68             draw.text((0, offset_y), line, font=font)

    69 

    70             # next offset

    71             offset_y += height + self.LINE_SPACING

    72         

    73         # output buffer

    74         buf = StringIO()

    75 

    76         # save

    77         img.save(buf, 'png')

    78 

    79         # return data

    80         return buf.getvalue()

    81