"""\
Copyright (c) 2022, Flagstaff Solutions, LLC
All rights reserved.
"""
import importlib.resources
import io
import pyqrcode
from PIL import Image, ImageDraw, ImageFont
from gofigr import APP_URL
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class Watermark:
"""\
Base class for drawing watermaks on figures.
"""
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def apply(self, image, revision):
"""\
Places a watermark on an image
:param image: PIL Image object
:param revision: GoFigr revision object
"""
raise NotImplementedError()
def _qr_to_image(text, **kwargs):
"""Creates a QR code for the text, and returns it as a PIL.Image"""
qr = pyqrcode.create(text)
bio = io.BytesIO()
qr.png(bio, **kwargs)
bio.seek(0)
image = Image.open(bio)
image.load()
return image
def _default_font():
"""Loads the default font and returns it as an ImageFont"""
# pylint: disable=deprecated-method
with importlib.resources.open_binary("gofigr.resources", "FreeMono.ttf") as f:
return ImageFont.truetype(f, 14)
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def stack_horizontally(*images, alignment="center"):
"""
Stacks images horizontally. Thanks, Stack Overflow!
https://stackoverflow.com/questions/30227466/combine-several-images-horizontally-with-python
"""
images = [im for im in images if im is not None]
widths, heights = zip(*(i.size for i in images))
total_width = sum(widths)
max_height = max(heights)
res = Image.new('RGBA', (total_width, max_height))
x_offset = 0
for im in images:
if alignment == "center":
res.paste(im, (x_offset, (max_height - im.size[1]) // 2))
elif alignment == "top":
res.paste(im, (x_offset, 0))
elif alignment == "bottom":
res.paste(im, (x_offset, max_height - im.size[1]))
else:
raise ValueError(alignment)
x_offset += im.size[0]
return res
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def stack_vertically(*images, alignment="center"):
"""Stacks images vertically."""
images = [im for im in images if im is not None]
widths, heights = zip(*(i.size for i in images))
total_height = sum(heights)
max_width = max(widths)
res = Image.new('RGBA', (max_width, total_height))
y_offset = 0
for im in images:
if alignment == "center":
res.paste(im, ((max_width - im.size[0]) // 2, y_offset))
elif alignment == "left":
res.paste(im, (0, y_offset))
elif alignment == "right":
res.paste(im, (max_width - im.size[0], y_offset))
else:
raise ValueError(alignment)
y_offset += im.size[1]
return res
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def add_margins(img, margins):
"""Adds margins to an image"""
res = Image.new('RGBA', (img.size[0] + margins[0] * 2,
img.size[1] + margins[1] * 2))
res.paste(img, (margins[0], margins[1]))
return res
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class DefaultWatermark:
"""\
Draws QR codes + URL watermark on figures.
"""
def __init__(self,
show_qr_code=True,
margin_px=10,
qr_background=(0x00, 0x00, 0x00, 0x00),
qr_foreground=(0x00, 0x00, 0x00, 0x99),
qr_scale=2, font=None):
"""
:param show_qr_code: whether to show the QR code. Default is True
:param margin_px: margin as an x, y tuple
:param qr_background: RGBA tuple for QR background color
:param qr_foreground: RGBA tuple for QR foreground color
:param qr_scale: QR scale, as an integer
:param font: font for the identifier
"""
self.margin_px = margin_px
if not hasattr(self.margin_px, '__iter__'):
self.margin_px = (self.margin_px, self.margin_px)
self.qr_background = qr_background
self.qr_foreground = qr_foreground
self.qr_scale = qr_scale
self.font = font if font is not None else _default_font()
self.show_qr_code = show_qr_code
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def draw_identifier(self, text):
"""Draws the GoFigr identifier text, returning it as a PIL image"""
left, top, right, bottom = self.font.getbbox(text)
text_height = bottom - top
text_width = right - left
img = Image.new(mode="RGBA", size=(text_width + 2 * self.margin_px[0], text_height + 2 * self.margin_px[1]))
draw = ImageDraw.Draw(img)
draw.text((self.margin_px[0], self.margin_px[1]), text, fill="black", font=self.font)
return img
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def get_watermark(self, revision):
"""\
Generates just the watermark for a revision.
:param revision: FigureRevision
:return: PIL.Image
"""
identifier_text = f'{APP_URL}/r/{revision.api_id}'
identifier_img = self.draw_identifier(identifier_text)
qr_img = None
if self.show_qr_code:
qr_img = _qr_to_image(f'{APP_URL}/r/{revision.api_id}', scale=self.qr_scale,
module_color=self.qr_foreground,
background=self.qr_background)
qr_img = add_margins(qr_img, self.margin_px)
return stack_horizontally(identifier_img, qr_img)
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def apply(self, image, revision):
"""\
Adds a QR watermark to an image.
:param image: PIL.Image
:param revision: instance of FigureRevision
:return: PIL.Image containing the watermarked image
"""
return stack_vertically(image, self.get_watermark(revision))