Source code for stoqlib.lib.imageutils

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4

## Copyright (C) 2017 Async Open Source
## This program is free software; you can redistribute it and/or
## modify it under the terms of the GNU Lesser General Public License
## as published by the Free Software Foundation; either version 2
## of the License, or (at your option) any later version.
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## GNU Lesser General Public License for more details.
## You should have received a copy of the GNU Lesser General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., or visit:
## Author(s): Stoq Team <>

"""Utilities for working with images.

Some of those functions were borrowed from datagrid_gtk3:

import io

import gtk
from PIL import Image, ImageFilter

_image_border_size = 6
_image_shadow_size = 6
_image_shadow_offset = 2
# Generating a drop shadow is an expensive operation. Keep a cache
# of already generated drop shadows so they can be reutilized
_drop_shadows_cache = {}

[docs]def image2pixbuf(image): """Convert a PIL image to a pixbuf. :param image: the image to convert :type image: `PIL.Image` :returns: the newly created pixbuf :rtype: `GdkPixbuf.Pixbuf` """ with io.BytesIO() as f:, 'png') loader = gtk.gdk.PixbufLoader('png') loader.write(f.getvalue()) pixbuf = loader.get_pixbuf() loader.close() return pixbuf
[docs]def add_border(image, border_size=5, background_color=(0xff, 0xff, 0xff, 0xff)): """Add a border to the image. :param image: the image to add the border :type image: `PIL.Image` :param int border_size: the size of the border :param tuple background_color: the color of the border as a tuple containing (r, g, b, a) information :returns: the new image with the border :rtype: `PIL.Image` """ width = image.size[0] + border_size * 2 height = image.size[1] + border_size * 2 try: image.convert("RGBA") image_parts = image.split() mask = image_parts[3] if len(image_parts) == 4 else None except IOError: # pragma: no cover mask = None border ="RGBA", (width, height), background_color) border.paste(image, (border_size, border_size), mask=mask) return border
[docs]def add_drop_shadow(image, iterations=3, border_size=2, offset=(2, 2), shadow_color=(0x00, 0x00, 0x00, 0xff)): """Add a drop shadow to the image. Based on this receipe:: :param image: the image to add the drop shadow :type image: `PIL.Image` :param int iterations: number of times to apply the blur filter :param int border_size: the size of the border to add to leave space for the shadow :param tuple offset: the offset of the shadow as (x, y) :param tuple shadow_color: the color of the shadow as a tuple containing (r, g, b, a) information :returns: the new image with the drop shadow :rtype: `PIL.Image` """ width = image.size[0] + abs(offset[0]) + 2 * border_size height = image.size[1] + abs(offset[1]) + 2 * border_size key = (width, height, iterations, border_size, offset, shadow_color) existing_shadow = _drop_shadows_cache.get(key) if existing_shadow: shadow = existing_shadow.copy() else: shadow ='RGBA', (width, height), (0xff, 0xff, 0xff, 0x00)) # Place the shadow, with the required offset # if < 0, push the rest of the image right shadow_lft = border_size + max(offset[0], 0) # if < 0, push the rest of the image down shadow_top = border_size + max(offset[1], 0) shadow.paste(shadow_color, [shadow_lft, shadow_top, shadow_lft + image.size[0], shadow_top + image.size[1]]) # Apply the BLUR filter repeatedly for i in range(iterations): shadow = shadow.filter(ImageFilter.BLUR) _drop_shadows_cache[key] = shadow.copy() # Paste the original image on top of the shadow # if the shadow offset was < 0, push right img_lft = border_size - min(offset[0], 0) # if the shadow offset was < 0, push down img_top = border_size - min(offset[1], 0) shadow.paste(image, (img_lft, img_top)) return shadow
[docs]def get_thumbnail(image_bytes, size): """Generate a thumbnail of the image by the given size. :param str image_bytes: The image bytes (e.g. the image from the database) :param tuple size: The size to generate the thumbnail :returns: The thumbnail image :rtype: str """ with io.BytesIO(image_bytes) as f: im = im.thumbnail(size, Image.BICUBIC) with io.BytesIO() as new_f:, 'png') return new_f.getvalue()
[docs]def get_pixbuf(image_bytes, draw_border=True, fill_image=None): """Render image into a pixbuf doing the necessary transformations. :param str image_bytes: The image bytes (e.g. the image from the database) :param bool draw_border: if we should add a border on the image :param tuple fill_image: If we should fill the image with a transparent background to make a smaller image be at least a square of (size, size), with the real image at the center. :returns: the resized pixbuf :rtype: :class:`GdkPixbuf.Pixbuf` """ with io.BytesIO(image_bytes) as f: image = w, h = image.size if draw_border: image = add_border(image, border_size=_image_border_size) image = add_drop_shadow( image, border_size=_image_shadow_size, offset=(_image_shadow_offset, _image_shadow_offset)) # After the border and the dropshadow, the size will be # slightly increased extra = ((_image_border_size * 2) + (_image_shadow_size * 2) + _image_shadow_offset) w += extra h += extra pixbuf = image2pixbuf(image) width = pixbuf.get_width() height = pixbuf.get_height() if fill_image is None: return pixbuf w = max(w, fill_image[0]) h = max(h, fill_image[1]) # Make sure the image is on the center of the image_max_size square_pic = gtk.gdk.Pixbuf( gtk.gdk.COLORSPACE_RGB, True, pixbuf.get_bits_per_sample(), w, h) # Fill with transparent white square_pic.fill(0xffffff00) dest_x = (w - width) / 2 dest_y = (h - height) / 2 pixbuf.copy_area(0, 0, width, height, square_pic, dest_x, dest_y) return square_pic