1 # Nick's web site: imgresize filter. Helper for resizing images during site
2 # compilations for thumbnails, etc.
4 # Copyright © 2016, 2020 Nick Bowler
6 # This program is free software: you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation, either version 3 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful,
12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 # GNU General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program. If not, see <https://www.gnu.org/licenses/>.
19 class ImgResize < Nanoc::Filter
23 def fetch_from_cache(filename, params)
24 return unless params[:cache]
26 cachefile = File.join(@config[:output_dir], params[:cache])
28 s = File.stat(cachefile)
33 return unless s.mtime >= File.stat(filename).mtime
36 File.link(cachefile, output_filename)
38 FileUtils.copy_file(cachefile, output_filename)
44 def run(filename, params = {})
45 w = if params[:width] then params[:width].to_i end
46 h = if params[:height] then params[:height].to_i end
47 scale = [w, h && "x", h].join
49 args = ["-scale", scale, filename]
52 args << "-quality" << "85"
54 args << output_filename
56 unless fetch_from_cache(filename, params)
57 system('gm', 'convert', *args)