“Rubber Matrix” and “Sparse Montage” wrapper for ImageMagick

Last night, I was working on a bunch of images and I really wanted to just get a visual overview along the lines of a scatter plot, but with images rather than dots. Unfortunately, no matter what I searched for, I couldn’t find anything to do what I wanted.

ImageMagick’s montage tool can do it… but you have to manually fill in the empty cells with the special filename null:

…so I wrote a script to do just that.

Oh, and I got carried away and wrote a “rubber matrix” class to abstract away the actual generation of the grid. Basically, it’s a DictMixin-based class that insists on consistently sized tuples as keys and then adds some extra methods to traverse them as sparse points in a matrix dynamically sized to only the rows/columns/etc. which exist.

I haven’t yet decided on what command-line syntax I want, so you have to import it, but it works perfectly in my preliminary tests.

#!/usr/bin/env python2 # -*- coding: utf-8 -*- """ @todo: Decide on how to give this a command-line interface. """ from __future__ import (absolute_import, division, print_function, with_statement, unicode_literals) __author__ = "Stephan Sokolow (deitarion/SSokolow)" __appname__ = "Sparse Matrix Wrapper for ImageMagic's 'montage' utility" __version__ = "0.1" __license__ = "MIT" import functools, subprocess from UserDict import DictMixin import logging log = logging.getLogger(__name__) DEFAULT_OPTIONS = ['-label', '%t', '-background', 'none', '-geometry', '1x1<+2+2'] def _dimensions_check(func): """Decorator to unify the dimensionality checks for get/set/del""" @functools.wraps(func) def wrapper(self, keys, *args): # pylint: disable=missing-docstring if self.dims is None: self.dims = len(keys) if len(keys) != self.dims: raise KeyError("Invalid dimensions: len(%r) != %s" % (keys, self.dims)) return func(self, keys, *args) return wrapper class RubberMatrix(object, DictMixin): """Dict-based, self-resizing, sparse matrix object with support for a whole-matrix iteration (full and empty cells) which only shows rows/columns/etc. which actually have content. """ def __init__(self, dims=None, null_val=None): """ @param dims: The number of dimensions to enforce. The default value of C{None} causes this to be determined by the key of the first value to be inserted. @type dims: C{int} @param null_val: The value to return when accessing an empty cell. """ self._dict = {} self.dims = dims # Treat this as read-only or things will break self.null_val = null_val @_dimensions_check def __getitem__(self, keys): if Ellipsis in keys: # TODO: Test this code return [y for x, y in self.iteritems() if all(kx in (x, Ellipsis) for k, kx in zip(keys, x))] else: return self._dict.get(keys, self.null_val) @_dimensions_check def __setitem__(self, keys, value): self._dict[keys] = value @_dimensions_check def __delitem__(self, keys): if keys in self._dict: del self._dict[keys] def _get_depthmap(self): """Build a dict showing which rows/cols/etc. actually exist""" _seqs = {} for key in self._dict.keys(): for depth, keyval in enumerate(key): _seqs.setdefault(depth, set()).add(keyval) return {x: sorted(y) for x, y in _seqs.items()} def _iterkeys_padded(self, key_prefix, depthmap): """Inner recursive function for iterkeys_padded()""" depth = len(key_prefix) for key in sorted(depthmap.get(depth, {})): if depth + 1 < self.dims: for x in self._iterkeys_padded(key_prefix + (key,), depthmap): yield x else: yield key_prefix + (key,) def iterkeys_padded(self): """iterkeys() through all cells rather than just ones with data""" depthmap = self._get_depthmap() return self._iterkeys_padded(tuple(), depthmap) def iteritems_padded(self): """iteritems() through all cells rather than just ones with data""" for x in self.iterkeys_padded(): yield (x, self[x]) def itervalues_padded(self): """itervalues() through all cells rather than just ones with data""" for x in self.iterkeys_padded(): yield self[x] def keys(self): """D.keys() -> list of D's keys""" return self._dict.keys() def __iter__(self): return self._dict.__iter__() # pylint: disable=dangerous-default-value def sparse_montage(inputs, outpath, options=DEFAULT_OPTIONS): """Apply ImageMagick's montage to an (x,y)-keyed dict of image paths. @type inputs: C{{(x, y): str}} @param outpath: A full file path, including extension. @param options: An C{argv} fragment to pass to C{montage} See http://www.imagemagick.org/Usage/montage/ for details """ if isinstance(inputs, RubberMatrix): in_matrix = inputs else: in_matrix = RubberMatrix(dims=2, null_val='null:') if isinstance(inputs, dict): inputs = inputs.items() for coords, path in inputs: in_matrix[coords] = path # TODO: Look for an elegant way to move rowlen-getting to RubberMatrix allkeys = list(in_matrix.iterkeys_padded()) rowlen = sum(1 for x in allkeys if x[0] == allkeys[0][0]) subprocess.call(['montage', '-tile', '%sx' % rowlen] + options + [in_matrix[x] for x in allkeys] + [outpath]) # vim: set sw=4 sts=4 expandtab :

“Rubber Matrix” and “Sparse Montage” wrapper for ImageMagick by Stephan Sokolow is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

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“Rubber Matrix” and “Sparse Montage” wrapper for ImageMagick

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