{"id":17894,"date":"2025-07-31T22:21:17","date_gmt":"2025-08-01T02:21:17","guid":{"rendered":"https:\/\/scruss.com\/blog\/?p=17894"},"modified":"2025-07-31T22:21:17","modified_gmt":"2025-08-01T02:21:17","slug":"img2blocks","status":"publish","type":"post","link":"https:\/\/scruss.com\/blog\/2025\/07\/31\/img2blocks\/","title":{"rendered":"img2blocks"},"content":{"rendered":"\n

this image is supposed to be made almost entirely of sextant blocks, the Unicode characters around U+1FB00 \u2013 U+1FB1E made out of two columns of three blocks. They’re originally from broadcast teletext<\/a>, and were made to build low-resolution images on a text screen<\/p>\n\n\n\n

\"a
redrawn from an image in Artificial intelligence used to reduce cassowary road deaths in Queensland<\/a><\/figcaption><\/figure>\n\n\n\n

And here’s the original tiny image:<\/p>\n\n\n\n

\"a
“Cassowary Detected”, at actual size<\/figcaption><\/figure>\n\n\n\n

Making the pixel to character map is quite tricky. The Sextant character block isn’t contiguous, and it’s not in the order we need. It’s also missing four characters: empty block, full block, left half block and right half block. These have to be pulled in from other Unicode blocks.<\/p>\n\n\n\n

This is the map I came up with, from 0\u201363 with LSB at bottom right and MSB at top left:<\/p>\n\n\n\n

 \ud83e\udf1e\ud83e\udf0f\ud83e\udf2d\ud83e\udf07\ud83e\udf26\ud83e\udf16\ud83e\udf35\ud83e\udf03\ud83e\udf22\ud83e\udf13\ud83e\udf31\ud83e\udf0b\ud83e\udf29\ud83e\udf1a\ud83e\udf39\ud83e\udf01\ud83e\udf20\ud83e\udf11\ud83e\udf2f\ud83e\udf09\u2590\ud83e\udf18\ud83e\udf37\ud83e\udf05\ud83e\udf24\ud83e\udf14\ud83e\udf33\ud83e\udf0d\ud83e\udf2b\ud83e\udf1c\ud83e\udf3b\ud83e\udf00\ud83e\udf1f\ud83e\udf10\ud83e\udf2e\ud83e\udf08\ud83e\udf27\ud83e\udf17\ud83e\udf36\ud83e\udf04\ud83e\udf23\u258c\ud83e\udf32\ud83e\udf0c\ud83e\udf2a\ud83e\udf1b\ud83e\udf3a\ud83e\udf02\ud83e\udf21\ud83e\udf12\ud83e\udf30\ud83e\udf0a\ud83e\udf28\ud83e\udf19\ud83e\udf38\ud83e\udf06\ud83e\udf25\ud83e\udf15\ud83e\udf34\ud83e\udf0e\ud83e\udf2c\ud83e\udf1d\u2588<\/pre>\n\n\n\n
After that, it’s a small matter of bashing something together in Python with PIL and Numpy. Here’s the source:<\/p>\n\n\n\n
img2blocks.zip<\/a>Download<\/a><\/div>\n\n\n\n
or if you want to take a look first: img2blocks – bitmap to Unicode sextants<\/a><\/p>\n\n\n\n
\"blocky
X11’s wide_weave, scaled up<\/figcaption><\/figure>\n\n\n\n
(yes, there are clever things like Chafa<\/a> that can do more, but it can’t do exactly what this does)<\/p>\n","protected":false},"excerpt":{"rendered":"
this image is supposed to be made almost entirely of sextant blocks, the Unicode characters around U+1FB00 \u2013 U+1FB1E made out of two columns of three blocks. They’re originally from broadcast teletext, and were made to build low-resolution images on a text screen And here’s the original tiny image: Making the pixel to character map […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[7,2],"tags":[1814,2540,638],"class_list":["post-17894","post","type-post","status-publish","format-standard","hentry","category-computers-suck","category-goatee-stroking-musing-or-something","tag-bitmap","tag-python","tag-unicode"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pQNZZ-4EC","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/17894","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/comments?post=17894"}],"version-history":[{"count":5,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/17894\/revisions"}],"predecessor-version":[{"id":17903,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/17894\/revisions\/17903"}],"wp:attachment":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/media?parent=17894"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/categories?post=17894"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/tags?post=17894"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}