b771908e5b
Add a PNG writer so the demos produce actual images. Two pieces: - src/jolt/png.janet — the encoder (8-bit RGB, filter None, stored/uncompressed DEFLATE so no compressor is needed; correct CRC32 + Adler32). It lives in Janet because per-byte work in the overlay is far too slow (a byte-array aset loop is ~30s for 360k bytes, and CRC32 over even a tiny image would be worse). Janet's bit ops are 32-bit signed, so the 32-bit-unsigned arithmetic is done with plain number ops (doubles hold 2^32) plus byte-level bxor. Exposed to the overlay as janet.png/* by importing it into eval_base's module-load-env. - src/jolt/jolt/png.clj — the jolt.png overlay wrapper: image / put! / write. The overlay only produces pixels; the host encodes them in one pass. mandelbrot gets a `render` subcommand (jolt -m mandelbrot render out.png [size]) that colours count-point's escape counts; the numeric-arg bench path is untouched. Verified end to end: macOS `sips` accepts the output (so CRC/zlib are valid). png-test covers the encoder structure (signature/IHDR/IEND) and the overlay round-trip. Co-authored-by: Yogthos <yogthos@gmail.com>
46 lines
2 KiB
Text
46 lines
2 KiB
Text
# jolt.png: the host PNG encoder (src/jolt/png.janet) + the overlay wrapper
|
|
# (src/jolt/jolt/png.clj), reachable as janet.png/* through eval_base's
|
|
# module-load-env. Checks the encoder emits a structurally valid PNG (signature,
|
|
# IHDR dims, IEND) and that the overlay path writes the same.
|
|
(import ../../src/jolt/png :as png)
|
|
(import ../../src/jolt/api :as api)
|
|
|
|
(print "jolt.png encoder + overlay...")
|
|
(var failures 0)
|
|
(defn check [label ok] (if ok (print " ok: " label) (do (++ failures) (eprintf " FAIL: %s" label))))
|
|
|
|
(defn- u32 [b o]
|
|
(+ (* (get b o) 16777216) (* (get b (+ o 1)) 65536) (* (get b (+ o 2)) 256) (get b (+ o 3))))
|
|
|
|
# --- host encoder ---
|
|
(def w 5)
|
|
(def h 3)
|
|
(def rgb (buffer/new (* w h 3)))
|
|
(for i 0 (* w h 3) (buffer/push-byte rgb (% (* i 7) 256)))
|
|
(def out (png/encode w h rgb))
|
|
(check "PNG signature" (= (string/slice out 0 8) "\x89PNG\r\n\x1a\n"))
|
|
(check "IHDR length is 13" (= 13 (u32 out 8)))
|
|
(check "IHDR type" (= "IHDR" (string/slice out 12 16)))
|
|
(check "IHDR width" (= w (u32 out 16)))
|
|
(check "IHDR height" (= h (u32 out 20)))
|
|
(check "8-bit RGB colour type" (and (= 8 (get out 24)) (= 2 (get out 25))))
|
|
(check "ends with an IEND chunk" (string/find "IEND" (string out)))
|
|
(check "encode rejects a wrong-sized buffer"
|
|
(= false (first (protect (png/encode w h (buffer/new 4))))))
|
|
|
|
# --- overlay (jolt.png from Clojure) writes a valid PNG ---
|
|
(def tmp (string (or (os/getenv "TMPDIR") "/tmp") "/jolt-png-overlay-test.png"))
|
|
(def ctx (api/init-cached {:compile? true}))
|
|
(api/eval-string ctx "(require '[jolt.png :as png])")
|
|
(api/eval-string ctx
|
|
(string "(let [img (png/image 4 2)]"
|
|
" (doseq [_ (range 8)] (png/put! img 10 20 30))"
|
|
" (png/write img 4 2 \"" tmp "\"))"))
|
|
(def wrote (slurp tmp))
|
|
(check "overlay wrote the PNG signature" (= (string/slice wrote 0 8) "\x89PNG\r\n\x1a\n"))
|
|
(check "overlay IHDR dims" (and (= 4 (u32 wrote 16)) (= 2 (u32 wrote 20))))
|
|
(os/rm tmp)
|
|
|
|
(if (= 0 failures)
|
|
(print "All tests passed.")
|
|
(do (eprintf "%d png check(s) failed" failures) (os/exit 1)))
|