Commit Graph

238 Commits

Author SHA1 Message Date
KrisKennaway f55e878b8e
Mark nogil functions as noexcept to avoid warning from newer cython (#15) 2023-10-29 14:43:55 +00:00
KrisKennaway 69a96b4719
Optimize palette initialization and NTSC image conversion (#13)
About 2x faster end-to-end with default dhr conversion options
2023-02-26 00:00:39 +00:00
KrisKennaway f8fbd768a5
Optimize dither_dhr.dither_image performance by about 2x (#12)
- avoid passing around a float[::1] memoryview across function barriers, this seems to require reference counting which has a large overhead
- inline some functions
- C division
- float instead of double
2023-02-25 21:21:43 +00:00
kris 7a4e27e0da Bump version in header 2023-02-03 00:42:11 +00:00
KrisKennaway 3aa29f2d2c
Add support for hi-res conversions (#11)
Hi-Res is essentially a more constrained version of Double Hi-Res, in which only about half of the 560 horizontal screen pixels can be independently addressed.

In particular an 8 bit byte in screen memory controls 14 or 15 screen pixels.  Bits 0-7 are doubled, and bit 8 shifts these 14 dots to the right if enabled.  In this case bit 7 of the previous byte is repeated a third time.

This means that we have to optimize all 8 bits at once and move forward in increments of 14 screen pixels.

There's also a timing difference that results in a phase shift of the NTSC colour signal, which means the mappings from dot patterns to effective colours are rotated.

Error diffusion seems to give best results if we only distribute about 2/3 of the quantization error according to the dither pattern.
2023-02-03 00:40:32 +00:00
KrisKennaway 6573bad509
Merge pull request #10 from KrisKennaway/fix-lookahead
Fix --lookahead parsing
2023-01-31 21:32:02 +00:00
kris 0560409717 Fix --lookahead parsing 2023-01-31 21:28:40 +00:00
KrisKennaway 055851aa9c
Merge pull request #9 from KrisKennaway/create-data-dir
Create data directory before writing to it
2023-01-31 21:15:03 +00:00
kris 2ab582790c Create data directory before writing to it 2023-01-31 21:12:42 +00:00
KrisKennaway 05a3624866
Merge pull request #5 from KrisKennaway/mono
Add support for DHGR mono conversions and fix compatibility with python 3.10
2023-01-21 17:32:14 +00:00
kris 39e8eac8ed Add support for DHGR mono conversions 2023-01-21 17:30:27 +00:00
kris 629104b933 Fixes for python 3.10 and/or latest dependency versions 2023-01-21 17:29:06 +00:00
kris 7b8b6bc12b Tweak 2022-07-19 22:41:38 +01:00
kris 7ce574dc06 Add SHR details 2022-07-19 22:39:56 +01:00
kris 2a1874face Tweak wording 2022-07-19 22:39:11 +01:00
kris c61bd258fd Add sample SHR conversions 2022-07-19 22:38:59 +01:00
kris b11b322c39 Move DHR examples to subdir in preparation for adding SHR examples 2022-07-18 23:11:23 +01:00
KrisKennaway bce2153d97
Merge pull request #4 from KrisKennaway/shr
Add support for Super Hi-Res conversions
2022-07-18 23:06:18 +01:00
kris 1468e06d2f Tweak 2022-07-18 23:02:49 +01:00
kris 1486f8a394 Add TODO 2022-07-18 22:31:22 +01:00
kris 12d6805617 Update docs for 2.0 and split out the technical details of dhr into its own file 2022-07-18 22:30:56 +01:00
kris e156dd3b48 Add a requirements.txt to simplify installation 2022-07-18 22:11:32 +01:00
kris 3196369b7d Tidy a bit and add a --save-intermediate flag 2022-07-18 10:00:19 +01:00
kris 1ffb2c9110 Tidy 2022-07-18 09:59:01 +01:00
kris 8fd0ec5dc6 Set window title and clean up a bit 2022-07-16 22:13:26 +01:00
kris e71352490d Add comments 2022-07-16 22:00:42 +01:00
kris 99aa394196 Tweak comment 2022-07-16 22:00:14 +01:00
kris cfef9fa3c9 Add arg type 2022-07-16 21:57:45 +01:00
kris ccbb6980d9 Load data files relative to script path 2021-11-27 10:43:41 +00:00
kris a2b67ba882 Require a subcommand 2021-11-26 13:36:29 +00:00
kris 4d5dea2c41 Restore dhr conversion support 2021-11-26 13:15:57 +00:00
kris 0a964b377a Move SHR conversion out into convert_shr in preparation for re-enabling dhr support 2021-11-26 12:35:45 +00:00
kris ae89682dab Split out common utility functions into a shared module 2021-11-26 12:26:46 +00:00
kris 0dc2c0a7a0 Disable bounds checking and wraparound by default 2021-11-26 12:12:55 +00:00
kris 4221c00701 Split dither into dither_dhr and dither_shr 2021-11-26 12:08:48 +00:00
kris 1075ff0136 Tidy a bit and remove support for tunable parameters that are no longer needed 2021-11-26 10:36:39 +00:00
kris cf63a35797 Cython tweaks to remove some unnecessary C code 2021-11-26 09:54:42 +00:00
kris 25e6ed7b88 Preserve palette order when deduplicating entries
Also make sure we're not mutating _global_palettes, though this should
currently be harmless.
2021-11-25 21:57:27 +00:00
kris 61b4cbb184 Tweak k-means convergence criterion to return once the total centroid position error stops decreasing. 2021-11-25 21:33:12 +00:00
kris fc35387360 - Fill any palettes that have fewer than 16 unique entries after
clustering, using the most frequent pixel colours that are not yet
  in the palette

- Reassign any palettes that are duplicated after clustering
2021-11-25 13:14:22 +00:00
kris ad50ed103d Improvements to image quality:
- Preprocess the source image by dithering with the full 12-bit //gs
  colour palette, ignoring SHR palette restrictions (i.e. each pixel
  chosen independently from 4096 colours)

- Using this as the ground truth allows much better handling of
  e.g. solid colours, which were being dithered inconsistently with
  the previous approach

- Also when fitting an SHR palette, fix any colours that comprise more
  than 10% of source pixels.  This also encourages more uniformity in
  regions of solid colour.
2021-11-25 11:46:42 +00:00
kris 870c008827 Parametrize quantization error decay and minimum value. The latter
helps with images where there are large solid colour fields that
sometimes cause uneven dithering because of colours that cannot be
matched with the //gs palette, but it's not a viable solution in
general since it reduces overall quality (sometimes substantially,
e.g. in case of vertical colour gradients)
2021-11-25 09:09:40 +00:00
kris 8b5c3dc6c1 Fix bool flags 2021-11-24 16:03:55 +00:00
kris 9a77af37aa Add a --show-final-score to output the final image quality score.
This is useful when used as part of an image repository build
pipeline, to avoid replacing existing images if the new score is

Hide intermediate output behind --verbose
2021-11-24 15:49:56 +00:00
kris 0036ee9522 Add default values to help 2021-11-24 15:44:37 +00:00
kris 8d3ab4f50e Add the ability to disable saving preview images. Also rename --gamma_correct to --gamma-correct for consistency 2021-11-24 15:41:32 +00:00
kris 8175dcb052 Add --fixed-colours to control how many colours will be kept identical
across all 16 SHR palettes.
2021-11-24 15:27:34 +00:00
kris 5fefd0b0bb Don't initialize pygame if --no-show-output 2021-11-24 15:24:58 +00:00
kris e77e7abd43 Rename 2021-11-24 15:24:45 +00:00
kris d645cc5964 Tidy 2021-11-24 15:21:50 +00:00