Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Lossy PNG for true-color images (Velocity Conf ...
Search
Kornel Lesiński
November 18, 2014
Design
2
870
Lossy PNG for true-color images (Velocity Conf EU 2014)
Kornel Lesiński
November 18, 2014
Tweet
Share
More Decks by Kornel Lesiński
See All by Kornel Lesiński
SudWeb
kornel
0
180
Modern PNG compressors
kornel
13
1.2k
Handling binary data in JS
kornel
1
380
Mobblestouch — W3C Touch Events and gestures
kornel
2
720
Server-Sent Events
kornel
5
950
"HTML5" Transport Protocol
kornel
3
370
Front-end Performance
kornel
5
460
Other Decks in Design
See All in Design
Night Shift concept 9/15/2024
cpineda57
0
740
太田博三(@usagisan2020)
otanet
0
190
20240921-図書館の実空間とデジタル資源の接点をデザインする-dtk55-Designing-the-interface-between-the-library's-physical-space-and-digital-resources
majimasachi
0
310
Managing Design Systems (Antwerp 2024)
nathanacurtis
1
300
Карта процесса-опыта. Презентация метода
ashapiro
0
330
Картирование процесса фасилитация стратсессий с Картой гипотез при помощи Карты процесса-опыта
ashapiro
0
400
Credence
lratmansunu
0
460
アフォーダンスとシグニファイア
ryokanakai
1
320
みんなでブラッシュアップするDesign Sprint_BASE BANKチームの場合
base
PRO
3
650
想像するためのデザイン - LARPの可能性を探求してみた話
okabemy
0
550
Commune_Brand_Guideline_JA
commune
1
160
ZKK_001.pdf
nicholaspegu
0
1.4k
Featured
See All Featured
Optimising Largest Contentful Paint
csswizardry
33
2.9k
The World Runs on Bad Software
bkeepers
PRO
65
11k
Designing for humans not robots
tammielis
250
25k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
506
140k
Performance Is Good for Brains [We Love Speed 2024]
tammyeverts
6
430
GitHub's CSS Performance
jonrohan
1030
460k
The Art of Programming - Codeland 2020
erikaheidi
52
13k
Gamification - CAS2011
davidbonilla
80
5k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
329
21k
個人開発の失敗を避けるイケてる考え方 / tips for indie hackers
panda_program
93
16k
Creating an realtime collaboration tool: Agile Flush - .NET Oxford
marcduiker
25
1.8k
Agile that works and the tools we love
rasmusluckow
327
21k
Transcript
Lossy PNG Kornel Lesiński 2014
PNG Lossless JPEG Lossy
PNG PNG JPEG Lossless Lossy PNG Opaque Alpha Channel WebP
JPEG 2000 JPEG XR JPEG XT if you need lossy and alpha, it becomes complicated. You may need to serve 4 different files for every image!
flickr.com/photos/ama711/8760361969 0% 100% Lossy PNG is a hack, but it
works like a truly lossy format
Pixels Math gzip Standard PNG
None
gzip finds and removes repeated sequences of identical pixels
00000000 00000001 00000010 00000011 00000100 00000101 00000110 00000111 00001000 00001001
00001010 0 10 110 1110 11110 111110 1111110 11111110 111111110 1111111110 11111111110 → → → → → → → → → → → Instead of storing 8 bits per byte, gzip uses variable-length sequences. Most popular bytes are given shortest sequences.
Some images don’t have repeated pixels and few very popular
colors
0 1 2 3 4 5 6 7 8 9
0 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 = = Instead of storing uncompressible absolute values PNG can store difference between neighboring pixels
5 6 4 6 5 5 6 4 5 4
5 + 1 -2 +2 - 1 0 + 1 -2 + 1 - 1 = = 5 0 0 0 0 0 0 0 0 0 0 Noisy images won’t compress well… unless you fake the data and remove the noise
Pixels Math gzip Lies Lossy PNG trick is about replacing
math with lies. Only the encoder changes, so it’s 100% compatible.
? When PNG “guesses” what the next pixel will be,
it can make the guess based on average of 2 neighbors, which in lossy PNG causes blur
flickr.com/photos/tundra-ice/5124841152 Original: 2MB 0.6MB 0.3MB
Original: 2MB 0.6MB 0.3MB
Original: 221KB Lossy: 67KB ed_g2s
182KB flickr.com/photos/_tar0_/6223343149
27KB flickr.com/photos/_tar0_/6223343149 The algorithm can decide quality of every pixel,
so it tends to preserve sharp edges, especially text
28KB flickr.com/photos/_tar0_/6223343149 Top of the file has 0% quality, bottom
80% quality
• Works everywhere—fully backwards-compatible • No color limit—supports 24 and
32-bit PNG • Preserves edges—per-pixel quality control • Very fast—small tweak in the encoder • Streamable—only needs 2 lines of the image
pngquant -Q 75-100 --skip-if-larger \ -o out.png in.png || posterize
-b -Q 75 in.jpg out.jpg pngquant is often more efficient, but can’t guarantee quality. You can combine the two for best results.
pngmini.com — ImageAlpha GUI github.com/pornel/mediancut-posterizer CLI logicnet.dk/Analyzer — Image Analyzer
GUI @pornelski pngmini.com/lossypng.html