Skip to content

DEV Community

hao jia

404 bio not found

Joined on Aug 24, 2026

hao jia

Nov 2

Counting LZW codes to see why dithered GIFs come out bigger

#webdev #javascript

4 min read

hao jia

Nov 1

pdf.js render() resolves fine on a huge page, but the canvas reads back transparent

#webdev #javascript

3 min read

hao jia

Oct 31

Why getImageData returns different colors than putImageData wrote, at low alpha

#webdev #javascript

4 min read

hao jia

Oct 30

A bash loop that logs bytes and seconds for each PNG optimization step

#webdev #javascript

4 min read

hao jia

Oct 29

Chromium turned my CFF OpenType font into Type 3 at every fsType value I tried

#webdev #javascript

3 min read

hao jia

Oct 28

Alpha is just a plane in the pixel format, and FFmpeg drops it in three quiet places

#webdev #javascript

4 min read

hao jia

Oct 27

Why 1-pass ABR landed under my target size: 60-second clip, x264, 25 and 10 MB

#webdev #javascript

3 min read

hao jia

Oct 26

Estimating skew from OCR word boxes before row clustering: one of my three estimators broke at 5 degrees

#webdev #javascript

4 min read

hao jia

Oct 25

Reading an image's matrix and clip from pdf.js getOperatorList: the last cm was enough until I nested one

#webdev #javascript

4 min read

hao jia

Oct 24

Where did the 254s go? A heatmap of non-255 pixels in a white JPEG

#webdev #javascript

4 min read

hao jia

Oct 23

Decode, draw, close, encode, save: one browser image loop, timed step by step

#webdev #javascript

4 min read

hao jia

Oct 22

Computing a GIF's per-frame change box: one stray pixel keeps it at full canvas

#webdev #javascript

4 min read

hao jia

Oct 21

How I put a number on the background-blur halo: luma difference in distance rings

#webdev #javascript

4 min read

hao jia

Oct 20

My WebCodecs encoder ladder for H.265: hardware hint first, a timed trial, H.264 as the floor

#webdev #javascript

4 min read

hao jia

Oct 19

I exported a long image at 300 DPI and got 175: the 16383-pixel ceiling

#webdev #javascript

3 min read

hao jia

Oct 18

pdfsig said my edited signed PDF was still valid, so I compare ByteRange with the file size

#webdev #javascript

3 min read

hao jia

Oct 17

Routing uploads to PNG-8 or WebP by content: the thumbnail, the fallback and the regression check

#webdev #javascript

5 min read

hao jia

Oct 16

Multi-threaded AVIF encoding in the browser was 2-3x faster, until I raised the speed setting

#webdev #javascript

4 min read

hao jia

Oct 15

FontFace loaded, check() said true, and my canvas still drew the fallback font

#webdev #javascript

4 min read

hao jia

Oct 14

Dropping a VideoFrame is not closing it: 1,508 graphics buffers vs 12

#webdev #javascript

4 min read

hao jia

Oct 13

Three ffmpeg one-liners that broke a portrait video, and the check that caught each one

#webdev #javascript

4 min read

hao jia

Oct 12

Mapping Word's srcRect crop to CSS and why center scaling drifts

#webdev #javascript

4 min read

hao jia

Oct 11

The preview used my font, but the PDF's embedded font list didn't

#webdev #javascript

5 min read

hao jia

Oct 10

Measure ink and lighting before you binarize an image for OCR

#webdev #javascript

4 min read

hao jia

Oct 9

256-colour PNGs can keep soft shadows. tRNS shows whether yours did

#webdev #javascript

5 min read

hao jia

Oct 8

Detecting open passwords and permission locks in PDFs with pdf.js

#webdev #javascript

4 min read

hao jia

Oct 7

A completed video seek did not always produce a new frame callback

#webdev #javascript

3 min read

hao jia

Oct 6

Testing MP4 delivery with identical media payloads and 200 or 206 responses

#webdev #javascript

3 min read

hao jia

Oct 5

Keep the original text when a PDF page falls back to OCR

#webdev #javascript

4 min read

hao jia

Oct 4

Reading a canvas back doubles its memory: numbers from three engines

#webdev #javascript

3 min read

hao jia

Oct 3

My cutout PNG looked fine in canvas 2D and glowed in WebGL

#webdev #javascript

3 min read

hao jia

Oct 2

Decoding a progressive JPEG took 14 MiB more memory in my test

#webdev #javascript

3 min read

hao jia

Oct 1

Why red text blurs in canvas JPEG exports, and where 4:4:4 kicks in

#webdev #javascript

5 min read

hao jia

Sep 30

Compress-to-size in the browser: probe the quality floor before you bisect

#webdev #javascript

4 min read

hao jia

Sep 29

onnxruntime-web numThreads silently falls back to 1 without COOP/COEP (6318 ms vs 2133 ms)

#webdev #javascript

3 min read

hao jia

Sep 28

Ask the browser to decode HEIC before you ship a 510 KB WASM decoder

#webdev #javascript

3 min read

hao jia

Sep 26

canvas.toBlob ignores a string quality, and my first check for it was wrong

#webdev #javascript

3 min read

hao jia

Sep 25

Your PDF export tool isn't the problem, your print CSS is

#webdev #javascript

4 min read

hao jia

Sep 24

I ship documents as one offline HTML file. Here is what I verify.

#webdev #javascript

5 min read

hao jia

Sep 23

Measure the text, not the frame, when you compress a screen recording

#webdev #javascript

4 min read

hao jia

Sep 22

The 4x upscale worked, and that was the problem: 30.7 MP, 41 MB, 38.7 s

#webdev #javascript

4 min read

hao jia

Sep 21

I replaced a docs-site GIF with animated WebP and it got bigger

#webdev #javascript

4 min read

hao jia

Sep 20

A PDF is its own reference when you verify the images you pulled out of it

#webdev #javascript

4 min read

hao jia

Sep 19

Our PDF upload limit says 2 MB. I tested auto-compression before adding it

#webdev #javascript

4 min read

hao jia

Sep 18

Same 150 KB, three formats: what you actually get

#webdev #javascript

4 min read

hao jia

Sep 17

Your thumbnails look washed out: it's the ICC profile, not JPEG quality

#webdev #javascript

4 min read

hao jia

Sep 16

Chrome fires onerror, WebKit shows it: feature-detect HEIC before you preview

#webdev #javascript

4 min read

hao jia

Sep 15

canPlayType said ‘probably’ in three engines; only two kept my transparent WebM transparent

#webdev #javascript

4 min read

hao jia

Sep 14

Upright in the upload preview, sideways after the server saved it

#webdev #javascript

5 min read

hao jia

Sep 12

sort=True put both columns of a real arXiv paper on the same line

#webdev #javascript

5 min read

hao jia

Sep 11

Client-side or server-side image compression? How I decide per project

#webdev #javascript

3 min read

hao jia

Sep 9

A 14-page report through HTML-to-PDF 4.8MB to 1.5MB

#webdev #javascript

3 min read

hao jia

Sep 8

Send a proposal without making them install Office or accept a PDF

#webdev #javascript

2 min read

hao jia

Sep 7

Fitting a video under a size cap without turning it to mush

#webdev #javascript

3 min read

hao jia

Sep 6

OCR's hard part isn't reading characters, it's rebuilding the layout

#webdev #javascript

2 min read

hao jia

Sep 5

Is a 4x upscale twice as sharp as 2x? I measured what it actually adds

#webdev #javascript

2 min read

hao jia

Sep 4

Four places I check before shipping a cutout

#webdev #javascript

3 min read

hao jia

Sep 3

The images can't leave our network, so I picked the tool that doesn't send them

#webdev #javascript #privacy

3 min read

hao jia

Sep 2

DPI is an input, not a property of the file you get back

#webdev #javascript #pdf

3 min read

hao jia

Sep 1

The WebP that was 92% smaller — because it only had one frame left

#webdev #javascript #images

4 min read

loading...