yihong0618 和朋友们的频道

Dijkstra的手写体，我觉得写的还挺好看的。他一生写了3000多篇文章（包括论文，博客，信件等……

面对别人讽刺营销的推文不生气不喷回去，顺着这个角度继续写篇能带来更多流量的推，确实营销大师。虽然我不太喜欢，但确实佩服。 https://x.com/huangyun_122/status/1788517681097806036?s=46

TIL: Link: https://github.com/simonw/til/blob/main/exif/orientation-and-location.md 📌 Interpreting photo orientation and locations in EXIF data I upgraded my Niche Museums site to use PhotoSwipe for its photo galleries today. Here's my issue. This lead me down a bit of a rabbit hole of photo EXIF data. The two problems I ended up solving: ⦁ Given photo EXIF data, what is the width and height of the image (taking photo orientation into account)? ⦁ Also given EXIF data, how can I determine the latitude and longitude of the photo? ✏️ Figuring out the width and height The PhotoSwipe gallery code needs to have the width and heights of the images embedded in custom data- attributes like this:

<a
  data-pswp-height="3024"
  data-pswp-width="4032"
  href="https://niche-museums.imgix.net/pioneer-history-19.jpeg?w=1200&auto=compress" 
  class="gallery-photo">
  <img
    src="https://niche-museums.imgix.net/pioneer-history-19.jpeg?w=400&blur=200&px=16&auto=format">
</a>

My database was only storing the URL to those images, not their widths and heights. In order to generate the correct HTML I needed that extra information. Niche Museums hosts photos in an S3 bucket behind Imgix, which means I can resize the photos on demand using the ?w= and ?h= query parameters. It also means I can get back JSON for the EXIF data of the images by appending ?fm=json. https://niche-museums.imgix.net/pioneer-history-18.jpeg?fm=json There's a lot of information in there, but the most important bits for solving this problem are:

{
  "Orientation": 3,
  "PixelWidth": 4032,
  "PixelHeight": 3024
}

For my first attempt, I assumed that PixelWidth and PixelHeight represented the width and height of the image, respectively. This almost worked... except for some photos which were displayed in portrait mode, for which the two values appeared to be swapped. The answer turned out to be in the Orientation parameter. GPT-4 helped me understand the following:

The values you mentioned (1, 3, 6, and 8) represent the most common orientations: ⦁ 1: Normal (0° rotation) ⦁ 3: Upside-down (180° rotation) ⦁ 6: Rotated 90° counterclockwise (270° clockwise) ⦁ 8: Rotated 90° clockwise (270° counterclockwise)

So I need to flip the width and height values if the orientation is 6 or 8. I ended up doing that using this SQL query:

select
    'https://niche-museums.imgix.net/' || filename as url,
    case
        when Orientation in (6, 8) then PixelHeight
        else PixelWidth
    end as width,
    case
        when Orientation in (6, 8) then PixelWidth
        else PixelHeight
    end as height
from raw_photos;

✏️ That raw_photos table I skipped a step here: how did I load the data into that raw_photos table in the first place? First I wrote a Python script to retrieve the JSON metadata for every photo. This dumped them into a photos-metadata/, each one with a name like IMG_0859.jpeg.json. That script now runs in GitHub to catch metadata for newly added photos - a form of Git scraping. Next, I wrote a sqlite-utils to load all of those JSON files into my SQLite database. That script also creates a photos view that implements the above case SQL logic. I initially wrote this as a shell script, but it was a LOT slower than doing it in Python:

for json_file in photos-metadata/*.json; do
  sqlite-utils insert browse.db raw_photos \
    --pk=filename \
    --replace \
    --alter \
    --

震惊了。。。儿子幼儿园的好朋友家长突然管我们借钱。。。。

gaotian 也太强了。。。成了cpython 的member 了。 cpython members 有两个华人了。

这篇有想法很久了，总算写了出来 https://frostming.com/2024/friendly-python-reuse/