forked from arussellsaw/news
/
handle_dither.go
78 lines (63 loc) · 1.59 KB
/
handle_dither.go
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package handler
import (
"image"
_ "image/gif"
"image/jpeg"
_ "image/jpeg"
_ "image/png"
"net/http"
"strconv"
dither "github.com/esimov/dithergo"
"github.com/monzo/slog"
"github.com/nfnt/resize"
"github.com/RusticPotatoes/news/domain"
"github.com/RusticPotatoes/news/pkg/util"
)
func handleDitherImage(w http.ResponseWriter, r *http.Request) {
ctx := r.Context()
q := r.URL.Query()
url := q.Get("url")
ctx = util.SetParam(ctx, "url", url)
cachedImage := domain.C.GetImage(url)
if cachedImage != nil {
jpeg.Encode(w, *cachedImage, nil)
return
}
res, err := http.Get(url)
if err != nil {
slog.Error(ctx, "Error getting image: %s", err)
http.Error(w, err.Error(), 500)
return
}
width, err := strconv.ParseInt(q.Get("w"), 10, 64)
if err != nil {
slog.Error(ctx, "Error parsing width: %s", err)
http.Error(w, err.Error(), 500)
return
}
img, _, err := image.Decode(res.Body)
if err != nil {
slog.Error(ctx, "Error decoding image: %s", err)
http.Error(w, err.Error(), 500)
return
}
newImage := resize.Resize(uint(width), 0, img, resize.Lanczos3)
d := dither.Dither{
Type: "FloydSteinberg",
Settings: dither.Settings{
Filter: [][]float32{
{0.0, 0.0, 0.0, 7.0 / 48.0, 5.0 / 48.0},
{3.0 / 48.0, 5.0 / 48.0, 7.0 / 48.0, 5.0 / 48.0, 3.0 / 48.0},
{1.0 / 48.0, 3.0 / 48.0, 5.0 / 48.0, 3.0 / 48.0, 1.0 / 48.0},
},
},
}
dithered := d.Color(newImage, 1)
w.Header().Set("Content-Type", "image/jpeg")
err = jpeg.Encode(w, dithered, nil)
if err != nil {
slog.Error(ctx, "Error encoding image: %s", err)
http.Error(w, err.Error(), 500)
return
}
}