go.mod

@@ -1,6 +1,6 @@
 module git.schreifuchs.ch/schreifuchs/schreifuchs.ch
 
-go 1.25.7
+go 1.26
 
 tool github.com/a-h/templ/cmd/templ
 
@@ -22,6 +22,7 @@ require (
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/natefinch/atomic v1.0.1 // indirect
 	github.com/yuin/gopher-lua v1.1.1 // indirect
+	golang.org/x/image v0.36.0 // indirect
 	golang.org/x/mod v0.26.0 // indirect
 	golang.org/x/net v0.48.0 // indirect
 	golang.org/x/sync v0.16.0 // indirect

go.sum

@@ -39,6 +39,8 @@ github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M
 github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+golang.org/x/image v0.36.0 h1:Iknbfm1afbgtwPTmHnS2gTM/6PPZfH+z2EFuOkSbqwc=
+golang.org/x/image v0.36.0/go.mod h1:YsWD2TyyGKiIX1kZlu9QfKIsQ4nAAK9bdgdrIsE7xy4=
 golang.org/x/mod v0.26.0 h1:EGMPT//Ezu+ylkCijjPc+f4Aih7sZvaAr+O3EHBxvZg=
 golang.org/x/mod v0.26.0/go.mod h1:/j6NAhSk8iQ723BGAUyoAcn7SlD7s15Dp9Nd/SfeaFQ=
 golang.org/x/net v0.48.0 h1:zyQRTTrjc33Lhh0fBgT/H3oZq9WuvRR5gPC70xpDiQU=
@@ -51,6 +53,7 @@ golang.org/x/sys v0.39.0 h1:CvCKL8MeisomCi6qNZ+wbb0DN9E5AATixKsvNtMoMFk=
 golang.org/x/sys v0.39.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/text v0.32.0 h1:ZD01bjUt1FQ9WJ0ClOL5vxgxOI/sVCNgX1YtKwcY0mU=
 golang.org/x/text v0.32.0/go.mod h1:o/rUWzghvpD5TXrTIBuJU77MTaN0ljMWE47kxGJQ7jY=
+golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
 golang.org/x/tools v0.35.0 h1:mBffYraMEf7aa0sB+NuKnuCy8qI/9Bughn8dC2Gu5r0=
 golang.org/x/tools v0.35.0/go.mod h1:NKdj5HkL/73byiZSJjqJgKn3ep7KjFkBOkR/Hps3VPw=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

internal/components/images/controller.go

@@ -3,10 +3,20 @@ package images
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
+	"encoding/binary"
 	"errors"
 	"fmt"
+	"hash/fnv"
+	"image"
+	"image/jpeg"
+	_ "image/jpeg"
+	_ "image/png"
 	"io"
 	"strings"
+	"time"
+
+	"github.com/valkey-io/valkey-go"
 )
 
 var ErrNotAnImage = errors.New("not an image")
@@ -24,7 +34,7 @@ func (s *Service) getMime(path string) (mimeType string, err error) {
 	return
 }
 
-func (s *Service) GetImage(ctx context.Context, uid string) (img io.Reader, mimeType string, err error) {
+func (s *Service) getImage(uid string) (file []byte, mimeType string, err error) {
 	path, err := PathFromUID(uid)
 	if err != nil {
 		err = fmt.Errorf("could not get path: %w", err)
@@ -40,10 +50,69 @@ func (s *Service) GetImage(ctx context.Context, uid string) (img io.Reader, mime
 		return
 	}
 
-	file, err := s.fs.Read(path)
+	file, err = s.fs.Read(path)
 	if err != nil {
 		err = fmt.Errorf("image file could not be fetched")
 	}
 
-	return bytes.NewBuffer(file), mimeType, err
+	return
+}
+
+func (s *Service) GetImage(ctx context.Context, uid string, options Options) (img io.Reader, mimeType string, err error) {
+	rawImage, mimeType, err := s.getImage(uid)
+	if err != nil {
+		return
+	}
+
+	hash, err := hash(rawImage, options)
+	if err != nil {
+		return
+	}
+
+	if imgBytes, err := s.cache.Do(ctx, s.cache.B().Get().Key("img:"+hash).Build()).AsBytes(); err == nil {
+		return bytes.NewBuffer(imgBytes), mimeType, err
+	}
+
+	decImage, _, err := image.Decode(bytes.NewBuffer(rawImage))
+	if err != nil {
+		return
+	}
+
+	decImage = scale(decImage, options)
+	outBuff := bytes.NewBuffer(make([]byte, 0, 1024))
+
+	if options.Quality == 0 {
+		options.Quality = 80
+	}
+
+	err = jpeg.Encode(outBuff, decImage, &jpeg.Options{Quality: options.Quality})
+	if err != nil {
+		return
+	}
+	if err = s.cache.Do(ctx, s.cache.B().Set().Key("img:"+hash).Value(valkey.BinaryString(outBuff.Bytes())).Ex(time.Hour*48).Build()).Error(); err == nil {
+		return outBuff, "image/jpeg", err
+	}
+
+	return outBuff, "image/jpeg", err
+}
+
+func hash(bytes []byte, options Options) (hash string, err error) {
+	h := fnv.New128()
+
+	if _, err = h.Write(bytes); err != nil {
+		return
+	}
+	if err = binary.Write(h, binary.LittleEndian, int64(options.Height)); err != nil {
+		return
+	}
+	if err = binary.Write(h, binary.LittleEndian, int64(options.Width)); err != nil {
+		return
+	}
+	if err = binary.Write(h, binary.LittleEndian, int64(options.Quality)); err != nil {
+		return
+	}
+
+	res := h.Sum(make([]byte, 0, 128/8))
+
+	return base64.RawStdEncoding.EncodeToString(res), nil
 }

internal/components/images/resorce.go

@@ -1,14 +1,26 @@
 package images
 
-import "os"
+import (
+	"os"
+
+	"github.com/valkey-io/valkey-go"
+)
+
+type Options struct {
+	Width   int // max width, 0 is unlimited
+	Height  int // max Height, 0 is unlimited
+	Quality int // quality of the output jpeg
+}
 
 type Service struct {
 	fs    fileSystem
+	cache valkey.Client
 }
 
-func New(fs fileSystem) *Service {
+func New(fs fileSystem, cache valkey.Client) *Service {
 	return &Service{
 		fs:    fs,
+		cache: cache,
 	}
 }
 

internal/components/images/scaling.go

@@ -0,0 +1,55 @@
+package images
+
+import (
+	"image"
+	"math"
+
+	"golang.org/x/image/draw"
+)
+
+func scale(src image.Image, options Options) image.Image {
+	// Set the expected size that you want:
+	dst := image.NewRGBA(
+		calculateFit(src.Bounds(), options),
+	)
+
+	// Resize:
+	draw.BiLinear.Scale(dst, dst.Rect, src, src.Bounds(), draw.Over, nil)
+
+	// Encode to `output`:
+	return dst
+}
+
+// calculateFit returns the new dimensions (width, height) that fit within the
+// provided Options without upscaling and while maintaining the aspect ratio.
+func calculateFit(bounds image.Rectangle, opt Options) image.Rectangle {
+	// If no limits are set, or the image is already smaller than the limits,
+	// return original dimensions (No Upscaling).
+	if (opt.Width == 0 || bounds.Max.X <= opt.Width) && (opt.Height == 0 || bounds.Max.Y <= opt.Height) {
+		return bounds
+	}
+
+	// Calculate ratios for width and height
+	ratioW := float64(opt.Width) / float64(bounds.Max.X)
+	ratioH := float64(opt.Height) / float64(bounds.Max.Y)
+
+	// Determine the scale factor
+	var scale float64
+	if opt.Width > 0 && opt.Height > 0 {
+		// Use the smaller ratio to ensure it fits in both bounds
+		scale = math.Min(ratioW, ratioH)
+	} else if opt.Width > 0 {
+		scale = ratioW
+	} else if opt.Height > 0 {
+		scale = ratioH
+	} else {
+		return bounds
+	}
+
+	return image.Rect(
+		0,
+		0,
+		int(math.Round(float64(bounds.Max.X)*scale)),
+		int(math.Round(float64(bounds.Max.Y)*scale)),
+	)
+}

internal/filesystem/cache.go

@@ -14,7 +14,7 @@ const keyStat = "webdav:stat:"
 // CachedClient wraps a FileSystem implementation with Valkey caching.
 type CachedClient struct {
 	impl        FS
-	client      valkey.Client
+	cache       valkey.Client
 	ttl         time.Duration
 	hits        atomic.Int64
 	misses      atomic.Int64
@@ -26,7 +26,7 @@ type CachedClient struct {
 func NewCachedClient(impl FS, client valkey.Client, refreshtime time.Duration) *CachedClient {
 	c := &CachedClient{
 		impl:  impl,
-		client: client,
+		cache: client,
 		ttl:   refreshtime * 5,
 	}
 
@@ -50,7 +50,7 @@ func (c *CachedClient) revalidate(ctx context.Context) {
 func (c *CachedClient) scanAndProcess(ctx context.Context, match string, process func(key string) error) {
 	cursor := uint64(0)
 	for {
-		res, err := c.client.Do(ctx, c.client.B().Scan().Cursor(cursor).Match(match).Build()).AsScanEntry()
+		res, err := c.cache.Do(ctx, c.cache.B().Scan().Cursor(cursor).Match(match).Build()).AsScanEntry()
 		if err != nil {
 			slog.Error("scan failed", "match", match, "err", err)
 			return

internal/filesystem/read.go

@@ -22,7 +22,7 @@ func (c *CachedClient) Read(path string) ([]byte, error) {
 	ctx := context.Background()
 
 	// Try cache
-	cached, err := c.client.Do(ctx, c.client.B().Get().Key(key).Build()).AsBytes()
+	cached, err := c.cache.Do(ctx, c.cache.B().Get().Key(key).Build()).AsBytes()
 	if err == nil && len(cached) > 0 {
 		c.readHits.Add(1)
 		c.hits.Add(1)
@@ -58,7 +58,7 @@ func (c *CachedClient) Read(path string) ([]byte, error) {
 	}
 
 	// Cache
-	c.client.Do(ctx, c.client.B().Set().Key(key).Value(valkey.BinaryString(cached)).Ex(c.ttl).Build())
+	c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(valkey.BinaryString(cached)).Ex(c.ttl).Build())
 
 	return data, nil
 }
@@ -67,7 +67,7 @@ func (c *CachedClient) revalidateRead(ctx context.Context) {
 	startTime := time.Now()
 	c.scanAndProcess(ctx, keyRead+"*", func(key string) error {
 		path := strings.TrimPrefix(key, keyRead)
-		cached, err := c.client.Do(ctx, c.client.B().Get().Key(key).Build()).AsBytes()
+		cached, err := c.cache.Do(ctx, c.cache.B().Get().Key(key).Build()).AsBytes()
 		if err != nil {
 			// Key might be gone or error fetching
 			return nil
@@ -76,13 +76,13 @@ func (c *CachedClient) revalidateRead(ctx context.Context) {
 		var cachedFile readFile
 		err = json.Unmarshal(cached, &cachedFile)
 		if err != nil {
-			c.client.Do(ctx, c.client.B().Del().Key(key).Build())
+			c.cache.Do(ctx, c.cache.B().Del().Key(key).Build())
 			return err
 		}
 
 		info, err := c.impl.Stat(path)
 		if err != nil {
-			c.client.Do(ctx, c.client.B().Del().Key(key).Build())
+			c.cache.Do(ctx, c.cache.B().Del().Key(key).Build())
 			return nil
 		}
 
@@ -99,9 +99,9 @@ func (c *CachedClient) revalidateRead(ctx context.Context) {
 				return err
 			}
 
-			c.client.Do(ctx, c.client.B().Set().Key(key).Value(valkey.BinaryString(newCached)).Ex(c.ttl).Build())
+			c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(valkey.BinaryString(newCached)).Ex(c.ttl).Build())
 		} else {
-			c.client.Do(ctx, c.client.B().Expire().Key(key).Seconds(int64(c.ttl/time.Second)).Build())
+			c.cache.Do(ctx, c.cache.B().Expire().Key(key).Seconds(int64(c.ttl/time.Second)).Build())
 		}
 		return nil
 	})

internal/filesystem/readdir.go

@@ -16,7 +16,7 @@ func (c *CachedClient) ReadDir(path string) ([]os.FileInfo, error) {
 	ctx := context.Background()
 
 	// Try cache
-	val, err := c.client.Do(ctx, c.client.B().Get().Key(key).Build()).ToString()
+	val, err := c.cache.Do(ctx, c.cache.B().Get().Key(key).Build()).ToString()
 	if err == nil && val != "" {
 		var cached []File
 		if err := json.Unmarshal([]byte(val), &cached); err == nil {
@@ -47,7 +47,7 @@ func (c *CachedClient) ReadDir(path string) ([]os.FileInfo, error) {
 
 	bytes, err := json.Marshal(cached)
 	if err == nil {
-		c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+		c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
 	}
 
 	return infos, nil
@@ -59,7 +59,7 @@ func (c *CachedClient) revalidateReadDir(ctx context.Context) {
 		path := strings.TrimPrefix(key, keyReadDir)
 		infos, err := c.impl.ReadDir(path)
 		if err != nil {
-			c.client.Do(ctx, c.client.B().Del().Key(key).Build())
+			c.cache.Do(ctx, c.cache.B().Del().Key(key).Build())
 			return err
 		}
 
@@ -71,7 +71,7 @@ func (c *CachedClient) revalidateReadDir(ctx context.Context) {
 
 		bytes, err := json.Marshal(cached)
 		if err == nil {
-			c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+			c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
 		}
 		return nil
 	})

internal/filesystem/stat.go

@@ -14,7 +14,7 @@ func (c *CachedClient) Stat(path string) (info os.FileInfo, err error) {
 	ctx := context.Background()
 
 	// Try cache
-	val, err := c.client.Do(ctx, c.client.B().Get().Key(key).Build()).ToString()
+	val, err := c.cache.Do(ctx, c.cache.B().Get().Key(key).Build()).ToString()
 	if err == nil && val != "" {
 		var f File
 		if err := json.Unmarshal([]byte(val), &f); err == nil {
@@ -39,7 +39,7 @@ func (c *CachedClient) Stat(path string) (info os.FileInfo, err error) {
 
 	bytes, err := json.Marshal(info)
 	if err == nil {
-		c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+		c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
 	}
 
 	return
@@ -51,7 +51,7 @@ func (c *CachedClient) revalidateStat(ctx context.Context) {
 		path := strings.TrimPrefix(key, keyStat)
 		info, err := c.impl.Stat(path)
 		if err != nil {
-			c.client.Do(ctx, c.client.B().Del().Key(key).Build())
+			c.cache.Do(ctx, c.cache.B().Del().Key(key).Build())
 			return err
 		}
 
@@ -59,7 +59,7 @@ func (c *CachedClient) revalidateStat(ctx context.Context) {
 		f := ParseToFile(info)
 		bytes, err := json.Marshal(f)
 		if err == nil {
-			c.client.Do(ctx, c.client.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
+			c.cache.Do(ctx, c.cache.B().Set().Key(key).Value(string(bytes)).Ex(c.ttl).Build())
 		}
 		return nil
 	})

internal/handlers/handleimage/conroler.go

@@ -1,20 +0,0 @@
-package handleimage
-
-import (
-	"io"
-	"log/slog"
-	"net/http"
-)
-
-func (h *Handler) getImage(w http.ResponseWriter, r *http.Request) {
-	uid := r.PathValue("uid")
-
-	img, mime, err := h.img.GetImage(r.Context(), uid)
-	if err != nil {
-		slog.Error("error wile serving image", "err", err, "uid", uid)
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-	w.Header().Add("Content-Type", mime)
-	io.Copy(w, img)
-}

internal/handlers/resthome/controller.go

@@ -1,4 +1,4 @@
-package handlehome
+package resthome
 
 import (
 	"net/http"

internal/handlers/resthome/resource.go

@@ -1,4 +1,4 @@
-package handlehome
+package resthome
 
 import (
 	"context"

internal/handlers/restimage/conroller.go

@@ -0,0 +1,43 @@
+package restimage
+
+import (
+	"io"
+	"log/slog"
+	"net/http"
+
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/images"
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/handlers/restutil"
+)
+
+func (h *Handler) getImage(w http.ResponseWriter, r *http.Request) {
+	uid := r.PathValue("uid")
+
+	var err error
+	options := images.Options{}
+	options.Height, err = restutil.IntParam(r, "h")
+	if err != nil {
+		restutil.SendErr(w, err)
+		return
+	}
+	options.Width, err = restutil.IntParam(r, "w")
+	if err != nil {
+		restutil.SendErr(w, err)
+		return
+	}
+
+	options.Quality, err = restutil.IntParam(r, "q")
+	if err != nil {
+		restutil.SendErr(w, err)
+		return
+	}
+
+	img, mime, err := h.img.GetImage(r.Context(), uid, options)
+	if err != nil {
+		slog.Error("error wile serving image", "err", err, "uid", uid)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Add("Content-Type", mime)
+	io.Copy(w, img)
+}

internal/handlers/restimage/resource.go

@@ -1,9 +1,11 @@
-package handleimage
+package restimage
 
 import (
 	"context"
 	"io"
 	"net/http"
+
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/images"
 )
 
 type Handler struct {
@@ -20,5 +22,5 @@ func New(mux *http.ServeMux, srv imageService) *Handler {
 }
 
 type imageService interface {
-	GetImage(ctx context.Context, uid string) (img io.Reader, mimeType string, err error)
+	GetImage(ctx context.Context, uid string, options images.Options) (img io.Reader, mimeType string, err error)
 }

internal/handlers/restutil/error.go

@@ -0,0 +1,68 @@
+package restutil
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+)
+
+type ErrorType string
+
+const (
+	ErrorTypeUndefinded  = ""
+	ErrorTypeValidation  = "VALIDATION"
+	ErrorTypeNotFound    = "NOT_FOUND"
+	ErrorTypeServerError = "SERVER_ERROR"
+)
+
+type Error struct {
+	Type    ErrorType `json:"type"`
+	Message string    `json:"message"`
+	err     error
+}
+
+func WrappErr(err error, errorType ErrorType, message string) *Error {
+	return &Error{
+		Type:    errorType,
+		Message: message,
+		err:     err,
+	}
+}
+
+func (e Error) Unwrap() error {
+	return e.err
+}
+
+func (e Error) Error() string {
+	return fmt.Sprintf("%s: %s", e.Message, e.err.Error())
+}
+
+func (e Error) StatusCode() int {
+	switch e.Type {
+	case ErrorTypeValidation:
+		return http.StatusBadRequest
+	case ErrorTypeNotFound:
+		return http.StatusNotFound
+	default:
+		return http.StatusInternalServerError
+	}
+}
+
+func SendErr(w http.ResponseWriter, err error) {
+	restErr := &Error{}
+
+	if !errors.As(err, &restErr) {
+		slog.Error("internal server error", "err", err)
+		restErr = &Error{
+			Type: ErrorTypeServerError,
+		}
+	}
+
+	w.WriteHeader(restErr.StatusCode())
+	w.Header().Add("Content-Type", "application/json")
+	err = json.NewEncoder(w).Encode(restErr)
+
+	slog.Error("could not send error", "err", err)
+}

internal/handlers/restutil/params.go

@@ -0,0 +1,24 @@
+package restutil
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+)
+
+func IntParam(r *http.Request, key string) (val int, err error) {
+	str := r.URL.Query().Get(key)
+	if str == "" {
+		return
+	}
+
+	val, err = strconv.Atoi(str)
+	if err != nil {
+		err = WrappErr(
+			err,
+			ErrorTypeValidation,
+			fmt.Sprintf("failed to parse query parameter '%s': not an int", key),
+		)
+	}
+	return
+}

internal/server/routes.go

@@ -10,8 +10,8 @@ import (
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/page"
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/translate"
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/filesystem"
-	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/handlers/handlehome"
-	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/handlers/handleimage"
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/handlers/resthome"
+	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/handlers/restimage"
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/templer"
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/web"
 	"github.com/studio-b12/gowebdav"
@@ -54,8 +54,8 @@ func registerOther() (h http.Handler) {
 		fs = filesystem.NewCachedClient(webdavClient, valkeyClient, 5*time.Hour)
 	}
 
-	_ = handlehome.New(mux, page.New(fs))
-	_ = handleimage.New(mux, images.New(fs))
+	_ = resthome.New(mux, page.New(fs))
+	_ = restimage.New(mux, images.New(fs, valkeyClient))
 
 	mux.Handle("/", http.FileServer(http.FS(web.GetStaticFS())))
 

web/components/imagetile.templ

@@ -1,9 +1,13 @@
 package components
 
+import "strings"
+import "fmt"
+
 templ ImageTile(src string) {
 	<div class="grid grid-cols-1 grid-rows-1">
 		<img
 			src={ src }
+			srcset={ makeSrcset(src) }
 			fetchpriority="high"
 			class="row-start-1 col-start-1 pointer-events-none w-full h-96 object-cover"
 		/>
@@ -12,3 +16,16 @@ templ ImageTile(src string) {
 		</div>
 	</div>
 }
+
+func makeSrcset(src string) string {
+	sb := strings.Builder{}
+
+	for i := range 19 {
+		sb.WriteString(fmt.Sprintf("%s?w=%d %dw, ", src, 100*(i+1), 50*(i+1)))
+	}
+
+	i := 20
+	sb.WriteString(fmt.Sprintf("%s?w=%d %dw", src, 100*(i+1), 50*(i+1)))
+
+	return sb.String()
+}

web/components/imagetile_templ.go

@@ -8,6 +8,9 @@ package components
 import "github.com/a-h/templ"
 import templruntime "github.com/a-h/templ/runtime"
 
+import "strings"
+import "fmt"
+
 func ImageTile(src string) templ.Component {
 	return templruntime.GeneratedTemplate(func(templ_7745c5c3_Input templruntime.GeneratedComponentInput) (templ_7745c5c3_Err error) {
 		templ_7745c5c3_W, ctx := templ_7745c5c3_Input.Writer, templ_7745c5c3_Input.Context
@@ -36,13 +39,26 @@ func ImageTile(src string) templ.Component {
 		var templ_7745c5c3_Var2 string
 		templ_7745c5c3_Var2, templ_7745c5c3_Err = templ.JoinStringErrs(src)
 		if templ_7745c5c3_Err != nil {
-			return templ.Error{Err: templ_7745c5c3_Err, FileName: `components/imagetile.templ`, Line: 6, Col: 12}
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `components/imagetile.templ`, Line: 9, Col: 12}
 		}
 		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var2))
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 2, "\" fetchpriority=\"high\" class=\"row-start-1 col-start-1 pointer-events-none w-full h-96 object-cover\"><div class=\"row-start-1 col-start-1\">")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 2, "\" srcset=\"")
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		var templ_7745c5c3_Var3 string
+		templ_7745c5c3_Var3, templ_7745c5c3_Err = templ.JoinStringErrs(makeSrcset(src))
+		if templ_7745c5c3_Err != nil {
+			return templ.Error{Err: templ_7745c5c3_Err, FileName: `components/imagetile.templ`, Line: 10, Col: 27}
+		}
+		_, templ_7745c5c3_Err = templ_7745c5c3_Buffer.WriteString(templ.EscapeString(templ_7745c5c3_Var3))
+		if templ_7745c5c3_Err != nil {
+			return templ_7745c5c3_Err
+		}
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 3, "\" fetchpriority=\"high\" class=\"row-start-1 col-start-1 pointer-events-none w-full h-96 object-cover\"><div class=\"row-start-1 col-start-1\">")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
@@ -50,7 +66,7 @@ func ImageTile(src string) templ.Component {
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
-		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 3, "</div></div>")
+		templ_7745c5c3_Err = templruntime.WriteString(templ_7745c5c3_Buffer, 4, "</div></div>")
 		if templ_7745c5c3_Err != nil {
 			return templ_7745c5c3_Err
 		}
@@ -58,4 +74,17 @@ func ImageTile(src string) templ.Component {
 	})
 }
 
+func makeSrcset(src string) string {
+	sb := strings.Builder{}
+
+	for i := range 19 {
+		sb.WriteString(fmt.Sprintf("%s?w=%d %dw, ", src, 100*(i+1), 50*(i+1)))
+	}
+
+	i := 20
+	sb.WriteString(fmt.Sprintf("%s?w=%d %dw", src, 100*(i+1), 50*(i+1)))
+
+	return sb.String()
+}
+
 var _ = templruntime.GeneratedTemplate