feat(gallery): packing

internal/components/gallery/controller.go

@@ -3,11 +3,27 @@ package gallery
 import (
 	"context"
 	"log/slog"
+	"math"
 	"path"
 
 	"git.schreifuchs.ch/schreifuchs/schreifuchs.ch/internal/components/images"
+	"github.com/InfinityTools/go-binpack2d"
 )
 
+type Gallery struct {
+	GridWith   int
+	GridHeight int
+	Images     []Image
+}
+
+type Image struct {
+	UID    string
+	X      int
+	Y      int
+	Width  int
+	Height int
+}
+
 func (s *Service) GetImages(ctx context.Context) (imgs []images.Image, err error) {
 	files, err := s.fs.ReadDir(s.cfg.Path)
 	if err != nil {
@@ -17,11 +33,67 @@ func (s *Service) GetImages(ctx context.Context) (imgs []images.Image, err error
 	for _, file := range files {
 		imagePath := path.Join(s.cfg.Path, file.Name())
 		img, err := s.img.GetImage(imagePath)
-		if err != nil {
-			slog.Warn("can not read image in gallery", "path", imagePath, "err", err)
+		if err != nil || img.Image == nil {
+			continue
 		}
 		imgs = append(imgs, img)
 	}
 
 	return
 }
+
+func (s *Service) GetGallery(ctx context.Context, width int) (gallery Gallery, err error) {
+	imgs, err := s.GetImages(ctx)
+	if err != nil {
+		return
+	}
+
+	packer := binpack2d.Create(50, 999999)
+
+	for len(imgs) > 0 {
+		unused := make([]images.Image, 0, len(imgs))
+		for _, img := range imgs {
+			width, height := adjustImageSize(img, 200)
+			rect, ok := packer.Insert(width, height, binpack2d.RULE_BEST_AREA_FIT)
+			if !ok {
+				unused = append(unused, img)
+				continue
+			}
+			uid, err := img.UID()
+			if err != nil {
+				return gallery, err
+			}
+			gallery.Images = append(gallery.Images, Image{
+				UID:    uid,
+				X:      rect.X,
+				Y:      rect.Y,
+				Width:  width,
+				Height: height,
+			})
+		}
+		imgs = unused
+	}
+
+	packer.ShrinkBin(false)
+
+	gallery.GridHeight = packer.GetHeight()
+	gallery.GridWith = packer.GetWidth()
+
+	slog.Info("serving gallery", "g", gallery)
+
+	return
+}
+
+// adjustImageSize adjusts the image size so that the aspect ratio stays the same
+// but the image area is the given parameter.
+func adjustImageSize(img images.Image, area int) (width, height int) {
+	// Calculate the original aspect ratio (W / H)
+	aspectRatio := float64(img.Bounds().Dx()) / float64(img.Bounds().Dy())
+
+	// Calculate new height and width using the derived formulas
+	newHeight := math.Sqrt(float64(area) / aspectRatio)
+	newWidth := newHeight * aspectRatio
+
+	// Round to the nearest integer to minimize precision loss
+	return int(math.Round(newWidth)), int(math.Round(newHeight))
+}