Initial commit

4 files changed, 287 insertions, 0 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..51a0039
--- /dev/null
+++ b/README.md
@@ -0,0 +1,7 @@
+# Thumbnailer
+
+Like ls but for images
+
+```
+go install roseh.moe/cmd/thumbnailer@latest
+```
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2e358c5
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,14 @@
+module roseh.moe/cmd/thumbnailer
+
+go 1.24.3
+
+require (
+	github.com/mattn/go-runewidth v0.0.23
+	golang.org/x/image v0.28.0
+	golang.org/x/term v0.32.0
+)
+
+require (
+	github.com/clipperhouse/uax29/v2 v2.2.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..82bd425
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,10 @@
+github.com/clipperhouse/uax29/v2 v2.2.0 h1:ChwIKnQN3kcZteTXMgb1wztSgaU+ZemkgWdohwgs8tY=
+github.com/clipperhouse/uax29/v2 v2.2.0/go.mod h1:EFJ2TJMRUaplDxHKj1qAEhCtQPW2tJSwu5BF98AuoVM=
+github.com/mattn/go-runewidth v0.0.23 h1:7ykA0T0jkPpzSvMS5i9uoNn2Xy3R383f9HDx3RybWcw=
+github.com/mattn/go-runewidth v0.0.23/go.mod h1:XBkDxAl56ILZc9knddidhrOlY5R/pDhgLpndooCuJAs=
+golang.org/x/image v0.28.0 h1:gdem5JW1OLS4FbkWgLO+7ZeFzYtL3xClb97GaUzYMFE=
+golang.org/x/image v0.28.0/go.mod h1:GUJYXtnGKEUgggyzh+Vxt+AviiCcyiwpsl8iQ8MvwGY=
+golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
+golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/term v0.32.0 h1:DR4lr0TjUs3epypdhTOkMmuF5CDFJ/8pOnbzMZPQ7bg=
+golang.org/x/term v0.32.0/go.mod h1:uZG1FhGx848Sqfsq4/DlJr3xGGsYMu/L5GW4abiaEPQ=
diff --git a/thumbnailer.go b/thumbnailer.go
new file mode 100644
index 0000000..40fb525
--- /dev/null
+++ b/thumbnailer.go
@@ -0,0 +1,256 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"flag"
+	"fmt"
+	"image"
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+
+	runewidth "github.com/mattn/go-runewidth"
+	_ "golang.org/x/image/bmp"
+	"golang.org/x/image/draw"
+	_ "golang.org/x/image/tiff"
+	_ "golang.org/x/image/webp"
+	"golang.org/x/term"
+)
+
+var (
+	x = flag.Int("x", 15, "set image width in columns")
+	y = flag.Int("y", 10, "set image height in rows")
+)
+
+func isDir(filename string) (bool, error) {
+	stat, err := os.Stat(filename)
+	if err != nil {
+		return false, err
+	}
+	return stat.IsDir(), nil
+}
+
+func isLink(filename string) (bool, error) {
+	stat, err := os.Lstat(filename)
+	if err != nil {
+		return false, err
+	}
+	return stat.Mode().Type() == fs.ModeSymlink, nil
+}
+
+var errNotAnImage = errors.New("not an image")
+
+type notAnImageError struct {
+	error
+}
+
+func (e *notAnImageError) Is(err error) bool {
+	return err == errNotAnImage
+}
+
+func load(filename string) (image.Image, error) {
+	file := os.Stdin
+	if filename != "-" {
+		var err error
+		file, err = os.Open(filename)
+		if err != nil {
+			if errors.Is(err, fs.ErrNotExist) {
+				if isLink, _ := isLink(filename); isLink {
+					return nil, &notAnImageError{err}
+				}
+			}
+			return nil, err
+		}
+		defer file.Close()
+	}
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		return nil, &notAnImageError{fmt.Errorf("decode %q: %s", filename, err)}
+	}
+
+	return img, nil
+}
+
+func printImg(img image.Image, cols, lines int) (string, int) {
+	// Try not to stretch the image.
+	if lines == 0 || cols != 0 && img.Bounds().Dy()*cols <= img.Bounds().Dx()*lines*5/2 {
+		lines = img.Bounds().Dy() * cols / (img.Bounds().Dx() * 5 / 2)
+	} else {
+		cols = img.Bounds().Dx() * lines * 5 / 2 / img.Bounds().Dy()
+	}
+
+	dst := image.NewRGBA(image.Rect(0, 0, cols, 2*lines))
+	draw.BiLinear.Scale(dst, dst.Bounds(), img, img.Bounds(), draw.Over, nil)
+
+	s := new(strings.Builder)
+	for y := 0; y < 2*lines; y += 2 {
+		if y > 0 {
+			fmt.Fprintln(s)
+		}
+		for x := 0; x < cols; x++ {
+			hiR, hiG, hiB, _ := dst.At(x, y).RGBA()
+			loR, loG, loB, _ := dst.At(x, y+1).RGBA()
+			fmt.Fprintf(s, "\033[38;2;%d;%d;%dm\033[48;2;%d;%d;%dm▀",
+				hiR>>8, hiG>>8, hiB>>8,
+				loR>>8, loG>>8, loB>>8)
+		}
+		fmt.Fprint(s, "\033[39m\033[49m")
+	}
+	return s.String(), cols
+}
+
+type img struct {
+	s        string
+	width    int
+	filename string
+}
+
+func compositeImages(w io.Writer, images []img, imageWidth, imagesPerRow int) {
+	firstRow := true
+	for row := range slices.Chunk(images, imagesPerRow) {
+		if !firstRow {
+			fmt.Fprintln(w)
+		}
+		firstRow = false
+		rowLines := make([][]string, len(row))
+		names := make([][]string, len(row))
+		for i, img := range row {
+			rowLines[i] = strings.Split(img.s, "\n")
+			names[i] = strings.Split(runewidth.Wrap(img.filename, imageWidth), "\n")
+		}
+		maxLen := 0
+		for imgIdx, img := range rowLines {
+			maxLen = max(maxLen, len(img)+len(names[imgIdx]))
+		}
+		for i := 0; i < maxLen; i++ {
+			if i > 0 {
+				fmt.Fprintln(w)
+			}
+			for imgIdx, img := range rowLines {
+				if imgIdx > 0 {
+					fmt.Fprint(w, " ")
+				}
+				if i < len(img) {
+					fmt.Fprintf(w, "%s%*s", img[i], max(imageWidth-row[imgIdx].width, 0), "")
+				} else if i < len(img)+len(names[imgIdx]) {
+					fmt.Fprintf(w, "%s", runewidth.FillRight(names[imgIdx][i-len(img)], imageWidth))
+				} else {
+					fmt.Fprintf(w, "%*s", imageWidth, "")
+				}
+			}
+		}
+		fmt.Fprintln(w)
+	}
+}
+
+func thumbnailFiles(w io.Writer, cols, lines, imagesPerRow int, args []string) error {
+	var images []img
+	for _, arg := range args {
+		image, err := load(arg)
+		if err != nil {
+			if errors.Is(err, errNotAnImage) {
+				continue
+			}
+			return err
+		}
+		imageString, width := printImg(image, cols, lines)
+		images = append(images, img{imageString, width, filepath.Base(arg)})
+	}
+	compositeImages(w, images, cols, imagesPerRow)
+	return nil
+}
+
+func readDir(d string) ([]string, error) {
+	files, err := os.ReadDir(d)
+	if err != nil {
+		return nil, err
+	}
+	filenames := make([]string, len(files))
+	for i, f := range files {
+		filenames[i] = filepath.Join(d, f.Name())
+	}
+	return filenames, nil
+}
+
+func thumbnailer(args []string) error {
+	cols := *x
+	lines := *y
+	termCols, _, err := term.GetSize(1)
+	if err != nil {
+		return fmt.Errorf("terminal size: %s", err)
+	}
+
+	imagesPerRow := termCols / (cols + 1)
+
+	var files, dirs []string
+	switch len(args) {
+	case 0:
+		files, err = readDir(".")
+		if err != nil {
+			return err
+		}
+	case 1:
+		arg := args[0]
+		isDir, err := isDir(arg)
+		if err != nil {
+			return err
+		}
+		if isDir {
+			files, err = readDir(arg)
+			if err != nil {
+				return err
+			}
+		} else {
+			files = []string{arg}
+		}
+	default:
+		for _, arg := range args {
+			isDir, err := isDir(arg)
+			if err != nil {
+				return err
+			}
+			if isDir {
+				dirs = append(dirs, arg)
+			} else {
+				files = append(files, arg)
+			}
+		}
+	}
+	w := bufio.NewWriter(os.Stdout)
+	defer w.Flush()
+	if err := thumbnailFiles(w, cols, lines, imagesPerRow, files); err != nil {
+		return err
+	}
+	for _, d := range dirs {
+		fmt.Fprintf(w, "\n%s:\n", d)
+		dirFiles, err := readDir(d)
+		if err != nil {
+			return err
+		}
+		if err := thumbnailFiles(w, cols, lines, imagesPerRow, dirFiles); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func main() {
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: icat FILE\n")
+	}
+	flag.Parse()
+
+	if err := thumbnailer(flag.Args()); err != nil {
+		fmt.Fprintf(os.Stderr, "Failed: %s\n", err)
+		os.Exit(1)
+	}
+}