1 files changed, 85 insertions, 0 deletions
diff --git a/vendor/github.com/charmbracelet/x/ansi/kitty/decoder.go b/vendor/github.com/charmbracelet/x/ansi/kitty/decoder.go
new file mode 100644
index 0000000..fbd0844
--- /dev/null
+++ b/vendor/github.com/charmbracelet/x/ansi/kitty/decoder.go
@@ -0,0 +1,85 @@
+package kitty
+
+import (
+	"compress/zlib"
+	"fmt"
+	"image"
+	"image/color"
+	"image/png"
+	"io"
+)
+
+// Decoder is a decoder for the Kitty graphics protocol. It supports decoding
+// images in the 24-bit [RGB], 32-bit [RGBA], and [PNG] formats. It can also
+// decompress data using zlib.
+// The default format is 32-bit [RGBA].
+type Decoder struct {
+	// Uses zlib decompression.
+	Decompress bool
+
+	// Can be one of [RGB], [RGBA], or [PNG].
+	Format int
+
+	// Width of the image in pixels. This can be omitted if the image is [PNG]
+	// formatted.
+	Width int
+
+	// Height of the image in pixels. This can be omitted if the image is [PNG]
+	// formatted.
+	Height int
+}
+
+// Decode decodes the image data from r in the specified format.
+func (d *Decoder) Decode(r io.Reader) (image.Image, error) {
+	if d.Decompress {
+		zr, err := zlib.NewReader(r)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create zlib reader: %w", err)
+		}
+
+		defer zr.Close() //nolint:errcheck
+		r = zr
+	}
+
+	if d.Format == 0 {
+		d.Format = RGBA
+	}
+
+	switch d.Format {
+	case RGBA, RGB:
+		return d.decodeRGBA(r, d.Format == RGBA)
+
+	case PNG:
+		return png.Decode(r)
+
+	default:
+		return nil, fmt.Errorf("unsupported format: %d", d.Format)
+	}
+}
+
+// decodeRGBA decodes the image data in 32-bit RGBA or 24-bit RGB formats.
+func (d *Decoder) decodeRGBA(r io.Reader, alpha bool) (image.Image, error) {
+	m := image.NewRGBA(image.Rect(0, 0, d.Width, d.Height))
+
+	var buf []byte
+	if alpha {
+		buf = make([]byte, 4)
+	} else {
+		buf = make([]byte, 3)
+	}
+
+	for y := 0; y < d.Height; y++ {
+		for x := 0; x < d.Width; x++ {
+			if _, err := io.ReadFull(r, buf[:]); err != nil {
+				return nil, fmt.Errorf("failed to read pixel data: %w", err)
+			}
+			if alpha {
+				m.SetRGBA(x, y, color.RGBA{buf[0], buf[1], buf[2], buf[3]})
+			} else {
+				m.SetRGBA(x, y, color.RGBA{buf[0], buf[1], buf[2], 0xff})
+			}
+		}
+	}
+
+	return m, nil
+}