Initial QSfera import

Server/vendor/github.com/kovidgoyal/imaging/prism/meta/tiffmeta/tiffmeta.go

@@ -0,0 +1,73 @@
+package tiffmeta
+
+import (
+	"fmt"
+	"image/color"
+	"io"
+	"strings"
+
+	"github.com/kovidgoyal/imaging/prism/meta"
+	"github.com/kovidgoyal/imaging/types"
+	"github.com/rwcarlsen/goexif/exif"
+	"golang.org/x/image/tiff"
+)
+
+var _ = fmt.Print
+
+func BitsPerComponent(c color.Model) uint32 {
+	switch c {
+	case color.RGBAModel, color.NRGBAModel, color.YCbCrModel, color.CMYKModel:
+		return 8
+	case color.GrayModel:
+		return 8
+	case color.Gray16Model:
+		return 16
+	case color.AlphaModel:
+		return 8
+	case color.Alpha16Model:
+		return 16
+	default:
+		// This handles paletted images and other custom color models.
+		// For a palette, each color in the palette has its own depth.
+		// We can check the bit depth by converting a color from the model to RGBA.
+		// The `Convert` method is part of the color.Model interface.
+		// A fully opaque red color is used for this check.
+		r, g, b, a := c.Convert(color.RGBA{R: 255, A: 255}).RGBA()
+
+		// The values returned by RGBA() are 16-bit alpha-premultiplied values (0-65535).
+		// If the highest value is <= 255, it's an 8-bit model.
+		if r|g|b|a <= 0xff {
+			return 8
+		} else {
+			return 16
+		}
+	}
+}
+
+func ExtractMetadata(r_ io.Reader) (md *meta.Data, err error) {
+	r := r_.(io.ReadSeeker)
+	pos, err := r.Seek(0, io.SeekCurrent)
+	if err != nil {
+		return nil, err
+	}
+	c, err := tiff.DecodeConfig(r)
+	if err != nil {
+		if strings.Contains(err.Error(), "malformed header") {
+			err = nil
+		}
+		return nil, err
+	}
+	md = &meta.Data{
+		Format: types.TIFF, PixelWidth: uint32(c.Width), PixelHeight: uint32(c.Height),
+		BitsPerComponent: BitsPerComponent(c.ColorModel),
+	}
+	if _, err = r.Seek(pos, io.SeekStart); err != nil {
+		return nil, err
+	}
+	if e, err := exif.Decode(r); err == nil {
+		md.SetExif(e)
+	} else {
+		md.SetExifError(err)
+	}
+	return md, nil
+}