func tagFormatString(tag *tiff.Tag) string {
switch tag.Format() {
case tiff.IntVal:
return "int"
case tiff.RatVal:
return "rat"
case tiff.FloatVal:
return "float"
case tiff.StringVal:
return "string"
}
return ""
}
func parse3Rat2(tag *tiff.Tag) ([3]float64, error) {
v := [3]float64{}
for i := range v {
num, den, err := tag.Rat2(i)
if err != nil {
return v, err
}
v[i] = ratFloat(num, den)
if tag.Count < uint32(i+2) {
break
}
}
return v, nil
}
func tagDegrees(tag *tiff.Tag) (float64, error) {
switch tag.Format() {
case tiff.RatVal:
// The usual case, according to the Exif spec
// (http://www.kodak.com/global/plugins/acrobat/en/service/digCam/exifStandard2.pdf,
// sec 4.6.6, p. 52 et seq.)
v, err := parse3Rat2(tag)
if err != nil {
return 0.0, err
}
return v[0] + v[1]/60 + v[2]/3600.0, nil
case tiff.StringVal:
// Encountered this weird case with a panorama picture taken with a HTC phone
s, err := tag.StringVal()
if err != nil {
return 0.0, err
}
return parseTagDegreesString(s)
default:
// don't know how to parse value, give up
return 0.0, fmt.Errorf("Malformed EXIF Tag Degrees")
}
}
func (_ Walker) Walk(name exif.FieldName, tag *tiff.Tag) error {
data, _ := tag.MarshalJSON()
fmt.Printf(" %v: %v\n", name, string(data))
return nil
}
