func Transform(input string, output string, transform TransformType) error {
var trans int
switch transform {
case TransformNone:
trans = C.EPEG_TRANSFORM_NONE
case TransformFlipH:
trans = C.EPEG_TRANSFORM_FLIP_H
case TransformFlipV:
trans = C.EPEG_TRANSFORM_FLIP_V
case TransformTranspose:
trans = C.EPEG_TRANSFORM_TRANSPOSE
case TransformTransverse:
trans = C.EPEG_TRANSFORM_TRANSVERSE
case TransformRot90:
trans = C.EPEG_TRANSFORM_ROT_90
case TransformRot180:
trans = C.EPEG_TRANSFORM_ROT_180
case TransformRot270:
trans = C.EPEG_TRANSFORM_ROT_270
default:
return fmt.Errorf("Epeg invalid transformation")
}
inputCString := C.CString(input)
defer C.free(unsafe.Pointer(inputCString))
outputCString := C.CString(output)
defer C.free(unsafe.Pointer(outputCString))
var img *C.Epeg_Image
img = C.epeg_file_open(inputCString)
if img == nil {
return fmt.Errorf("Epeg could not open image %s", input)
}
defer C.epeg_close(img)
C.epeg_transform_set(img, C.Epeg_Transform(trans))
C.epeg_file_output_set(img, outputCString)
if code := int(C.epeg_transform(img)); code != 0 {
buf := [1024]byte{}
C.epeg_error(img, (*C.char)((unsafe.Pointer(&buf[0]))))
return fmt.Errorf("Epeg transform error: error %d: %s", code, buf)
}
return nil
}
func Thumbnail(input string, output string, size int, quality int, scaleType ScaleType) error {
var img *C.Epeg_Image
img = C.epeg_file_open(C.CString(input))
if img == nil {
return fmt.Errorf("Epeg could not open image %s", input)
}
defer C.epeg_close(img)
var cw C.int
var ch C.int
C.epeg_size_get(img, &cw, &ch)
w := int(cw)
h := int(ch)
var thumbWidth int
var thumbHeight int
if scaleType == ScaleTypeFitMin {
if w > h {
if w > size {
thumbWidth = size * w / h
thumbHeight = size
} else {
thumbWidth = w
thumbHeight = h
}
} else {
if h > size {
thumbWidth = size
thumbHeight = size * h / w
} else {
thumbWidth = w
thumbHeight = h
}
}
} else {
if w > h {
if w > size {
thumbWidth = size
thumbHeight = size * h / w
} else {
thumbWidth = w
thumbHeight = h
}
} else {
if h > size {
thumbWidth = size * w / h
thumbHeight = size
} else {
thumbWidth = w
thumbHeight = h
}
}
}
C.epeg_decode_size_set(img, C.int(thumbWidth), C.int(thumbHeight))
C.epeg_quality_set(img, C.int(quality))
C.epeg_file_output_set(img, C.CString(output))
if C.epeg_encode(img) != 0 {
return fmt.Errorf("Epeg encode error")
}
return nil
}