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restic/vendor/cloud.google.com/go/vision/image.go
2017-08-06 21:47:56 +02:00

91 lines
3.1 KiB
Go

// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package vision
import (
"io"
"io/ioutil"
pb "google.golang.org/genproto/googleapis/cloud/vision/v1"
)
// An Image represents the contents of an image to run detection algorithms on,
// along with metadata. Images may be described by their raw bytes, or by a
// reference to a a Google Cloude Storage (GCS) object.
type Image struct {
// Exactly one of content and gcsURI will be non-zero.
content []byte // raw image bytes
uri string // URI of the form "gs://BUCKET/OBJECT", or public URL
// Rect is a rectangle on the Earth's surface represented by the
// image. It is optional.
Rect *LatLngRect
// LanguageHints is a list of languages to use for text detection. In most
// cases, leaving this field nil yields the best results since it enables
// automatic language detection. For languages based on the Latin alphabet,
// setting LanguageHints is not needed. In rare cases, when the language of
// the text in the image is known, setting a hint will help get better
// results (although it will be a significant hindrance if the hint is
// wrong). Text detection returns an error if one or more of the specified
// languages is not one of the supported languages (See
// https://cloud.google.com/translate/v2/translate-reference#supported_languages).
LanguageHints []string
}
// NewImageFromReader reads the bytes of an image from rc, then closes rc.
//
// You may optionally set Rect and LanguageHints on the returned Image before
// using it.
func NewImageFromReader(r io.ReadCloser) (*Image, error) {
bytes, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
if err := r.Close(); err != nil {
return nil, err
}
return &Image{content: bytes}, nil
}
// NewImageFromURI returns an image that refers to an object in Google Cloud Storage
// (when the uri is of the form "gs://BUCKET/OBJECT") or at a public URL.
//
// You may optionally set Rect and LanguageHints on the returned Image before
// using it.
func NewImageFromURI(uri string) *Image {
return &Image{uri: uri}
}
// toProtos converts the Image to the two underlying API protos it represents,
// pb.Image and pb.ImageContext.
func (img *Image) toProtos() (*pb.Image, *pb.ImageContext) {
var pimg *pb.Image
switch {
case img.content != nil:
pimg = &pb.Image{Content: img.content}
case img.uri != "":
pimg = &pb.Image{Source: &pb.ImageSource{ImageUri: img.uri}}
}
var pctx *pb.ImageContext
if img.Rect != nil || len(img.LanguageHints) > 0 {
pctx = &pb.ImageContext{
LatLongRect: img.Rect.toProto(),
LanguageHints: img.LanguageHints,
}
}
return pimg, pctx
}