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