feat(ocr): add plugin (#3044)

src/@ionic-native/plugins/ocr/index.ts

@@ -0,0 +1,167 @@
+import { Injectable } from '@angular/core';
+import { Cordova, IonicNativePlugin, Plugin } from '@ionic-native/core';
+
+export enum OCRSourceType {
+  /**
+   * Normal processing from a file URL. This is the overall recommended choice
+   * for most applications. The distinction between file and native URLs is
+   * only relevant on iOS; under Android `NORMFILEURL` and `NORMNATIVEURL`
+   * are interchangeable.
+   */
+  NORMFILEURL = 0,
+
+  /**
+   * Normal processing from a native URL. Since this source type uses deprecated
+   * OS APIs to interact with the camera plugin, it is best avoided, especially
+   * if ongoing forward compatibility is a concern. For further information, see
+   * https://github.com/NeutrinosPlatform/cordova-plugin-mobile-ocr#plugin-usage
+   * Under Android, this is equivalent to `NORMFILEURL`.
+   */
+  NORMNATIVEURL = 1,
+
+  /**
+   * Fast processing from a file URL. As the compression done internally causes
+   * a significant loss in extraction quality, it should only be preferred when
+   * dealing with large images containing significant amounts of text, where
+   * the execution time required to perform normal processing is prohibitive.
+   * The distinction between file and native URLs is only relevant on iOS;
+   * under Android `FASTFILEURL` and `FASTNATIVEURL` are interchangeable.
+   */
+  FASTFILEURL = 2,
+
+  /**
+   * Fast processing from a native URL. See comments above for `FASTFILEURL`
+   * concerning quality loss.
+   *
+   * The distinction between file and native URLs is only relevant on iOS;
+   * under Android `FASTFILEURL` and `FASTNATIVEURL` are interchangeable.
+   */
+  FASTNATIVEURL = 3,
+
+  /**
+   * Normal processing from a base64-encoded string. Quality is equivalent
+   * to `NORMFILEURL`, but due to significantly higher memory requirements,
+   * is only appropriate for use with very small images.
+   */
+  BASE64 = 4,
+}
+
+/**
+ * Four points (ordered in clockwise direction) that enclose a text
+ * component. May not be axis-aligned due to perspective skew.
+ */
+export interface OCRCorners {
+  x1: number;
+  y1: number;
+  x2: number;
+  y2: number;
+  x3: number;
+  y3: number;
+  x4: number;
+  y4: number;
+}
+
+/**
+ * An axis-aligned bounding rectangle. `x` and `y` represent the top left.
+ */
+export interface OCRRect {
+  x: number;
+  y: number;
+  height: number;
+  width: number;
+}
+
+/**
+ * This is the return value from the `recText` method.
+ */
+export interface OCRResult {
+  /**
+   * Was any text extracted? If `foundText` is false, no other fields are
+   * returned. If foundText is true, all other fields are reliable.
+   */
+  foundText: boolean;
+
+  /**
+   * A block is the largest unit of text, which can be thought of as a paragraph.
+   * This field consists of several parallel arrays, so the text in `blocktext[0]`
+   * is bounded by `blockpoints[0]` and `blockframe[0]`.
+   */
+  blocks: {
+    blocktext: string[];
+    blockpoints: OCRCorners[];
+    blockframe: OCRRect[];
+  };
+
+  /**
+   * A line is the central unit of text, containing several elements. A block
+   * can contain N lines. This field consists of several parallel arrays, so the
+   * text in `linetext[0]` is bounded by `linepoints[0]` and `lineframe[0]`.
+   */
+  lines: {
+    linetext: string[];
+    linepoints: OCRCorners[];
+    lineframe: OCRRect[];
+  };
+
+  /**
+   * A word (or element) is the smallest unit of text. This field consists of
+   * several parallel arrays, so the text in `wordtext[0]` is bounded by
+   * `wordpoints[0]` and `wordframe[0]`.
+   */
+  words: {
+    wordtext: string[];
+    wordpoints: OCRCorners[];
+    wordframe: OCRRect[];
+  };
+}
+
+/**
+ * @name MobileOCR
+ * @description
+ * This plugin attempts to identify and extract text from an image.
+ *
+ * @usage
+ * ```typescript
+ * import { MobileOCR, OCRSourceType } from '@ionic-native/ocr/ngx';
+ *
+ *
+ * constructor(private ocr: MobileOCR) { }
+ *
+ * ...
+ *
+ * this.ocr.recText(OCRSourceType.NORMFILEURL, "file://path/to/image.png")
+ *   .then((res: OCRResult) => console.log(JSON.stringify(res)))
+ *   .catch((error: any) => console.error(error));
+ *
+ * ```
+ *
+ * @interfaces
+ * OCRCorners
+ * OCRRect
+ * OCRResult
+ *
+ * @enums
+ * OCRSourceType
+ */
+@Plugin({
+  pluginName: 'OCR',
+  plugin: 'cordova-plugin-mobile-ocr',
+  pluginRef: 'textocr',
+  repo: 'https://github.com/NeutrinosPlatform/cordova-plugin-mobile-ocr',
+  platforms: ['Android', 'iOS']
+})
+@Injectable()
+export class OCR extends IonicNativePlugin {
+
+  /**
+   * Extract text from image
+   * @param sourceType {OCRSourceType} type of image source
+   * @param source {string} image source (either file URL or base64 string)
+   * @return {Promise<OCRResult>} extracted text and geometry
+   */
+  @Cordova()
+  recText(sourceType: OCRSourceType, source: string): Promise<OCRResult> {
+    return;
+  }
+
+}