(Node.js) Google Cloud Vision Text Detection

Demonstrates calling the Google Cloud Vision for text detection (performs Optical Character Recognition). "Detects and extracts text within an image with support for a broad range of languages. It also features automatic language identification." See https://cloud.google.com/vision/docs/detecting-text

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // Build the following request:

    // {
    //   "requests": [
    //     {
    //       "image": {
    //         "content": "/9j/7QBEUGhvdG9zaG9...base64-encoded-image-content...fXNWzvDEeYxxxzj/Coa6Bax//Z"
    //       },
    //       "features": [
    //         {
    //           "type": "TEXT_DETECTION"
    //         }
    //       ]
    //     }
    //   ]
    // }

    // Use this online tool to generate the code from sample JSON: 
    // Generate Code to Create JSON

    // Load an image file.
    var imageData = new chilkat.BinData();
    // This image file contains some text...
    var success = imageData.LoadFile("qa_data/jpg/text.jpg");
    if (success !== true) {
        console.log("Failed to load image file.");
        return;
    }

    // Create the above JSON.
    var json = new chilkat.JsonObject();
    json.UpdateBd("requests[0].image.content","base64",imageData);
    json.UpdateString("requests[0].features[0].type","TEXT_DETECTION");

    // Send the following POST with the HTTP request body containing the above JSON.
    // POST https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY

    var http = new chilkat.Http();
    http.SessionLogFilename = "c:/aaworkarea/sessionLog.txt";

    var sb = new chilkat.StringBuilder();
    var url = "https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY";
    // resp: HttpResponse
    var resp = http.PostJson3(url,"application/json",json);
    if (http.LastMethodSuccess !== true) {
        console.log(http.LastErrorText);
        return;
    }

    console.log("status = " + resp.StatusCode);

    // A 200 response status indicate success.
    if (resp.StatusCode !== 200) {
        console.log(resp.BodyStr);
        console.log("Failed.");

        return;
    }

    var sbResponseBody = new chilkat.StringBuilder();
    resp.GetBodySb(sbResponseBody);
    sbResponseBody.WriteFile("qa_output/textDetectResponse.json","utf-8",false);
    json.LoadSb(sbResponseBody);

    // The response is a JSON document like this:

    // Use this online tool to generate parsing code from sample JSON: 
    // Generate Parsing Code from JSON

    // {
    //   "responses": [
    //     {
    //       "textAnnotations": [
    //         {
    //           "locale": "en",
    //           "description": "Chilkat is a cross-language, cross-platform\nAPl providing 90+ classes for many Internet\nprotocols, formats, and algorithms.\n",
    //           "boundingPoly": {
    //             "vertices": [
    //               {
    //                 "x": 17,
    //                 "y": 14
    //               },
    // 	...
    //             ]
    //           }
    //         ],
    //         "text": "Chilkat is a cross-language, cross-platform\nAPl providing 90+ classes for many Internet\nprotocols, formats, and algorithms.\n"
    //       }
    //     }
    //   ]
    // }

    // The parsing code generated from the online tool:

    var i;
    var count_i;
    var fullTextAnnotationText;
    var j;
    var count_j;
    var locale;
    var description;
    var k;
    var count_k;
    var x;
    var y;
    var width;
    var height;
    var languageCode;
    var blockType;
    var i1;
    var count_i1;
    // json1: JsonObject
    var json1;
    var j1;
    var count_j1;
    var k1;
    var count_k1;
    var text;
    var propertyDetectedBreakType;
    var i2;
    var count_i2;
    // json2: JsonObject
    var json2;

    i = 0;
    count_i = json.SizeOfArray("responses");
    while (i < count_i) {
        json.I = i;
        fullTextAnnotationText = json.StringOf("responses[i].fullTextAnnotation.text");
        j = 0;
        count_j = json.SizeOfArray("responses[i].textAnnotations");
        while (j < count_j) {
            json.J = j;
            locale = json.StringOf("responses[i].textAnnotations[j].locale");
            description = json.StringOf("responses[i].textAnnotations[j].description");
            k = 0;
            count_k = json.SizeOfArray("responses[i].textAnnotations[j].boundingPoly.vertices");
            while (k < count_k) {
                json.K = k;
                x = json.IntOf("responses[i].textAnnotations[j].boundingPoly.vertices[k].x");
                y = json.IntOf("responses[i].textAnnotations[j].boundingPoly.vertices[k].y");
                k = k+1;
            }

            j = j+1;
        }

        j = 0;
        count_j = json.SizeOfArray("responses[i].fullTextAnnotation.pages");
        while (j < count_j) {
            json.J = j;
            width = json.IntOf("responses[i].fullTextAnnotation.pages[j].width");
            height = json.IntOf("responses[i].fullTextAnnotation.pages[j].height");
            k = 0;
            count_k = json.SizeOfArray("responses[i].fullTextAnnotation.pages[j].property.detectedLanguages");
            while (k < count_k) {
                json.K = k;
                languageCode = json.StringOf("responses[i].fullTextAnnotation.pages[j].property.detectedLanguages[k].languageCode");
                k = k+1;
            }

            k = 0;
            count_k = json.SizeOfArray("responses[i].fullTextAnnotation.pages[j].blocks");
            while (k < count_k) {
                json.K = k;
                blockType = json.StringOf("responses[i].fullTextAnnotation.pages[j].blocks[k].blockType");

                json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
                i1 = 0;
                count_i1 = json1.SizeOfArray("property.detectedLanguages");
                while (i1 < count_i1) {
                    json1.I = i1;
                    languageCode = json1.StringOf("property.detectedLanguages[i].languageCode");
                    i1 = i1+1;
                }

                json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
                i1 = 0;
                count_i1 = json1.SizeOfArray("boundingBox.vertices");
                while (i1 < count_i1) {
                    json1.I = i1;
                    x = json1.IntOf("boundingBox.vertices[i].x");
                    y = json1.IntOf("boundingBox.vertices[i].y");
                    i1 = i1+1;
                }

                json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
                i1 = 0;
                count_i1 = json1.SizeOfArray("paragraphs");
                while (i1 < count_i1) {
                    json1.I = i1;
                    j1 = 0;
                    count_j1 = json1.SizeOfArray("paragraphs[i].property.detectedLanguages");
                    while (j1 < count_j1) {
                        json1.J = j1;
                        languageCode = json1.StringOf("paragraphs[i].property.detectedLanguages[j].languageCode");
                        j1 = j1+1;
                    }

                    j1 = 0;
                    count_j1 = json1.SizeOfArray("paragraphs[i].boundingBox.vertices");
                    while (j1 < count_j1) {
                        json1.J = j1;
                        x = json1.IntOf("paragraphs[i].boundingBox.vertices[j].x");
                        y = json1.IntOf("paragraphs[i].boundingBox.vertices[j].y");
                        j1 = j1+1;
                    }

                    j1 = 0;
                    count_j1 = json1.SizeOfArray("paragraphs[i].words");
                    while (j1 < count_j1) {
                        json1.J = j1;
                        k1 = 0;
                        count_k1 = json1.SizeOfArray("paragraphs[i].words[j].property.detectedLanguages");
                        while (k1 < count_k1) {
                            json1.K = k1;
                            languageCode = json1.StringOf("paragraphs[i].words[j].property.detectedLanguages[k].languageCode");
                            k1 = k1+1;
                        }

                        k1 = 0;
                        count_k1 = json1.SizeOfArray("paragraphs[i].words[j].boundingBox.vertices");
                        while (k1 < count_k1) {
                            json1.K = k1;
                            x = json1.IntOf("paragraphs[i].words[j].boundingBox.vertices[k].x");
                            y = json1.IntOf("paragraphs[i].words[j].boundingBox.vertices[k].y");
                            k1 = k1+1;
                        }

                        k1 = 0;
                        count_k1 = json1.SizeOfArray("paragraphs[i].words[j].symbols");
                        while (k1 < count_k1) {
                            json1.K = k1;
                            text = json1.StringOf("paragraphs[i].words[j].symbols[k].text");
                            propertyDetectedBreakType = json1.StringOf("paragraphs[i].words[j].symbols[k].property.detectedBreak.type");

                            json2 = json1.ObjectOf("paragraphs[i].words[j].symbols[k]");
                            i2 = 0;
                            count_i2 = json2.SizeOfArray("property.detectedLanguages");
                            while (i2 < count_i2) {
                                json2.I = i2;
                                languageCode = json2.StringOf("property.detectedLanguages[i].languageCode");
                                i2 = i2+1;
                            }

                            json2 = json1.ObjectOf("paragraphs[i].words[j].symbols[k]");
                            i2 = 0;
                            count_i2 = json2.SizeOfArray("boundingBox.vertices");
                            while (i2 < count_i2) {
                                json2.I = i2;
                                x = json2.IntOf("boundingBox.vertices[i].x");
                                y = json2.IntOf("boundingBox.vertices[i].y");
                                i2 = i2+1;
                            }

                            k1 = k1+1;
                        }

                        j1 = j1+1;
                    }

                    i1 = i1+1;
                }

                k = k+1;
            }

            j = j+1;
        }

        i = i+1;
    }

    console.log("Success.");

}

chilkatExample();