(MFC) 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

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkBinData.h>
#include <CkJsonObject.h>
#include <CkHttp.h>
#include <CkStringBuilder.h>
#include <CkHttpResponse.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // 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.
    CkBinData imageData;
    // This image file contains some text...
    bool success = imageData.LoadFile("qa_data/jpg/text.jpg");
    if (success != true) {
        strOut.append("Failed to load image file.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    // Create the above JSON.
    CkJsonObject json;
    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

    CkHttp http;
    CkStringBuilder sb;
    const char *url = "https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY";
    CkHttpResponse *resp = http.PostJson3(url,"application/json",json);
    if (http.get_LastMethodSuccess() != true) {
        strOut.append(http.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append("status = ");
    strOut.appendInt(resp->get_StatusCode());
    strOut.append("\r\n");

    // A 200 response status indicate success.
    if (resp->get_StatusCode() != 200) {
        strOut.append(resp->bodyStr());
        strOut.append("\r\n");
        strOut.append("Failed.");
        strOut.append("\r\n");
        delete resp;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    CkStringBuilder sbResponseBody;
    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:

    int i;
    int count_i;
    const char *fullTextAnnotationText = 0;
    int j;
    int count_j;
    const char *locale = 0;
    const char *description = 0;
    int k;
    int count_k;
    int x;
    int y;
    int width;
    int height;
    const char *languageCode = 0;
    const char *blockType = 0;
    int i1;
    int count_i1;
    CkJsonObject *json1 = 0;
    int j1;
    int count_j1;
    int k1;
    int count_k1;
    const char *text = 0;
    const char *propertyDetectedBreakType = 0;
    int i2;
    int count_i2;
    CkJsonObject *json2 = 0;

    i = 0;
    count_i = json.SizeOfArray("responses");
    while (i < count_i) {
        json.put_I(i);
        fullTextAnnotationText = json.stringOf("responses[i].fullTextAnnotation.text");
        j = 0;
        count_j = json.SizeOfArray("responses[i].textAnnotations");
        while (j < count_j) {
            json.put_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.put_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.put_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.put_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.put_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->put_I(i1);
                    languageCode = json1->stringOf("property.detectedLanguages[i].languageCode");
                    i1 = i1 + 1;
                }

                delete json1;

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

                delete json1;

                json1 = json.ObjectOf("responses[i].fullTextAnnotation.pages[j].blocks[k]");
                i1 = 0;
                count_i1 = json1->SizeOfArray("paragraphs");
                while (i1 < count_i1) {
                    json1->put_I(i1);
                    j1 = 0;
                    count_j1 = json1->SizeOfArray("paragraphs[i].property.detectedLanguages");
                    while (j1 < count_j1) {
                        json1->put_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->put_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->put_J(j1);
                        k1 = 0;
                        count_k1 = json1->SizeOfArray("paragraphs[i].words[j].property.detectedLanguages");
                        while (k1 < count_k1) {
                            json1->put_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->put_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->put_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->put_I(i2);
                                languageCode = json2->stringOf("property.detectedLanguages[i].languageCode");
                                i2 = i2 + 1;
                            }

                            delete json2;

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

                            delete json2;
                            k1 = k1 + 1;
                        }

                        j1 = j1 + 1;
                    }

                    i1 = i1 + 1;
                }

                delete json1;
                k = k + 1;
            }

            j = j + 1;
        }

        i = i + 1;
    }

    delete resp;

    strOut.append("Success.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }