(Delphi DLL) 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 for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Http, BinData, StringBuilder, HttpResponse, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
imageData: HCkBinData;
success: Boolean;
json: HCkJsonObject;
http: HCkHttp;
sb: HCkStringBuilder;
url: PWideChar;
resp: HCkHttpResponse;
sbResponseBody: HCkStringBuilder;
i: Integer;
count_i: Integer;
fullTextAnnotationText: PWideChar;
j: Integer;
count_j: Integer;
locale: PWideChar;
description: PWideChar;
k: Integer;
count_k: Integer;
x: Integer;
y: Integer;
width: Integer;
height: Integer;
languageCode: PWideChar;
blockType: PWideChar;
i1: Integer;
count_i1: Integer;
json1: HCkJsonObject;
j1: Integer;
count_j1: Integer;
k1: Integer;
count_k1: Integer;
text: PWideChar;
propertyDetectedBreakType: PWideChar;
i2: Integer;
count_i2: Integer;
json2: HCkJsonObject;

begin
// 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.
imageData := CkBinData_Create();
// This image file contains some text...
success := CkBinData_LoadFile(imageData,'qa_data/jpg/text.jpg');
if (success <> True) then
  begin
    Memo1.Lines.Add('Failed to load image file.');
    Exit;
  end;

// Create the above JSON.
json := CkJsonObject_Create();
CkJsonObject_UpdateBd(json,'requests[0].image.content','base64',imageData);
CkJsonObject_UpdateString(json,'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

http := CkHttp_Create();
sb := CkStringBuilder_Create();
url := 'https://vision.googleapis.com/v1/images:annotate?key=YOUR_API_KEY';
resp := CkHttp_PostJson3(http,url,'application/json',json);
if (CkHttp_getLastMethodSuccess(http) <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

Memo1.Lines.Add('status = ' + IntToStr(CkHttpResponse_getStatusCode(resp)));

// A 200 response status indicate success.
if (CkHttpResponse_getStatusCode(resp) <> 200) then
  begin
    Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));
    Memo1.Lines.Add('Failed.');
    CkHttpResponse_Dispose(resp);
    Exit;
  end;

sbResponseBody := CkStringBuilder_Create();
CkHttpResponse_GetBodySb(resp,sbResponseBody);
CkStringBuilder_WriteFile(sbResponseBody,'qa_output/textDetectResponse.json','utf-8',False);
CkJsonObject_LoadSb(json,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:

i := 0;
count_i := CkJsonObject_SizeOfArray(json,'responses');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    fullTextAnnotationText := CkJsonObject__stringOf(json,'responses[i].fullTextAnnotation.text');
    j := 0;
    count_j := CkJsonObject_SizeOfArray(json,'responses[i].textAnnotations');
    while j < count_j do
      begin
        CkJsonObject_putJ(json,j);
        locale := CkJsonObject__stringOf(json,'responses[i].textAnnotations[j].locale');
        description := CkJsonObject__stringOf(json,'responses[i].textAnnotations[j].description');
        k := 0;
        count_k := CkJsonObject_SizeOfArray(json,'responses[i].textAnnotations[j].boundingPoly.vertices');
        while k < count_k do
          begin
            CkJsonObject_putK(json,k);
            x := CkJsonObject_IntOf(json,'responses[i].textAnnotations[j].boundingPoly.vertices[k].x');
            y := CkJsonObject_IntOf(json,'responses[i].textAnnotations[j].boundingPoly.vertices[k].y');
            k := k + 1;
          end;

        j := j + 1;
      end;

    j := 0;
    count_j := CkJsonObject_SizeOfArray(json,'responses[i].fullTextAnnotation.pages');
    while j < count_j do
      begin
        CkJsonObject_putJ(json,j);
        width := CkJsonObject_IntOf(json,'responses[i].fullTextAnnotation.pages[j].width');
        height := CkJsonObject_IntOf(json,'responses[i].fullTextAnnotation.pages[j].height');
        k := 0;
        count_k := CkJsonObject_SizeOfArray(json,'responses[i].fullTextAnnotation.pages[j].property.detectedLanguages');
        while k < count_k do
          begin
            CkJsonObject_putK(json,k);
            languageCode := CkJsonObject__stringOf(json,'responses[i].fullTextAnnotation.pages[j].property.detectedLanguages[k].languageCode');
            k := k + 1;
          end;

        k := 0;
        count_k := CkJsonObject_SizeOfArray(json,'responses[i].fullTextAnnotation.pages[j].blocks');
        while k < count_k do
          begin
            CkJsonObject_putK(json,k);
            blockType := CkJsonObject__stringOf(json,'responses[i].fullTextAnnotation.pages[j].blocks[k].blockType');

            json1 := CkJsonObject_ObjectOf(json,'responses[i].fullTextAnnotation.pages[j].blocks[k]');
            i1 := 0;
            count_i1 := CkJsonObject_SizeOfArray(json1,'property.detectedLanguages');
            while i1 < count_i1 do
              begin
                CkJsonObject_putI(json1,i1);
                languageCode := CkJsonObject__stringOf(json1,'property.detectedLanguages[i].languageCode');
                i1 := i1 + 1;
              end;

            CkJsonObject_Dispose(json1);

            json1 := CkJsonObject_ObjectOf(json,'responses[i].fullTextAnnotation.pages[j].blocks[k]');
            i1 := 0;
            count_i1 := CkJsonObject_SizeOfArray(json1,'boundingBox.vertices');
            while i1 < count_i1 do
              begin
                CkJsonObject_putI(json1,i1);
                x := CkJsonObject_IntOf(json1,'boundingBox.vertices[i].x');
                y := CkJsonObject_IntOf(json1,'boundingBox.vertices[i].y');
                i1 := i1 + 1;
              end;

            CkJsonObject_Dispose(json1);

            json1 := CkJsonObject_ObjectOf(json,'responses[i].fullTextAnnotation.pages[j].blocks[k]');
            i1 := 0;
            count_i1 := CkJsonObject_SizeOfArray(json1,'paragraphs');
            while i1 < count_i1 do
              begin
                CkJsonObject_putI(json1,i1);
                j1 := 0;
                count_j1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].property.detectedLanguages');
                while j1 < count_j1 do
                  begin
                    CkJsonObject_putJ(json1,j1);
                    languageCode := CkJsonObject__stringOf(json1,'paragraphs[i].property.detectedLanguages[j].languageCode');
                    j1 := j1 + 1;
                  end;

                j1 := 0;
                count_j1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].boundingBox.vertices');
                while j1 < count_j1 do
                  begin
                    CkJsonObject_putJ(json1,j1);
                    x := CkJsonObject_IntOf(json1,'paragraphs[i].boundingBox.vertices[j].x');
                    y := CkJsonObject_IntOf(json1,'paragraphs[i].boundingBox.vertices[j].y');
                    j1 := j1 + 1;
                  end;

                j1 := 0;
                count_j1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].words');
                while j1 < count_j1 do
                  begin
                    CkJsonObject_putJ(json1,j1);
                    k1 := 0;
                    count_k1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].words[j].property.detectedLanguages');
                    while k1 < count_k1 do
                      begin
                        CkJsonObject_putK(json1,k1);
                        languageCode := CkJsonObject__stringOf(json1,'paragraphs[i].words[j].property.detectedLanguages[k].languageCode');
                        k1 := k1 + 1;
                      end;

                    k1 := 0;
                    count_k1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].words[j].boundingBox.vertices');
                    while k1 < count_k1 do
                      begin
                        CkJsonObject_putK(json1,k1);
                        x := CkJsonObject_IntOf(json1,'paragraphs[i].words[j].boundingBox.vertices[k].x');
                        y := CkJsonObject_IntOf(json1,'paragraphs[i].words[j].boundingBox.vertices[k].y');
                        k1 := k1 + 1;
                      end;

                    k1 := 0;
                    count_k1 := CkJsonObject_SizeOfArray(json1,'paragraphs[i].words[j].symbols');
                    while k1 < count_k1 do
                      begin
                        CkJsonObject_putK(json1,k1);
                        text := CkJsonObject__stringOf(json1,'paragraphs[i].words[j].symbols[k].text');
                        propertyDetectedBreakType := CkJsonObject__stringOf(json1,'paragraphs[i].words[j].symbols[k].property.detectedBreak.type');

                        json2 := CkJsonObject_ObjectOf(json1,'paragraphs[i].words[j].symbols[k]');
                        i2 := 0;
                        count_i2 := CkJsonObject_SizeOfArray(json2,'property.detectedLanguages');
                        while i2 < count_i2 do
                          begin
                            CkJsonObject_putI(json2,i2);
                            languageCode := CkJsonObject__stringOf(json2,'property.detectedLanguages[i].languageCode');
                            i2 := i2 + 1;
                          end;

                        CkJsonObject_Dispose(json2);

                        json2 := CkJsonObject_ObjectOf(json1,'paragraphs[i].words[j].symbols[k]');
                        i2 := 0;
                        count_i2 := CkJsonObject_SizeOfArray(json2,'boundingBox.vertices');
                        while i2 < count_i2 do
                          begin
                            CkJsonObject_putI(json2,i2);
                            x := CkJsonObject_IntOf(json2,'boundingBox.vertices[i].x');
                            y := CkJsonObject_IntOf(json2,'boundingBox.vertices[i].y');
                            i2 := i2 + 1;
                          end;

                        CkJsonObject_Dispose(json2);
                        k1 := k1 + 1;
                      end;

                    j1 := j1 + 1;
                  end;

                i1 := i1 + 1;
              end;

            CkJsonObject_Dispose(json1);
            k := k + 1;
          end;

        j := j + 1;
      end;

    i := i + 1;
  end;

CkHttpResponse_Dispose(resp);

Memo1.Lines.Add('Success.');

CkBinData_Dispose(imageData);
CkJsonObject_Dispose(json);
CkHttp_Dispose(http);
CkStringBuilder_Dispose(sb);
CkStringBuilder_Dispose(sbResponseBody);

end;