zbar — PPM

zbar clib

ZBar barcode and QR code scanner — decode from image files, bytes, or raw camera frames. QR, EAN, UPC, Code128, DataMatrix, PDF417 and more.

ppm install zbar

Requires libzbar-dev: sudo apt install libzbar-dev

Supported Symbologies

QR Code

EAN-13

EAN-8

UPC-A

UPC-E

Code 128

Code 39

Code 93

DataMatrix

PDF417

ISBN-10/13

I2 of 5

CodaBar

DataBar

SQ Code

EAN-2/5

Quick Start

uses zbar;

{ One-shot — scan file, get first result }
var data := ScanFileFirst('/tmp/qr.png');
Writeln(data);  { e.g. 'https://example.com' }

{ Scan file — get all codes }
var result := ScanFile('/tmp/multi.png');
Writeln(IntToStr(result.Count) + ' codes found');

for sym in result.Symbols do
  Writeln(sym.TypeName + ': ' + sym.Data);

Full API — With Position

uses zbar;

var scanner := NewScanner();
var result  := ScanImageFile(scanner, '/tmp/invoice.jpg');

for sym in result.Symbols do
begin
  Writeln('Type: '    + sym.TypeName);
  Writeln('Data: '    + sym.Data);
  Writeln('Quality: ' + IntToStr(sym.Quality));

  var x, y, w, h: Integer;
  GetBoundingBox(sym, x, y, w, h);
  Writeln('At: (' + IntToStr(x) + ',' + IntToStr(y) +
          ') size ' + IntToStr(w) + 'x' + IntToStr(h));
end;

FreeScanner(scanner);

Only QR Codes (Faster)

var scanner := NewScanner();
DisableAll(scanner);
EnableSymbol(scanner, zbQRCode, True);

var result := ScanImageFile(scanner, '/tmp/qr.png');
Writeln(result.Symbols[0].Data);
FreeScanner(scanner);

Camera / Video Frames

{ Call this for every camera frame — raw grayscale bytes (width * height) }
{ Pair with opencv or portaudio to capture frames }

var scanner := NewScanner();
SetCacheEnabled(scanner, True);  { suppress duplicate reads }

{ In your capture loop: }
var frame   := { ... get grayscale bytes from camera ... }
var result  := ScanGrayscale(scanner, frame, 640, 480);
if result.Count > 0 then
  Writeln('Scanned: ' + result.Symbols[0].Data);

FreeScanner(scanner);

Filter by Type

var all   := ScanFile('/tmp/mixed.png');  { has QR + EAN codes }
var qrOnly := FilterByType(all, zbQRCode);

for sym in qrOnly.Symbols do
  Writeln(sym.Data);

API Reference

Scanner Lifecycle

Function	Description
NewScanner	Create scanner with all symbologies enabled.
NewScannerEx(Config)	Create with custom TZBarConfig.
FreeScanner(Scanner)	Destroy scanner and free resources.
EnableSymbol(Scanner, Type, Enable)	Enable or disable a specific symbology.
DisableAll(Scanner)	Disable all symbologies (then re-enable selectively).
SetMinQuality(Scanner, N)	Reject reads below quality N (0–100).
SetCacheEnabled(Scanner, Enable)	Suppress duplicate reads in video mode.

Scan

Function	Description
ScanImageFile(Scanner, Path)	Scan from image file. Returns TZBarResult.
ScanImageBytes(Scanner, Data)	Scan from image byte string.
ScanGrayscale(Scanner, Pixels, W, H)	Raw grayscale bytes — fastest path for video.
ScanRGB(Scanner, Pixels, W, H)	Raw RGB bytes.

Convenience (no handle)

Function	Description
ScanFile(Path)	Scan file, return all results.
ScanFileFirst(Path)	Scan file, return first symbol data string.
ScanBytesFirst(Data)	Scan bytes, return first symbol data.

Result Helpers

Function	Description
FilterByType(Result, Type)	Keep only symbols of the given type.
GetBoundingBox(Symbol, X,Y,W,H)	Minimum enclosing rectangle of the symbol polygon.
GetCenter(Symbol, CX, CY)	Center point of the bounding polygon.
SymbolTypeName(Type)	Human-readable name for a TZBarSymbolType constant.