您可以使用phpBarcode库来生成条形码，并设置尺寸和颜色。以下是一个示例代码：
// Include the library
require_once('class/BCGFontFile.php');
require_once('class/BCGColor.php');
require_once('class/BCGDrawing.php');
// Including all required barcode classes
require_once('class/BCGcodabar.barcode.php');
// The arguments are R, G, B for color.
$colorFront = new BCGColor(0, 0, 0);
$colorBack = new BCGColor(255, 255, 255);
// Barcode Part
$code = new BCGcodabar();
$code->setScale(2); // Resolution
$code->setThickness(30); // Thickness
$code->setForegroundColor($colorFront); // Color of bars
$code->setBackgroundColor($colorBack); // Color of spaces
$code->setFont(5); // Font (or 0)
$code->parse('1234');
// Drawing Part
$drawing = new BCGDrawing('', $colorBack);
$drawing->setBarcode($code);
$drawing->draw();
// Header that says it is an image (remove it if you save the barcode to a file)
header('Content-Type: image/png');
// Draw (or save) the image into PNG format.
$drawing->finish(BCGDrawing::IMG_FORMAT_PNG);
在上面的代码中，您可以通过设置setScale方法来设置条形码的大小，通过设置setForegroundColor和setBackgroundColor来设置条形码的前景色和背景色。您还可以通过设置setThickness方法来设置条形码的粗细。
