Cleaning up the QrEncoder interface

Author: jklein24

composeqrcode/src/main/java/com/lightspark/composeqr/QrCodeView.kt

@@ -36,7 +36,7 @@ fun QrCodeView(
     modifier: Modifier = Modifier,
     colors: QrCodeColors = QrCodeColors.default(),
     dotShape: DotShape = DotShape.Square,
-    encoder: QrEncoder = QrEncoder(),
+    encoder: QrEncoder = ZxingQrEncoder(),
     overlayContent: (@Composable () -> Unit)? = null,
 ) {
     Box(modifier = modifier, contentAlignment = Alignment.Center) {
@@ -70,9 +70,9 @@ fun QrCodeView(
     modifier: Modifier = Modifier,
     colors: QrCodeColors = QrCodeColors.default(),
     dotShape: DotShape = DotShape.Square,
-    encoder: QrEncoder = QrEncoder()
+    encoder: QrEncoder = ZxingQrEncoder()
 ) {
-    val encodedData = remember(data, encoder) { encoder(data) }
+    val encodedData = remember(data, encoder) { encoder.encode(data) }
 
     Canvas(modifier = modifier.background(colors.background)) {
         encodedData?.let { matrix ->

composeqrcode/src/main/java/com/lightspark/composeqr/QrEncoder.kt

@@ -6,10 +6,18 @@ import com.google.zxing.qrcode.encoder.ByteMatrix
 import com.google.zxing.qrcode.encoder.Encoder
 
 /**
- * Encodes a string into a QR code ByteMatrix. This is just a small wrapper around the ZXing library with sane defaults.
+ * Encodes a string into a QR code ByteMatrix. The default implementation, `ZxingQrEncoder` just
+ * wraps the ZXing library with sane defaults.
  */
-class QrEncoder {
-    operator fun invoke(qrData: String): ByteMatrix? {
+interface QrEncoder {
+    fun encode(qrData: String): ByteMatrix?
+}
+
+/**
+ * This is just a small wrapper around the ZXing library with sane defaults.
+ */
+class ZxingQrEncoder : QrEncoder {
+    override fun encode(qrData: String): ByteMatrix? {
         return Encoder.encode(
             qrData,
             ErrorCorrectionLevel.H,