More small changes from code inspection

[zxing.git] / core / src / com / google / zxing / qrcode / QRCodeWriter.java

diff --git a/core/src/com/google/zxing/qrcode/QRCodeWriter.java b/core/src/com/google/zxing/qrcode/QRCodeWriter.java
index f223935..c3f24ea 100644 (file)
--- a/core/src/com/google/zxing/qrcode/QRCodeWriter.java
+++ b/core/src/com/google/zxing/qrcode/QRCodeWriter.java
@@ -17,24 +17,35 @@
 package com.google.zxing.qrcode;
 
 import com.google.zxing.BarcodeFormat;
+import com.google.zxing.EncodeHintType;
 import com.google.zxing.Writer;
+import com.google.zxing.WriterException;
 import com.google.zxing.common.ByteMatrix;
-import com.google.zxing.qrcode.encoder.ByteArray;
 import com.google.zxing.qrcode.encoder.Encoder;
 import com.google.zxing.qrcode.encoder.QRCode;
+import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
 
 import java.util.Hashtable;
 
+/**
+ * This object renders a QR Code as a ByteMatrix 2D array of greyscale values.
+ *
+ * @author dswitkin@google.com (Daniel Switkin)
+ */
 public final class QRCodeWriter implements Writer {
 
-  public ByteMatrix encode(byte[] contents, BarcodeFormat format, int width, int height) {
+  private static final int QUIET_ZONE_SIZE = 4;
+
+  public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height)
+      throws WriterException {
 
     return encode(contents, format, width, height, null);
   }
 
-  public ByteMatrix encode(byte[] contents, BarcodeFormat format, int width, int height, Hashtable hints) {
+  public ByteMatrix encode(String contents, BarcodeFormat format, int width, int height,
+      Hashtable hints) throws WriterException {
 
-    if (contents == null || contents.length == 0) {
+    if (contents == null || contents.length() == 0) {
       throw new IllegalArgumentException("Found empty contents");
     }
 
@@ -43,31 +54,39 @@ public final class QRCodeWriter implements Writer {
     }
 
     if (width < 0 || height < 0) {
-      throw new IllegalArgumentException("Requested dimensions are too small: " + width + "x" +
+      throw new IllegalArgumentException("Requested dimensions are too small: " + width + 'x' +
           height);
     }
 
-    // TODO: Check hints for error correction level instead of hardcoding
-    int errorCorrectionLevel = QRCode.EC_LEVEL_L;
-    QRCode code = new QRCode();
-    if (Encoder.Encode(new ByteArray(contents), errorCorrectionLevel, code)) {
-      return renderResult(code, width, height);
-    } else {
-      // TODO need a "WriterException" or something
-      throw new RuntimeException("Could not generate a QR Code");
+    ErrorCorrectionLevel errorCorrectionLevel = ErrorCorrectionLevel.L;
+    if (hints != null) {
+      ErrorCorrectionLevel requestedECLevel = (ErrorCorrectionLevel) hints.get(EncodeHintType.ERROR_CORRECTION);
+      if (requestedECLevel != null) {
+        errorCorrectionLevel = requestedECLevel;
+      }
     }
+
+    QRCode code = new QRCode();
+    Encoder.encode(contents, errorCorrectionLevel, code);
+    return renderResult(code, width, height);
   }
 
   // Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
   // 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
-  private ByteMatrix renderResult(QRCode code, final int width, final int height) {
-    ByteMatrix input = code.matrix();
+  private static ByteMatrix renderResult(QRCode code, int width, int height) {
+    ByteMatrix input = code.getMatrix();
     int inputWidth = input.width();
     int inputHeight = input.height();
-    int outputWidth = Math.max(width, inputWidth);
-    int outputHeight = Math.max(height, inputHeight);
-
-    int multiple = Math.min(outputWidth / inputWidth, outputHeight / inputHeight);
+    int qrWidth = inputWidth + (QUIET_ZONE_SIZE << 1);
+    int qrHeight = inputHeight + (QUIET_ZONE_SIZE << 1);
+    int outputWidth = Math.max(width, qrWidth);
+    int outputHeight = Math.max(height, qrHeight);
+
+    int multiple = Math.min(outputWidth / qrWidth, outputHeight / qrHeight);
+    // Padding includes both the quiet zone and the extra white pixels to accomodate the requested
+    // dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
+    // If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
+    // handle all the padding from 100x100 (the actual QR) up to 200x160.
     int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
     int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
 
@@ -84,7 +103,7 @@ public final class QRCodeWriter implements Writer {
     }
 
     // 2. Expand the QR image to the multiple
-    final byte[][] inputArray = input.getArray();
+    byte[][] inputArray = input.getArray();
     for (int y = 0; y < inputHeight; y++) {
       // a. Write the white pixels at the left of each row
       for (int x = 0; x < leftPadding; x++) {