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git-svn-id: https://zxing.googlecode.com/svn/trunk@11 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
srowen 2007-11-06 19:41:49 +00:00
parent 4a39981245
commit 424c19f542
1 changed files with 17 additions and 2 deletions
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19
core/src/com/google/zxing/qrcode/QRCodeReader.java
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@ -30,10 +30,14 @@ import com.google.zxing.qrcode.detector.DetectorResult;
import java.util.Hashtable;
/**
* This implementation can detect and decode QR Codes in an image.
*
* @author srowen@google.com (Sean Owen)
*/
public final class QRCodeReader implements Reader {
private static final ResultPoint[] NO_POINTS = new ResultPoint[0];
/**
* Locates and decodes a QR code in an image.
*
@ -51,7 +55,7 @@ public final class QRCodeReader implements Reader {
if (hints != null && hints.containsKey(DecodeHintType.PURE_BARCODE)) {
BitMatrix bits = extractPureBits(image);
text = Decoder.decode(bits);
points = new ResultPoint[0];
points = NO_POINTS;
} else {
DetectorResult result = new Detector(image).detect();
text = Decoder.decode(result.getBits());
@ -60,26 +64,36 @@ public final class QRCodeReader implements Reader {
return new Result(text, points);
}
/**
* This method detects a barcode in a "pure" image -- that is, pure monochrome image
* which contains only an unrotated, unskewed, image of a barcode, with some white border
* around it. This is a specialized method that works exceptionally fast in this special
* case.
*/
private static BitMatrix extractPureBits(MonochromeBitmapSource image)
throws ReaderException {
// Now need to determine module size in pixels
// First, skip white border
// First, skip white border by tracking diagonally from the top left down and to the right:
int borderWidth = 0;
while (!image.isBlack(borderWidth, borderWidth)) {
borderWidth++;
}
// And then keep tracking across the top-left black module to determine module size
int moduleEnd = borderWidth;
while (image.isBlack(moduleEnd, moduleEnd)) {
moduleEnd++;
}
int moduleSize = moduleEnd - borderWidth;
// And now find where the rightmost black module on the first row ends
int rowEndOfSymbol = image.getWidth() - 1;
while (!image.isBlack(rowEndOfSymbol, borderWidth)) {
rowEndOfSymbol--;
}
rowEndOfSymbol++;
// Make sure width of barcode is a multiple of module size
if ((rowEndOfSymbol - borderWidth) % moduleSize != 0) {
throw new ReaderException("Bad module size / width: " + moduleSize +
" / " + (rowEndOfSymbol - borderWidth));
@ -91,6 +105,7 @@ public final class QRCodeReader implements Reader {
// little off, this will help recover.
borderWidth += moduleSize >> 1;
// Now just read off the bits
BitMatrix bits = new BitMatrix(dimension);
for (int i = 0; i < dimension; i++) {
int iOffset = borderWidth + i * moduleSize;