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Modified the library entry point in a way which lets continuous scan clients reuse the same decoding objects at each pass. This is source and semantically compatible with the previous version, so you have to choose to call decodeWithState() to get the benefits. The unit tests cannot use this because they test each image in normal and then try harder mode, which requires changing the hints object.

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git-svn-id: https://zxing.googlecode.com/svn/trunk@524 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
dswitkin 2008-07-22 16:16:21 +00:00
parent a79fad4b9c
commit 08d44240aa
1 changed files with 61 additions and 10 deletions
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71
core/src/com/google/zxing/MultiFormatReader.java
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@ -23,31 +23,80 @@ import java.util.Hashtable;
import java.util.Vector;
/**
* <p>This implementation can detect barcodes in one of several formats within
* an image, and then decode what it finds. This implementation supports all
* barcode formats that this library supports.</p>
* MultiFormatReader is a convenience class and the main entry point into the library for most uses.
* By default it attempts to decode all barcode formats that the library supports. Optionally, you
* can provide a hints object to request different behavior, for example only decoding QR codes.
*
* @author srowen@google.com (Sean Owen), dswitkin@google.com (Daniel Switkin)
*/
public final class MultiFormatReader implements Reader {
private Hashtable hints;
private Vector readers;
/**
* This version of decode honors the intent of Reader.decode(MonochromeBitmapSource) in that it
* passes null as a hint to the decoders. However, that makes it inefficient to call repeatedly.
* Use setHints() followed by decodeWithState() for continuous scan applications.
*
* @param image The pixel data to decode
* @return The contents of the image
* @throws ReaderException Any errors which occurred
*/
public Result decode(MonochromeBitmapSource image) throws ReaderException {
return decode(image, null);
setHints(null);
return decodeInternal(image);
}
/**
* Decode an image using the hints provided. Does not honor existing state.
*
* @param image The pixel data to decode
* @param hints The hints to use, clearing the previous state.
* @return The contents of the image
* @throws ReaderException Any errors which occurred
*/
public Result decode(MonochromeBitmapSource image, Hashtable hints) throws ReaderException {
setHints(hints);
return decodeInternal(image);
}
/**
* Decode an image using the state set up by calling setHints() previously.
*
* @param image The pixel data to decode
* @return The contents of the image
* @throws ReaderException Any errors which occurred
*/
public Result decodeWithState(MonochromeBitmapSource image) throws ReaderException {
// Make sure to set up the default state so we don't crash
if (readers == null) {
setHints(null);
}
return decodeInternal(image);
}
/**
* This method adds state to the MultiFormatReader. By setting the hints once, subsequent calls
* to decodeWithState(image) can reuse the same set of readers without reallocating memory. This
* is important for performance in continuous scan clients.
*
* @param hints The set of hints to use for subsequent calls to decode(image)
*/
public void setHints(Hashtable hints) {
this.hints = hints;
boolean tryHarder = hints != null && hints.containsKey(DecodeHintType.TRY_HARDER);
Vector possibleFormats = hints == null ? null : (Vector) hints.get(DecodeHintType.POSSIBLE_FORMATS);
Vector readers = new Vector();
readers = new Vector();
if (possibleFormats != null) {
boolean addOneDReader =
possibleFormats.contains(BarcodeFormat.UPC_A) ||
possibleFormats.contains(BarcodeFormat.UPC_E) ||
possibleFormats.contains(BarcodeFormat.EAN_13) ||
possibleFormats.contains(BarcodeFormat.EAN_8) ||
possibleFormats.contains(BarcodeFormat.CODE_39) ||
possibleFormats.contains(BarcodeFormat.CODE_128);
possibleFormats.contains(BarcodeFormat.UPC_E) ||
possibleFormats.contains(BarcodeFormat.EAN_13) ||
possibleFormats.contains(BarcodeFormat.EAN_8) ||
possibleFormats.contains(BarcodeFormat.CODE_39) ||
possibleFormats.contains(BarcodeFormat.CODE_128);
// Put 1D readers upfront in "normal" mode
if (addOneDReader && !tryHarder) {
readers.addElement(new MultiFormatOneDReader());
@ -75,7 +124,9 @@ public final class MultiFormatReader implements Reader {
readers.addElement(new MultiFormatOneDReader());
}
}
}
private Result decodeInternal(MonochromeBitmapSource image) throws ReaderException {
for (int i = 0; i < readers.size(); i++) {
Reader reader = (Reader) readers.elementAt(i);
try {