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| author | Wolfgang Wiedmeyer <wolfgit@wiedmeyer.de> | 2017-01-04 21:31:56 +0100 |
|---|---|---|
| committer | Wolfgang Wiedmeyer <wolfgit@wiedmeyer.de> | 2017-01-04 22:09:26 +0100 |
| commit | a57394a0be5e601c447a07786487bd4c34b0d899 (patch) | |
| tree | 1fb85dda43d385a34a15bb345a503b761dc0bdf0 /api | |
| parent | 0fa5925b0a6ef96bdddee7328aa007fdb6c23b36 (diff) | |
| download | frameworks_base-a57394a0be5e601c447a07786487bd4c34b0d899.zip frameworks_base-a57394a0be5e601c447a07786487bd4c34b0d899.tar.gz frameworks_base-a57394a0be5e601c447a07786487bd4c34b0d899.tar.bz2 | |
Camera: Working barcode scanning with software rendering
Barcode scanner apps expect YUV as preview format. However, the
software renderer cannot handle YUV. Thus, RGB 565 is used. Barcode
scanner apps only need the first plane Y which is basically
greyscale.
The solution is a conversion from RGB to greyscale of preview frames
that are requested by apps for processing. Apps request preview frames
via onPreviewFrame(). The conversion is done using native code for
optimal speed. The conversion algorithm is based on the implementations
in the RGBLuminanceSource class of ZXing[1] and the
RGB565LuminanceSource class of FastBarcodeScanner[2].
Signed-off-by: Wolfgang Wiedmeyer <wolfgit@wiedmeyer.de>
[1] https://github.com/zxing/zxing/blob/cc16a72c85e4958ce406af9547764e5eee9adb6e/core/src/main/java/com/google/zxing/RGBLuminanceSource.java
[2] https://github.com/tschaumburg/FastBarcodeScanner/blob/5a4c166a722730d0099d4c6a1c15d312b93547da/tracking-barcode-scanner/src/main/java/dk/schaumburgit/trackingbarcodescanner/RGB565LuminanceSource.java
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