Android Zxing 转换竖屏扫描且提高识别率
最近的一个Android需要用到扫码功能，用的是Zxing开源库。Zxing的集成就不说了，但是Zxing默认的是横屏扫码，在实际生产中并不适用，需要改为竖屏扫描。
转竖屏步骤：
1>. AndroidManifest.xml中把activity标签CaptureActivity部分的screenOrientation改为portrait。
android:screenOrientation="portrait"
2>. CameraManager类中的getFramingRectInPreview()方法，将left， right， top， bottom改变。
1 //竖屏 2 rect.left = rect.left * cameraResolution.y / screenResolution.x; 3 rect.right = rect.right * cameraResolution.y / screenResolution.x; 4 rect.top = rect.top * cameraResolution.x / screenResolution.y; 5 rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
3>. CameraConfigurationManager类中的setDesiredCameraParameters(OpenCamera camera, boolean safeMode)方法，在setParameters之前添加
theCamera.setDisplayOrientation(90);
4>. DecodeHandler类中的decode(byte[] data, int width, int height)方法，在PlanarYUVLuminanceSource source = activity.getCameraManager().buildLuminanceSource(data, width, height)之前添加
1 byte[] rotatedData = new byte[data.length]; 2 for (int y = 0; y < height; y++) { 3 for (int x = 0; x < width; x++) 4 rotatedData[x * height + height - y - 1] = data[x + y * width]; 5 } 6 int tmp = width; // Here we are swapping, that's the difference to #11 7 width = height; 8 height = tmp; 9 data = rotatedData;
此时，竖屏扫描已经可以实现了，但是扫描复杂的图码时，分辨率低的已经分不清纹理了，很难识别出来，所以需要优化识别率。
识别率优化：
1>. CameraConfigurationUtils类中的findBestPreviewSizeValue(Camera.Parameters parameters, Point screenResolution)方法，将double screenAspectRatio = screenResolution.x / (double) screenResolution.y改为
1 double screenAspectRatio; 2 if (screenResolution.x > screenResolution.y) { 3 screenAspectRatio = (double) screenResolution.x / (double) screenResolution.y; 4 } else { 5 screenAspectRatio = (double) screenResolution.y / (double) screenResolution.x; 6 }
2>. 至此，识别率已经很大程度上的提高了，若在要提高识别率，可通过修改CameraManager类中的MAX_FRAME_WIDTH和MAX_FRAME_HEIGHT来提高精度。
