/*
- * Copyright (C) 2008 Google Inc.
+ * Copyright (C) 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
package com.google.zxing.client.android;
import android.content.Context;
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
import android.graphics.Point;
import android.graphics.Rect;
-import android.hardware.CameraDevice;
+import android.hardware.Camera;
+import android.os.Handler;
+import android.os.Message;
import android.util.Log;
import android.view.Display;
+import android.view.SurfaceHolder;
import android.view.WindowManager;
import com.google.zxing.ResultPoint;
/**
- * This object wraps the CameraDevice and expects to be the only one talking to it. The
- * implementation encapsulates the steps needed to take preview-sized images and well as high
- * resolution stills.
- *
- * @author dswitkin@google.com (Daniel Switkin)
+ * This object wraps the Camera service object and expects to be the only one talking to it. The
+ * implementation encapsulates the steps needed to take preview-sized images, which are used for
+ * both preview and decoding.
*/
final class CameraManager {
private static final String TAG = "CameraManager";
- private final Context context;
- private Point cameraResolution;
- private Point stillResolution;
- private int stillMultiplier;
- private Point screenResolution;
- private Rect framingRect;
- private final Bitmap bitmap;
- private CameraDevice camera;
- private final CameraDevice.CaptureParams params;
- private boolean previewMode;
-
- CameraManager(Context context) {
- this.context = context;
- calculateStillResolution();
- getScreenResolution();
- bitmap = Bitmap.createBitmap(stillResolution.x, stillResolution.y, false);
- camera = CameraDevice.open();
- params = new CameraDevice.CaptureParams();
- previewMode = false;
- setPreviewMode(true);
+ private static CameraManager mCameraManager;
+ private Camera mCamera;
+ private final Context mContext;
+ private Point mScreenResolution;
+ private Rect mFramingRect;
+ private Handler mPreviewHandler;
+ private int mPreviewMessage;
+ private Handler mAutoFocusHandler;
+ private int mAutoFocusMessage;
+ private boolean mInitialized;
+ private boolean mPreviewing;
+
+ public static void init(Context context) {
+ if (mCameraManager == null) {
+ mCameraManager = new CameraManager(context);
+ }
}
- public void openDriver() {
- if (camera == null) {
- camera = CameraDevice.open();
+ public static CameraManager get() {
+ return mCameraManager;
+ }
+
+ private CameraManager(Context context) {
+ mContext = context;
+ mCamera = null;
+ mInitialized = false;
+ mPreviewing = false;
+ }
+
+ public void openDriver(SurfaceHolder holder) {
+ if (mCamera == null) {
+ mCamera = Camera.open();
+ mCamera.setPreviewDisplay(holder);
+
+ if (!mInitialized) {
+ mInitialized = true;
+ getScreenResolution();
+ }
+
+ setCameraParameters();
}
}
public void closeDriver() {
- if (camera != null) {
- camera.close();
- camera = null;
+ if (mCamera != null) {
+ mCamera.release();
+ mCamera = null;
}
}
- public void capturePreview(Canvas canvas) {
- setPreviewMode(true);
- camera.capture(canvas);
+ public void startPreview() {
+ if (mCamera != null && !mPreviewing) {
+ mCamera.startPreview();
+ mPreviewing = true;
+ }
}
- public Bitmap captureStill() {
- setPreviewMode(false);
- Canvas canvas = new Canvas(bitmap);
- camera.capture(canvas);
- return bitmap;
+ public void stopPreview() {
+ if (mCamera != null && mPreviewing) {
+ mCamera.setPreviewCallback(null);
+ mCamera.stopPreview();
+ mPreviewHandler = null;
+ mAutoFocusHandler = null;
+ mPreviewing = false;
+ }
+ }
+
+ /**
+ * A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
+ * in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
+ * respectively.
+ *
+ * @param handler The handler to send the message to.
+ * @param message The what field of the message to be sent.
+ */
+ public void requestPreviewFrame(Handler handler, int message) {
+ if (mCamera != null && mPreviewing) {
+ mPreviewHandler = handler;
+ mPreviewMessage = message;
+ mCamera.setPreviewCallback(previewCallback);
+ }
+ }
+
+ public void requestAutoFocus(Handler handler, int message) {
+ if (mCamera != null && mPreviewing) {
+ mAutoFocusHandler = handler;
+ mAutoFocusMessage = message;
+ mCamera.autoFocus(autoFocusCallback);
+ }
}
/**
* @return The rectangle to draw on screen in window coordinates.
*/
public Rect getFramingRect() {
- if (framingRect == null) {
- int size = stillResolution.x * screenResolution.x / cameraResolution.x;
- int leftOffset = (screenResolution.x - size) / 2;
- int topOffset = (screenResolution.y - size) / 2;
- framingRect = new Rect(leftOffset, topOffset, leftOffset + size, topOffset + size);
+ if (mFramingRect == null) {
+ int size = ((mScreenResolution.x < mScreenResolution.y) ? mScreenResolution.x :
+ mScreenResolution.y) * 3 / 4;
+ int leftOffset = (mScreenResolution.x - size) / 2;
+ int topOffset = (mScreenResolution.y - size) / 2;
+ mFramingRect = new Rect(leftOffset, topOffset, leftOffset + size, topOffset + size);
+ Log.v(TAG, "Calculated framing rect: " + mFramingRect);
}
- return framingRect;
+ return mFramingRect;
}
/**
*/
public Point[] convertResultPoints(ResultPoint[] points) {
Rect frame = getFramingRect();
- int frameSize = frame.width();
int count = points.length;
Point[] output = new Point[count];
for (int x = 0; x < count; x++) {
output[x] = new Point();
- output[x].x = frame.left + (int) (points[x].getX() * frameSize / stillResolution.x + 0.5f);
- output[x].y = frame.top + (int) (points[x].getY() * frameSize / stillResolution.y + 0.5f);
+ output[x].x = frame.left + (int) (points[x].getX() + 0.5f);
+ output[x].y = frame.top + (int) (points[x].getY() + 0.5f);
}
return output;
}
/**
- * Images for the live preview are taken at low resolution in RGB. The final stills for the
- * decoding step are taken in YUV, since we only need the luminance channel. Other code depends
- * on the ability to call this method for free if the correct mode is already set.
- *
- * @param on Setting on true will engage preview mode, setting it false will request still mode.
+ * Preview frames are delivered here, which we pass on to the registered handler. Make sure to
+ * clear the handler so it will only receive one message.
*/
- private void setPreviewMode(boolean on) {
- if (on != previewMode) {
- if (on) {
- params.type = 1; // preview
- if (cameraResolution.x / (float) cameraResolution.y <
- screenResolution.x / (float) screenResolution.y) {
- params.srcWidth = cameraResolution.x;
- params.srcHeight = cameraResolution.x * screenResolution.y / screenResolution.x;
- params.leftPixel = 0;
- params.topPixel = (cameraResolution.y - params.srcHeight) / 2;
- } else {
- params.srcWidth = cameraResolution.y * screenResolution.x / screenResolution.y;
- params.srcHeight = cameraResolution.y;
- params.leftPixel = (cameraResolution.x - params.srcWidth) / 2;
- params.topPixel = 0;
- }
- params.outputWidth = screenResolution.x;
- params.outputHeight = screenResolution.y;
- params.dataFormat = 2; // RGB565
- } else {
- params.type = 0; // still
- params.srcWidth = stillResolution.x * stillMultiplier;
- params.srcHeight = stillResolution.y * stillMultiplier;
- params.leftPixel = (cameraResolution.x - params.srcWidth) / 2;
- params.topPixel = (cameraResolution.y - params.srcHeight) / 2;
- params.outputWidth = stillResolution.x;
- params.outputHeight = stillResolution.y;
- params.dataFormat = 2; // RGB565
+ private final Camera.PreviewCallback previewCallback = new Camera.PreviewCallback() {
+ public void onPreviewFrame(byte[] data, Camera camera) {
+ camera.setPreviewCallback(null);
+ if (mPreviewHandler != null) {
+ Message message = mPreviewHandler.obtainMessage(mPreviewMessage, mScreenResolution.x,
+ mScreenResolution.y, data);
+ message.sendToTarget();
+ mPreviewHandler = null;
}
- String captureType = on ? "preview" : "still";
- Log.v(TAG, "Setting params for " + captureType + ": srcWidth " + params.srcWidth +
- " srcHeight " + params.srcHeight + " leftPixel " + params.leftPixel + " topPixel " +
- params.topPixel + " outputWidth " + params.outputWidth + " outputHeight " +
- params.outputHeight);
- camera.setCaptureParams(params);
- previewMode = on;
}
- }
+ };
+
+ private final Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
+ public void onAutoFocus(boolean success, Camera camera) {
+ if (mAutoFocusHandler != null) {
+ Message message = mAutoFocusHandler.obtainMessage(mAutoFocusMessage, success);
+ // Simulate continuous autofocus by sending a focus request every 1.5 seconds.
+ mAutoFocusHandler.sendMessageDelayed(message, 1500);
+ mAutoFocusHandler = null;
+ }
+ }
+ };
/**
- * This method determines how to take the highest quality image (i.e. the one which has the best
- * chance of being decoded) given the capabilities of the camera. It is a balancing act between
- * having enough resolution to read UPCs and having few enough pixels to keep the QR Code
- * processing fast. The result is the dimensions of the rectangle to capture from the center of
- * the sensor, plus a stillMultiplier which indicates whether we'll ask the driver to downsample
- * for us. This has the added benefit of keeping the memory footprint of the bitmap as small as
- * possible.
+ * Sets the camera up to take preview images which are used for both preview and decoding. We're
+ * counting on the default YUV420 semi-planar data. If that changes in the future, we'll need to
+ * specify it explicitly with setPreviewFormat().
*/
- private void calculateStillResolution() {
- cameraResolution = getMaximumCameraResolution();
- int minDimension = (cameraResolution.x < cameraResolution.y) ? cameraResolution.x :
- cameraResolution.y;
- int diagonalResolution = (int) Math.sqrt(cameraResolution.x * cameraResolution.x +
- cameraResolution.y * cameraResolution.y);
- float diagonalFov = getFieldOfView();
-
- // Determine the field of view in the smaller dimension, then calculate how large an object
- // would be at the minimum focus distance.
- float fov = diagonalFov * minDimension / diagonalResolution;
- double objectSize = Math.tan(Math.toRadians(fov / 2.0)) * getMinimumFocusDistance() * 2;
-
- // Let's assume the largest barcode we might photograph at this distance is 3 inches across. By
- // cropping to this size, we can avoid processing surrounding pixels, which helps with speed and
- // accuracy.
- // TODO(dswitkin): Handle a device with a great macro mode where objectSize < 4 inches.
- double crop = 3.0 / objectSize;
- int nativeResolution = (int) (minDimension * crop);
-
- // The camera driver can only capture images which are a multiple of eight, so it's necessary to
- // round up.
- nativeResolution = ((nativeResolution + 7) >> 3) << 3;
- if (nativeResolution > minDimension) {
- nativeResolution = minDimension;
- }
-
- // There's no point in capturing too much detail, so ask the driver to downsample. I haven't
- // tried a non-integer multiple, but it seems unlikely to work.
- double dpi = nativeResolution / objectSize;
- stillMultiplier = 1;
- if (dpi > 200) {
- stillMultiplier = (int) (dpi / 200 + 1);
- }
- stillResolution = new Point(nativeResolution, nativeResolution);
- Log.v(TAG, "FOV " + fov + " objectSize " + objectSize + " crop " + crop + " dpi " + dpi +
- " nativeResolution " + nativeResolution + " stillMultiplier " + stillMultiplier);
- }
-
- // FIXME(dswitkin): These three methods have temporary constants until the new Camera API can
- // provide the real values for the current device.
- // Temporary: the camera's maximum resolution in pixels.
- private static Point getMaximumCameraResolution() {
- return new Point(1280, 1024);
- }
-
- // Temporary: the diagonal field of view in degrees.
- private static float getFieldOfView() {
- return 60.0f;
- }
-
- // Temporary: the minimum focus distance in inches.
- private static float getMinimumFocusDistance() {
- return 12.0f;
+ private void setCameraParameters() {
+ Camera.Parameters parameters = mCamera.getParameters();
+ parameters.setPreviewSize(mScreenResolution.x, mScreenResolution.y);
+ mCamera.setParameters(parameters);
+ Log.v(TAG, "Setting params for preview: width " + mScreenResolution.x + " height " +
+ mScreenResolution.y);
}
private Point getScreenResolution() {
- if (screenResolution == null) {
- WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
+ if (mScreenResolution == null) {
+ WindowManager manager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
Display display = manager.getDefaultDisplay();
- screenResolution = new Point(display.getWidth(), display.getHeight());
+ mScreenResolution = new Point(display.getWidth(), display.getHeight());
}
- return screenResolution;
+ return mScreenResolution;
}
}
projects / zxing.git / blobdiff