+++ /dev/null
-/*
- * Copyright (C) 2008 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under 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.util.Log;
-import android.view.Display;
-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)
- */
-final class CameraManager {
-
- private static final String TAG = "CameraManager";
-
- private final Context context;
- private Point cameraResolution;
- private Point stillResolution;
- private Point previewResolution;
- private int stillMultiplier;
- private Point screenResolution;
- private Rect framingRect;
- private Bitmap bitmap;
- private CameraDevice camera;
- private final CameraDevice.CaptureParams params;
- private boolean previewMode;
- private boolean usePreviewForDecode;
-
- CameraManager(Context context) {
- this.context = context;
- getScreenResolution();
- calculateStillResolution();
- calculatePreviewResolution();
-
- usePreviewForDecode = true;
- setUsePreviewForDecode(false);
-
- camera = null;
- params = new CameraDevice.CaptureParams();
- }
-
- public void openDriver() {
- if (camera == null) {
- camera = CameraDevice.open();
- // If we're reopening the camera, we need to reset the capture params.
- previewMode = false;
- setPreviewMode(true);
- }
- }
-
- public void closeDriver() {
- if (camera != null) {
- camera.close();
- camera = null;
- }
- }
-
- public void capturePreview(Canvas canvas) {
- setPreviewMode(true);
- camera.capture(canvas);
- }
-
- public Bitmap captureStill() {
- setPreviewMode(usePreviewForDecode);
- Canvas canvas = new Canvas(bitmap);
- camera.capture(canvas);
- return bitmap;
- }
-
- /**
- * This method exists to help us evaluate how to best set up and use the camera.
- * @param usePreview Decode at preview resolution if true, else use still resolution.
- */
- public void setUsePreviewForDecode(boolean usePreview) {
- if (usePreviewForDecode != usePreview) {
- usePreviewForDecode = usePreview;
- if (usePreview) {
- Log.v(TAG, "Creating bitmap at screen resolution: " + screenResolution.x + "," +
- screenResolution.y);
- bitmap = Bitmap.createBitmap(screenResolution.x, screenResolution.y, false);
- } else {
- Log.v(TAG, "Creating bitmap at still resolution: " + stillResolution.x + "," +
- stillResolution.y);
- bitmap = Bitmap.createBitmap(stillResolution.x, stillResolution.y, false);
- }
- }
- }
-
- /**
- * Calculates the framing rect which the UI should draw to show the user where to place the
- * barcode. The actual captured image should be a bit larger than indicated because they might
- * frame the shot too tightly. This target helps with alignment as well as forces the user to hold
- * the device far enough away to ensure the image will be in focus.
- *
- * @return The rectangle to draw on screen in window coordinates.
- */
- public Rect getFramingRect() {
- if (framingRect == null) {
- int size = stillResolution.x * screenResolution.x / previewResolution.x;
- int leftOffset = (screenResolution.x - size) / 2;
- int topOffset = (screenResolution.y - size) / 2;
- framingRect = new Rect(leftOffset, topOffset, leftOffset + size, topOffset + size);
- Log.v(TAG, "Calculated framing rect: " + framingRect);
- }
- return framingRect;
- }
-
- /**
- * Converts the result points from still resolution coordinates to screen coordinates.
- *
- * @param points The points returned by the Reader subclass through Result.getResultPoints().
- * @return An array of Points scaled to the size of the framing rect and offset appropriately
- * so they can be drawn in screen coordinates.
- */
- 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();
- if (usePreviewForDecode) {
- output[x].x = (int) (points[x].getX() + 0.5f);
- output[x].y = (int) (points[x].getY() + 0.5f);
- } else {
- 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);
- }
- }
- 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.
- */
- private void setPreviewMode(boolean on) {
- if (on != previewMode) {
- if (on) {
- params.type = 1; // preview
- params.srcWidth = previewResolution.x;
- params.srcHeight = previewResolution.y;
- params.leftPixel = (cameraResolution.x - params.srcWidth) / 2;
- params.topPixel = (cameraResolution.y - params.srcHeight) / 2;
- 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
- }
- 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;
- }
- }
-
- /**
- * 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.
- */
- 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);
- }
-
- /**
- * The goal of the preview resolution is to show a little context around the framing rectangle
- * which is the actual captured area in still mode.
- */
- private void calculatePreviewResolution() {
- if (previewResolution == null) {
- int previewHeight = (int) (stillResolution.x * stillMultiplier * 1.5f);
- int previewWidth = previewHeight * screenResolution.x / screenResolution.y;
- previewWidth = ((previewWidth + 7) >> 3) << 3;
- if (previewWidth > cameraResolution.x) previewWidth = cameraResolution.x;
- previewHeight = previewWidth * screenResolution.y / screenResolution.x;
- previewResolution = new Point(previewWidth, previewHeight);
- Log.v(TAG, "previewWidth " + previewWidth + " previewHeight " + previewHeight);
- }
- }
-
- // 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 Point getScreenResolution() {
- if (screenResolution == null) {
- WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
- Display display = manager.getDefaultDisplay();
- screenResolution = new Point(display.getWidth(), display.getHeight());
- }
- return screenResolution;
- }
-
-}
projects / zxing.git / blobdiff