相机的连拍和水印的功能

首先介绍相机的连拍功能

说到连拍的功能，大家很容易想到就是拍照获取照片，其实这样的连拍是最常见的，不过会出现卡一下的现象，需要做类似录像截屏的操作。

下面我就简单的说明一下这种连拍的实现，都要实现无卡顿的连拍我们就不能再通过

camera.takePicture(null, null, pictureCallback);

而要换成另外的方法，

/*** <p>Installs a callback to be invoked for the next preview frame in* addition to displaying it on the screen.  After one invocation, the* callback is cleared. This method can be called any time, even when* preview is live.  Any other preview callbacks are overridden.</p>** <p>If you are using the preview data to create video or still images,* strongly consider using {@link android.media.MediaActionSound} to* properly indicate image capture or recording start/stop to the user.</p>** @param cb a callback object that receives a copy of the next preview frame,*     or null to stop receiving callbacks.* @see android.media.MediaActionSound*/
camera.setOneShotPreviewCallback(new Camera.PreviewCallback() {/*** Called as preview frames are displayed.  This callback is invoked* on the event thread {@link #open(int)} was called from.** <p>If using the {@link android.graphics.ImageFormat#YV12} format,* refer to the equations in {@link Camera.Parameters#setPreviewFormat}* for the arrangement of the pixel data in the preview callback* buffers.** @param data the contents of the preview frame in the format defined*  by {@link android.graphics.ImageFormat}, which can be queried*  with {@link android.hardware.Camera.Parameters#getPreviewFormat()}.*  If {@link android.hardware.Camera.Parameters#setPreviewFormat(int)}*             is never called, the default will be the YCbCr_420_SP*             (NV21) format.* @param camera the Camera service object.*/@Overridepublic void onPreviewFrame(byte[] data, Camera camera) {});

下面的方法主要不直接获取jpeg的图片流，是获取视频流格式的数据，这里只要将格式做转换即可得到数据图片，下面是转换的代码：

 Size size = camera.getParameters().getPreviewSize();Bitmap bitmap = null;try {YuvImage image = new YuvImage(data, ImageFormat.NV21, size.width, size.height, null);if (image != null) {ByteArrayOutputStream stream = new ByteArrayOutputStream();image.compressToJpeg(new Rect(0, 0, size.width, size.height), 80, stream);bitmap = BitmapFactory.decodeByteArray(stream.toByteArray(), 0, stream.size());stream.close();}} catch (Exception ex) {Log.e("Sys", "Error:" + ex.getMessage());}

这样即实现了简单的连拍功能。

相机的水印功能添加

水印添加主要是两部分，一部分是预览界面的水印，一部分是实际打到照片上的水印。

下面分开介绍:

水印旋转的秘密

上图是完成后的图片，主要的要求是水印信息要根据屏幕旋转而旋转。

这里主要是在预览的suferview上方覆盖一层水印层，然后在通过设置水印层view的参数实现，因为我这个水印会根据横屏或竖屏来变化水印的显示效果，所以会有对坐标的转换。

下面是水印文字旋转的核心代码：

private void rotateText(int orientation) {switch (orientation) {case ORIGIN:LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) linearLayout.getLayoutParams();lp.setMargins(0, 0, 0, 0);linearLayout.setLayoutParams(lp);linearLayout.setRotation(0);break;case LEFT:int marginRight = ll_preview_watermark.getWidth() - ll_preview_watermark.getHeight();lp = (LinearLayout.LayoutParams) linearLayout.getLayoutParams();lp.setMargins(0, 0, marginRight, 0);linearLayout.setLayoutParams(lp);linearLayout.measure(View.MeasureSpec.makeMeasureSpec(linearLayout.getWidth() - marginRight, View.MeasureSpec.EXACTLY), 0);int hRoot = ll_preview_watermark.getHeight();int hBottom = linearLayout.getMeasuredHeight();int x1 = hBottom;int y1 = 0;int x2 = 0;int y2 = hRoot - hBottom;float[] pivot = calcPivot(x1, y1, x2, y2, false, hRoot / 2);linearLayout.setPivotX(pivot[0]);linearLayout.setPivotY(pivot[1] - y2);linearLayout.setRotation(90);break;case RIGHT:marginRight = ll_preview_watermark.getWidth() - ll_preview_watermark.getHeight();lp = (LinearLayout.LayoutParams) linearLayout.getLayoutParams();lp.setMargins(0, 0, marginRight, 0);linearLayout.setLayoutParams(lp);linearLayout.measure(View.MeasureSpec.makeMeasureSpec(linearLayout.getWidth() - marginRight, View.MeasureSpec.EXACTLY), 0);int wRoot = ll_preview_watermark.getWidth();hRoot = ll_preview_watermark.getHeight();hBottom = linearLayout.getMeasuredHeight();x1 = 0;y1 = hRoot - hBottom;x2 = wRoot - hBottom;y2 = hRoot;pivot = calcPivot(x1, y1, x2, y2, true, wRoot / 2);linearLayout.setPivotX(pivot[0]);linearLayout.setPivotY(pivot[1] - y1);linearLayout.setRotation(-90);break;case TOP:lp = (LinearLayout.LayoutParams) linearLayout.getLayoutParams();lp.setMargins(0, 0, 0, 0);linearLayout.setLayoutParams(lp);wRoot = ll_preview_watermark.getWidth();hRoot = ll_preview_watermark.getHeight();hBottom = linearLayout.getHeight();linearLayout.setPivotX(wRoot / 2);linearLayout.setPivotY(hBottom - hRoot / 2);linearLayout.setRotation(180);break;}}private float[] calcPivot(int x1, int y1, int x2, int y2, boolean isConstantX, int constant) {double k1 = ((double) y2 - y1) / (x2 - x1);double k2 = -1d / k1;int x3 = (x1 + x2) / 2;int y3 = (y1 + y2) / 2;double b = y3 - k2 * x3;if (isConstantX) {return new float[] {constant, (float) (k2 * constant + b)};} else {return new float[] {(float) ((constant - b) / k2), constant};}}

通过传入屏幕的四个方向的标记来做相应的旋转。

水印是如何打到照片上

方式有很多，我是用两种方式来实现的：

1.因为我这的水印信息分为两部分，一个是icon一个是文字，我之前是通过在拍照获取到的照片上，通过canvas来进行绘制的，不过如果说你的水印信息很简单，这个方法是很好的选择，以为写上去的水印清晰度很高。

2.另一种就是通过照片合成来做，不过这里遇到了比较多的问题，主要的原因是因为对图片的压缩到导致的，我简单介绍一下我这的图片合成操作，我的水印信息是一个view上承载的内容，图片是通过相机获取的，我吧水印view上的内容转换为图片在做合成即可。

下面介绍一下view获取图片的代码，

    public static Bitmap convertViewToBitmap(View view) {
//        view.measure(View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED),
// View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED));
//        view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());view.destroyDrawingCache();view.setDrawingCacheEnabled(true);view.buildDrawingCache();Bitmap bitmap = view.getDrawingCache();
//        Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),
//                Bitmap.Config.ARGB_8888);
//        Canvas canvas = new Canvas(bitmap);
//        view.draw(canvas);return bitmap;}

获取到view转换过来的图片后就可以和照片进行合成了，照片和成主要是看水印在照片上的位置，

下面就是简单的工具类：

 public static Bitmap newBitmapToWatermark(Bitmap src, Bitmap watermark) {if (src == null) {return null;}int screenWidth = FSScreen.getScreenWidth();int screenHeight = FSScreen.getScreenHeight();int w = src.getWidth();int h = src.getHeight();Log.i("图片尺寸，宽", w + "--高" + h);//横着 宽: 1920--高1080//竖着 宽: 1080--高1920
//      create the new blank bitmapBitmap newb = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);// 创建一个新的和SRC长度宽度一样的位图,Bitmap.Config.ARGB_8888Canvas cv = new Canvas(newb);
//      draw src intocv.drawBitmap(src, 0, 0, null);// 在 0，0坐标开始画入srcif (null != watermark) {int ww = watermark.getWidth();int wh = watermark.getHeight();watermark = watermark.copy(Bitmap.Config.ARGB_8888, true);Canvas c = new Canvas(watermark);Paint p1 = new Paint();int removeColor = 0;//要去除的背景色; // store this color's int for later usep1.setAlpha(0);p1.setXfermode(new AvoidXfermode(removeColor, 0, AvoidXfermode.Mode.TARGET));c.drawPaint(p1);/**下面是绘制黑色背景,判断照片横竖**/Paint p = new Paint();//CLAMP夹紧   REPEAT重复  MIRROR镜像LinearGradient lg = newLinearGradient(0, h - wh, 0, h, Color.parseColor("#00000000"), Color.parseColor("#99000000"), Shader.TileMode.CLAMP);p.setShader(lg);if (ww > w) {float i = w / (float) ww;int result = (int) (wh * i);watermark = cropPhotoImage(src, watermark, result);cv.drawRect(0, h, screenWidth, wh, p);cv.drawBitmap(watermark, 5, h - result + 5, null);// 在src的左下角画入水印} else {cv.drawRect(0, h, screenWidth, wh, p);cv.drawBitmap(watermark, 5, h - wh + 5, null);// 在src的左下角画入水印}}// save all clipcv.save(Canvas.ALL_SAVE_FLAG);// 保存// storecv.restore();// 存储return newb;}

里面涉及到一个LinearGradient线性渐变的类，这个类可以去看官方的文档，里面介绍的比较清除，主要是通过几种模式来绘制不同样式，我这里主要是在水印的背景上绘制一个渐变的黑色背景条，防止水印打在白色区域无法看到的问题。

上面基本上就这主要和两个知识点了，如果有什么问题，欢迎反馈。