用于TextureView的裁剪相机预览
用于TextureView的裁剪相机预览
提问于 2013-06-10 16:19:21
我有一个固定宽度和高度的TextureView，我想在它里面显示相机预览。我需要裁剪相机预览，这样它在我的TextureView中看起来就不会拉伸。如何裁剪？如果我需要使用OpenGL，如何将表面纹理绑定到OpenGL，以及如何使用OpenGL进行裁剪？
public class MyActivity extends Activity implements TextureView.SurfaceTextureListener
{
private Camera mCamera;
private TextureView mTextureView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_options);
mTextureView = (TextureView) findViewById(R.id.camera_preview);
mTextureView.setSurfaceTextureListener(this);
}
@Override
public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
mCamera = Camera.open();
try
{
mCamera.setPreviewTexture(surface);
mCamera.startPreview();
} catch (IOException ioe) {
// Something bad happened
}
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
mCamera.stopPreview();
mCamera.release();
return true;
}
@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
}
@Override
public void onSurfaceTextureUpdated(SurfaceTexture surface)
{
// Invoked every time there's a new Camera preview frame
}
}此外，在正确进行预览后，我需要能够实时读取在裁剪图像中心找到的像素。
回答 6
Stack Overflow用户
发布于 2014-02-07 22:48:20
早先由@Romanski提供的解决方案运行良好，但它可以根据裁剪进行缩放。如果您需要缩放以适应需求，请使用以下解决方案。每次更改曲面视图时调用updateTextureMatrix :即在onSurfaceTextureAvailable和onSurfaceTextureSizeChanged方法中。还要注意，此解决方案依赖于忽略配置更改的活动(即android:configChanges="orientation|screenSize|keyboardHidden“或类似的东西)：
private void updateTextureMatrix(int width, int height)
{
boolean isPortrait = false;
Display display = getWindowManager().getDefaultDisplay();
if (display.getRotation() == Surface.ROTATION_0 || display.getRotation() == Surface.ROTATION_180) isPortrait = true;
else if (display.getRotation() == Surface.ROTATION_90 || display.getRotation() == Surface.ROTATION_270) isPortrait = false;
int previewWidth = orgPreviewWidth;
int previewHeight = orgPreviewHeight;
if (isPortrait)
{
previewWidth = orgPreviewHeight;
previewHeight = orgPreviewWidth;
}
float ratioSurface = (float) width / height;
float ratioPreview = (float) previewWidth / previewHeight;
float scaleX;
float scaleY;
if (ratioSurface > ratioPreview)
{
scaleX = (float) height / previewHeight;
scaleY = 1;
}
else
{
scaleX = 1;
scaleY = (float) width / previewWidth;
}
Matrix matrix = new Matrix();
matrix.setScale(scaleX, scaleY);
textureView.setTransform(matrix);
float scaledWidth = width * scaleX;
float scaledHeight = height * scaleY;
float dx = (width - scaledWidth) / 2;
float dy = (height - scaledHeight) / 2;
textureView.setTranslationX(dx);
textureView.setTranslationY(dy);
}此外，您还需要以下字段：
private int orgPreviewWidth;
private int orgPreviewHeight;在调用updateTextureMatrix前，先用onSurfaceTextureAvailable方法初始化：
Camera.Parameters parameters = camera.getParameters();
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_VIDEO);
Pair<Integer, Integer> size = getMaxSize(parameters.getSupportedPreviewSizes());
parameters.setPreviewSize(size.first, size.second);
orgPreviewWidth = size.first;
orgPreviewHeight = size.second;
camera.setParameters(parameters);getMaxSize方法：
private static Pair<Integer, Integer> getMaxSize(List<Camera.Size> list)
{
int width = 0;
int height = 0;
for (Camera.Size size : list) {
if (size.width * size.height > width * height)
{
width = size.width;
height = size.height;
}
}
return new Pair<Integer, Integer>(width, height);
}最后一件事--你需要纠正相机的旋转。因此在Activity onConfigurationChanged方法中调用setCameraDisplayOrientation方法(也可以在onSurfaceTextureAvailable方法中进行初始调用)：
public static void setCameraDisplayOrientation(Activity activity, int cameraId, Camera camera)
{
Camera.CameraInfo info = new Camera.CameraInfo();
Camera.getCameraInfo(cameraId, info);
int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
int degrees = 0;
switch (rotation)
{
case Surface.ROTATION_0:
degrees = 0;
break;
case Surface.ROTATION_90:
degrees = 90;
break;
case Surface.ROTATION_180:
degrees = 180;
break;
case Surface.ROTATION_270:
degrees = 270;
break;
}
int result;
if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT)
{
result = (info.orientation + degrees) % 360;
result = (360 - result) % 360; // compensate the mirror
}
else
{ // back-facing
result = (info.orientation - degrees + 360) % 360;
}
camera.setDisplayOrientation(result);
Camera.Parameters params = camera.getParameters();
params.setRotation(result);
camera.setParameters(params);
}Stack Overflow用户
发布于 2013-07-26 18:20:09
只需计算宽高比，生成缩放矩阵并将其应用于TextureView即可。基于表面的纵横比和预览图像的纵横比，预览图像被裁剪到顶部和底部或左侧和右侧。我发现的另一个解决方案是，如果你在 SurfaceTexture可用之前打开相机，预览已经自动缩放。在设置SurfaceTextureListener之后，只需尝试将mCamera = Camera.open()；移动到onCreate函数即可。这对我在N4上很有效。使用此解决方案，当您从纵向旋转到横向旋转时，您可能会遇到问题。如果您需要纵向和横向支持，则使用scale矩阵解决方案！
private void initPreview(SurfaceTexture surface, int width, int height) {
try {
camera.setPreviewTexture(surface);
} catch (Throwable t) {
Log.e("CameraManager", "Exception in setPreviewTexture()", t);
}
Camera.Parameters parameters = camera.getParameters();
previewSize = parameters.getSupportedPreviewSizes().get(0);
float ratioSurface = width > height ? (float) width / height : (float) height / width;
float ratioPreview = (float) previewSize.width / previewSize.height;
int scaledHeight = 0;
int scaledWidth = 0;
float scaleX = 1f;
float scaleY = 1f;
boolean isPortrait = false;
if (previewSize != null) {
parameters.setPreviewSize(previewSize.width, previewSize.height);
if (display.getRotation() == Surface.ROTATION_0 || display.getRotation() == Surface.ROTATION_180) {
camera.setDisplayOrientation(display.getRotation() == Surface.ROTATION_0 ? 90 : 270);
isPortrait = true;
} else if (display.getRotation() == Surface.ROTATION_90 || display.getRotation() == Surface.ROTATION_270) {
camera.setDisplayOrientation(display.getRotation() == Surface.ROTATION_90 ? 0 : 180);
isPortrait = false;
}
if (isPortrait && ratioPreview > ratioSurface) {
scaledWidth = width;
scaledHeight = (int) (((float) previewSize.width / previewSize.height) * width);
scaleX = 1f;
scaleY = (float) scaledHeight / height;
} else if (isPortrait && ratioPreview < ratioSurface) {
scaledWidth = (int) (height / ((float) previewSize.width / previewSize.height));
scaledHeight = height;
scaleX = (float) scaledWidth / width;
scaleY = 1f;
} else if (!isPortrait && ratioPreview < ratioSurface) {
scaledWidth = width;
scaledHeight = (int) (width / ((float) previewSize.width / previewSize.height));
scaleX = 1f;
scaleY = (float) scaledHeight / height;
} else if (!isPortrait && ratioPreview > ratioSurface) {
scaledWidth = (int) (((float) previewSize.width / previewSize.height) * width);
scaledHeight = height;
scaleX = (float) scaledWidth / width;
scaleY = 1f;
}
camera.setParameters(parameters);
}
// calculate transformation matrix
Matrix matrix = new Matrix();
matrix.setScale(scaleX, scaleY);
textureView.setTransform(matrix);
}Stack Overflow用户
发布于 2013-06-25 15:58:55
您可以从onPreview()操作byte[] data。
我想你必须：
将它放入位图中，然后在Bitmap
- do中执行裁剪a stretching/resizing
- and
- 将
Bitmap传递给您的SurfaceView
这不是一种性能很好的方式。也许你可以直接操作byte[]，但是你必须处理像NV21这样的图片格式。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/17019588
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