如何以1：1的比例获得Android Camera2？

Question

我的问题很简单：

如何获得一个Android android.hardware.Camera2以1：1分的比例，并没有像Instagram的变形？

我使用GoogeSamples项目android-Camera2Basic进行了测试。但是，当我以1：1的比例更改预览时，图像会变形。有没有人有这个想法？

Answer 1

谢谢@CommonsWare。

我遵循你的建议使用负边距（顶部和底部），它的工作原理。

为了做到这一点，我刚刚更新AutoFitTextureView的GoogeSamples项目android-Camera2Basic这样：

public class AutoFitTextureView extends TextureView { 

    //... 
    private boolean mWithMargin = false; 

    //... 

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
     super.onMeasure(widthMeasureSpec, widthMeasureSpec); 
     int width = MeasureSpec.getSize(widthMeasureSpec); 
     int height = MeasureSpec.getSize(heightMeasureSpec); 
     int margin = (height - width)/2; 

     if(!mWithMargin) { 
      mWithMargin = true; 
      ViewGroup.MarginLayoutParams margins = ViewGroup.MarginLayoutParams.class.cast(getLayoutParams()); 
      margins.topMargin = -margin; 
      margins.bottomMargin = -margin; 
      margins.leftMargin = 0; 
      margins.rightMargin = 0; 
      setLayoutParams(margins); 
     } 

     if (0 == mRatioWidth || 0 == mRatioHeight) { 
      setMeasuredDimension(width, height); 
     } else { 
      if (width < height) { 
       setMeasuredDimension(width, width * mRatioHeight/mRatioWidth); 
      } else { 
       setMeasuredDimension(height * mRatioWidth/mRatioHeight, height); 
      } 
     } 
    } 
} 

Answer 2

像这样创建自定义纹理观点：

public class AutoFitTextureView extends TextureView { 

    private int mCameraWidth = 0; 
    private int mCameraHeight = 0; 
    private boolean mSquarePreview = false; 

    public AutoFitTextureView(Context context) { 
     this(context, null); 
    } 

    public AutoFitTextureView(Context context, AttributeSet attrs) { 
     this(context, attrs, 0); 
    } 

    public AutoFitTextureView(Context context, AttributeSet attrs, int defStyle) { 
     super(context, attrs, defStyle); 
    } 

    public void setAspectRatio(int width, int height, boolean squarePreview) { 
     if (width < 0 || height < 0) { 
      throw new IllegalArgumentException("Size cannot be negative."); 
     } 
     mCameraWidth = width; 
     mCameraHeight = height; 
     mSquarePreview = squarePreview; 
     requestLayout(); 
    } 

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { 
     super.onMeasure(widthMeasureSpec, heightMeasureSpec); 
     int width = MeasureSpec.getSize(widthMeasureSpec); 
     int height = MeasureSpec.getSize(heightMeasureSpec); 
     if (0 == mCameraWidth || 0 == mCameraHeight) { 
      setMeasuredDimension(width, height); 
     } else { 
      /** 
      * Vertical orientation 
      */ 
      if (width < height) { 
       if (mSquarePreview) { 
        setTransform(squareTransform(width, height)); 
        setMeasuredDimension(width, width); 
       } else { 
        setMeasuredDimension(width, width * mCameraHeight/mCameraWidth); 
       } 
      } 
      /** 
      * Horizontal orientation 
      */ 
      else { 
       if (mSquarePreview) { 
        setTransform(squareTransform(width, height)); 
        setMeasuredDimension(height, height); 
       } else { 
        setMeasuredDimension(height * mCameraWidth/mCameraHeight, height); 
       } 
      } 
     } 
    } 

    private Matrix setupTransform(int sw, int sh, int dw, int dh) { 
     Matrix matrix = new Matrix(); 
     RectF src = new RectF(0, 0, sw, sh); 
     RectF dst = new RectF(0, 0, dw, dh); 
     RectF screen = new RectF(0, 0, dw, dh); 

     matrix.postRotate(-90, screen.centerX(), screen.centerY()); 
     matrix.mapRect(dst); 

     matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER); 
     matrix.mapRect(src); 

     matrix.setRectToRect(screen, src, Matrix.ScaleToFit.FILL); 
     matrix.postRotate(-90, screen.centerX(), screen.centerY()); 

     return matrix; 
    } 

    private Matrix squareTransform(int viewWidth, int viewHeight) { 
     Matrix matrix = new Matrix(); 

     if (viewWidth < viewHeight) { 
      MyLogger.log(AutoFitTextureView.class, "Horizontal"); 
      matrix.setScale(1, (float) mCameraHeight/(float) mCameraWidth, viewWidth/2, viewHeight/2); 
     } else { 
      MyLogger.log(AutoFitTextureView.class, "Vertical"); 
      matrix.setScale((float) mCameraHeight/(float) mCameraWidth, 1, viewWidth/2, viewHeight/2); 
     } 

     return matrix; 
    } 
} 

并调用调用setAspectRatio您在活动/片段的纹理视图。

if (mVideoSize.width > mVideoSize.height) { 
    mTextureView.setAspectRatio(mVideoSize.height, mVideoSize.width, true); 
} else { 
    mTextureView.setAspectRatio(mVideoSize.width, mVideoSize.height, true); 
} 
mCamera.setPreviewTexture(mTextureView.getSurfaceTexture()); 
mCamera.startPreview();