Android zxing - 人像相机预览/surfaceview 被拉伸/扭曲

Question

我已设法使用此处的答案将相机预览旋转为纵向： http://code.google.com/p/zxing/issues/detail?id=178#c46

但是预览本身被拉伸/扭曲 - 高度似乎被拉伸以填充框（但可能是宽度对于屏幕来说太大并且被挤压以适应）

有什么方法可以“包装”内容而不是使其拉伸以适应表面视图？

编辑：我通过更改“CameraConfigurationManager”中的“findBestPreviewSizeValue”方法并反转 X 和 Y 点（感谢 sean owen 提供下面的指针！）对其进行了排序，代码如下：

private static Point findBestPreviewSizeValue(CharSequence previewSizeValueString,
  Point screenResolution) {
int bestX = 0;
int bestY = 0;
int diff = Integer.MAX_VALUE;
for (String previewSize : COMMA_PATTERN.split(previewSizeValueString)) {

  previewSize = previewSize.trim();
  int dimPosition = previewSize.indexOf('x');
  if (dimPosition < 0) {
    Log.w(TAG, "Bad preview-size: " + previewSize);
    continue;
  }

  int newX;
  int newY;
  try {
    newY = Integer.parseInt(previewSize.substring(0, dimPosition));
    newX = Integer.parseInt(previewSize.substring(dimPosition + 1));
    //original:
    //newX = Integer.parseInt(previewSize.substring(0, dimPosition));
    //newY = Integer.parseInt(previewSize.substring(dimPosition + 1));
  } catch (NumberFormatException nfe) {
    Log.w(TAG, "Bad preview-size: " + previewSize);
    continue;
  }

  int newDiff = Math.abs(newX - screenResolution.x) + Math.abs(newY - screenResolution.y);
  if (newDiff == 0) {
    bestX = newY;
    bestY = newX;
    //original:
    //bestX = newX;
    //bestY = newY;
    break;
  } else if (newDiff < diff) {
    bestX = newY;
    bestY = newX;
    //original:
    //bestX = newX;
    //bestY = newY;
    diff = newDiff;
  }

}

if (bestX > 0 && bestY > 0) {
  return new Point(bestX, bestY);
}
return null;
}

Answer 1

变形的原因可能是相机的预览纵横比与显示器的纵横比不匹配。

大部分手机屏幕的宽高比是4:3，如2560x1440、1920x1080等。当您使用 parameter.setPreviewSize(width,height) 设置相机预览尺寸时，如果 height : width 的值不等于您手机屏幕的纵横比，相机的图片将变形以填满屏幕。

Answer 2

我设法通过更改CameraConfigurationManager.java 中的以下代码来实现此功能：

float screenAspectRatio = (float) screenResolution.x / (float) screenResolution.y;

收件人：

float screenAspectRatio = (float) screenResolution.y / (float) screenResolution.x;

与

float aspectRatio = (float) maybeFlippedWidth / (float) maybeFlippedHeight;

到：

float aspectRatio = (float) maybeFlippedHeight / (float) maybeFlippedWidth;

我在这篇文章旁边做了这个：Zxing Camera in Portrait mode on Android

希望这对其他人有所帮助。

Answer 3

你可以通过这个函数获取Priview大小：

私有列表 mSupportedPreviewSizes = parameters.getSupportedPreviewSizes();

if (mSupportedPreviewSizes != null) {
                mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
            }

private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
            final double ASPECT_TOLERANCE = 0.1;
            double targetRatio = (double) h / w;

            if (sizes == null)
                return null;

            Camera.Size optimalSize = null;
            double minDiff = Double.MAX_VALUE;

            int targetHeight = h;

            for (Camera.Size size : sizes) {
                double ratio = (double) size.height / size.width;
                if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                    continue;

                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }

            if (optimalSize == null) {
                minDiff = Double.MAX_VALUE;
                for (Camera.Size size : sizes) {
                    if (Math.abs(size.height - targetHeight) < minDiff) {
                        optimalSize = size;
                        minDiff = Math.abs(size.height - targetHeight);
                    }
                }
            }

            return optimalSize;
        }


            float ratio;
            if (mPreviewSize.height >= mPreviewSize.width)
                ratio = (float) mPreviewSize.height / (float) mPreviewSize.width;
            else
                ratio = (float) mPreviewSize.width / (float) mPreviewSize.height;

            after getting ratio set your size in 

            protected void onMeasure(int widthMeasureSpec, int                              heightMeasureSpec) {

            setMeasuredDimension((int) (width * ratio), height);
            }

Answer 4

我有同样的问题，但我可以通过反转 findBestPreviewSizeValue 中 CameraConfigurationManager.java 文件的纵横比来解决它

 float screenAspectRatio = (float) screenResolution.x / (float) screenResolution.y;

到这里

 float screenAspectRatio = (float) screenResolution.y / (float) screenResolution.x;

我在这里找到了解决方案。

http://bighow.net/4660010-Android_zxing___portrait_camera_preview_surfaceview_is_stretched_warped.html

Answer 5

除了将预览设置为纵向模式外，您还需要做更多的工作才能使其正常工作。例如，您需要选择合适的预览尺寸，因为它是纵向的，而不是横向的。

包装肯定是不可取的吗？不，你不能让它包装；它总是将整个预览图像投射到SurfaceView，如果需要，可以拉伸。我想你可以重新实现很多代码来做一些不同的事情，但这会很困难。