Android摄像头preVIEW错误的宽高比 [英] android camera preview wrong aspect ratio

问题描述

我创建了一个基于教程的一个摄像头应用程序。我用的是preVIEW类是由API-演示相机preVIEW。我从加修改<一个href="http://stackoverflow.com/questions/3841122/android-camera-$p$pview-is-sideways/5110406#5110406">here （preVIEW由90°始终旋转）。因此，这是我怎么设置preVIEW尺寸：

i created a camera app based on tutorial. the preview class i use is from api-Demos "CameraPreview". I added a modification from here (preview was always rotated by 90°). So this is how i set preview size:

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
    // Now that the size is known, set up the camera parameters and begin
    // the preview.
    Camera.Parameters parameters = mCamera.getParameters();
    Display display = ((WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();

    if (display.getRotation() == Surface.ROTATION_0) {
        parameters.setPreviewSize(mPreviewSize.height, mPreviewSize.width);
        mCamera.setDisplayOrientation(90);
    }

    if (display.getRotation() == Surface.ROTATION_90) {
        parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
    }

    if (display.getRotation() == Surface.ROTATION_180) {
        parameters.setPreviewSize(mPreviewSize.height, mPreviewSize.width);
    }

    if (display.getRotation() == Surface.ROTATION_270) {
        parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
        mCamera.setDisplayOrientation(180);
    }
    parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);

    requestLayout();

    mCamera.setParameters(parameters);
    mCamera.startPreview();
}

不过，preVIEW显示有错误的纵横比。是因为code以上的布局我使用的可能是因为或者：？

But the Preview is displayed with wrong aspect ratio. Is it because of the code above or probably because of the layout i use?:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<Button
    android:id="@+id/button_capture"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true" 
    android:text="@string/capture" />

<FrameLayout
    android:id="@+id/camera_preview"
    android:layout_width="100dp"
    android:layout_height="match_parent"/>

那么如何得到正确的纵横比例是多少？先谢谢了。

So how to get the correct aspect ratio? Thanks in advance.

P.S。我读了答案： Android摄像头preVIEW异样的目光 但是，这不是为我工作。

P.S. i read the answer from: Android camera preview look strange But this isn't working for me.

推荐答案

试着改变preVIEW尺寸的增加这个功能：

Try changing the preview sizes with adding this function:

private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
    final double ASPECT_TOLERANCE = 0.05;
    double targetRatio = (double) w/h;

    if (sizes==null) return null;

    Camera.Size optimalSize = null;

    double minDiff = Double.MAX_VALUE;

    int targetHeight = h;

    // Find size
    for (Camera.Size size : sizes) {
        double ratio = (double) size.width / size.height;
        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;
}

和这些优化的值设置大小：

And the setting the sizes from these optimized values:

List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
Camera.Size optimalSize = getOptimalPreviewSize(sizes, getResources().getDisplayMetrics().widthPixels, getResources().getDisplayMetrics().heightPixels);

parameters.setPreviewSize(optimalSize.width, optimalSize.height);

我希望这个作品：）

I hope this works :)

最好的问候

Henric

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