纵向模式下的相机横向预览

Camera landscape preview in portrait mode

我有一个对话框设计,相机预览在纵向模式下应该是横向的(见图片)。我通过 getOptimalPreviewSize() 正确选择了预览大小,当我不使用 setDisplayOrientation(90) 时,我得到这个:

当我使用 setDisplayOrientation(90) 时,我得到这个:

有人知道如何解决吗? android能做那种事吗?

回答(感谢 Eddy Talvala):
由于 xml 中的摄像头视图是水平的,因此您无法纵向处理整个摄像头图片,因此您应该裁剪。我决定水平放置并裁剪底部的所有内容:

|           |
| _________ |   _____
||         ||  |     |
||         ||  | ^-^ |
||  ______ ||  | \_/ |
|| | ^-^  |||  |  |  |    
|| |_\_/_ |||  |__|__|
||   image ||   sensor
||         ||
||         ||
||_________||
||  < O [] ||
|___________|
    device

您应该使用 TextureView 指定适合和裁剪的矩阵。类似的东西 (kotlin):

fun camInit() {
    val camParam = camera.parameters
    val optimalSize = getOptimalPortraitPreviewSize(camParam.supportedPreviewSizes, width, height)

    camParam.setPreviewSize(optimalSize.width, optimalSize.height)
    camera.parameters = camParam

    camera.setPreviewTexture(surface)

    val scaleDelta = optimalSize.height - preview.width // for portrait
    val scaleY: Float = (optimalSize.width.toFloat() - scaleDelta) / preview.height // for portrait

    val matrix = Matrix()
    matrix.setScale(1f, scaleY)    // 1f cause we fit horizontally

    preview.setTransform(matrix)

    camera.startPreview()
}

请注意,对于纵向模式,您应该使用特定的 getOptimalProtraitPreviewSize(),因为每个人都使用标准函数来获得相机预览的最佳尺寸(使用 ASPECT_TOLERANCE 和其他东西)可以 return 你一个尺寸分辨率小。尝试这样的事情:

fun getOptimalPortraitPreviewSize(sizes: List<Camera.Size>, previewWidth: Int) {

    var selectedSize: Camera.Size = sizes[0]

    for (size in sizes) {
        // use size's height cause of portrait
        val currentSizeWidthDelta = abs(size.height - previewWidth)
        val selectedSizeWidthDelta = abs(selectedSize.height - previewWidth)
        if (currentSizeWidthDelta < selectedSizeWidthDelta) selectedSize = size
    }

    return selectedSize
}

图像传感器的长边与设备的长边对齐。

(bad ascii art):
____________
|           |
| _________ |   _____
||         ||  |     |
||         ||  |     |
||         ||  |     |
||         ||  |     |
||         ||  |_____|
||         ||   sensor
||         ||   physical 
||         ||   orientation
||_________||
||  < O [] ||
|___________|
    device

鉴于此,您无法像这样绘制图像:

_____________
|           |
| _________ |   _____
||         ||  |     |
||         ||  |     |
||  ______ ||  |     |
|| |      |||  |     |
|| |______|||  |_____|
||   image ||   sensor
||         ||
||         ||
||_________||
||  < O [] ||
|___________|
    device

除非您旋转图像(在这种情况下向上不是向上):

_____________
|           |
| _________ |   _____
||         ||  |     |
||         ||  | ^-^ |
||  ______ ||  | \_/ |
|| | <-\__|||  |  |  |    
|| |_<-/__|||  |__|__|
||   image ||   sensor
||         ||
||         ||
||_________||
||  < O [] ||
|___________|
    device

或者你水平拉伸图像,看起来很糟糕:

_____________
|           |
| _________ |   _____
||         ||  |     |
||         ||  | ^-^ |
||  ______ ||  | \_/ |
|| | ^___^|||  |  |  |    
|| |___|__|||  |__|__|
||   image ||   sensor
||         ||
||         ||
||_________||
||  < O [] ||
|___________|
    device

或者您裁剪图像的一部分,这会大大降低 FOV:

_____________
|           |
| _________ |   _____
||         ||  |     |
||         ||  | ^-^ |
||  ______ ||  | \_/ |
|| | ^-^  |||  |  |  |    
|| |_\_/__|||  |__|__|
||   image ||   sensor
||         ||
||         ||
||_________||
||  < O [] ||
|___________|
    device

因为图像传感器是横向的,而 phone 是横向的,所以如果不发生这三种情况之一,就无法在纵向中放置横向预览 UI。您要么需要在人像 UI 中进行人像预览,要么需要裁剪图像。这不是 Android 的限制,它只是几何形状的限制。

如果你想裁剪,你可能想要将相机数据发送到 SurfaceTexture,然后在 OpenGL 中裁剪,如果你想要实时预览。

如果您使用的是 Camera2 API。当通过 ChooseOptimalSize 获取 mPreviewSize 时,您可以交换宽度和高度。 (宽度和高度来自您的视图)。 然后

textureView.setAspectRatio(mPreviewSize.Height, mPreviewSize.Width);

创建预览会话时

texture.SetDefaultBufferSize(mPreviewSize.Width, mPreviewSize.Height);

然后你将预览正常图像

感谢@Eddy Talvala 和@blinker!我使用我的功能来正确更新任何方向的尺寸:

  public void invalidateSize(TextureView textureView) {
        Point cameraResolution = getCameraResolution();
        int previewRotation = getPreviewRotation();

        // Camera and preview on screen in the opposite orientation
        if (previewRotation == 90 || previewRotation == 270) {
            //noinspection SuspiciousNameCombination
            cameraResolution = new Point(cameraResolution.y, cameraResolution.x);
        }

        float cameraAspectRatio = cameraResolution.x / (float) cameraResolution.y;
        float textureAspectRatio = textureView.getWidth() / (float) textureView.getHeight();

        float scaleX = cameraAspectRatio / textureAspectRatio;
        float scaleY = textureAspectRatio / cameraAspectRatio;

        if (scaleX > scaleY) {
            scaleY = 1;
        } else {
            scaleX = 1;
        }

        Matrix matrix = new Matrix();
        matrix.setScale(scaleX, scaleY,
                textureView.getWidth() / 2f, textureView.getHeight() / 2f);

        textureView.setTransform(matrix);
}