getSupportedPictureSize（）返回实际上并非Nexus4支持的值 [英] getSupportedPictureSize() returns a value which is not actually supported by Nexus4

问题描述

我纷纷伸出SurfaceView显示摄像头输入一个非常简单的摄像头应用程序。为了找到最佳的preVIEW大小为每​​个设备，我用这个样本code这是用在几乎所有的开源应用程序的摄像头我都看到：

I have extended a SurfaceView for displaying the camera feed for a very simple camera application. To find the optimal preview size for each device, I used this sample code which is used in almost all the open source camera apps I have seen:

    List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
    double minDiff = Double.MAX_VALUE;
    for (Camera.Size size : sizes) {
        if (Math.abs(size.width - width) < minDiff) {
        screenWidth = size.width;
        screenHeight = size.height;
        minDiff = Math.abs(size.width - width);
        }
    }

一切完美了这一点。

Everything works perfectly up to this point.

现在，由于应用程序的性质，我必须保持在内存中的两个位图在一个会话过程，并为简单起见（避免在测试过程中的内存问题）我用同样的$ C $下图片大小（取代了getSupported previewSizes（）与getSupportedPictureSizes（））。一切的伟大工程的大部分设备，虽然我已经决定选择最佳的图像大小为每个设备一些其他的方式。

Now, due to the nature of the application, I have to keep two bitmaps in the memory during the course of a session and for the sake of simplicity(avoiding memory issues during testing) I used the same code for the PICTURE SIZE(replaced the getSupportedPreviewSizes() with getSupportedPictureSizes()). Everything works great on most of the devices though I have to decide some other way to choose the optimum picture size for each device.

近日，在测试的的Nexus 4设备上，这上面的循环未能选择最佳的图像大小。经调查，我发现了getSupportedPictureSizes（）函数返回一个值，也就是1280 * 960这是不实际的的Nexus 4摄像头的支持。那么，一个人如何解决这个问题？我的意思是，是不是这个功能应该只返回该设备的摄像头支持这些价值观？我相信还会有其他设备，我就不能来测试相同的问题。任何线索，如何这个问题应该得到解决？

Recently, while testing on an Nexus 4 device, this above loop failed in choosing the optimum picture size. Upon investigation, I found out that the getSupportedPictureSizes() functions returns a value i.e 1280*960 which is not actually supported by the Nexus 4 camera. So, how does one solve this issue? I mean, isn't this function supposed to ONLY return those values which the CAMERA of the device supports? I am sure there will be other devices with the same issue which I won't be able to test on. Any clues as to how this issue should be resolved?

更新： 发生了什么是它不接受任何错误，它返回被扭曲的图像错误的参数，我将努力让图片在这里。另外，还有一些不运行时异常。

UPDATE: Whats happening is that it accepts the wrong parameter without any error and the image that it returns is distorted, I will try to get a picture here as well. Also, there are no runtime exceptions.

推荐答案

我有一个LG清醒（型号为VS840 4G）同样的问题。基本上， getSupportedPictureSizes（）返回这些大小：

I have the same problem on an LG Lucid (model number VS840 4G). Basically, getSupportedPictureSizes() returns these sizes:

Size        Aspect Ratio
2560x1920   (1.3333333333333333)
3072x1728   (1.7777777777777777)
2048x1536   (1.3333333333333333)
2304x1296   (1.7777777777777777)
1536x864    (1.7777777777777777)
1280x960    (1.3333333333333333)
640x480     (1.3333333333333333)

如果我们称之为 setPictureSize（）与任何尺寸的1.7纵横比，摄像头硬件不引发错误，但它返回的是扭曲的图像：

If we call setPictureSize() with any of the sizes with a 1.7 aspect ratio, the camera hardware throws no errors, but it returns an image that is distorted:

我尝试了一些技术，让摄像头驱动承认这个尺寸并没有真正的支持，包括检查 getPictureSize的结果（）和 getSupportedPictureFormats（）呼叫后 setParameters（）。我无法找到任何东西，一语道破了这种行为。

I tried a number of techniques to get the camera driver to admit this size was not really supported, including checking the result of getPictureSize() and getSupportedPictureFormats() after calling setParameters(). I couldn't find anything that gave away this behavior.

要解决这个问题，我们现在模仿股票相机应用程序的行为：我们试图找到从 getSupportedPictureSizes一个preferred大小（）名单前回落至选择的最大（为计算由宽*高）。由于preferred尺寸都具有的高宽比1.333（4：3），此工作解决问题此设备上

To work around this, we now mimic the behavior of the stock Camera app: we attempt to find a "preferred" size from the getSupportedPictureSizes() list before falling back to selecting the largest (as computed by width * height). Since the preferred sizes all have an aspect ratio of 1.333 (4:3), this works around the issue on this device.

请参阅相机的应用程序源代码<一href="https://android.googlesource.com/platform/packages/apps/Camera.git/+/master/src/com/android/camera/CameraSettings.java">where它将该值设置（111线）和<一href="https://android.googlesource.com/platform/packages/apps/Camera.git/+/android-cts-2.3_r12/res/values/arrays.xml">hard$c$cd确定其大小prefers （63行）的确切落实。

See the Camera app source where it sets the value (line 111) and the hardcoded sizes it prefers (line 63) for the exact implementation.

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