问题描述
我试图直接使用camera api捕获照片,但这是我的预览:
I'm trying to capture photos directly using the camera api, but this is the preview I got:
&这是调用 takePicture()
之后拍摄的图片,比预览本身大:
& this is the image taken after calling takePicture()
which is bigger than the preview itself:
(注意:我裁剪了前面2张照片,以提高问题的可读性,并保持原样的宽度)
(note: I cropped the height of the previous 2 photos to enhance question readability, & kept the width as is)
我使用此实用程序方法选择最佳最佳预览大小开始相机预览之前:
I'm using this utility method to choose best optimal preview size before starting the camera preview:
public static Camera.Size getBestAspectPreviewSize(int displayOrientation,
int width,
int height,
Camera.Parameters parameters) {
double targetRatio = (double) width / height;
Camera.Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
if (displayOrientation == 90 || displayOrientation == 270) {
targetRatio = (double) height / width;
}
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
Collections.sort(sizes,
Collections.reverseOrder(new SizeComparator()));
for (Camera.Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) < minDiff) {
optimalSize = size;
minDiff = Math.abs(ratio - targetRatio);
}
if (minDiff < 0.0d) {
break;
}
}
return (optimalSize);
}
&这种方法选择合适的图片大小:
& this method to choose a suitable picture size:
public static Camera.Size getBiggestSafePictureSize(Camera.Parameters parameters) {
Camera.Size result = null;
long used = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
long availableMemory = Runtime.getRuntime().maxMemory() - used;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
int newArea = size.width * size.height;
long neededMemory = newArea * 4 * 4; // newArea * 4 Bytes/pixel * 4 needed copies of the bitmap (for safety :) )
if (neededMemory > availableMemory)
continue;
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
if (newArea > resultArea) {
result = size;
}
}
}
return (result);
}
&这是布局中的相机预览元素:
& this is the camera preview element in the layout:
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/cameraPreview"></FrameLayout>
&我正在中创建相机预览本身
& I'm following the official documentation for creating the camera preview itself
那么,如何强制相机预览显示准确的照片?
So, how to force the camera preview to show the exact photo that will be taken?
推荐答案
最后我发现:
根据&我引用:
according to this answer & I quote:
我们需要找到一个预览大小图片尺寸(均为 4:3 宽高比),以便能够利用相机的全角度,因此我更改了我的代码:
So we need to find a preview size & a picture size, both with 4:3 aspect ratio to be able to utilize the full angle of the camera, so I changed my code like this:
public static Camera.Size determineBestPreviewSize(Camera.Parameters parameters) {
List<Camera.Size> sizes = parameters.getSupportedPreviewSizes();
return determineBestSize(sizes);
}
public static Camera.Size determineBestPictureSize(Camera.Parameters parameters) {
List<Camera.Size> sizes = parameters.getSupportedPictureSizes();
return determineBestSize(sizes);
}
protected static Camera.Size determineBestSize(List<Camera.Size> sizes) {
Camera.Size bestSize = null;
long used = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
long availableMemory = Runtime.getRuntime().maxMemory() - used;
for (Camera.Size currentSize : sizes) {
int newArea = currentSize.width * currentSize.height;
long neededMemory = newArea * 4 * 4; // newArea * 4 Bytes/pixel * 4 needed copies of the bitmap (for safety :) )
boolean isDesiredRatio = (currentSize.width / 4) == (currentSize.height / 3);
boolean isBetterSize = (bestSize == null || currentSize.width > bestSize.width);
boolean isSafe = neededMemory < availableMemory;
if (isDesiredRatio && isBetterSize && isSafe) {
bestSize = currentSize;
}
}
if (bestSize == null) {
return sizes.get(0);
}
return bestSize;
}
这篇关于Android:拍摄的照片比预览大的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!