安卓相機圖像壓縮

Question

我正在製作相機應用程序。我必須在照相機點擊服務器之後保存圖像，並且所拍攝圖像的大小始終非常大（以Mb爲單位）。所以我一直很難將大尺寸的圖像保存在服務器上。在保存之前有沒有壓縮圖像？

我必須只使用Android原生相機

感謝

Answer 1

另一種方法是直接做更小的圖片。優點是你使用較少的內存，但你可能需要在應用程序的另一部分有一個大的圖片。

這是可以做到如下：

public void surfaceChanged(SurfaceHolder holder, int format, int width, int height){ 
... 
    Camera.Parameters mParameters = mCamera.getParameters(); 
    List<Size> sizes = mParameters.getSupportedPictureSizes(); 
    Size optimalSize = getOptimalSize(sizes, width, height); 
    if (optimalSize != null && !mParameters.getPictureSize().equals(optimalSize)) 
     mParameters.setPictureSize(optimalSize.width, optimalSize.height); 
... 
} 

選擇最佳的尺寸，你可以使用任何你想要的標準。我試圖儘可能接近屏幕尺寸：

private Size getOptimalSize(List<Size> sizes, int w, int h){ 

    final double ASPECT_TOLERANCE = 0.05; 
    double targetRatio = (double) w/h; 
    if (sizes == null) 
     return null; 

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

    int targetHeight = h; 

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

    return optimalSize; 

} 

Answer 2

你需要真正上傳到服務器之前調整位圖。 該代碼返回一個調整大小的位圖。將位圖縮小到所需的寬度和所需的高度 - 這會導致圖像文件更小。

public static Bitmap getBitmapImages(final String imagePath, final int requiredWidth, final int requiredHeight) 
{ 
    System.out.println(" --- image_path in getBitmapForCameraImages --- "+imagePath+" - reqWidth & reqHeight "+requiredWidth+" "+requiredHeight); 
    Bitmap bitmap = null; 
    BitmapFactory.Options options = new BitmapFactory.Options(); 
    options.inScaled = true; 
    options.inJustDecodeBounds = true; 

    // First decode with inJustDecodeBounds=true to check dimensions 
    bitmap = BitmapFactory.decodeFile(imagePath, options); 

    // Calculate inSampleSize 
    options.inSampleSize = calculateInSampleSize(options, requiredWidth, requiredHeight); 

    options.inJustDecodeBounds = false; 

    // Decode bitmap with inSampleSize set 
    bitmap = BitmapFactory.decodeFile(imagePath, options); 

    return bitmap; 
} 

Answer 3

試試這個

  Bitmap bmp = (Bitmap) data.getExtras().get("data"); 

      ByteArrayOutputStream stream = new ByteArrayOutputStream(); 
      bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);