如何將位圖從相機的10mb圖像壓縮到300kb beforw設置為Android中的imageview

Question

我有一些代碼：

Bitmap bitmap;
BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
bitmap = BitmapFactory.decodeFile(f.getAbsolutePath(),bitmapOptions); 

最終，位圖具有來自相機的圖像（我正在從高分辨率相機拍攝圖像），因此大小可能為10mb。

---

我正在嘗試做的事情：

我正在嘗試在imageview中設置位圖，如下所示

portfolioPicImgId.setImageBitmap(bitmap);

• 在此之前，我想將圖像壓縮到300kb，我該如何實現！
• 我看到了其他stackoverflow答案，但如何確切地指定為300kb

Answer 1

很難准確獲得300kb。 這取決於質量，每個像素包含4（32位）或2（16位）字節，這意味着圖像應包含75000像素（在32位圖像中）。 下一步，為簡單起見，將圖像比例取為1：1的圖像比例-sqrt（75000）〜274像素，我們得到274x274像素在ram中約為300kb。

您需要處理的所有數據都在選項中指定了寬度和高度。

Answer 2

你有嘗試過嗎？ ：

//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
    try {
        //Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(f),null,o);

        //The new size we want to scale to
        final int REQUIRED_SIZE=70;

        //Find the correct scale value. It should be the power of 2.
        int scale=1;
        while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE)
            scale*=2;

        //Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize=scale;
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {}
    return null;
}

Answer 3

只需在下面的函數中傳遞圖像的路徑

    public Bitmap get_Reduce_bitmap_Picture(String imagePath) {

    int ample_size = 16;
     // change ample_size to 32 or any power of 2 to increase or decrease bitmap size of image


    Bitmap bitmap = null;
    BitmapFactory.Options bitoption = new BitmapFactory.Options();
    bitoption.inSampleSize = ample_size;

    Bitmap bitmapPhoto = BitmapFactory.decodeFile(imagePath, bitoption);

    ExifInterface exif = null;
    try {
        exif = new ExifInterface(imagePath);
    } catch (IOException e) {
        // Auto-generated catch block
        e.printStackTrace();
    }
    int orientation = exif
            .getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
    Matrix matrix = new Matrix();

    if ((orientation == 3)) {
        matrix.postRotate(180);
        bitmap = Bitmap.createBitmap(bitmapPhoto, 0, 0,
                bitmapPhoto.getWidth(), bitmapPhoto.getHeight(), matrix,
                true);

    } else if (orientation == 6) {
        matrix.postRotate(90);
        bitmap = Bitmap.createBitmap(bitmapPhoto, 0, 0,
                bitmapPhoto.getWidth(), bitmapPhoto.getHeight(), matrix,
                true);

    } else if (orientation == 8) {
        matrix.postRotate(270);
        bitmap = Bitmap.createBitmap(bitmapPhoto, 0, 0,
                bitmapPhoto.getWidth(), bitmapPhoto.getHeight(), matrix,
                true);

    } else {
        matrix.postRotate(0);
        bitmap = Bitmap.createBitmap(bitmapPhoto, 0, 0,
                bitmapPhoto.getWidth(), bitmapPhoto.getHeight(), matrix,
                true);

    }

    return bitmap;

}