如何将图像(位图)调整为给定大小？

Question

如何以编程方式将图像(位图)调整为800*480？我已经在我的应用程序中检索到了大约1MB的图片,我需要将其缩小到800*480我已经加载了该图片并对其进行了压缩但是我该如何缩小它:

ByteArrayOutputStream bos = new ByteArrayOutputStream(8192);
photo.compress(CompressFormat.JPEG, 25, bos); 

Answer 1

Bitmap scaledBitmap = scaleDown(realImage, MAX_IMAGE_SIZE, true);

缩小方法:

public static Bitmap scaleDown(Bitmap realImage, float maxImageSize,
        boolean filter) {
    float ratio = Math.min(
            (float) maxImageSize / realImage.getWidth(),
            (float) maxImageSize / realImage.getHeight());
    int width = Math.round((float) ratio * realImage.getWidth());
    int height = Math.round((float) ratio * realImage.getHeight());

    Bitmap newBitmap = Bitmap.createScaledBitmap(realImage, width,
            height, filter);
    return newBitmap;
}

Answer 2

 Bitmap yourBitmap;
 Bitmap resized = Bitmap.createScaledBitmap(yourBitmap, newWidth, newHeight, true);

要么:

 resized = Bitmap.createScaledBitmap(yourBitmap,(int)(yourBitmap.getWidth()*0.8), (int)(yourBitmap.getHeight()*0.8), true);

Answer 3

您可以使用canvas.drawBitmap并使用提供矩阵来缩放位图,例如:

public static Bitmap scaleBitmap(Bitmap bitmap, int wantedWidth, int wantedHeight) {
        Bitmap output = Bitmap.createBitmap(wantedWidth, wantedHeight, Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        Matrix m = new Matrix();
        m.setScale((float) wantedWidth / bitmap.getWidth(), (float) wantedHeight / bitmap.getHeight());
        canvas.drawBitmap(bitmap, m, new Paint());

        return output;
    }