LetterTileProvider.java 文件源码

/**
 * Creates a Bitmap object from a Drawable object.
 */
private static Bitmap drawableToBitmap(Drawable dr) {
    // Attempt to retrieve any existing Bitmap, if possible
    if (dr instanceof BitmapDrawable) {
        BitmapDrawable bDr = (BitmapDrawable)dr;
        if (bDr.getBitmap() != null) {
            return bDr.getBitmap();
        }
    }

    // Create a valid blank Bitmap
    final Bitmap bitmap;
    if (dr.getIntrinsicWidth() <= 0 || dr.getIntrinsicHeight() <= 0) {
        // Single color bitmap will be create of 1x1 pixel
        bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888);
    } else {
        bitmap = Bitmap.createBitmap(dr.getIntrinsicWidth(),
                dr.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
    }

    // Use our Canvas to draw the Drawable onto the Bitmap
    Canvas canvas = new Canvas(bitmap);
    dr.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
    dr.draw(canvas);
    return bitmap;
}