Here you can find the source of decodeBitmap(Resources res, int resId)
public static Bitmap decodeBitmap(Resources res, int resId)
//package com.java2s; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; public class Main { public static Bitmap decodeBitmap(Resources res, int resId) { return BitmapFactory.decodeResource(res, resId); }//from w ww .j ava 2 s .c om public static Bitmap decodeBitmap(Resources res, int resId, int reqWidth, int reqHeight) { final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resId, options); options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); options.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, resId, options); } private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { final int heightRatio = Math.round((float) height / (float) reqHeight); final int widthRatio = Math.round((float) width / (float) reqWidth); inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio; } return inSampleSize; } }