Java tutorial
//package com.java2s; //License from project: Apache License import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.DisplayMetrics; import android.util.TypedValue; public class Main { public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, int reqWidthInPixel, int reqHeightInPixel) { // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resId, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidthInPixel, reqHeightInPixel); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, resId, options); } public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, float reqWidthInDip, float reqHeightInDip) { int reqWidthInPixel = (int) dipToPixels(res, reqWidthInDip); int reqHeightInPixel = (int) dipToPixels(res, reqHeightInDip); // First decode with inJustDecodeBounds=true to check dimensions final BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resId, options); // Calculate inSampleSize options.inSampleSize = calculateInSampleSize(options, reqWidthInPixel, reqHeightInPixel); // Decode bitmap with inSampleSize set options.inJustDecodeBounds = false; return BitmapFactory.decodeResource(res, resId, options); } public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) { // Raw height and width of image final int height = options.outHeight; final int width = options.outWidth; int inSampleSize = 1; if (height > reqHeight || width > reqWidth) { final int halfHeight = height / 2; final int halfWidth = width / 2; // Calculate the largest inSampleSize value that is a power of 2 and keeps both // height and width larger than the requested height and width. while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) { inSampleSize *= 2; } } return inSampleSize; } public static float dipToPixels(Resources res, float dipValue) { DisplayMetrics metrics = res.getDisplayMetrics(); return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dipValue, metrics); } }