Java tutorial
//package com.java2s; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.RectF; public class Main { private static final Bitmap.Config CONFIG = Bitmap.Config.RGB_565; public static Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth) { int sourceWidth = source.getWidth(); int sourceHeight = source.getHeight(); // Compute the scaling factors to fit the new height and width, respectively. // To cover the final image, the final scaling will be the bigger // of these two. float xScale = (float) newWidth / sourceWidth; float yScale = (float) newHeight / sourceHeight; float scale = Math.max(xScale, yScale); // Now get the size of the source bitmap when scaled float scaledWidth = scale * sourceWidth; float scaledHeight = scale * sourceHeight; // Let's find out the upper left coordinates if the scaled bitmap // should be centered in the new size give by the parameters float left = (newWidth - scaledWidth) / 2; float top = (newHeight - scaledHeight) / 2; // The target rectangle for the new, scaled version of the source bitmap will now // be RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight); // Finally, we create a new bitmap of the specified size and draw our new, // scaled bitmap onto it. Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, CONFIG); Canvas canvas = new Canvas(dest); Paint paint = new Paint(); paint.setAntiAlias(true); paint.setFilterBitmap(true); paint.setDither(true); canvas.drawBitmap(source, null, targetRect, paint); return dest; } }