Android Bitmap Scaling
call it in main class
BitmapScaler scaler = new BitmapScaler(getResources(), R.drawable.moorwen, newWidth);
imageView.setImageBitmap(scaler.getScaled())
//----------------------------------------
class BitmapScaler {
private static class Size {
int sample;
float scale;
}
private Bitmap scaled;
BitmapScaler(Resources resources, int resId, int newWidth)
throws IOException {
Size size = getRoughSize(resources, resId, newWidth);
roughScaleImage(resources, resId, size);
scaleImage(newWidth);
}
BitmapScaler(File file, int newWidth) throws IOException {
InputStream is = null;
try {
is = new FileInputStream(file);
Size size = getRoughSize(is, newWidth);
try {
is = new FileInputStream(file);
roughScaleImage(is, size);
scaleImage(newWidth);
} finally {
is.close();
}
} finally {
is.close();
}
}
BitmapScaler(AssetManager manager, String assetName, int newWidth)
throws IOException {
InputStream is = null;
try {
is = manager.open(assetName);
Size size = getRoughSize(is, newWidth);
try {
is = manager.open(assetName);
roughScaleImage(is, size);
scaleImage(newWidth);
} finally {
is.close();
}
} finally {
is.close();
}
}
Bitmap getScaled() {
return scaled;
}
private void scaleImage(int newWidth) {
int width = scaled.getWidth();
int height = scaled.getHeight();
float scaleWidth = ((float) newWidth) / width;
float ratio = ((float) scaled.getWidth()) / newWidth;
int newHeight = (int) (height / ratio);
float scaleHeight = ((float) newHeight) / height;
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
scaled = Bitmap.createBitmap(scaled, 0, 0, width, height, matrix, true);
}
private void roughScaleImage(InputStream is, Size size) {
Matrix matrix = new Matrix();
matrix.postScale(size.scale, size.scale);
BitmapFactory.Options scaledOpts = new BitmapFactory.Options();
scaledOpts.inSampleSize = size.sample;
scaled = BitmapFactory.decodeStream(is, null, scaledOpts);
}
private void roughScaleImage(Resources resources, int resId, Size size) {
Matrix matrix = new Matrix();
matrix.postScale(size.scale, size.scale);
BitmapFactory.Options scaledOpts = new BitmapFactory.Options();
scaledOpts.inSampleSize = size.sample;
scaled = BitmapFactory.decodeResource(resources, resId, scaledOpts);
}
private Size getRoughSize(InputStream is, int newWidth) {
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(is, null, o);
Size size = getRoughSize(o.outWidth, o.outHeight, newWidth);
return size;
}
private Size getRoughSize(Resources resources, int resId, int newWidth) {
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeResource(resources, resId, o);
Size size = getRoughSize(o.outWidth, o.outHeight, newWidth);
return size;
}
private Size getRoughSize(int outWidth, int outHeight, int newWidth) {
Size size = new Size();
size.scale = outWidth / newWidth;
size.sample = 1;
int width = outWidth;
int height = outHeight;
int newHeight = (int) (outHeight / size.scale);
while (true) {
if (width / 2 < newWidth || height / 2 < newHeight) {
break;
}
width /= 2;
height /= 2;
size.sample *= 2;
}
return size;
}
}
