- ensure_j2k ();
-
- if (_j2k->precision(0) < 12) {
- int const shift = 12 - _j2k->precision (0);
- for (int c = 0; c < 3; ++c) {
- int* p = _j2k->data (c);
- for (int y = 0; y < _j2k->size().height; ++y) {
- for (int x = 0; x < _j2k->size().width; ++x) {
- *p++ <<= shift;
+ if (!_j2k || target_size != _j2k_target_size) {
+ int reduce = 0;
+
+ while (target_size && (_size.width / pow(2, reduce)) > target_size->width && (_size.height / pow(2, reduce)) > target_size->height) {
+ ++reduce;
+ }
+
+ --reduce;
+ reduce = max (0, reduce);
+ _j2k = dcp::decompress_j2k (const_cast<uint8_t*> (_data.data().get()), _data.size (), reduce);
+
+ if (_j2k->precision(0) < 12) {
+ int const shift = 12 - _j2k->precision (0);
+ for (int c = 0; c < 3; ++c) {
+ int* p = _j2k->data (c);
+ for (int y = 0; y < _j2k->size().height; ++y) {
+ for (int x = 0; x < _j2k->size().width; ++x) {
+ *p++ <<= shift;
+ }