88   std::vector<Real> data_;  variable
95   : height_(height), width_(width), data_(width*height, 0.0) {  in PGMImage()
108   for (int i = 0; i < data_.size(); ++i) {  in Set()
109     data_[i] = constant;  in Set()
142   CHECK(index < data_.size());  in MutablePixelFromLinearIndex()
143   return &data_[index];  in MutablePixelFromLinearIndex()
150   CHECK(index < data_.size());  in PixelFromLinearIndex()
151   return data_[index];  in PixelFromLinearIndex()
162   CHECK(data_.size() == image.data_.size());
163   for (int i = 0; i < data_.size(); ++i) {
164     data_[i] += image.data_[i];
171   for (int i = 0; i < data_.size(); ++i) {
172     data_[i] += a;
179   for (int i = 0; i < data_.size(); ++i) {
180     data_[i] *= a;
197     outputfile << static_cast<int>(data_[i] + 0.5) << ' ';  in WriteToFile()
257   data_.resize(num_pixels);  in ReadFromFile()
266       data_[i] = pixel_data;  in ReadFromFile()
287       data_[i] = pixel_data;  in ReadFromFile()
303   if (new_data.size() != data_.size()) {  in SetData()
306   std::copy(new_data.begin(), new_data.end(), data_.begin());  in SetData()
312   return data_;  in data()