[j.833] correct Tiff r/w, fix Galaxi example read-in (#833) (Closes #833)

Merging branch 'j.833'  into 'main'.

See merge request !2132

Device/IO/ReadWriteTiff.cpp

@@ -102,13 +102,10 @@ Datafield* Util::RW::readTiff(std::istream& input_stream)
 
     //... Read data.
 
-    const size_t width = (size_t)w;
-    const size_t height = (size_t)h;
-
     ASSERT(0 == bitsPerSample % 8);
     uint16_t bytesPerSample = bitsPerSample / 8;
     tmsize_t buf_size = TIFFScanlineSize(tiffstream);
-    tmsize_t expected_size = bytesPerSample * width;
+    tmsize_t expected_size = bytesPerSample * w;
     if (buf_size != expected_size)
         throw std::runtime_error("Cannot read TIFF file: wrong scanline size" + ref_to_doc);
 
@@ -117,25 +114,19 @@ Datafield* Util::RW::readTiff(std::istream& input_stream)
         throw std::runtime_error("Cannot read TIFF file: failed allocating buffer" + ref_to_doc);
 
     auto data = std::make_unique<Datafield>(
-        std::vector<const Scale*>{newEquiDivision("u (bin)", width, 0.0, double(width)),
-                                  newEquiDivision("v (bin)", height, 0.0, double(height))});
+        std::vector<const Scale*>{newEquiDivision("u (bin)", w, 0.0, double(w)),
+                                  newEquiDivision("v (bin)", h, 0.0, double(h))});
 
     std::vector<int8_t> line_buf;
     line_buf.resize(buf_size, 0);
 
-    std::vector<unsigned> axes_indices(2);
-
-    for (uint32_t row = 0; row < (uint32_t)height; row++) {
+    for (uint32_t row = 0; row < h; row++) {
         if (TIFFReadScanline(tiffstream, buf, row) < 0)
             throw std::runtime_error("Cannot read TIFF file: error in scanline." + ref_to_doc);
 
         memcpy(&line_buf[0], buf, buf_size);
 
-        for (unsigned col = 0; col < width; ++col) {
-            axes_indices[0] = col;
-            axes_indices[1] = static_cast<unsigned>(height) - 1 - row;
-            size_t global_index = data->frame().toGlobalIndex(axes_indices);
-
+        for (unsigned col = 0; col < w; ++col) {
             void* incoming = &line_buf[col * bytesPerSample];
             double sample = 0;
 
@@ -174,7 +165,7 @@ Datafield* Util::RW::readTiff(std::istream& input_stream)
                                          + ref_to_doc);
             }
 
-            (*data)[global_index] = sample;
+            (*data)[(h - 1 - row) * w + col] = sample;
         }
     }
     _TIFFfree(buf);
@@ -223,14 +214,9 @@ void Util::RW::writeTiff(const Datafield& data, std::ostream& output_stream)
 
     std::vector<sample_t> line_buf;
     line_buf.resize(m_width, 0);
-    std::vector<unsigned> axes_indices(2);
     for (unsigned row = 0; row < (uint32_t)m_height; row++) {
-        for (unsigned col = 0; col < line_buf.size(); ++col) {
-            axes_indices[0] = col;
-            axes_indices[1] = static_cast<unsigned>(m_height) - 1 - row;
-            const size_t global_index = data.frame().toGlobalIndex(axes_indices);
-            line_buf[col] = static_cast<sample_t>(data[global_index]);
-        }
+        for (unsigned col = 0; col < line_buf.size(); ++col)
+            line_buf[col] = static_cast<sample_t>(data[(m_height - 1 - row) * m_width + col]);
         memcpy(buf, &line_buf[0], buf_size);
 
         if (TIFFWriteScanline(tiffstream, buf, row) < 0)