Rename io fodler to export folder, add import array fro file using Op…

…enCV imread

HighMap/include/highmap/export.hpp

@@ -243,6 +243,21 @@ void export_vector_glyph_png_16bit(const std::string fname,
                                    const float       scale = 0.05f,
                                    const uint        seed = 0);
 
+/**
+ * @brief Reads an image file and converts it to a 2D array.
+ *
+ * This function uses the OpenCV `imread` function to load an image from the
+ * specified file. The supported file formats are those recognized by OpenCV's
+ * `imread` function, such as JPEG, PNG, BMP, and others. If the image is in
+ * color, it is automatically converted to grayscale using the built-in OpenCV
+ * codec converter. This conversion process may introduce artifacts depending on
+ * the image's original format and content.
+ *
+ * @param fname The name of the image file to be read.
+ * @return Array A 2D array containing the pixel values of the grayscale image.
+ */
+Array read_to_array(std::string fname);
+
 /**
  * @brief Read an 8bit grayscale image to a png file.
  *

HighMap/src/export/read_to_array.cpp

@@ -0,0 +1,28 @@
+/* Copyright (c) 2023 Otto Link. Distributed under the terms of the GNU General
+ * Public License. The full license is in the file LICENSE, distributed with
+ * this software. */
+#include "macrologger.h"
+
+#include "highmap/array.hpp"
+
+namespace hmap
+{
+
+Array read_to_array(std::string fname)
+{
+  cv::Mat mat = cv::imread(fname, cv::IMREAD_GRAYSCALE);
+
+  if (mat.data == nullptr)
+  {
+    LOG_ERROR("error while reading the image file: %s", fname.c_str());
+    return Array();
+  }
+  else
+  {
+    cv::rotate(mat, mat, cv::ROTATE_90_CLOCKWISE);
+    bool remap = true;
+    return cv_mat_to_array(mat, remap);
+  }
+}
+
+} // namespace hmap

examples/ex_read_to_array/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(ex_read_to_array ex_read_to_array.cpp)
+target_link_libraries(ex_read_to_array highmap)

examples/ex_read_to_array/ex_read_to_array.cpp

@@ -0,0 +1,21 @@
+#include "highmap.hpp"
+
+int main(void)
+{
+  hmap::Vec2<int>   shape = {256, 128};
+  hmap::Vec2<float> res = {4.f, 2.f};
+  int               seed = 1;
+
+  hmap::Array z0 = hmap::noise_fbm(hmap::NoiseType::PERLIN, shape, res, seed);
+  hmap::remap(z0, 0.f, 1.f);
+
+  z0.to_png("out1.png", hmap::Cmap::GRAY); // grayscale
+  z0.to_png("out2.png", hmap::Cmap::JET);  // RGB image
+
+  hmap::Array z1 = hmap::read_to_array("out1.png");
+  hmap::Array z2 = hmap::read_to_array("out2.png"); // converted to grayscale
+
+  hmap::export_banner_png("ex_read_to_array.png",
+                          {z0, z1, z2},
+                          hmap::Cmap::INFERNO);
+}