PNG image read with libpng

src/libslic3r/PNGRead.hpp

@@ -0,0 +1,30 @@
+#ifndef PNGREAD_HPP
+#define PNGREAD_HPP
+
+#include <vector>
+#include <string>
+
+namespace Slic3r { namespace png {
+
+struct ReadBuf { const void *buf = nullptr; const size_t sz = 0; };
+
+template<class PxT> struct Image {
+    std::vector<PxT> buf;
+    size_t rows, cols;
+    PxT get(size_t row, size_t col) const { return buf[row * cols + col]; }
+};
+
+struct RGB { uint8_t r, g, b; };
+
+using ImageRGB = Image<RGB>;
+using ImageGreyscale = Image<uint8_t>;
+
+// TODO
+// bool decode_png(Buffer &&pngbuf, ImageRGB &img);
+
+bool is_png(const ReadBuf &pngbuf);
+
+bool decode_png(const ReadBuf &pngbuf, ImageGreyscale &img);
+
+}}
+#endif // PNGREAD_HPP