+/*
+ * Load the raster from an image file. The file extension is used to
+ * determine which importer is actually called.
+ */
+raster_t* raster_import(const char* filename);
+
+/*
+ * Load the raster from a PPM file.
+ */
+raster_t* raster_import_ppm(const char* filename);
+
+/*
+ * Load the raster from a BMP file.
+ */
+raster_t* raster_import_bmp(const char* filename);
+
+