API: moved functions to files to make it easier to import to other projects

include/filters.h

@@ -0,0 +1,44 @@
+#ifndef FILTERS_H
+#define FILTERS_H
+#include "utils.h"
+
+unsigned int
+u32_put_alpha(const unsigned int clr, const unsigned char alpha);
+
+unsigned int
+u32_invert(const unsigned int clr);
+
+unsigned int
+u32_swap_rb(const unsigned int clr);
+
+unsigned int
+u32_grayscale(const unsigned int clr);
+
+unsigned int
+u32_step(const unsigned int clr, const unsigned char max);
+
+unsigned int
+u32_brighten(const unsigned int clr, const float factor);
+
+unsigned int
+u32_mix(const unsigned int clr_a, const unsigned int clr_b);
+
+unsigned int
+u32_lerp(const unsigned clr_a, const unsigned int clr_b, const float ratio);
+
+unsigned int
+u32_mask(const unsigned int clr, const char keep);
+
+unsigned int
+u32_rotl(const unsigned int clr, const int n);
+
+unsigned int
+u32_contrast(const unsigned int clr, const float factor);
+
+unsigned int
+u32_avg_gb(const unsigned int clr);
+
+unsigned int*
+box_blur(const unsigned int* src_buf, const PPM* img, const int radius);
+
+#endif