chroma

diff --git a/lib/test_common.c b/lib/test_common.cnew file mode 100644index 0000000..c19e34f--- /dev/null+++ b/lib/test_common.c@@ -0,0 +1,190 @@+#define STB_IMAGE_IMPLEMENTATION+#define STB_IMAGE_WRITE_IMPLEMENTATION+#include "test_common.h"+#include "stb_image.h"+#include "stb_image_write.h"+#include <math.h>+#include <sys/time.h>++uint8_t *load_image(const char *path, int *width, int *height, int *channels) {+    return stbi_load(path, width, height, channels, 4);+}++int save_image(const char *path, uint8_t *data, int width, int height, int channels) {+    return stbi_write_png(path, width, height, channels, data, width * channels);+}++uint8_t *downsample_image(uint8_t *src, int sw, int sh, int sc, int *dw, int *dh, float scale) {+    if (!src || sw <= 0 || sh <= 0 || sc <= 0 || scale <= 0) {+        if (dw) *dw = 0;+        if (dh) *dh = 0;+        return NULL;+    }++    int tw = (int)(sw * scale);+    int th = (int)(sh * scale);++    if (tw < 1) tw = 1;+    if (th < 1) th = 1;++    uint8_t *dst = malloc(tw * th * sc);+    if (!dst) return NULL;++    float inv_scale = 1.0f / scale;+    for (int y = 0; y < th; y++) {+        for (int x = 0; x < tw; x++) {+            float sx = (x + 0.5f) * inv_scale;+            float sy = (y + 0.5f) * inv_scale;++            int ix = (int)sx;+            int iy = (int)sy;++            if (sw > 1) {+                ix = (ix < sw - 2) ? ix : sw - 2;+            } else {+                ix = 0;+            }+            if (sh > 1) {+                iy = (iy < sh - 2) ? iy : sh - 2;+            } else {+                iy = 0;+            }++            if (ix < 0) ix = 0;+            if (iy < 0) iy = 0;++            float fx = sx - ix;+            float fy = sy - iy;++            if (sw == 1) fx = 0.0f;+            if (sh == 1) fy = 0.0f;++            for (int c = 0; c < sc; c++) {+                uint8_t p00 = src[(iy * sw + ix) * sc + c];+                uint8_t p01 = (sw > 1) ? src[(iy * sw + ix + 1) * sc + c] : p00;+                uint8_t p10 = (sh > 1) ? src[((iy + 1) * sw + ix) * sc + c] : p00;+                uint8_t p11 = (sw > 1 && sh > 1) ? src[((iy + 1) * sw + ix + 1) * sc + c] : p00;++                float interp = p00 * (1 - fx) * (1 - fy) ++                              p01 * fx * (1 - fy) ++                              p10 * (1 - fx) * fy ++                              p11 * fx * fy;++                dst[(y * tw + x) * sc + c] = (uint8_t)(interp + 0.5f);+            }+        }+    }++    *dw = tw;+    *dh = th;+    return dst;+}++double get_time_ms(void) {+    struct timeval tv;+    gettimeofday(&tv, NULL);+    return tv.tv_sec * 1000.0 + tv.tv_usec / 1000.0;+}++double run_benchmark(double (*fn)(void), int iterations) {+    double warmup = fn();+    (void)warmup;++    double total = 0.0;+    for (int i = 0; i < iterations; i++) {+        total += fn();+    }+    return total / iterations;+}++int compare_images(uint8_t *a, uint8_t *b, int w, int h, int ch, float threshold) {+    int max_diff = 0;+    for (int i = 0; i < w * h * ch; i++) {+        int diff = abs((int)a[i] - (int)b[i]);+        if (diff > max_diff) max_diff = diff;+        if (diff > (int)(threshold * 255.0f)) {+            return 0;+        }+    }+    return 1;+}++float compute_psnr(uint8_t *a, uint8_t *b, int w, int h, int ch) {+    double mse = 0.0;+    int total = w * h * ch;++    for (int i = 0; i < total; i++) {+        double diff = (double)a[i] - (double)b[i];+        mse += diff * diff;+    }++    mse /= total;++    if (mse < 1e-10) return 99.99f;++    return (float)(10.0 * log10(255.0 * 255.0 / mse));+}++uint8_t *create_gradient_image(int w, int h) {+    uint8_t *img = malloc(w * h * 4);+    if (!img) return NULL;++    for (int y = 0; y < h; y++) {+        for (int x = 0; x < w; x++) {+            int idx = (y * w + x) * 4;+            img[idx + 0] = (uint8_t)((float)x / w * 255);+            img[idx + 1] = (uint8_t)((float)y / h * 255);+            img[idx + 2] = 128;+            img[idx + 3] = 255;+        }+    }+    return img;+}++uint8_t *create_noise_image(int w, int h, unsigned int seed) {+    uint8_t *img = malloc(w * h * 4);+    if (!img) return NULL;++    srand(seed);+    for (int i = 0; i < w * h * 4; i++) {+        img[i] = (uint8_t)(rand() % 256);+    }+    return img;+}++uint8_t *create_uniform_image(int w, int h, uint8_t r, uint8_t g, uint8_t b) {+    uint8_t *img = malloc(w * h * 4);+    if (!img) return NULL;++    for (int i = 0; i < w * h; i++) {+        img[i * 4 + 0] = r;+        img[i * 4 + 1] = g;+        img[i * 4 + 2] = b;+        img[i * 4 + 3] = 255;+    }+    return img;+}++uint8_t *create_checkerboard(int w, int h, int check_size) {+    uint8_t *img = malloc(w * h * 4);+    if (!img) return NULL;++    for (int y = 0; y < h; y++) {+        for (int x = 0; x < w; x++) {+            int idx = (y * w + x) * 4;+            int cx = x / check_size;+            int cy = y / check_size;+            if ((cx + cy) % 2 == 0) {+                img[idx + 0] = 255;+                img[idx + 1] = 255;+                img[idx + 2] = 255;+            } else {+                img[idx + 0] = 0;+                img[idx + 1] = 0;+                img[idx + 2] = 0;+            }+            img[idx + 3] = 255;+        }+    }+    return img;+}