> Those manual use/optimization of SIMD are done in C anyway. C seems to be used only for SSE intrinsics support. ~16 LoC of "C". This is all C in the whole p

> Those manual use/optimization of SIMD are done in C anyway. C seems to be used only for SSE intrinsics support. ~16 LoC of "C". This is all C in the whole project, if you really think you can call it as such: https://github.com/google/font-rs/blob/master/src/accumulate.c https://github.com/google/font-rs/blob/master/src/accumulate... void accumulate_sse(const float *in, uint8_t *out, uint32_t n) { __m128 offset = _mm_setzero_ps(); __m128i mask = _mm_set1_epi32(0x0c080400); __m128 sign_mask = _mm_set1_ps(-0.f); for (int i = 0; i < n; i += 4) { __m128 x = _mm_load_ps(&in[i]); x = _mm_add_ps(x, _mm_castsi128_ps(_mm_slli_si128(_mm_castps_si128(x), 4))); x = _mm_add_ps(x, _mm_shuffle_ps(_mm_setzero_ps(), x, 0x40)); x = _mm_add_ps(x, offset); __m128 y = _mm_andnot_ps(sign_mask, x); // fabs(x) y = _mm_min_ps(y, _mm_set1_ps(1.0f)); y = _mm_mul_ps(y, _mm_set1_ps(255.0f)); __m128i z = _mm_cvtps_epi32(y); z = _mm_shuffle_epi8(z, mask); _mm_store_ss((float *)&out[i], (__m128)z); offset = _mm_shuffle_ps(x, x, _MM_SHUFFLE(3, 3, 3, 3)); } } Also consider top level: https://github.com/google/font-rs/tree/master/src https://github.com/google/font-rs/tree/master/src > What is the main benefit of using Rust? Safety and performance. From the article: "With the SIMD speedup, font-rs is approximately 7.6x faster than FreeType in larger sizes (keep in mind that 42 pixels/em is the default for xxhdpi Android devices)."