diff --git a/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp b/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp index d0d4f4a9277..fb15896429c 100644 --- a/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp +++ b/Userland/Libraries/LibGfx/ImageFormats/JPEGLoader.cpp @@ -1432,6 +1432,8 @@ static void dequantize(JPEGLoadingContext& context, Vector& macroblo static void inverse_dct_8x8(i16* block_component) { + // Does a 2-D IDCT by doing two 1-D IDCTs as described in https://unix4lyfe.org/dct/ + // The 1-D DCT idea is described at https://unix4lyfe.org/dct-1d/, read aan.cc from bottom to top. static float const m0 = 2.0f * AK::cos(1.0f / 16.0f * 2.0f * AK::Pi); static float const m1 = 2.0f * AK::cos(2.0f / 16.0f * 2.0f * AK::Pi); static float const m3 = 2.0f * AK::cos(2.0f / 16.0f * 2.0f * AK::Pi);