diff --git a/stb_image_resize2.h b/stb_image_resize2.h index 2c693c5..ac2f065 100644 --- a/stb_image_resize2.h +++ b/stb_image_resize2.h @@ -3202,8 +3202,8 @@ static void stbir__calculate_in_pixel_range( int * first_pixel, int * last_pixel if ( edge == STBIR_EDGE_WRAP ) { - if ( first <= -input_size ) - first = -(input_size-1); + if ( first < -input_size ) + first = -input_size; if ( last >= (input_size*2)) last = (input_size*2) - 1; } @@ -3562,7 +3562,7 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter filter_info->widest = widest; } -static int stbir__pack_coefficients( int num_contributors, stbir__contributors* contributors, float * coefficents, int coefficient_width, int widest, int row_width ) +static int stbir__pack_coefficients( int num_contributors, stbir__contributors* contributors, float * coefficents, int coefficient_width, int widest, int row0, int row1 ) { #define STBIR_MOVE_1( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint32*)(dest))[0] = ((stbir_uint32*)(src))[0]; } #define STBIR_MOVE_2( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint64*)(dest))[0] = ((stbir_uint64*)(src))[0]; } @@ -3571,6 +3571,9 @@ static int stbir__pack_coefficients( int num_contributors, stbir__contributors* #else #define STBIR_MOVE_4( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint64*)(dest))[0] = ((stbir_uint64*)(src))[0]; ((stbir_uint64*)(dest))[1] = ((stbir_uint64*)(src))[1]; } #endif + + int row_end = row1 + 1; + if ( coefficient_width != widest ) { float * pc = coefficents; @@ -3712,10 +3715,10 @@ static int stbir__pack_coefficients( int num_contributors, stbir__contributors* float * coeffs = coefficents + widest * ( num_contributors - 1 ); // go until no chance of clipping (this is usually less than 8 lops) - while ( ( contribs >= contributors ) && ( ( contribs->n0 + widest*2 ) >= row_width ) ) + while ( ( contribs >= contributors ) && ( ( contribs->n0 + widest*2 ) >= row_end ) ) { // might we clip?? - if ( ( contribs->n0 + widest ) > row_width ) + if ( ( contribs->n0 + widest ) > row_end ) { int stop_range = widest; @@ -3734,15 +3737,15 @@ static int stbir__pack_coefficients( int num_contributors, stbir__contributors* } // now see if we still clip with the refined range - if ( ( contribs->n0 + stop_range ) > row_width ) + if ( ( contribs->n0 + stop_range ) > row_end ) { - int new_n0 = row_width - stop_range; + int new_n0 = row_end - stop_range; int num = contribs->n1 - contribs->n0 + 1; int backup = contribs->n0 - new_n0; float * from_co = coeffs + num - 1; float * to_co = from_co + backup; - STBIR_ASSERT( ( new_n0 >= 0 ) && ( new_n0 < contribs->n0 ) ); + STBIR_ASSERT( ( new_n0 >= row0 ) && ( new_n0 < contribs->n0 ) ); // move the coeffs over while( num ) @@ -6354,24 +6357,31 @@ static void stbir__set_sampler(stbir__sampler * samp, stbir_filter filter, stbir // pre calculate stuff based on the above samp->coefficient_width = stbir__get_coefficient_width(samp, samp->is_gather, user_data); - // don't double reflect on edges (happens on 2 pixel to 1 pixel output) - if ( samp->filter_pixel_width > ( scale_info->input_full_size * 3 ) ) - samp->filter_pixel_width = scale_info->input_full_size * 3; + // filter_pixel_width is the conservative size in pixels of input that affect an output pixel. + // In rare cases (only with 2 pix to 1 pix with the default filters), it's possible that the + // filter will extend before or after the scanline beyond just one extra entire copy of the + // scanline (we would hit the edge twice). We don't let you do that, so we clamp the total + // width to 3x the total of input pixel (once for the scanline, once for the left side + // overhang, and once for the right side). We only do this for edge mode, since the other + // modes can just re-edge clamp back in again. + if ( edge == STBIR_EDGE_WRAP ) + if ( samp->filter_pixel_width > ( scale_info->input_full_size * 3 ) ) + samp->filter_pixel_width = scale_info->input_full_size * 3; // This is how much to expand buffers to account for filters seeking outside // the image boundaries. samp->filter_pixel_margin = samp->filter_pixel_width / 2; - // again, no double reflect - if ( samp->filter_pixel_margin > scale_info->input_full_size ) - samp->filter_pixel_margin = scale_info->input_full_size; + // filter_pixel_margin is the amount that this filter can overhang on just one side of either + // end of the scanline (left or the right). Since we only allow you to overhang 1 scanline's + // worth of pixels, we clamp this one side of overhang to the input scanline size. Again, + // this clamping only happens in rare cases with the default filters (2 pix to 1 pix). + if ( edge == STBIR_EDGE_WRAP ) + if ( samp->filter_pixel_margin > scale_info->input_full_size ) + samp->filter_pixel_margin = scale_info->input_full_size; samp->num_contributors = stbir__get_contributors(samp, samp->is_gather); - // again, no double reflect - if ( samp->num_contributors > ( scale_info->input_full_size * 3 ) ) - samp->num_contributors = scale_info->input_full_size * 3; - samp->contributors_size = samp->num_contributors * sizeof(stbir__contributors); samp->coefficients_size = samp->num_contributors * samp->coefficient_width * sizeof(float) + sizeof(float); // extra sizeof(float) is padding @@ -7007,7 +7017,7 @@ static stbir__info * stbir__alloc_internal_mem_and_build_samplers( stbir__sample stbir__get_extents( horizontal, &info->scanline_extents ); // pack the horizontal coeffs - horizontal->coefficient_width = stbir__pack_coefficients(horizontal->num_contributors, horizontal->contributors, horizontal->coefficients, horizontal->coefficient_width, horizontal->extent_info.widest, info->scanline_extents.conservative.n1 + 1 ); + horizontal->coefficient_width = stbir__pack_coefficients(horizontal->num_contributors, horizontal->contributors, horizontal->coefficients, horizontal->coefficient_width, horizontal->extent_info.widest, info->scanline_extents.conservative.n0, info->scanline_extents.conservative.n1 ); STBIR_MEMCPY( &info->horizontal, horizontal, sizeof( stbir__sampler ) );