diff options
| author | Glenn Randers-Pehrson <glennrp at users.sourceforge.net> | 2016-06-29 21:52:53 -0500 |
|---|---|---|
| committer | Glenn Randers-Pehrson <glennrp at users.sourceforge.net> | 2016-06-29 21:53:57 -0500 |
| commit | d9779744f9e1e7211933e12701a05c80c93c9de2 (patch) | |
| tree | 6583282212736918737610c42c4b675ca839a947 /pngwutil.c | |
| parent | ed5a01d922269f1241afeb5d19fde4330d481964 (diff) | |
[libpng16] Optimized absolute value calculation in filter selection, similar to
code in the PAETH decoder in pngrutil.c. Build with PNG_USE_ABS to use this.
Diffstat (limited to 'pngwutil.c')
| -rw-r--r-- | pngwutil.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/pngwutil.c b/pngwutil.c index ddac9bfba..1f7ec5289 100644 --- a/pngwutil.c +++ b/pngwutil.c @@ -2262,14 +2262,22 @@ png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp, i++, rp++, dp++) { v = *dp = *rp; +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif } for (lp = png_ptr->row_buf + 1; i < row_bytes; i++, rp++, lp++, dp++) { v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif if (sum > lmins) /* We are already worse, don't continue. */ break; @@ -2294,7 +2302,11 @@ png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes, i++, rp++, pp++, dp++) { v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif if (sum > lmins) /* We are already worse, don't continue. */ break; @@ -2319,7 +2331,11 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp, { v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif } for (lp = png_ptr->row_buf + 1; i < row_bytes; i++) @@ -2327,7 +2343,11 @@ png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp, v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif if (sum > lmins) /* We are already worse, don't continue. */ break; @@ -2352,7 +2372,11 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp, { v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif } for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes; @@ -2381,7 +2405,11 @@ png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp, v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff); +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif if (sum > lmins) /* We are already worse, don't continue. */ break; @@ -2465,7 +2493,11 @@ png_write_find_filter(png_structrp png_ptr, png_row_infop row_info) for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++) { v = *rp; +#ifdef PNG_USE_ABS + sum += 128 - abs(v - 128); +#else sum += (v < 128) ? v : 256 - v; +#endif } } |