diff options
Diffstat (limited to 'base/gxshade.c')
| -rw-r--r-- | base/gxshade.c | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/base/gxshade.c b/base/gxshade.c index 2372c85f..27413ac1 100644 --- a/base/gxshade.c +++ b/base/gxshade.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2001-2019 Artifex Software, Inc. +/* Copyright (C) 2001-2020 Artifex Software, Inc. All Rights Reserved. This software is provided AS-IS with no warranty, either express or @@ -173,12 +173,13 @@ cs_next_packed_decoded(shade_coord_stream_t * cs, int num_bits, int code = cs->get_value(cs, num_bits, &value); double max_value = (double)(uint) (num_bits == sizeof(uint) * 8 ? ~0 : ((1 << num_bits) - 1)); + double dvalue = (double)value; if (code < 0) return code; *pvalue = - (decode == 0 ? value / max_value : - decode[0] + value * (decode[1] - decode[0]) / max_value); + (decode == 0 ? dvalue / max_value : + decode[0] + dvalue * (decode[1] - decode[0]) / max_value); return 0; } @@ -433,6 +434,33 @@ top: if (cs_lin_test && !gx_has_transfer(pgs, dev->color_info.num_components)) { pfs->cs_always_linear = true; } + +#ifdef IGNORE_SPEC_MATCH_ADOBE_SHADINGS + /* Per the spec. If the source space is DeviceN or Separation and the + colorants are not supported (i.e. if we are using the alternate tint + transform) the interpolation should occur in the source space to + accommodate non-linear tint transform functions. + e.g. We had a case where the transform function + was an increasing staircase. Including that function in the + gradient smoothness calculation gave us severe quantization. AR on + the other hand is doing the interpolation in device color space + and has a smooth result for that case. So AR is not following the spec. The + bit below solves the issues for Type 4 and Type 5 shadings as + this will avoid interpolations in source space. Type 6 and Type 7 will still + have interpolations in the source space even if pfs->cs_always_linear == true. + So the approach below does not solve those issues. To do that + without changing the shading code, we could make a linear + approximation to the alternate tint transform, which would + ensure smoothness like what AR provides. + */ + if ((gs_color_space_get_index(pcs) == gs_color_space_index_DeviceN || + gs_color_space_get_index(pcs) == gs_color_space_index_Separation) && + using_alt_color_space((gs_gstate*)pgs) && (psh->head.type == 4 || + psh->head.type == 5)) { + pfs->cs_always_linear = true; + } +#endif + return 0; } |