diff options
Diffstat (limited to 'base/gxipixel.c')
| -rw-r--r-- | base/gxipixel.c | 64 |
1 files changed, 34 insertions, 30 deletions
diff --git a/base/gxipixel.c b/base/gxipixel.c index 2f367e14..8b81aaa5 100644 --- a/base/gxipixel.c +++ b/base/gxipixel.c @@ -1,4 +1,4 @@ -/* Copyright (C) 2001-2021 Artifex Software, Inc. +/* Copyright (C) 2001-2022 Artifex Software, Inc. All Rights Reserved. This software is provided AS-IS with no warranty, either express or @@ -434,7 +434,7 @@ gx_image_enum_begin(gx_device * dev, const gs_gstate * pgs, /* Can we restrict the amount of image we need? */ while (pcpath) /* So we can break out of it */ { - gs_rect rect, rect_out; + gs_rect rect, rect_src; gs_matrix mi; const gs_matrix *m = pgs != NULL ? &ctm_only(pgs) : NULL; gs_fixed_rect obox; @@ -449,15 +449,42 @@ gx_image_enum_begin(gx_device * dev, const gs_gstate * pgs, rect.p.y = fixed2float(obox.p.y); rect.q.x = fixed2float(obox.q.x); rect.q.y = fixed2float(obox.q.y); - code = gs_bbox_transform(&rect, &mi, &rect_out); + /* rect is in destination space. Calculate rect_src, in source space. */ + code = gs_bbox_transform(&rect, &mi, &rect_src); if (code < 0) { /* Give up trying to shrink the render/decode boxes, but continue processing */ break; } - irect.p.x = (int)(rect_out.p.x-1.0); - irect.p.y = (int)(rect_out.p.y-1.0); - irect.q.x = (int)(rect_out.q.x+1.0); - irect.q.y = (int)(rect_out.q.y+1.0); + /* Need to expand the region to allow for the fact that the mitchell + * scaler reads multiple pixels in. */ + /* If mi.{xx,yy} > 1 then we are downscaling. During downscaling, + * the support increases to ensure that we don't lose pixels contributions + * entirely. */ + { + float support = any_abs(mi.xx); + int isupport; + if (any_abs(mi.yy) > support) + support = any_abs(mi.yy); + if (any_abs(mi.xy) > support) + support = any_abs(mi.xy); + if (any_abs(mi.yx) > support) + support = any_abs(mi.yx); + /* If upscaling (support < 1) then we need 2 extra lines on each side of the source region + * (2 being the maximum support for mitchell scaling). + * If downscaling, then the number of lines is increased to avoid individual + * contributions dropping out. */ + isupport = 2; /* Mitchell support. */ + if (support > 1) + isupport = (int)ceil(isupport * support); + rect_src.p.x -= isupport; + rect_src.p.y -= isupport; + rect_src.q.x += isupport; + rect_src.q.y += isupport; + } + irect.p.x = (int)floor(rect_src.p.x); + irect.p.y = (int)floor(rect_src.p.y); + irect.q.x = (int)ceil(rect_src.q.x); + irect.q.y = (int)ceil(rect_src.q.y); /* We therefore only need to render within irect. Restrict rrect to this. */ if (penum->rrect.x < irect.p.x) { penum->rrect.w -= irect.p.x - penum->rrect.x; @@ -481,29 +508,6 @@ gx_image_enum_begin(gx_device * dev, const gs_gstate * pgs, if (penum->rrect.h < 0) penum->rrect.h = 0; } - /* Need to expand the region to allow for the fact that the mitchell - * scaler reads multiple pixels in. */ - /* If mi.{xx,yy} > 1 then we are downscaling. During downscaling, - * the support increases to ensure that we don't lose pixels contributions - * entirely. */ - /* I do not understand the need for the +/- 1 fudge factors, - * but they seem to be required. Increasing the decode rectangle can - * never be bad at least... RJW */ - { - float support = any_abs(mi.xx); - int isupport; - if (any_abs(mi.yy) > support) - support = any_abs(mi.yy); - if (any_abs(mi.xy) > support) - support = any_abs(mi.xy); - if (any_abs(mi.yx) > support) - support = any_abs(mi.yx); - isupport = (int)(MAX_ISCALE_SUPPORT * (support+1)) + 1; - irect.p.x -= isupport; - irect.p.y -= isupport; - irect.q.x += isupport; - irect.q.y += isupport; - } if (penum->drect.x < irect.p.x) { penum->drect.w -= irect.p.x - penum->drect.x; if (penum->drect.w < 0) |