From 438e848356d7ef6d1dd4a07eee38e0bcf74d2989 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Mon, 28 Sep 2009 14:20:44 -0500
Subject: [PATCH] fix reverse png filtering with klazuka's idea
---
basis/images/png/png.factor | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/basis/images/png/png.factor b/basis/images/png/png.factor
index 7e8f69d555..88ec97aadf 100755
--- a/basis/images/png/png.factor
+++ b/basis/images/png/png.factor
@@ -99,11 +99,11 @@ ERROR: unimplemented-color-type image ;
a b + c - { a b c } [ [ - abs ] keep 2array ] with map
sort-keys first second ;
-:: png-unfilter-line ( prev curr filter -- curr' )
+:: png-unfilter-line ( width prev curr filter -- curr' )
prev :> c
- prev 3 tail-slice :> b
+ prev width tail-slice :> b
curr :> a
- curr 3 tail-slice :> x
+ curr width tail-slice :> x
x length [0,b)
filter {
{ filter-none [ drop ] }
@@ -112,18 +112,18 @@ ERROR: unimplemented-color-type image ;
{ filter-average [ [| n | n x nth n a nth n b nth + 2/ + 256 wrap n x set-nth ] each ] }
{ filter-paeth [ [| n | n x nth n a nth n b nth n c nth paeth + 256 wrap n x set-nth ] each ] }
} case
- curr 3 tail ;
+ curr width tail ;
-: reverse-png-filter ( lines -- byte-array )
- dup first length 0 <array> prefix
- [ { 0 0 } prepend ] map
+:: reverse-png-filter ( n lines -- byte-array )
+ lines dup first length 0 <array> prefix
+ [ n 1 - 0 <array> prepend ] map
2 clump [
- first2 dup [ third ] [ [ 0 2 ] dip set-nth ] bi
+ n swap first2 [ ] [ n 1 - swap nth ] [ [ 0 n 1 - ] dip set-nth ] tri
png-unfilter-line
] map B{ } concat-as ;
: png-image-bytes ( loading-png -- byte-array )
- [ inflate-data ] [ png-group-width ] bi group reverse-png-filter ;
+ [ png-bytes-per-pixel ] [ inflate-data ] [ png-group-width ] tri group reverse-png-filter ;
: decode-greyscale ( loading-png -- loading-png )
unimplemented-color-type ;