From 47a2f42c9f4da07bc16ba4adc37daeece7df89e7 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Sat, 14 Feb 2009 19:24:42 -0600
Subject: [PATCH] handle associated alpha data in tiffs
---
basis/images/tiff/tiff.factor | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/basis/images/tiff/tiff.factor b/basis/images/tiff/tiff.factor
index c91edbae39..29f36495f0 100755
--- a/basis/images/tiff/tiff.factor
+++ b/basis/images/tiff/tiff.factor
@@ -5,7 +5,7 @@ compression.lzw constructors endian fry grouping images io
io.binary io.encodings.ascii io.encodings.binary
io.encodings.string io.encodings.utf8 io.files kernel math
math.bitwise math.order math.parser pack prettyprint sequences
-strings math.vectors ;
+strings math.vectors specialized-arrays.float ;
IN: images.tiff
TUPLE: tiff-image < image ;
@@ -343,6 +343,25 @@ ERROR: unknown-component-order ifd ;
[ unknown-component-order ]
} case ;
+: handle-alpha-data ( ifd -- ifd )
+ dup extra-samples find-tag {
+ { extra-samples-associated-alpha-data [
+ [
+ B{ } like dup
+ byte-array>float-array
+ 4 <sliced-groups>
+ [
+ dup fourth dup 0 = [
+ 2drop
+ ] [
+ [ 3 head-slice ] dip '[ _ / ] change-each
+ ] if
+ ] each
+ ] change-bitmap
+ ] }
+ [ bad-extra-samples ]
+ } case ;
+
: ifd>image ( ifd -- image )
{
[ [ image-width find-tag ] [ image-length find-tag ] bi 2array ]
@@ -364,6 +383,7 @@ ERROR: unknown-component-order ifd ;
strips>bitmap
fix-bitmap-endianness
strips-predictor
+ handle-alpha-data
drop
] each
] with-endianness