steve
/
factor
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

compute the correct width for png rows, use all the data when decompressing a png, check for impossible png color modes/bit-depths

db4
Doug Coleman 2009-09-26 15:24:09 -05:00
parent caf8e5d159
commit 55dd1a7401
1 changed files with 38 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
basis/images/png/png.factor
View File

@ -64,23 +64,26 @@ ERROR: bad-checksum ;
chunks>> [ type>> "IDAT" = ] filter
[ data>> ] map concat ;
: zlib-data ( loading-png -- bytes )
chunks>> [ type>> "IDAT" = ] find nip data>> ;
ERROR: unknown-color-type n ;
ERROR: unimplemented-color-type image ;
: inflate-data ( loading-png -- bytes )
zlib-data zlib-inflate ;
find-compressed-bytes zlib-inflate ;
: png-group-width ( loading-png -- n )
dup color-type>> {
{ 2 [ [ bit-depth>> 8 / 3 * ] [ width>> ] bi * 1 + ] }
{ 6 [ [ bit-depth>> 8 / 4 * ] [ width>> ] bi * 1 + ] }
[ unknown-color-type ]
} case ;
: png-image-bytes ( loading-png -- byte-array )
[ inflate-data ] [ png-group-width ] bi group
reverse-png-filter ;
: decode-greyscale ( loading-png -- loading-png )
unimplemented-color-type ;
: png-image-bytes ( loading-png -- byte-array )
[ inflate-data ] [ width>> 3 * 1 + ] bi group
reverse-png-filter ;
: decode-truecolor ( loading-png -- loading-png )
[ <image> ] dip {
[ png-image-bytes >>bitmap ]
@ -101,13 +104,34 @@ ERROR: unimplemented-color-type image ;
[ drop RGBA >>component-order ubyte-components >>component-type ]
} cleave ;
ERROR: invalid-color-type/bit-depth loading-png ;
: validate-bit-depth ( loading-png seq -- loading-png )
[ dup bit-depth>> ] dip member?
[ invalid-color-type/bit-depth ] unless ;
: validate-greyscale ( loading-png -- loading-png )
{ 1 2 4 8 16 } validate-bit-depth ;
: validate-truecolor ( loading-png -- loading-png )
{ 8 16 } validate-bit-depth ;
: validate-indexed-color ( loading-png -- loading-png )
{ 1 2 4 8 } validate-bit-depth ;
: validate-greyscale-alpha ( loading-png -- loading-png )
{ 8 16 } validate-bit-depth ;
: validate-truecolor-alpha ( loading-png -- loading-png )
{ 8 16 } validate-bit-depth ;
: decode-png ( loading-png -- loading-png )
dup color-type>> {
{ 0 [ decode-greyscale ] }
{ 2 [ decode-truecolor ] }
{ 3 [ decode-indexed-color ] }
{ 4 [ decode-greyscale-alpha ] }
{ 6 [ decode-truecolor-alpha ] }
{ 0 [ validate-greyscale decode-greyscale ] }
{ 2 [ validate-truecolor decode-truecolor ] }
{ 3 [ validate-indexed-color decode-indexed-color ] }
{ 4 [ validate-greyscale-alpha decode-greyscale-alpha ] }
{ 6 [ validate-truecolor-alpha decode-truecolor-alpha ] }
[ unknown-color-type ]
} case ;