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EnigmA Amiga Run 1997 February
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EnigmA AMIGA RUN 15 (1997)(G.R. Edizioni)(IT)[!][issue 1997-02][PLANET CD V].iso
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bwmapmaker_1.11
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ifflib.doc
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TABLE OF CONTENTS
iff.library/IFFL_CloseIFF
iff.library/IFFL_CompressBlock
iff.library/IFFL_DecodePic
iff.library/IFFL_DecompressBlock
iff.library/IFFL_FindChunk
iff.library/IFFL_GetBMHD
iff.library/IFFL_GetColorTab
iff.library/IFFL_GetViewModes
iff.library/IFFL_IFFError
iff.library/IFFL_ModifyFrame
iff.library/IFFL_OpenIFF
iff.library/IFFL_PopChunk
iff.library/IFFL_PushChunk
iff.library/IFFL_SaveBitMap
iff.library/IFFL_SaveClip
iff.library/IFFL_WriteChunkBytes
iff.library/NewOpenIFF
iff.library/OpenIFF
iff.library/IFFL_CloseIFF iff.library/IFFL_CloseIFF
NAME
IFFL_CloseIFF -- Close an IFF file and deallocate buffers
SYNOPSIS
IFFL_CloseIFF( iff )
A1
void IFFL_CloseIFF( IFFL_HANDLE )
FUNCTION
Returns the memory previously allocated by IFFL_OpenIFF().
INPUTS
iff - IFF file handle, from IFFL_OpenIFF()
RESULTS
For now, always results TRUE (this may change in the future).
SEE ALSO
IFFL_OpenIFF()
iff.library/IFFL_CompressBlock iff.library/IFFL_CompressBlock
NAME
IFFL_CompressBlock -- Compress a memory block
SYNOPSIS
result = IFFL_CompressBlock( source, destination, size, mode )
A0 A1 D0 D1
ULONG IFFL_CompressBlock( APTR, APTR, ULONG, ULONG )
FUNCTION
Compress the memory block using the appropriate compression mode.
If the compressed data would become longer than the uncompressed,
an error is returned.
INPUTS
source - Pointer to data to compress
destination - Target address for compression
size - Number of data bytes to compress
mode - Compression mode. Currently, the following modes
are supported:
IFFL_COMPR_NONE - Vanilla copy
IFFL_COMPR_BYTERUN1 - CmpByteRun1 (ILBM BODY data)
IFFL_COMPR_FIBDELTA - Fibonacci Delta (8SVX BODY data)
RESULTS
Length of compressed data or 0 if an error occurred.
IFFL_IFFError() returns IFFL_ERROR_BADCOMPRESSION if you ask for
an unsupported compression mode.
BUGS
In IFFL_COMPR_BYTERUN1, if the compressed data would become longer,
the buffer will be overwritten, and no error is returned. So be
sure to supply a destination buffer which is big enough!
SEE ALSO
IFFL_DecompressBlock()
iff.library/IFFL_DecodePic iff.library/IFFL_DecodePic
NAME
IFFL_DecodePic -- decode the BODY of an ILBM file into a BitMap
SYNOPSIS
success = IFFL_DecodePic( iff, bitmap )
D0 A1 A0
BOOL IFFL_DecodePic( IFFL_HANDLE, struct BitMap * )
FUNCTION
Decodes and decompresses a picture into the user supplied BitMap.
If the picture is higher than your BitMap, it will be truncated.
If your BitMap is larger than the picture, the picture will be
drawn into the top left corner of your BitMap.
If the picture has less planes than the BitMap, the unused planes
are NOT touched by this routine, so you may wish to clear them
before calling IFFL_DecodePic(). If the picture has more planes
than your BitMap, the surplus planes of the picture are ignored.
INPUTS
iff - IFF file handle, from IFFL_OpenIFF()
bitmap - Pointer to a properly initialized BitMap structure:
bm_Planes[] must point to valid BitPlanes,
bm_Depth contains the number of planes.
bm_Width and bm_Height must be set according to the
size of your bit planes.
RESULTS
Non-zero if successful, zero if error. Call IFFL_IFFError() to
know the reason of the failure
BUGS
If the picture is wider than your BitMap, one line of innocent
memory will be overwritten at the end of each bitplane. You can
avoid this by allocating a few bytes more for each plane.
Normally, you allocate your BitMap after inspecting the BMHD
chunk, so this should not be a problem.
NOTE
This routine needs at least 650 bytes of stack space
SEE ALSO
iff.library/IFFL_DecompressBlock iff.library/IFFL_DecompressBlock
NAME
IFFL_DecompressBlock -- Decompress a memory block
SYNOPSIS
result = IFFL_DecompressBlock( source, destination, size, mode )
A0 A1 D0 D1
ULONG IFFL_DecompressBlock( APTR, APTR, ULONG, ULONG )
FUNCTION
Decompress the memory block using the appropriate Decompression mode.
If the Decompressed data would become longer than the unDecompressed,
an error is returned.
INPUTS
source - Pointer to data to decompress
destination - Target address for decompression
size - Number of _DECOMPRESSED_ data bytes
mode - Compression mode. Currently, the following modes
are supported:
IFFL_COMPR_NONE - Vanilla copy
IFFL_COMPR_BYTERUN1 - CmpByteRun1 (ILBM BODY data)
IFFL_COMPR_FIBDELTA - Fibonacci Delta (8SVX BODY data)
RESULTS
Length of uncompressed data or 0 if an error occurred.
IFFL_IFFError() returns IFFL_ERROR_BADCOMPRESSION if you ask for
an unsupported compression mode.
SEE ALSO
IFFL_CompressBlock()
iff.library/IFFL_FindChunk iff.library/IFFL_FindChunk
NAME
IFFL_FindChunk -- find an IFF-chunk
SYNOPSIS
chunk = IFFL_FindChunk( iff, chunkname )
D0 A1 D0
APTR IFFL_FindChunk( IFFL_HANDLE, ULONG )
FUNCTION
Find a specific chunk in an IFF file
INPUTS
iff - IFF file handle, from IFFL_OpenIFF()
chunkname - 4 characters packed ASCII ('BODY', 'VHDR' ...)
if chunkname is 0, FindChunk() returns a pointer to the
first byte after the end of the current FORM. This can
be used by ANIM readers for jumping from FORM to FORM.
RESULTS
Pointer to the beginning of the chunk (that means to the chunk
name itself, followed by the chunk size); zero if chunk not found
BUGS
none known
SEE ALSO
IFFL_GetBMHD(), IFFL_GetColorTab()
iff.library/IFFL_GetBMHD iff.library/IFFL_GetBMHD
NAME
IFFL_GetBMHD -- find a BitMapHeader of an IFF-file
SYNOPSIS
header = IFFL_GetBMHD( iff )
D0 A1
struct BitMapHeader *IFFL_GetBMHD( IFFL_HANDLE )
FUNCTION
Returns a pointer to a BMHD (BitMapHeader) structure as defined
in iff.h and iff.i
INPUTS
iff - IFF file handle, from IFFL_OpenIFF()
RESULTS
Pointer to the BitMapHeader, or NULL if no BMHD chunk found
SEE ALSO
IFFL_FindChunk(), IFFL_GetColorTab()
iff.library/IFFL_GetColorTab iff.library/IFFL_GetColorTab
NAME
IFFL_GetColorTab -- find a CMAP and convert it to a ColorTable
SYNOPSIS
count = IFFL_GetColorTab( iff, colortable )
D0 A1 A0
LONG IFFFL_GetColorTab( IFF_HANDLE, UWORD * )
FUNCTION
Searches the CMAP chunk of an IFF file and converts it, if it's
there, to an Amiga color table structure. This colortable can
directly be used as a parameter for the LoadRGB4() function.
INPUTS
iff - IFF file handle, from IFFL_OpenIFF()
colortable - Pointer to a block of memory which must be large
enough to hold the colortable (2 bytes per color).
Must be WORD aligned.
RESULT
Number of colors actually found, or zero if the file has no
CMAP chunk
SEE ALSO
IFFL_FindChunk(), IFFL_GetBMHD()
iff.library/IFFL_GetViewModes iff.library/IFFL_GetViewModes
NAME
IFFL_GetViewModes() -- Get Amiga-specific ViewModes
SYNOPSIS
viewmodes = IFFL_GetViewModes( iff )
D0 A1
ULONG IFFL_GetViewModes( IFFL_HANDLE )
FUNCTION
Searches the IFF file for a 'CAMG' chunk which holds the view modes
information. If there is no CAMG chunk, the view modes are calcu-
lated using the information in the BitMapHeader structure.
You can directly put the low WORD of the result of a call to
IFFL_ GetViewModes() into the ns_ViewModes field of a NewScreen
structure, or you can use the whole ULONG for the SA_DisplayID tag
under OS 2.x.
INPUTS
iff - IFF file handle, from OpenIFF()
RESULT
viewmodes - ULONG containing the view modes (HAM, LACE, HIRES ...)
All forbidden bits are masked out, as suggested by CBM.
Under Kickstart V1.3, only the lower WORD is used.
BUGS
If the IFF file has no CAMG chunk and 6 bitplanes, the HAM bit
will be set. This is not always correct since the picture could
be in the Extra Halfbrite mode. You can load such Halfbrite
pictures into DPaint III and save them again, DPaint will generate
the correct CAMG chunk.
SEE ALSO
<graphics/displayinfo.h>
iff.library/IFFL_IFFError iff.library/IFFL_IFFError
NAME
IFFL_IFFError -- Get detailed error descrpition after an error
SYNOPSIS
error = IFFL_IFFError()
D0
LONG IFFL_IFFError( VOID )
FUNCTION
If one of the iff.library functions returns zero, you can call
IFFL_IFFError() to know the reason for the failure. An error
code is returned, please refer to the files 'iff.h' or 'iff.i'
for the complete list of errors.
INPUTS
none
RESULT
Error-number generated by the latest function call, or zero if
no error.
BUGS
If you don't close the IFF library at the end of your program
(using CloseLibrary()) the error node will not be freed. The
same task will then not be able to re-open the iff.library.
(This is not a bug, it's a feature ;-))
SEE ALSO
<iff.h>
iff.library/IFFL_ModifyFrame iff.library/IFFL_ModifyFrame
NAME
IFFL_ModifyFrame -- Modify an anim frame using a DLTA chunk
SYNOPSIS
success = IFFL_ModifyFrame( modifyform, bitmap )
D0 A1 A0
BOOL IFFL_ModifyFrame( VOID *, struct BitMap * )
FUNCTION
Uses the DLTA chunk of the supplied FORM to modify the planes-data
of the bitmap. Usually, playback of ANIMs will require two buffers,
and double-buffering between them. So the data in the bitmap must
be two frames back, and the DLTA chunk is used to modify the hidden
frame to the next frame to be shown.
INPUTS
modifyform - pointer to the FORM containing the actual DLTA chunk
bitmap - Pointer to a properly initialized BitMap structure,
the planes must contain the image which was displayed
to frames back (using double-buffering)
RESULT
Non-zero if OK, 0 if error; call IFFL_IFFError() to know the reason
of the failure
RESTRICTIONS
Currently, only compression type 5 (Byte Vertical Delta Mode) is
implemented. If you have animations which use modes 1 to 4, try
loading them with DPaint III and saving them again.
Sculpt-Animate ('J' type ANIM, Movie format) support will be
added soon.
I will implement some more compression types upon request.
NOTE
This routine needs at least 820 bytes of stack.
The size of the bitmap is not checked by this routine, the planes
must have at least the size described in the BMHD of the anim
file.
SEE ALSO
IFFL_IFFError()
iff.library/IFFL_OpenIFF iff.library/IFFL_OpenIFF
NAME
IFFL_OpenIFF -- Open an IFF file for reading or writing
SYNOPSIS
iff = IFFL_OpenIFF( filename, mode )
D0 A0 D0
IFFL_HANDLE IFFL_OpenIFF( char *, ULONG )
FUNCTION
If mode == IFFL_MODE_READ:
This function opens a file on a disk and looks whether it's an IFF
file or not. If it is an IFF file, memory is allocated and the file
is read into memory.
New for V22:
If xpkmaster.library is installed in your system, IFFL_OpenIFF()
will be able to read and decompress compressed IFF files, if they
use one of the xpk standard compression schemes.
If mode == IFFL_MODE_WRITE:
Initializes an IFF file handle for writing. You may create chunks
with IFFL_PushChunk() and IFFL_PopChunk(), and you can write data
using the IFFL_WriteChunkBytes() routine.
INPUTS
filename - Pointer to a null-terminated string
mode - IFFL_MODE_READ: Open file for reading
IFFL_MODE_WRITE: Open file for writing
RESULT
iff - IFF handle. Making assumptions about the internal structure
of this handle is unwise, and may break in the future.
If this function fails, NULL will be returned, and you may
call IFFL_IFFError() to know the reason of the failure.
SEE ALSO
IFFL_CloseIFF(), IFFL_PushChunk(), IFFL_PopChunk(),
IFFL_WriteChunkBytes(), IFFL_IFFError()
BUGS
None known
iff.library/IFFL_PopChunk iff.library/IFFL_PopChunk
NAME
IFFL_PopChunk -- Pop top context node off context stack.
SYNOPSIS
success = IFFL_PopChunk( iff )
D0 A0
BOOL IFFL_PopChunk( IFFL_HANDLE )
FUNCTION
Pops top context chunk and updates the file accordingly.
The function is normally called only for writing files and signals
the end of a chunk.
INPUTS
iff - IFF handle
RESULTS
Non-zero if successful or 0 if not successful (call IFFL_IFFError()
to get an IFFL_ERROR_... error code.
SEE ALSO
IFFL_PushChunk(), IFFL_WriteChunkBytes()
iff.library/IFFL_PushChunk iff.library/IFFL_PushChunk
NAME
IFFL_PushChunk -- Push a new context node on the context stack.
SYNOPSIS
success = IFFL_PushChunk( iff, type, id )
D0 A0 D0 D1
BOOL IFFL_PushChunk( IFFL_HANDLE, ULONG, ULONG )
FUNCTION
Pushes a new context node on the context stack by reading it from the
stream if this is a read file, or by creating it from the passed
parameters if this is a write file. Normally this function is only
called in write mode, where the type and id codes specify the new
chunk to create. If this is a leaf chunk, i.e. a local chunk inside
a FORM or PROP chunk, then the type argument is ignored.
INPUTS
iff - IFF handle
type - chunk type specifier (ex. ILBM) (ignored for read mode or
leaf chunks).
id - chunk id specifier (ex. CMAP) (ignored for read mode).
RESULTS
Non-zero if successful or 0 if not successful (call IFFL_IFFError()
to get an IFFL_ERROR_... error code.
NOTE
Currently, the level of nested FORMs is restricted to 7.
SEE ALSO
IFFL_PopChunk(), IFFL_WriteChunkBytes()
iff.library/IFFL_SaveBitMap iff.library/IFFL_SaveBitMap
NAME
IFFL_SaveBitMap -- save the planes of a BitMap as an IFF-file
SYNOPSIS
result = IFFL_SaveBitMap( filename, bitmap, colortable, flags )
D0 A0 A1 A2 D0
BOOL IFFL_SaveBitMap(char *, struct BitMap *, UWORD *, ULONG )
FUNCTION
Save the planes of a BitMap as an IFF-file, optionally with a
colortable. The IFF file will contain the following chunks:
FORM - The IFF header, with the type ILBM
BMHD - The BitMap Header structre
CMAP - The color map, this chunk is omitted if colortable is zero
CAMG - The Amiga ViewModes word, contains the special ViewModes
information (HAM, LACE, HIRES ...)
BODY - The (crunched or uncompressed) picture
INPUTS
filename - Name of the IFF file to create
bitmap - Pointer to the BitMap holding your picture
colortable - Pointer to an Amiga ColorTable structure or zero
(if colortable = 0, no CMAP chunk will be generated).
flags - Bit 0: 1 = Use the "CmpByteRun1" compression algorythm,
0 = Save the file uncompressed
Bit 7: 1 = This is a HAM (Hold and modify) picture
0 = This is a normal or Extra-Halfbrite picture
RESULT
Non-zero if successful, 0 if an error occurred. You can then call
IFFL_IFFError() to know more about the reason of the failure.
NOTE
Up to V19 this routine needs at least 650 bytes of stack space
SEE ALSO
IFFL_SaveClip()
iff.library/IFFL_SaveClip iff.library/IFFL_SaveClip
NAME
IFFL_SaveClip -- save a part of a BitMap as an IFF-file
SYNOPSIS
result = IFFL_SaveClip
D0 ( filename, bitmap, coltab, flags, xoff, yoff, width, height )
A0 A1 A2 D0 D1 D2 D3 D4
FUNCTION
Save a part of a BitMap as an IFF file
INPUTS
filename - Name of the IFF file to create
bitmap - Pointer to the BitMap holding your picture
colortable - Pointer to an Amiga ColorTable structure or zero
(if colortable = 0, no CMAP chunk will be generated).
flags - Bit 0: 1 = Use the "CmpByteRun1" compression algorythm,
0 = Save the file uncompressed
Bit 7: 1 = This is a HAM (Hold and modify) picture
0 = This is a normal or Extra-Halfbrite picture
xoff - X offset of the clip to be saved (bytes from the left)
yoff - Y offset of the clip to be saved (lines from the top)
width - width in bytes of the rectangle
height - height in lines of the rectangle
RESULTS
Non-zero if successful, 0 if an error occurred. You can then call
IFFL_IFFError() to know more about the reason of the failure.
NOTE
Up to V19 this routine needs at least 650 bytes of stack space
BUGS
The width of the rectangle will be truncated to WORD boundaries,
because DPAINT wants it!
SEE ALSO
IFFL_SaveBitMap()
iff.library/IFFL_WriteChunkBytes iff.library/IFFL_WriteChunkBytes
NAME
IFFL_WriteChunkBytes -- Write data into the current chunk
SYNOPSIS
success = IFFL_WriteChunkBytes( iff, buf, size )
D0 A0 A1 D0
LONG IFFL_WriteChunkBytes( IFFL_HANDLE, APTR, LONG )
FUNCTION
Writes "size" bytes from the specified buffer into the current chunk.
INPUTS
iff - IFF file handle, from IFFL_OpenIFF().
buf - pointer to buffer area with bytes to be written.
size - number of bytes to write.
RESULT
Non-NULL if the write was successful, or NULL if an error
occurred. Call IFFL_IFFError() to know what's going on.
SEE ALSO
IFFL_PushChunk(), IFFL_PopChunk(), IFFL_IFFError()
iff.library/NewOpenIFF iff.library/NewOpenIFF
NAME
NewOpenIFF -- allocate memory for an IFF-file and read it
SYNOPSIS
ifffile = NewOpenIFF( filename, memattr )
D0 A0 D0
IFFFILE OpenIFF( char * )
FUNCTION
THIS FUNCTION IS OBSOLETE. USE IFFL_OpenIFF() INSTEAD.
INPUTS
filename - Pointer to a null-terminated string
memattr - Memory requirements as used for Exec's AllocMem(),
such as MEMF_CHIP, MEMF_PUBLIC ...
(MEMF_CLEAR is not necessary)
RESULT
ifffile - 'FileHandle', points to the beginning of the IFF file
("FORM...."), Zero if unsuccessful. Call IFFError() to get
the reason of the failure.
SEE ALSO
IFFL_OpenIFF(), IFFL_CloseIFF(), IFFL_IFFError()
BUGS
None known
iff.library/OpenIFF iff.library/OpenIFF
NAME
OpenIFF -- allocate memory for an IFF-file and read it
SYNOPSIS
ifffile = OpenIFF( filename )
D0 A0
IFFFILE OpenIFF( char * )
FUNCTION
THIS FUNCTION IS OBSOLETE. USE IFFL_OpenIFF() INSTEAD.
INPUTS
filename - Pointer to a null-terminated string
RESULT
ifffile - 'FileHandle', points to the beginning of the IFF file
("FORM...."), 0 if unsuccessful. Call IFFError() to get the
reason of the failure.
BUGS
None
SEE ALSO
IFFL_OpenIFF(), IFFL_CloseIFF(), IFFL_IFFError()