riff: A wrapper to the FLIF library.

7.2

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riff: A wrapper to the FLIF library.

Lehi Toskin

(require riff)

package: riff

riff is a simple wrapper to the FLIF library, providing a mostly C-like interface.

1 Common FLIF Functions

2 Decoder Functions

3 Encoder Functions

Index

1 Common FLIF Functions

value
_FLIF-IMAGE : ctype?

This ctype is the basis for the functions in this section. It is associated with an image itself - either from file or its bytes.

procedure
(flif? img) → boolean?
img : any/c

Determines if the given file has a FLIF header.

procedure
(flif-create-image width height) → _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-create-image-rgb width height) → _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-create-image-gray width height) → _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-create-image-gray16 width height) → _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-create-image-palette width height) → _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-create-image-hdr width height) → _FLIF-IMAGE
  width : integer?
  height : integer?

Creates a pointer to a _FLIF-IMAGE struct. Note: flif-create-image is RGBA.

procedure
(flif-import-image-rgba! width
height
rgba
stride) → _FLIF-IMAGE
  width : integer?
  height : integer?
  rgba : bytes?
  stride : integer?
procedure
(flif-import-image-rgb! width
height
rgb
stride) → _FLIF-IMAGE
  width : integer?
  height : integer?
  rgb : bytes?
  stride : integer?
procedure
(flif-import-image-gray! width
height
gray
stride) → _FLIF-IMAGE
  width : integer?
  height : integer?
  gray : bytes?
  stride : integer?
procedure
(flif-import-image-gray16! width
height
gray
stride) → _FLIF-IMAGE
  width : integer?
  height : integer?
  gray : bytes?
  stride : integer?
procedure
(flif-import-image-palette! width
height
palette
stride) → _FLIF-IMAGE
  width : integer?
  height : integer?
  palette : bytes?
  stride : integer?

Creates a pointer to a _FLIF-IMAGE struct by importing the associated bytes.

procedure
(flif-destroy-image! image) → void?
image : _FLIF-IMAGE

Destroy the image pointer.

procedure
(flif-image-get-width image) → integer?
  image : _FLIF-IMAGE
procedure
(flif-image-get-height image) → integer?
  image : _FLIF-IMAGE
procedure
(flif-image-get-nb-channels image) → integer?
  image : _FLIF-IMAGE

Gets the associated information from the image pointer.

procedure
(flif-image-get-palette-size image) → integer?
image : _FLIF-IMAGE

Gets the size of the palette from the image pointer, where 0 means no palette and 1 - 256 means nb of colors in the palette.

procedure
(flif-image-get-palette image) → bytes?
image : _FLIF-IMAGE

Gets the bytes of the image palette from a newly-created byte buffer, allocated with flif-image-get-palette-size.

procedure
(flif-image-set-palette! image buffer) → void?
image : _FLIF-IMAGE
buffer : bytes?

Puts the RGBA bytes into the image pointer (must be (* 4 palette-size) in size).

procedure
(flif-image-get-depth image) → integer?
image : _FLIF-IMAGE

Gets the bit-depth of the image (e.g. 8).

procedure
(flif-image-get-frame-delay image) → integer?
  image : _FLIF-IMAGE
procedure
(flif-image-set-frame-delay! image
frame-delay) → void?
  image : _FLIF-IMAGE
  frame-delay : integer?

Gets or sets the frame delay for an image. Only applicable for FLIF images with animation.

procedure
(flif-image-get-metadata image chunkname) → bytes?
image : _FLIF-IMAGE
chunkname : string?

Gets the metadata from the image from a newly-created pointer that is passed to the FFI.

procedure
(flif-image-set-metadata! image
chunkname
data) → void?
  image : _FLIF-IMAGE
  chunkname : string?
  data : bytes?

Sets the metadata for the image.

procedure
(flif-image-free-metadata! image data) → void?
image : _FLIF-IMAGE
data : cpointer?

Free the data pointer returned by flif-image-get-metadata – this function is largely worthless because there is no pointer to free and it is visible to the garbage collector anyway. However, just for gits and shiggles, I added this function to the end of flif-image-get-metadata to free the generated data pointer.

procedure
(flif-image-write-row-palette8! image
row
buffer) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : bytes?
procedure
(flif-image-read-row-palette8! image
row
buffer
len) → bytes?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
  len : integer?
procedure
(flif-image-read-palette8 image
width
height) → bytes?
  image : _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-image-write-row-gray8! image
row
buffer) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : bytes?
procedure
(flif-image-read-row-gray8! image
row
buffer
len) → bytes?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
  len : integer?
procedure
(flif-image-read-gray8 image width height) → bytes?
  image : _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-image-write-row-rgba8! image
row
buffer) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : bytes?
procedure
(flif-image-read-row-rgba8! image
row
buffer
len) → bytes?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
  len : integer?
procedure
(flif-image-read-rgba8 image width height) → bytes?
  image : _FLIF-IMAGE
  width : integer?
  height : integer?

Read or write 8-bit depth image data. read-row-type functions will return a byte string of length len with the row pixels inside, while read-type functions will reaturn a byte string width x height in size.

procedure
(flif-image-write-row-rgba16! image
row
buffer) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
procedure
(flif-image-read-row-rgba16! image
row
buffer
len) → bytes?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
  len : integer?
procedure
(flif-image-read-rgba16 image width height) → bytes?
  image : _FLIF-IMAGE
  width : integer?
  height : integer?
procedure
(flif-image-write-row-gray16! image
row
buffer) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
procedure
(flif-image-read-row-gray16! image
row
buffer
len) → void?
  image : _FLIF-IMAGE
  row : integer?
  buffer : cpointer?
  len : integer?
procedure
(flif-image-read-gray16 image width height) → bytes?
  image : _FLIF-IMAGE
  width : integer?
  height : integer?

Read or write 16-bit depth image data. read-row-type functions will return a byte string of length len with the row pixels inside, while read-type functions will reaturn a byte string width x height in size.

procedure
(flif-free-memory! buffer) → void?
buffer : cpointer?

Free the memory located inside the buffer gcpointer. Again, this is kind of a useless function.

2 Decoder Functions

procedure
(_callback-t quality
bytes-read
decode-over?
user-data
context) → integer?
  quality : integer?
  bytes-read : integer?
  decode-over? : boolean?
  user-data : cpointer?
  context : cpointer?

The generalized form of the progressive callback function.

value
_FLIF-DECODER : ctype?
value
_FLIF-INFO : ctype?

These ctypes are the basis for the functions in this section. They keep track of the image you are working on.

procedure
(flif-animated? img) → boolean?
img : flif?

Determine if the FLIF image provided is animated.

procedure
(flif-create-decoder) → _FLIF-DECODER

Create a new pointer to a _FLIF-DECODER struct.

procedure
(flif-decoder-decode-file! decoder file) → boolean?
  decoder : _FLIF-DECODER
  file : string?
procedure
(flif-decoder-decode-memory! decoder
buffer) → boolean?
  decoder : _FLIF-DECODER
  buffer : bytes?
procedure
(flif-decoder-decode-filepointer! decoder
filepointer
filename) → boolean?
  decoder : _FLIF-DECODER
  filepointer : cpointer?
  filename : string?

Decode the FLIF either from a string to the file, from its bytes, or from a filepointer.

procedure
(flif-decoder-num-images decoder) → integer?
decoder : _FLIF-DECODER

Obtain the number of frames in the FLIF.

procedure
(flif-decoder-num-loops decoder) → integer?
decoder : _FLIF-DECODER

The number of times the FLIF animation should be looped (0 indicates the FLIF should be looped forever).

procedure
(flif-decoder-get-image decoder index) → _FLIF-IMAGE
decoder : _FLIF-DECODER
index : integer?

Obtain the _FLIF-IMAGE pointer to the frame located at index.

procedure
(flif-decoder-generate-preview context) → void?
context : cpointer?

Generate a preview to display.

procedure
(flif-destroy-decoder! decoder) → void?
decoder : _FLIF-DECODER

Free memory associated with the pointer.

procedure
(flif-abort-decoder! decoder) → void?
decoder : _FLIF-DECODER

Abort the decoder (may be used before decoding is complete).

procedure
(flif-decoder-set-crc-check! decoder
check?) → void?
decoder : _FLIF-DECODER
check? : boolean?

Set whether the decoder should check the CRC. The default behavior is to not check the CRC.

procedure
(flif-decoder-set-quality! decoder quality) → void?
decoder : _FLIF-DECODER
quality : (integer-in 0 100)

Set the decoder quality.

procedure
(flif-decoder-set-scale! decoder scale) → void?
decoder : _FLIF-DECODER
scale : integer?

Set the decoder scale. scale must be a number that is a power of 2: 1, 2, 4, 8, 16 ...

procedure
(flif-decoder-set-resize! decoder resize) → void?
decoder : _FLIF-DECODER
resize : integer?

Set the decoder resize.

procedure
(flif-decoder-set-fit! decoder fit) → void?
decoder : _FLIF-DECODER
fit : integer?

Set the decoder fit.

procedure
(flif-decoder-set-callback! decoder
callback
user-data) → void?
  decoder : _FLIF-DECODER
  callback : _callback-t
  user-data : ctype?

Set the decoder callback. Useful for progressive decoding where the callback is called at every new level of quality achieved.

procedure
(flif-decoder-set-first-callback-quality! decoder
quality) → void?
decoder : _FLIF-DECODER
quality : integer?

Set the first quality level to send to the decoder callback. Note: setting decoder quality is different from setting the initial callback quality.

procedure
(flif-read-info-from-memory buffer) → _FLIF-INFO
buffer : bytes?

Generate an info pointer with information gained from buffer.

procedure
(flif-destroy-info! info) → void?
info : _FLIF-INFO

Destroy the info pointer.

procedure
(flif-dimensions img) → list?
img : flif?

Read width and height information from img. This procedure is provided because the flif-info C functions can be finicky and may report incorrect values if the image has not yet been decoded.

procedure
(flif-info-get-width info) → integer?
  info : _FLIF-INFO
procedure
(flif-info-get-height info) → integer?
  info : _FLIF-INFO
procedure
(flif-info-get-nb-channels info) → integer?
  info : _FLIF-INFO
procedure
(flif-info-get-depth info) → integer?
  info : _FLIF-INFO
procedure
(flif-info-num-images info) → integer?
  info : _FLIF-INFO

Obtain various data from the info pointer.

3 Encoder Functions

value
_FLIF-ENCODER : ctype?

This ctype is the basis for the functions in this section. It is associated with an image itself - either from file or its bytes.

procedure
(flif-create-encoder) → _FLIF-ENCODER

Create a pointer to an encoder struct.

procedure
(flif-encoder-add-image! encoder image) → void?
encoder : _FLIF-ENCODER
image : _FLIF-IMAGE

Add the image onto the encoder — add more than one image to create an animation. This function will clone the image (so the input image is not touched and you have to flif-destroy-image! on it yourself to free the memory).

procedure
(flif-encoder-add-image-move! encoder
image) → void?
encoder : _FLIF-ENCODER
image : _FLIF-IMAGE

Add the image onto the encoder — add more than one image to create an animation. This function will move the image (input image becomes invalid during encode and flif-destroy-encoder! will free it.

procedure
(flif-encoder-encode-file! encoder
filename) → void?
encoder : _FLIF-ENCODER
filename : string?

Encode to the supplied filename.

procedure
(flif-encoder-encode-memory encoder) → bytes?
encoder : _FLIF-ENCODER

Encode to a newly-generated byte string. If the encoding fails, it will raise-result-error.

procedure
(flif-destroy-encoder! encoder) → void?
encoder : _FLIF-ENCODER

Destroy the encoder pointer.

procedure
(flif-encoder-set-interlaced! encoder
interlaced?) → void?
encoder : _FLIF-ENCODER
interlaced? : boolean?

Set whether the image is interlaced or non-interlaced (default is #t).

procedure
(flif-encoder-set-learn-repeat! encoder
learn) → void?
encoder : _FLIF-ENCODER
learn : integer?

Set how many times FLIF should learn the MANIAC tree (default is 2).

procedure
(flif-encoder-set-auto-color-buckets! encoder
acb?) → void?
encoder : _FLIF-ENCODER
acb? : boolean?

Default is #t.

procedure
(flif-encoder-set-palette-size! encoder
size) → void?
encoder : _FLIF-ENCODER
size : integer?

Default is 512, the max.

procedure
(flif-encoder-set-lookback! encoder
looback?) → void?
encoder : _FLIF-ENCODER
looback? : boolean?

Default is #t.

procedure
(flif-encoder-set-divisor! encoder divisor) → void?
encoder : _FLIF-ENCODER
divisor : integer?

Default is 30.

procedure
(flif-encoder-set-min-size! encoder size) → void?
encoder : _FLIF-ENCODER
size : integer?

Default is 50.

procedure
(flif-encoder-set-split-threshold! encoder
split) → void?
encoder : _FLIF-ENCODER
split : integer?

Default is 64.

procedure
(flif-encoder-set-alpha-zero-lossless! encoder
azl) → void?
encoder : _FLIF-ENCODER
azl : boolean?

Default is #f.

procedure
(flif-encoder-set-chance-cutoff! encoder
cutoff) → void?
encoder : _FLIF-ENCODER
cutoff : integer?

Default is 2.

procedure
(flif-encoder-set-chance-alpha! encoder
alpha) → void?
encoder : _FLIF-ENCODER
alpha : integer?

Default is 19.

procedure
(flif-encoder-set-crc-check! encoder
check?) → void?
encoder : _FLIF-ENCODER
check? : boolean?

Set whether or not a CRC check should be added.

procedure
(flif-encoder-set-channel-compact! encoder
plc?) → void?
encoder : _FLIF-ENCODER
plc? : boolean?

Default is #t.

procedure
(flif-encoder-set-ycocg! encoder ycocg?) → void?
encoder : _FLIF-ENCODER
ycocg? : boolean?

Default is #t.

procedure
(flif-encoder-set-frame-shape! encoder
shape?) → void?
encoder : _FLIF-ENCODER
shape? : boolean?

Default is #t.

procedure
(flif-encoder-set-lossy! encoder loss) → void?
encoder : _FLIF-ENCODER
loss : integer?

Set the amount of quality loss: 0 means no loss and 100 means maximum loss. Negative values indicate adaptive lossy (second image should be the saliency map). Default is 0.

Index

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

_callback-t
_FLIF-DECODER
_FLIF-ENCODER
_FLIF-IMAGE
_FLIF-INFO
Common FLIF Functions
Decoder Functions
Encoder Functions
flif-abort-decoder!
flif-animated?
flif-create-decoder
flif-create-encoder
flif-create-image
flif-create-image-gray
flif-create-image-gray16
flif-create-image-hdr
flif-create-image-palette
flif-create-image-rgb
flif-decoder-decode-file!
flif-decoder-decode-filepointer!
flif-decoder-decode-memory!
flif-decoder-generate-preview
flif-decoder-get-image
flif-decoder-num-images
flif-decoder-num-loops
flif-decoder-set-callback!
flif-decoder-set-crc-check!
flif-decoder-set-first-callback-quality!
flif-decoder-set-fit!
flif-decoder-set-quality!
flif-decoder-set-resize!
flif-decoder-set-scale!
flif-destroy-decoder!
flif-destroy-encoder!
flif-destroy-image!
flif-destroy-info!
flif-dimensions
flif-encoder-add-image!
flif-encoder-add-image-move!
flif-encoder-encode-file!
flif-encoder-encode-memory
flif-encoder-set-alpha-zero-lossless!
flif-encoder-set-auto-color-buckets!
flif-encoder-set-chance-alpha!
flif-encoder-set-chance-cutoff!
flif-encoder-set-channel-compact!
flif-encoder-set-crc-check!
flif-encoder-set-divisor!
flif-encoder-set-frame-shape!
flif-encoder-set-interlaced!
flif-encoder-set-learn-repeat!
flif-encoder-set-lookback!
flif-encoder-set-lossy!
flif-encoder-set-min-size!
flif-encoder-set-palette-size!
flif-encoder-set-split-threshold!
flif-encoder-set-ycocg!
flif-free-memory!
flif-image-free-metadata!
flif-image-get-depth
flif-image-get-frame-delay
flif-image-get-height
flif-image-get-metadata
flif-image-get-nb-channels
flif-image-get-palette
flif-image-get-palette-size
flif-image-get-width
flif-image-read-gray16
flif-image-read-gray8
flif-image-read-palette8
flif-image-read-rgba16
flif-image-read-rgba8
flif-image-read-row-gray16!
flif-image-read-row-gray8!
flif-image-read-row-palette8!
flif-image-read-row-rgba16!
flif-image-read-row-rgba8!
flif-image-set-frame-delay!
flif-image-set-metadata!
flif-image-set-palette!
flif-image-write-row-gray16!
flif-image-write-row-gray8!
flif-image-write-row-palette8!
flif-image-write-row-rgba16!
flif-image-write-row-rgba8!
flif-import-image-gray!
flif-import-image-gray16!
flif-import-image-palette!
flif-import-image-rgb!
flif-import-image-rgba!
flif-info-get-depth
flif-info-get-height
flif-info-get-nb-channels
flif-info-get-width
flif-info-num-images
flif-read-info-from-memory
flif?
riff
riff: A wrapper to the FLIF library.

top ← prev up next →

1	Common FLIF Functions
2	Decoder Functions
3	Encoder Functions
	Index