The skippy Reference Manual

Table of Contents

The skippy Reference Manual

This is the skippy Reference Manual, version 1.3.12, generated automatically by Declt version 2.4 "Will Decker" on Wed Jun 20 12:35:08 2018 GMT+0.

1 Introduction

Skippy can read and write GIF files. It is available under a BSD-style
license.

For documentation, see HTML docs in doc/index.html.

For any questions and comments, please email Zach Beane
.

2 Systems

The main system appears first, followed by any subsystem dependency.

2.1 skippy

Author

Zachary Beane <xach@xach.com>

License

BSD

Description

Read and write GIF files

Version

1.3.12

Source

skippy.asd (file)

Components

• package.lisp (file)
• conditions.lisp (file)
• types.lisp (file)
• bitstream.lisp (file)
• lzw.lisp (file)
• color-table.lisp (file)
• canvas.lisp (file)
• data-stream.lisp (file)
• image.lisp (file)
• gif89a.lisp (file)
• load-gif.lisp (file)

3 Files

Files are sorted by type and then listed depth-first from the systems components trees.

3.1 Lisp

3.1.1 skippy.asd

Location

skippy.asd

Systems

skippy (system)

Packages

skippy-system

3.1.2 skippy/package.lisp

Parent

skippy (system)

Location

package.lisp

Packages

skippy

3.1.3 skippy/conditions.lisp

Dependency

package.lisp (file)

Parent

skippy (system)

Location

conditions.lisp

Exported Definitions

• color-table-full (condition)
• lzw-error (condition)
• missing-color-table (condition)
• signature-error (condition)
• skippy-error (condition)
• skippy-warning (condition)
• unexpected-value (condition)

Internal Definitions

• color-table-full-color-table (method)
• invalid-image-dimension-height (method)
• invalid-image-dimension-width (method)
• invalid-image-dimensions (condition)
• lzw-error-description (method)
• missing-color-table-image (method)
• short-signature (condition)
• signature-error-position (method)
• signature-error-source (method)
• signature-mismatch (condition)
• skippy-warn (function)
• unexpected-value-actual-value (method)
• unexpected-value-description (method)
• unexpected-value-expected-value (method)
• unexpected-value-source (method)
• unexpected-value-source-position (method)

3.1.4 skippy/types.lisp

Dependency

package.lisp (file)

Parent

skippy (system)

Location

types.lisp

Internal Definitions

• bitstream-buffer (type)
• buffer-offset (type)
• image-dimension (type)
• octet (type)

3.1.5 skippy/bitstream.lisp

Dependencies

• package.lisp (file)
• types.lisp (file)

Parent

skippy (system)

Location

bitstream.lisp

Internal Definitions

• %make-bitstream (function)
• *bitstream-slot-attributes* (special variable)
• bitstream (structure)
• bitstream-bits-left (function)
• (setf bitstream-bits-left) (function)
• bitstream-buffer (function)
• (setf bitstream-buffer) (function)
• bitstream-count (function)
• (setf bitstream-count) (function)
• bitstream-octet (function)
• (setf bitstream-octet) (function)
• bitstream-offset (function)
• (setf bitstream-offset) (function)
• bitstream-p (function)
• bitstream-stream (function)
• (setf bitstream-stream) (function)
• copy-bitstream (function)
• finish-input (function)
• make-bitstream (function)
• make-input-bitstream (function)
• read-bits (function)
• reset-stream (function)
• with-bitstream-slots (macro)
• write-bits (function)

3.1.6 skippy/lzw.lisp

Dependencies

• package.lisp (file)
• conditions.lisp (file)
• bitstream.lisp (file)

Parent

skippy (system)

Location

lzw.lisp

Internal Definitions

• compression-context (class)
• decompression-context (class)
• entries (method)
• lzw-compress (function)
• lzw-decompress (function)
• preds (method)
• string-table-entry (type)
• string-table-vector (type)
• table (method)

3.1.7 skippy/color-table.lisp

Dependencies

• package.lisp (file)
• conditions.lisp (file)

Parent

skippy (system)

Location

color-table.lisp

Exported Definitions

• add-color (function)
• color-rgb (function)
• color-table (class)
• color-table-entry (function)
• (setf color-table-entry) (function)
• color-table-entry (type)
• color-table-size (function)
• copy-color-table (function)
• ensure-color (function)
• find-color (function)
• make-color-table (function)
• rgb-color (function)

Internal Definitions

• +max-color-table-size+ (constant)
• color-table-code-size (function)
• entries (method)

3.1.8 skippy/canvas.lisp

Dependencies

• package.lisp (file)
• color-table.lisp (file)

Parent

skippy (system)

Location

canvas.lisp

Exported Definitions

• clip-canvas (function)
• clone (method)
• composite (function)
• fill-area (method)
• fill-canvas (function)
• flip-horizontal (method)
• flip-vertical (method)
• height (method)
• image-data (method)
• (setf image-data) (method)
• load-canvas (function)
• make-canvas (function)
• make-image-data (function)
• pixel-ref (method)
• (setf pixel-ref) (method)
• read-canvas (function)
• rotate-180 (method)
• save-canvas (function)
• scale (method)
• width (method)
• write-canvas (function)

Internal Definitions

• *canvas-magic* (special variable)
• *file-format-version* (special variable)
• canvas (class)
• canvas-data (type)
• canvas-index (type)
• clip (function)
• deinterlaced-image-data (function)
• interlaced-image-data (function)
• palette-index (type)
• read-u32 (function)
• write-u32 (function)

3.1.9 skippy/data-stream.lisp

Dependency

package.lisp (file)

Parent

skippy (system)

Location

data-stream.lisp

Exported Definitions

• add-delay (function)
• add-image (function)
• color-table (method)
• (setf color-table) (method)
• comment (method)
• (setf comment) (method)
• height (method)
• images (method)
• last-image (function)
• loopingp (method)
• (setf loopingp) (method)
• make-data-stream (function)
• width (method)

Internal Definitions

• check-dimensions (function)
• data-stream (class)

3.1.10 skippy/image.lisp

Dependencies

• data-stream.lisp (file)
• color-table.lisp (file)
• canvas.lisp (file)

Parent

skippy (system)

Location

image.lisp

Exported Definitions

• *default-delay-time* (special variable)
• canvas-image (function)
• clone (method)
• color-table (method)
• (setf color-table) (method)
• delay-time (method)
• (setf delay-time) (method)
• disposal-method (method)
• (setf disposal-method) (method)
• height (method)
• (setf height) (method)
• image-data (method)
• (setf image-data) (method)
• left-position (method)
• (setf left-position) (method)
• make-image (function)
• top-position (method)
• (setf top-position) (method)
• transparency-index (method)
• (setf transparency-index) (method)
• width (method)
• (setf width) (method)

Internal Definitions

• check-image-dimensions (function)
• data-stream (method)
• (setf data-stream) (method)
• (setf data-stream) (method)
• image (class)
• interlacedp (method)
• (setf interlacedp) (method)
• transparentp (generic function)
• transparentp (method)
• wrap-image (method)

3.1.11 skippy/gif89a.lisp

Dependencies

• package.lisp (file)
• conditions.lisp (file)
• types.lisp (file)
• lzw.lisp (file)
• data-stream.lisp (file)
• image.lisp (file)

Parent

skippy (system)

Location

gif89a.lisp

Exported Definitions

• output-data-stream (function)
• write-data-stream (function)

Internal Definitions

• *disposal-methods* (special variable)
• *gif-signature* (special variable)
• *netscape-signature* (special variable)
• +gif-trailer-code+ (constant)
• +image-separator-code+ (constant)
• +pixel-aspect-ratio+ (constant)
• boolean-bit (function)
• compression-code-size (function)
• disposal-method-value (function)
• effective-color-table (function)
• write-block-terminator (function)
• write-color-table (function)
• write-comment (function)
• write-data-stream-header (function)
• write-end-code (function)
• write-graphic-control-block (function)
• write-image (function)
• write-netscape-looping-block (function)
• write-uint16 (function)

3.1.12 skippy/load-gif.lisp

Dependencies

• package.lisp (file)
• conditions.lisp (file)
• types.lisp (file)
• lzw.lisp (file)
• data-stream.lisp (file)
• image.lisp (file)
• gif89a.lisp (file)

Parent

skippy (system)

Location

load-gif.lisp

Exported Definitions

• delay-time (method)
• disposal-method (method)
• load-data-stream (function)
• read-data-stream (function)
• transparency-index (method)

Internal Definitions

• *effective-graphic-control* (special variable)
• *gif87a-signature* (special variable)
• *gif89a-signature* (special variable)
• +application-label+ (constant)
• +comment-label+ (constant)
• +extension-introducer+ (constant)
• +graphic-control-label+ (constant)
• +plain-text-label+ (constant)
• advance-stream-position (function)
• bind-bits (macro)
• check-gif-signature (function)
• disposal-method-keyword (function)
• graphic-control-extension (class)
• merge-graphic-control (function)
• process-objects (function)
• read-application-extension (function)
• read-color (function)
• read-color-table (function)
• read-comment-extension (function)
• read-extension-object (function)
• read-graphic-control-extension (function)
• read-image (function)
• read-uint16 (function)
• skip-data-blocks (function)
• stream-position (function)

4 Packages

Packages are listed by definition order.

4.1 skippy-system

Source

skippy.asd

Use List

• asdf/interface
• common-lisp

4.2 skippy

Source

package.lisp (file)

Use List

common-lisp

Exported Definitions

• *default-delay-time* (special variable)
• add-color (function)
• add-delay (function)
• add-image (function)
• canvas-image (function)
• clip-canvas (function)
• clone (generic function)
• clone (method)
• clone (method)
• color-rgb (function)
• color-table (generic function)
• color-table (method)
• (setf color-table) (method)
• color-table (method)
• (setf color-table) (method)
• (setf color-table) (generic function)
• color-table (class)
• color-table-entry (function)
• (setf color-table-entry) (function)
• color-table-entry (type)
• color-table-full (condition)
• color-table-size (function)
• comment (generic function)
• comment (method)
• (setf comment) (method)
• (setf comment) (generic function)
• composite (function)
• copy-color-table (function)
• delay-time (generic function)
• delay-time (method)
• delay-time (method)
• (setf delay-time) (method)
• (setf delay-time) (generic function)
• disposal-method (generic function)
• disposal-method (method)
• disposal-method (method)
• (setf disposal-method) (method)
• (setf disposal-method) (generic function)
• ensure-color (function)
• fill-area (generic function)
• fill-area (method)
• fill-canvas (function)
• find-color (function)
• flip-horizontal (generic function)
• flip-horizontal (method)
• flip-vertical (generic function)
• flip-vertical (method)
• height (generic function)
• height (method)
• (setf height) (method)
• height (method)
• height (method)
• (setf height) (generic function)
• image-data (generic function)
• image-data (method)
• (setf image-data) (method)
• image-data (method)
• (setf image-data) (method)
• (setf image-data) (generic function)
• images (generic function)
• images (method)
• last-image (function)
• left-position (generic function)
• left-position (method)
• (setf left-position) (method)
• (setf left-position) (generic function)
• load-canvas (function)
• load-data-stream (function)
• loopingp (generic function)
• loopingp (method)
• (setf loopingp) (method)
• (setf loopingp) (generic function)
• lzw-error (condition)
• make-canvas (function)
• make-color-table (function)
• make-data-stream (function)
• make-image (function)
• make-image-data (function)
• missing-color-table (condition)
• output-data-stream (function)
• pixel-ref (generic function)
• pixel-ref (method)
• (setf pixel-ref) (method)
• (setf pixel-ref) (generic function)
• read-canvas (function)
• read-data-stream (function)
• rgb-color (function)
• rotate-180 (generic function)
• rotate-180 (method)
• save-canvas (function)
• scale (generic function)
• scale (method)
• signature-error (condition)
• skippy-error (condition)
• skippy-warning (condition)
• top-position (generic function)
• top-position (method)
• (setf top-position) (method)
• (setf top-position) (generic function)
• transparency-index (generic function)
• transparency-index (method)
• transparency-index (method)
• (setf transparency-index) (method)
• (setf transparency-index) (generic function)
• unexpected-value (condition)
• width (generic function)
• width (method)
• (setf width) (method)
• width (method)
• width (method)
• (setf width) (generic function)
• write-canvas (function)
• write-data-stream (function)

Internal Definitions

• %make-bitstream (function)
• *bitstream-slot-attributes* (special variable)
• *canvas-magic* (special variable)
• *disposal-methods* (special variable)
• *effective-graphic-control* (special variable)
• *file-format-version* (special variable)
• *gif-signature* (special variable)
• *gif87a-signature* (special variable)
• *gif89a-signature* (special variable)
• *netscape-signature* (special variable)
• +application-label+ (constant)
• +comment-label+ (constant)
• +extension-introducer+ (constant)
• +gif-trailer-code+ (constant)
• +graphic-control-label+ (constant)
• +image-separator-code+ (constant)
• +max-color-table-size+ (constant)
• +pixel-aspect-ratio+ (constant)
• +plain-text-label+ (constant)
• advance-stream-position (function)
• bind-bits (macro)
• bitstream (structure)
• bitstream-bits-left (function)
• (setf bitstream-bits-left) (function)
• bitstream-buffer (function)
• (setf bitstream-buffer) (function)
• bitstream-buffer (type)
• bitstream-count (function)
• (setf bitstream-count) (function)
• bitstream-octet (function)
• (setf bitstream-octet) (function)
• bitstream-offset (function)
• (setf bitstream-offset) (function)
• bitstream-p (function)
• bitstream-stream (function)
• (setf bitstream-stream) (function)
• boolean-bit (function)
• buffer-offset (type)
• canvas (class)
• canvas-data (type)
• canvas-index (type)
• check-dimensions (function)
• check-gif-signature (function)
• check-image-dimensions (function)
• clip (function)
• color-table-code-size (function)
• color-table-full-color-table (generic function)
• color-table-full-color-table (method)
• compression-code-size (function)
• compression-context (class)
• copy-bitstream (function)
• data-stream (generic function)
• data-stream (method)
• (setf data-stream) (method)
• (setf data-stream) (generic function)
• (setf data-stream) (method)
• data-stream (class)
• decompression-context (class)
• deinterlaced-image-data (function)
• disposal-method-keyword (function)
• disposal-method-value (function)
• effective-color-table (function)
• entries (generic function)
• entries (method)
• entries (method)
• finish-input (function)
• graphic-control-extension (class)
• image (class)
• image-dimension (type)
• interlaced-image-data (function)
• interlacedp (generic function)
• interlacedp (method)
• (setf interlacedp) (method)
• (setf interlacedp) (generic function)
• invalid-image-dimension-height (generic function)
• invalid-image-dimension-height (method)
• invalid-image-dimension-width (generic function)
• invalid-image-dimension-width (method)
• invalid-image-dimensions (condition)
• lzw-compress (function)
• lzw-decompress (function)
• lzw-error-description (generic function)
• lzw-error-description (method)
• make-bitstream (function)
• make-input-bitstream (function)
• merge-graphic-control (function)
• missing-color-table-image (generic function)
• missing-color-table-image (method)
• octet (type)
• palette-index (type)
• preds (generic function)
• preds (method)
• process-objects (function)
• read-application-extension (function)
• read-bits (function)
• read-color (function)
• read-color-table (function)
• read-comment-extension (function)
• read-extension-object (function)
• read-graphic-control-extension (function)
• read-image (function)
• read-u32 (function)
• read-uint16 (function)
• reset-stream (function)
• short-signature (condition)
• signature-error-position (generic function)
• signature-error-position (method)
• signature-error-source (generic function)
• signature-error-source (method)
• signature-mismatch (condition)
• skip-data-blocks (function)
• skippy-warn (function)
• stream-position (function)
• string-table-entry (type)
• string-table-vector (type)
• table (generic function)
• table (method)
• transparentp (generic function)
• transparentp (method)
• unexpected-value-actual-value (generic function)
• unexpected-value-actual-value (method)
• unexpected-value-description (generic function)
• unexpected-value-description (method)
• unexpected-value-expected-value (generic function)
• unexpected-value-expected-value (method)
• unexpected-value-source (generic function)
• unexpected-value-source (method)
• unexpected-value-source-position (generic function)
• unexpected-value-source-position (method)
• with-bitstream-slots (macro)
• wrap-image (generic function)
• wrap-image (method)
• write-bits (function)
• write-block-terminator (function)
• write-color-table (function)
• write-comment (function)
• write-data-stream-header (function)
• write-end-code (function)
• write-graphic-control-block (function)
• write-image (function)
• write-netscape-looping-block (function)
• write-u32 (function)
• write-uint16 (function)

5 Definitions

Definitions are sorted by export status, category, package, and then by lexicographic order.

5.1 Exported definitions

5.1.1 Special variables

Special Variable: *default-delay-time*

Package

skippy

Source

image.lisp (file)

5.1.2 Functions

Function: add-color COLOR TABLE

Package

skippy

Source

color-table.lisp (file)

Function: add-delay DELAY DATA-STREAM

Package

skippy

Source

data-stream.lisp (file)

Function: add-image IMAGE DATA-STREAM

Package

skippy

Source

data-stream.lisp (file)

Function: canvas-image CANVAS

Package

skippy

Source

image.lisp (file)

Function: clip-canvas SOURCE DEST &key SX SY DX DY WIDTH HEIGHT

Return new dx,dy and sx,sy and width,height values to use when clipping SOURCE to fit within the bounds of DEST.

Package

skippy

Source

canvas.lisp (file)

Function: color-rgb COLOR

Package

skippy

Source

color-table.lisp (file)

Function: color-table-entry TABLE INDEX

Function: (setf color-table-entry) NEW-COLOR TABLE INDEX

Package

skippy

Source

color-table.lisp (file)

Function: color-table-size TABLE

Package

skippy

Source

color-table.lisp (file)

Function: composite SOURCE DEST &key SX SY DX DY WIDTH HEIGHT

Package

skippy

Source

canvas.lisp (file)

Function: copy-color-table TABLE

Package

skippy

Source

color-table.lisp (file)

Function: ensure-color COLOR TABLE

Package

skippy

Source

color-table.lisp (file)

Function: fill-canvas CANVAS PALETTE-INDEX

Package

skippy

Source

canvas.lisp (file)

Function: find-color COLOR TABLE

Package

skippy

Source

color-table.lisp (file)

Function: last-image DATA-STREAM

Package

skippy

Source

data-stream.lisp (file)

Function: load-canvas FILE

Package

skippy

Source

canvas.lisp (file)

Function: load-data-stream FILE

Package

skippy

Source

load-gif.lisp (file)

Function: make-canvas &key WIDTH HEIGHT IMAGE-DATA INITIAL-ELEMENT INITIAL-CONTENTS

Package

skippy

Source

canvas.lisp (file)

Function: make-color-table &key INITIAL-CONTENTS

Package

skippy

Source

color-table.lisp (file)

Function: make-data-stream &key HEIGHT WIDTH COLOR-TABLE LOOPINGP COMMENT INITIAL-IMAGES

Package

skippy

Source

data-stream.lisp (file)

Function: make-image &key HEIGHT WIDTH IMAGE-DATA DATA-STREAM TOP-POSITION LEFT-POSITION COLOR-TABLE INTERLACEDP DELAY-TIME TRANSPARENCY-INDEX DISPOSAL-METHOD

Package

skippy

Source

image.lisp (file)

Function: make-image-data WIDTH HEIGHT &key INITIAL-ELEMENT INITIAL-CONTENTS

Package

skippy

Source

canvas.lisp (file)

Function: output-data-stream DATA-STREAM FILE &key IF-EXISTS

Package

skippy

Source

gif89a.lisp (file)

Function: read-canvas STREAM

Package

skippy

Source

canvas.lisp (file)

Function: read-data-stream STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: rgb-color R G B

Package

skippy

Source

color-table.lisp (file)

Function: save-canvas CANVAS FILE &key IF-EXISTS

Package

skippy

Source

canvas.lisp (file)

Function: write-canvas CANVAS STREAM

Package

skippy

Source

canvas.lisp (file)

Function: write-data-stream DATA-STREAM STREAM

Package

skippy

Source

gif89a.lisp (file)

5.1.3 Generic functions

Generic Function: clone CANVAS

Package

skippy

Methods

Method: clone (IMAGE image)

Source

image.lisp (file)

Method: clone (CANVAS canvas)

Source

canvas.lisp (file)

Generic Function: color-table OBJECT

Generic Function: (setf color-table) NEW-VALUE OBJECT

Package

skippy

Methods

Method: color-table (IMAGE image)

Method: (setf color-table) NEW-VALUE (IMAGE image)

The local color table of the image, if any.

Source

image.lisp (file)

Method: color-table (DATA-STREAM data-stream)

Method: (setf color-table) NEW-VALUE (DATA-STREAM data-stream)

The global color table for the data stream (optional)

Source

data-stream.lisp (file)

Generic Function: comment OBJECT

Generic Function: (setf comment) NEW-VALUE OBJECT

Package

skippy

Methods

Method: comment (DATA-STREAM data-stream)

automatically generated reader method

Source

data-stream.lisp (file)

Method: (setf comment) NEW-VALUE (DATA-STREAM data-stream)

automatically generated writer method

Source

data-stream.lisp (file)

Generic Function: delay-time OBJECT

Generic Function: (setf delay-time) NEW-VALUE OBJECT

Package

skippy

Methods

Method: delay-time (GRAPHIC-CONTROL-EXTENSION graphic-control-extension)

automatically generated reader method

Source

load-gif.lisp (file)

Method: delay-time (IMAGE image)

Method: (setf delay-time) NEW-VALUE (IMAGE image)

The time, in hundredths of a second, to wait after this image before displaying the next image

Source

image.lisp (file)

Generic Function: disposal-method OBJECT

Generic Function: (setf disposal-method) NEW-VALUE OBJECT

Package

skippy

Methods

Method: disposal-method (GRAPHIC-CONTROL-EXTENSION graphic-control-extension)

automatically generated reader method

Source

load-gif.lisp (file)

Method: disposal-method (IMAGE image)

automatically generated reader method

Source

image.lisp (file)

Method: (setf disposal-method) NEW-VALUE (IMAGE image)

automatically generated writer method

Source

image.lisp (file)

Generic Function: fill-area CANVAS PALETTE-INDEX &key X Y WIDTH HEIGHT

Package

skippy

Methods

Method: fill-area CANVAS PALETTE-INDEX &key X Y WIDTH HEIGHT

Source

canvas.lisp (file)

Generic Function: flip-horizontal CANVAS

Package

skippy

Methods

Method: flip-horizontal CANVAS

Horizontally mirror the image data of CANVAS.

Source

canvas.lisp (file)

Generic Function: flip-vertical CANVAS

Package

skippy

Methods

Method: flip-vertical CANVAS

Vertically mirror the image data of CANVAS.

Source

canvas.lisp (file)

Generic Function: height OBJECT

Generic Function: (setf height) NEW-VALUE OBJECT

Package

skippy

Methods

Method: height (IMAGE image)

automatically generated reader method

Source

image.lisp (file)

Method: (setf height) NEW-VALUE (IMAGE image)

automatically generated writer method

Source

image.lisp (file)

Method: height (DATA-STREAM data-stream)

The height of the logical screen

Source

data-stream.lisp (file)

Method: height (CANVAS canvas)

automatically generated reader method

Source

canvas.lisp (file)

Generic Function: image-data OBJECT

Generic Function: (setf image-data) NEW-VALUE OBJECT

Package

skippy

Methods

Method: image-data (IMAGE image)

automatically generated reader method

Source

image.lisp (file)

Method: (setf image-data) NEW-VALUE (IMAGE image)

automatically generated writer method

Source

image.lisp (file)

Method: image-data (CANVAS canvas)

automatically generated reader method

Source

canvas.lisp (file)

Method: (setf image-data) NEW-VALUE (CANVAS canvas)

automatically generated writer method

Source

canvas.lisp (file)

Generic Function: images OBJECT

Package

skippy

Methods

Method: images (DATA-STREAM data-stream)

A vector of the images in the data stream

Source

data-stream.lisp (file)

Generic Function: left-position OBJECT

Generic Function: (setf left-position) NEW-VALUE OBJECT

Package

skippy

Methods

Method: left-position (IMAGE image)

Method: (setf left-position) NEW-VALUE (IMAGE image)

The position of the image relative to the left of the logical screen

Source

image.lisp (file)

Generic Function: loopingp OBJECT

Generic Function: (setf loopingp) NEW-VALUE OBJECT

Package

skippy

Methods

Method: loopingp (DATA-STREAM data-stream)

automatically generated reader method

Source

data-stream.lisp (file)

Method: (setf loopingp) NEW-VALUE (DATA-STREAM data-stream)

automatically generated writer method

Source

data-stream.lisp (file)

Generic Function: pixel-ref CANVAS X Y

Generic Function: (setf pixel-ref) NEW-VALUE CANVAS X Y

Package

skippy

Methods

Method: pixel-ref CANVAS X Y

Method: (setf pixel-ref) NEW-VALUE CANVAS X Y

Source

canvas.lisp (file)

Generic Function: rotate-180 CANVAS

Package

skippy

Methods

Method: rotate-180 CANVAS

Does a 180-degree rotation of the image data of CANVAS.

Source

canvas.lisp (file)

Generic Function: scale CANVAS FACTOR

Package

skippy

Methods

Method: scale (CANVAS canvas) FACTOR

Integer scale CANVAS and return it as a new canvas.

Source

canvas.lisp (file)

Generic Function: top-position OBJECT

Generic Function: (setf top-position) NEW-VALUE OBJECT

Package

skippy

Methods

Method: top-position (IMAGE image)

Method: (setf top-position) NEW-VALUE (IMAGE image)

The position of the image relative to the top of the logical screen

Source

image.lisp (file)

Generic Function: transparency-index OBJECT

Generic Function: (setf transparency-index) NEW-VALUE OBJECT

Package

skippy

Methods

Method: transparency-index (GRAPHIC-CONTROL-EXTENSION graphic-control-extension)

automatically generated reader method

Source

load-gif.lisp (file)

Method: transparency-index (IMAGE image)

Method: (setf transparency-index) NEW-VALUE (IMAGE image)

The color table index of the transparent color for this image. If null, the image has no transparent color.

Source

image.lisp (file)

Generic Function: width OBJECT

Generic Function: (setf width) NEW-VALUE OBJECT

Package

skippy

Methods

Method: width (IMAGE image)

automatically generated reader method

Source

image.lisp (file)

Method: (setf width) NEW-VALUE (IMAGE image)

automatically generated writer method

Source

image.lisp (file)

Method: width (DATA-STREAM data-stream)

The width of the logical screen

Source

data-stream.lisp (file)

Method: width (CANVAS canvas)

automatically generated reader method

Source

canvas.lisp (file)

5.1.4 Conditions

Condition: color-table-full ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct methods

color-table-full-color-table (method)

Direct slots

Slot: color-table

Initargs

:color-table

Readers

color-table-full-color-table (generic function)

Condition: lzw-error ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct methods

lzw-error-description (method)

Direct slots

Slot: description

Initargs

:description

Readers

lzw-error-description (generic function)

Condition: missing-color-table ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct methods

missing-color-table-image (method)

Direct slots

Slot: image

Initargs

:image

Readers

missing-color-table-image (generic function)

Condition: signature-error ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct subclasses

• short-signature (condition)
• signature-mismatch (condition)

Direct methods

• signature-error-position (method)
• signature-error-source (method)

Direct slots

Slot: source

Initargs

:source

Readers

signature-error-source (generic function)

Slot: position

Initargs

:position

Initform

(quote nil)

Readers

signature-error-position (generic function)

Condition: skippy-error ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

error (condition)

Direct subclasses

• lzw-error (condition)
• unexpected-value (condition)
• missing-color-table (condition)
• signature-error (condition)
• color-table-full (condition)
• invalid-image-dimensions (condition)

Condition: skippy-warning ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

simple-warning (condition)

Condition: unexpected-value ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct methods

• unexpected-value-source-position (method)
• unexpected-value-source (method)
• unexpected-value-expected-value (method)
• unexpected-value-actual-value (method)
• unexpected-value-description (method)

Direct slots

Slot: description

Initargs

:description

Initform

(quote nil)

Readers

unexpected-value-description (generic function)

Slot: actual-value

Initargs

:actual-value

Readers

unexpected-value-actual-value (generic function)

Slot: expected-value

Initargs

:expected-value

Initform

(quote nil)

Readers

unexpected-value-expected-value (generic function)

Slot: source

Initargs

:source

Initform

(quote nil)

Readers

unexpected-value-source (generic function)

Slot: source-position

Initargs

:source-position

Initform

(quote nil)

Readers

unexpected-value-source-position (generic function)

5.1.5 Classes

Class: color-table ()

Package

skippy

Source

color-table.lisp (file)

Direct superclasses

standard-object (class)

Direct methods

• print-object (method)
• entries (method)

Direct slots

Slot: entries

Initform

(make-array 4 :adjustable t :element-type (quote skippy:color-table-entry) :initial-element 0 :fill-pointer 0)

Readers

entries (generic function)

5.1.6 Types

Type: color-table-entry ()

Package

skippy

Source

color-table.lisp (file)

5.2 Internal definitions

5.2.1 Constants

Constant: +application-label+

Package

skippy

Source

load-gif.lisp (file)

Constant: +comment-label+

Package

skippy

Source

load-gif.lisp (file)

Constant: +extension-introducer+

Package

skippy

Source

load-gif.lisp (file)

Constant: +gif-trailer-code+

The end-of-GIF marker.

Package

skippy

Source

gif89a.lisp (file)

Constant: +graphic-control-label+

Package

skippy

Source

load-gif.lisp (file)

Constant: +image-separator-code+

Package

skippy

Source

gif89a.lisp (file)

Constant: +max-color-table-size+

Color tables are restricted by the GIF89a specification to 256 entries.

Package

skippy

Source

color-table.lisp (file)

Constant: +pixel-aspect-ratio+

Pixel aspect ratios are not set.

Package

skippy

Source

gif89a.lisp (file)

Constant: +plain-text-label+

Package

skippy

Source

load-gif.lisp (file)

5.2.2 Special variables

Special Variable: *bitstream-slot-attributes*

Package

skippy

Source

bitstream.lisp (file)

Special Variable: *canvas-magic*

Package

skippy

Source

canvas.lisp (file)

Special Variable: *disposal-methods*

Package

skippy

Source

gif89a.lisp (file)

Special Variable: *effective-graphic-control*

The graphic control extension in effect for the current image.

Package

skippy

Source

load-gif.lisp (file)

Special Variable: *file-format-version*

Package

skippy

Source

canvas.lisp (file)

Special Variable: *gif-signature*

The ASCII codes for the characters of the string "GIF89a".

Package

skippy

Source

gif89a.lisp (file)

Special Variable: *gif87a-signature*

Package

skippy

Source

load-gif.lisp (file)

Special Variable: *gif89a-signature*

Package

skippy

Source

load-gif.lisp (file)

Special Variable: *netscape-signature*

The ASCII codes for the characters of the string "NETSCAPE2.0".

Package

skippy

Source

gif89a.lisp (file)

5.2.3 Macros

Macro: bind-bits (INTEGER SIZE) BINDINGS &body BODY

Package

skippy

Source

load-gif.lisp (file)

Macro: with-bitstream-slots NAME-BINDINGS BITSTREAM &body BODY

Package

skippy

Source

bitstream.lisp (file)

5.2.4 Functions

Function: %make-bitstream BUFFER OFFSET COUNT OCTET BITS-LEFT STREAM

Package

skippy

Source

bitstream.lisp (file)

Function: advance-stream-position STREAM COUNT

Skip past COUNT bytes of input in STREAM.

Package

skippy

Source

load-gif.lisp (file)

Function: bitstream-bits-left INSTANCE

Function: (setf bitstream-bits-left) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-buffer INSTANCE

Function: (setf bitstream-buffer) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-count INSTANCE

Function: (setf bitstream-count) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-octet INSTANCE

Function: (setf bitstream-octet) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-offset INSTANCE

Function: (setf bitstream-offset) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-p OBJECT

Package

skippy

Source

bitstream.lisp (file)

Function: bitstream-stream INSTANCE

Function: (setf bitstream-stream) VALUE INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: boolean-bit VALUE

Package

skippy

Source

gif89a.lisp (file)

Function: check-dimensions DATA-STREAM IMAGE

Package

skippy

Source

data-stream.lisp (file)

Function: check-gif-signature STREAM

Check that STREAM starts with the ASCII string "GIF89a" or "GIF87a".

Package

skippy

Source

load-gif.lisp (file)

Function: check-image-dimensions WIDTH HEIGHT

Package

skippy

Source

image.lisp (file)

Function: clip XMIN0 YMIN0 XMAX0 YMAX0 XMIN1 YMIN1 XMAX1 YMAX1

Package

skippy

Source

canvas.lisp (file)

Function: color-table-code-size TABLE

The number of bits needed to store the largest index in the color table. The spec-imposed minimum is 2.

Package

skippy

Source

color-table.lisp (file)

Function: compression-code-size IMAGE

Return the number of bits needed to represent the largest index in the effective color table of INDEX.

Package

skippy

Source

gif89a.lisp (file)

Function: copy-bitstream INSTANCE

Package

skippy

Source

bitstream.lisp (file)

Function: deinterlaced-image-data CANVAS

Package

skippy

Source

canvas.lisp (file)

Function: disposal-method-keyword METHOD

Package

skippy

Source

load-gif.lisp (file)

Function: disposal-method-value KEYWORD

Package

skippy

Source

gif89a.lisp (file)

Function: effective-color-table IMAGE

Return the color table in effect when writing out IMAGE, or signal an error if no color table is available.

Package

skippy

Source

gif89a.lisp (file)

Function: finish-input BITSTREAM

Package

skippy

Source

bitstream.lisp (file)

Function: interlaced-image-data CANVAS

Package

skippy

Source

canvas.lisp (file)

Function: lzw-compress VECTOR CODE-SIZE CONTEXT STREAM

Package

skippy

Source

lzw.lisp (file)

Function: lzw-decompress VECTOR CODE-SIZE CONTEXT STREAM

Decompress the GIF LZW data from STREAM into VECTOR.

Package

skippy

Source

lzw.lisp (file)

Function: make-bitstream STREAM

Package

skippy

Source

bitstream.lisp (file)

Function: make-input-bitstream STREAM

Package

skippy

Source

bitstream.lisp (file)

Function: merge-graphic-control IMAGE

Package

skippy

Source

load-gif.lisp (file)

Function: process-objects DATA-STREAM STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-application-extension STREAM DATA-STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-bits LENGTH BITSTREAM

Package

skippy

Source

bitstream.lisp (file)

Function: read-color STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-color-table COUNT STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-comment-extension STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-extension-object STREAM DATA-STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-graphic-control-extension STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-image CONTEXT STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: read-u32 STREAM

Package

skippy

Source

canvas.lisp (file)

Function: read-uint16 STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: reset-stream BITSTREAM

Package

skippy

Source

bitstream.lisp (file)

Function: skip-data-blocks STREAM

Package

skippy

Source

load-gif.lisp (file)

Function: skippy-warn CONTROL &rest ARGS

Package

skippy

Source

conditions.lisp (file)

Function: stream-position STREAM &key OFFSET

FILE-POSITION may return NIL or may signal an error (for e.g. Gray streams); wrap it.

Package

skippy

Source

load-gif.lisp (file)

Function: write-bits CODE LENGTH BITSTREAM

Package

skippy

Source

bitstream.lisp (file)

Function: write-block-terminator STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-color-table TABLE STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-comment COMMENT STREAM

Write COMMENT to the GIF. Since the characters must be ASCII, replace any out-of-range character codes with #\Space.

Package

skippy

Source

gif89a.lisp (file)

Function: write-data-stream-header DATA-STREAM STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-end-code DATA-STREAM STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-graphic-control-block IMAGE STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-image IMAGE CONTEXT STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-netscape-looping-block STREAM

Package

skippy

Source

gif89a.lisp (file)

Function: write-u32 I STREAM

Package

skippy

Source

canvas.lisp (file)

Function: write-uint16 NUMBER STREAM

Package

skippy

Source

gif89a.lisp (file)

5.2.5 Generic functions

Generic Function: color-table-full-color-table CONDITION

Package

skippy

Methods

Method: color-table-full-color-table (CONDITION color-table-full)

Source

conditions.lisp (file)

Generic Function: data-stream OBJECT

Generic Function: (setf data-stream) NEW-VALUE OBJECT

Package

skippy

Methods

Method: data-stream (IMAGE image)

Method: (setf data-stream) NEW-VALUE (IMAGE image)

The data stream in which this image occurs.

Source

image.lisp (file)

Method: (setf data-stream) IMAGE (DATA-STREAM data-stream) after

Source

image.lisp (file)

Generic Function: entries OBJECT

Package

skippy

Methods

Method: entries (COLOR-TABLE color-table)

automatically generated reader method

Source

color-table.lisp (file)

Method: entries (DECOMPRESSION-CONTEXT decompression-context)

automatically generated reader method

Source

lzw.lisp (file)

Generic Function: interlacedp OBJECT

Generic Function: (setf interlacedp) NEW-VALUE OBJECT

Package

skippy

Methods

Method: interlacedp (IMAGE image)

Method: (setf interlacedp) NEW-VALUE (IMAGE image)

Is the image interlaced?

Source

image.lisp (file)

Generic Function: invalid-image-dimension-height CONDITION

Package

skippy

Methods

Method: invalid-image-dimension-height (CONDITION invalid-image-dimensions)

Source

conditions.lisp (file)

Generic Function: invalid-image-dimension-width CONDITION

Package

skippy

Methods

Method: invalid-image-dimension-width (CONDITION invalid-image-dimensions)

Source

conditions.lisp (file)

Generic Function: lzw-error-description CONDITION

Package

skippy

Methods

Method: lzw-error-description (CONDITION lzw-error)

Source

conditions.lisp (file)

Generic Function: missing-color-table-image CONDITION

Package

skippy

Methods

Method: missing-color-table-image (CONDITION missing-color-table)

Source

conditions.lisp (file)

Generic Function: preds OBJECT

Package

skippy

Methods

Method: preds (DECOMPRESSION-CONTEXT decompression-context)

automatically generated reader method

Source

lzw.lisp (file)

Generic Function: signature-error-position CONDITION

Package

skippy

Methods

Method: signature-error-position (CONDITION signature-error)

Source

conditions.lisp (file)

Generic Function: signature-error-source CONDITION

Package

skippy

Methods

Method: signature-error-source (CONDITION signature-error)

Source

conditions.lisp (file)

Generic Function: table OBJECT

Package

skippy

Methods

Method: table (COMPRESSION-CONTEXT compression-context)

automatically generated reader method

Source

lzw.lisp (file)

Generic Function: transparentp IMAGE

Package

skippy

Source

image.lisp (file)

Methods

Method: transparentp IMAGE

Generic Function: unexpected-value-actual-value CONDITION

Package

skippy

Methods

Method: unexpected-value-actual-value (CONDITION unexpected-value)

Source

conditions.lisp (file)

Generic Function: unexpected-value-description CONDITION

Package

skippy

Methods

Method: unexpected-value-description (CONDITION unexpected-value)

Source

conditions.lisp (file)

Generic Function: unexpected-value-expected-value CONDITION

Package

skippy

Methods

Method: unexpected-value-expected-value (CONDITION unexpected-value)

Source

conditions.lisp (file)

Generic Function: unexpected-value-source CONDITION

Package

skippy

Methods

Method: unexpected-value-source (CONDITION unexpected-value)

Source

conditions.lisp (file)

Generic Function: unexpected-value-source-position CONDITION

Package

skippy

Methods

Method: unexpected-value-source-position (CONDITION unexpected-value)

Source

conditions.lisp (file)

Generic Function: wrap-image IMAGE

Package

skippy

Methods

Method: wrap-image IMAGE

Return a data stream of the appropriate size that contains IMAGE.

Source

image.lisp (file)

5.2.6 Conditions

Condition: invalid-image-dimensions ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

skippy-error (condition)

Direct methods

• invalid-image-dimension-height (method)
• invalid-image-dimension-width (method)

Direct slots

Slot: width

Initargs

:width

Readers

invalid-image-dimension-width (generic function)

Slot: height

Initargs

:height

Readers

invalid-image-dimension-height (generic function)

Condition: short-signature ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

signature-error (condition)

Condition: signature-mismatch ()

Package

skippy

Source

conditions.lisp (file)

Direct superclasses

signature-error (condition)

5.2.7 Structures

Structure: bitstream ()

Package

skippy

Source

bitstream.lisp (file)

Direct superclasses

structure-object (structure)

Direct slots

Slot: buffer

Type

skippy::bitstream-buffer

Initform

(make-array 255 :element-type (quote skippy::octet))

Readers

bitstream-buffer (function)

Writers

(setf bitstream-buffer) (function)

Slot: offset

Type

skippy::octet

Initform

0

Readers

bitstream-offset (function)

Writers

(setf bitstream-offset) (function)

Slot: count

Type

skippy::octet

Initform

0

Readers

bitstream-count (function)

Writers

(setf bitstream-count) (function)

Slot: octet

Type

skippy::octet

Initform

0

Readers

bitstream-octet (function)

Writers

(setf bitstream-octet) (function)

Slot: bits-left

Type

(mod 9)

Initform

8

Readers

bitstream-bits-left (function)

Writers

(setf bitstream-bits-left) (function)

Slot: stream

Readers

bitstream-stream (function)

Writers

(setf bitstream-stream) (function)

5.2.8 Classes

Class: canvas ()

Package

skippy

Source

canvas.lisp (file)

Direct superclasses

standard-object (class)

Direct subclasses

image (class)

Direct methods

• scale (method)
• clone (method)
• initialize-instance (method)
• print-object (method)
• image-data (method)
• image-data (method)
• width (method)
• height (method)

Direct slots

Slot: height

Initargs

:height

Readers

height (generic function)

Slot: width

Initargs

:width

Readers

width (generic function)

Slot: image-data

Initargs

:image-data

Readers

image-data (generic function)

Writers

(setf image-data) (generic function)

Direct Default Initargs

Initarg	Value
:height	(error "~s required" :height)
:width	(error "~s required" :width)

Class: compression-context ()

Store data structures that may be re-used when writing out multiple images in a GIF animation.

Package

skippy

Source

lzw.lisp (file)

Direct superclasses

standard-object (class)

Direct methods

table (method)

Direct slots

Slot: table

Initform

(make-hash-table)

Readers

table (generic function)

Class: data-stream ()

A DATA-STREAM instance represents a container for GIF image data. It defines the logical dimensions of the overall image. It may contain a color table, which is used if an individual image does not provide its own color table.

Package

skippy

Source

data-stream.lisp (file)

Direct superclasses

standard-object (class)

Direct methods

• (setf data-stream) (method)
• print-object (method)
• initialize-instance (method)
• images (method)
• comment (method)
• comment (method)
• loopingp (method)
• loopingp (method)
• color-table (method)
• color-table (method)
• width (method)
• height (method)

Direct slots

Slot: height

The height of the logical screen

Initargs

:height

Readers

height (generic function)

Slot: width

The width of the logical screen

Initargs

:width

Readers

width (generic function)

Slot: color-table

The global color table for the data stream (optional)

Initargs

:color-table

Readers

color-table (generic function)

Writers

(setf color-table) (generic function)

Slot: loopingp

Initargs

:loopingp

Readers

loopingp (generic function)

Writers

(setf loopingp) (generic function)

Slot: comment

Initargs

:comment

Readers

comment (generic function)

Writers

(setf comment) (generic function)

Slot: images

A vector of the images in the data stream

Initargs

:images

Readers

images (generic function)

Direct Default Initargs

Initarg	Value
:height	(error "~a initarg is required" :height)
:width	(error "~a initarg is required" :width)
:color-table	nil
:loopingp	nil
:comment	nil
:images	(make-array 10 :adjustable t :fill-pointer 0)

Class: decompression-context ()

A decompression context is used to hold data structures that may be re-used for repeated calls to lzw-decompress, so they don’t have to be allocated fresh each time.

Package

skippy

Source

lzw.lisp (file)

Direct superclasses

standard-object (class)

Direct methods

• preds (method)
• entries (method)

Direct slots

Slot: entries

Initform

(make-array 4096 :element-type (quote skippy::string-table-entry) :initial-element -1)

Readers

entries (generic function)

Slot: preds

Initform

(make-array 4096 :element-type (quote skippy::string-table-entry) :initial-element -1)

Readers

preds (generic function)