gif.cpp.hpp File Reference

Detailed Description

GIF image decoder.

The GIF format is thoroughly documented; a full description can be found at http://www.w3.org/Graphics/GIF/spec-gif89a.txt

Todo

Plain text and comment extensions should be implemented.

Definition in file gif.cpp.hpp.

#include "fl/stl/cstddef.h"
#include "fl/stl/assert.h"
#include "fl/stl/int.h"
#include "fl/stl/limits.h"
#include "fl/stl/allocator.h"
#include "fl/stl/cstring.h"
#include "fl/stl/string.h"
#include "fl/stl/noexcept.h"
#include "lzw.h"
#include "third_party/libnsgif/include/nsgif.hpp"

Include dependency graph for gif.cpp.hpp:

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Classes
struct	fl::third_party::nsgif
	GIF animation data. More...
struct	fl::third_party::nsgif_colour_layout
	Pixel format: colour component order. More...
struct	fl::third_party::nsgif_frame
	GIF frame data. More...

Namespaces
namespace	fl
	Base definition for an LED controller.
namespace	fl::third_party

Macros
#define	NSGIF_ARRAY_LEN(_a)
	Helper macro to get number of elements in an array.
#define	NSGIF_BLOCK_TERMINATOR   0x00
#define	NSGIF_COLOUR_TABLE_MASK   0x80
#define	NSGIF_COLOUR_TABLE_SIZE_MASK   0x07
#define	NSGIF_FRAME_DELAY_DEFAULT   10
	Default frame delay to apply.
#define	NSGIF_FRAME_DELAY_MIN   2
	Default minimum allowable frame delay in cs.
#define	NSGIF_FRAME_INVALID   (fl::numeric_limits<fl::u32>::max)()
	Internal flag that a frame is invalid/unprocessed.
#define	NSGIF_NO_TRANSPARENCY   (0xFFFFFFFFu)
	No transparency.
#define	NSGIF_PROCESS_COLOURS   0xaa000000
	Internal flag that the colour table needs to be processed.
#define	NSGIF_TRAILER   0x3b
#define	NSGIF_TRANSPARENT_COLOUR   0x00
	Transparent colour.

Typedefs
typedef struct fl::third_party::nsgif_frame	fl::third_party::nsgif_frame
	GIF frame data.

Functions
static fl::u32	fl::third_party::gif__clip (fl::u32 frame_off, fl::u32 frame_dim, fl::u32 image_ext) FL_NOEXCEPT
	Get any frame clip adjustment for the image extent.
static void	fl::third_party::gif__jump_data (fl::u32 *skip, fl::u32 *available, const fl::u8 **pos) FL_NOEXCEPT
	Perform any jump over decoded data, to accommodate clipped portion of frame.
static bool	fl::third_party::nsgif__animation_complete (int count, int max) FL_NOEXCEPT
static bool	fl::third_party::nsgif__app_ext_is_loop_count (const fl::u8 *data, fl::size len) FL_NOEXCEPT
	Check an app ext identifier and authentication code for loop count extension.
static struct nsgif_colour_layout	fl::third_party::nsgif__bitmap_fmt_to_colour_layout (nsgif_bitmap_fmt_t bitmap_fmt) FL_NOEXCEPT
static fl::u32 *	fl::third_party::nsgif__bitmap_get (struct nsgif *gif) FL_NOEXCEPT
	Helper to get the rendering bitmap for a gif.
static bool	fl::third_party::nsgif__bitmap_get_opaque (const struct nsgif *gif) FL_NOEXCEPT
	Helper to get the client to determine if the bitmap is opaque.
static void	fl::third_party::nsgif__bitmap_modified (const struct nsgif *gif) FL_NOEXCEPT
	Helper to tell the client that their bitmap was modified.
static void	fl::third_party::nsgif__bitmap_set_opaque (const struct nsgif *gif, const struct nsgif_frame *frame) FL_NOEXCEPT
	Helper to tell the client that whether the bitmap is opaque.
static void	fl::third_party::nsgif__colour_table_decode (fl::u32 colour_table[NSGIF_MAX_COLOURS], const struct nsgif_colour_layout *layout, fl::size colour_table_entries, const fl::u8 *data) FL_NOEXCEPT
	Extract a GIF colour table into a LibNSGIF colour table buffer.
static nsgif_error	fl::third_party::nsgif__colour_table_extract (fl::u32 colour_table[NSGIF_MAX_COLOURS], const struct nsgif_colour_layout *layout, fl::size colour_table_entries, const fl::u8 *data, fl::size data_len, fl::size *used, bool decode) FL_NOEXCEPT
	Extract a GIF colour table into a LibNSGIF colour table buffer.
static nsgif_error	fl::third_party::nsgif__decode (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 *data, fl::u32 *frame_data) FL_NOEXCEPT
static nsgif_error	fl::third_party::nsgif__decode_complex (struct nsgif *gif, fl::u32 width, fl::u32 height, fl::u32 offset_x, fl::u32 offset_y, fl::u32 interlace, const fl::u8 *data, fl::u32 transparency_index, fl::u32 *frame_data, fl::u32 *colour_table) FL_NOEXCEPT
static nsgif_error	fl::third_party::nsgif__decode_simple (struct nsgif *gif, fl::u32 height, fl::u32 offset_y, const fl::u8 *data, fl::u32 transparency_index, fl::u32 *frame_data, fl::u32 *colour_table) FL_NOEXCEPT
static bool	fl::third_party::nsgif__deinterlace (fl::u32 height, fl::u32 *y, fl::u8 *step) FL_NOEXCEPT
	Get the next line for GIF decode.
static nsgif_error	fl::third_party::nsgif__error_from_lzw (lzw_result l_res) FL_NOEXCEPT
	Convert an LZW result code to equivalent GIF result code.
static fl::u32	fl::third_party::nsgif__frame_next (const nsgif_t *gif, bool partial, fl::u32 frame) FL_NOEXCEPT
static struct nsgif_frame *	fl::third_party::nsgif__get_frame (struct nsgif *gif, fl::u32 frame_idx) FL_NOEXCEPT
static bool	fl::third_party::nsgif__host_is_little_endian (void) FL_NOEXCEPT
	Check whether the host is little endian.
static nsgif_error	fl::third_party::nsgif__initialise_sprite (struct nsgif *gif, fl::u32 width, fl::u32 height) FL_NOEXCEPT
	Updates the sprite memory size.
static nsgif_error	fl::third_party::nsgif__next_displayable_frame (const nsgif_t *gif, fl::u32 *frame, fl::u32 *delay) FL_NOEXCEPT
static bool	fl::third_party::nsgif__next_row (fl::u32 interlace, fl::u32 height, fl::u32 *y, fl::u8 *step) FL_NOEXCEPT
	Get the next line for GIF decode.
static nsgif_error	fl::third_party::nsgif__parse_colour_table (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 **pos, bool decode) FL_NOEXCEPT
	Get a frame's colour table.
static nsgif_error	fl::third_party::nsgif__parse_extension_application (struct nsgif *gif, const fl::u8 *data, fl::size len) FL_NOEXCEPT
	Parse the application extension.
static nsgif_error	fl::third_party::nsgif__parse_extension_graphic_control (struct nsgif_frame *frame, const fl::u8 *data, fl::size len) FL_NOEXCEPT
	Parse the graphic control extension.
static nsgif_error	fl::third_party::nsgif__parse_frame_extensions (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 **pos, bool decode) FL_NOEXCEPT
	Parse the frame's extensions.
static nsgif_error	fl::third_party::nsgif__parse_header (struct nsgif *gif, const fl::u8 **pos, bool strict) FL_NOEXCEPT
	Read GIF header.
static nsgif_error	fl::third_party::nsgif__parse_image_data (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 **pos, bool decode) FL_NOEXCEPT
	Parse the image data for a gif frame.
static nsgif_error	fl::third_party::nsgif__parse_image_descriptor (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 **pos, bool decode) FL_NOEXCEPT
	Parse a GIF Image Descriptor.
static nsgif_error	fl::third_party::nsgif__parse_logical_screen_descriptor (struct nsgif *gif, const fl::u8 **pos) FL_NOEXCEPT
	Read Logical Screen Descriptor.
static nsgif_error	fl::third_party::nsgif__process_frame (struct nsgif *gif, fl::u32 frame_idx, bool decode) FL_NOEXCEPT
	Attempts to initialise the next frame.
static void	fl::third_party::nsgif__record_frame (struct nsgif *gif, const fl::u32 *bitmap) FL_NOEXCEPT
static nsgif_error	fl::third_party::nsgif__recover_frame (const struct nsgif *gif, fl::u32 *bitmap) FL_NOEXCEPT
static void	fl::third_party::nsgif__redraw_rect_extend (const nsgif_rect_t *frame, nsgif_rect_t *redraw) FL_NOEXCEPT
static void	fl::third_party::nsgif__restore_bg (struct nsgif *gif, struct nsgif_frame *frame, fl::u32 *bitmap) FL_NOEXCEPT
	Restore a GIF to the background colour.
static nsgif_error	fl::third_party::nsgif__update_bitmap (struct nsgif *gif, struct nsgif_frame *frame, const fl::u8 *data, fl::u32 frame_idx) FL_NOEXCEPT
nsgif_error	fl::third_party::nsgif_create (const nsgif_bitmap_cb_vt *bitmap_vt, nsgif_bitmap_fmt_t bitmap_fmt, nsgif_t **gif_out) FL_NOEXCEPT
	Create the NSGIF object.
void	fl::third_party::nsgif_data_complete (nsgif_t *gif) FL_NOEXCEPT
	Tell libnsgif that all the gif data has been provided.
nsgif_error	fl::third_party::nsgif_data_scan (nsgif_t *gif, fl::size size, const fl::u8 *data) FL_NOEXCEPT
	Scan the source image data.
void	fl::third_party::nsgif_destroy (nsgif_t *gif) FL_NOEXCEPT
	Free a NSGIF object.
nsgif_error	fl::third_party::nsgif_frame_decode (nsgif_t *gif, fl::u32 frame, nsgif_bitmap_t **bitmap) FL_NOEXCEPT
	Decodes a GIF frame.
nsgif_error	fl::third_party::nsgif_frame_prepare (nsgif_t *gif, nsgif_rect_t *area, fl::u32 *delay_cs, fl::u32 *frame_new) FL_NOEXCEPT
	Prepare to show a frame.
const nsgif_frame_info_t *	fl::third_party::nsgif_get_frame_info (const nsgif_t *gif, fl::u32 frame) FL_NOEXCEPT
	Get information about a GIF from an nsgif_t object.
const nsgif_info_t *	fl::third_party::nsgif_get_info (const nsgif_t *gif) FL_NOEXCEPT
	Get information about a GIF from an nsgif_t object.
void	fl::third_party::nsgif_global_palette (const nsgif_t *gif, fl::u32 table[NSGIF_MAX_COLOURS], fl::size *entries) FL_NOEXCEPT
	Get the global colour palette.
bool	fl::third_party::nsgif_local_palette (const nsgif_t *gif, fl::u32 frame, fl::u32 table[NSGIF_MAX_COLOURS], fl::size *entries) FL_NOEXCEPT
	Get the local colour palette for a frame.
nsgif_error	fl::third_party::nsgif_reset (nsgif_t *gif) FL_NOEXCEPT
	Reset a GIF animation.
void	fl::third_party::nsgif_set_frame_delay_behaviour (nsgif_t *gif, fl::u16 delay_min, fl::u16 delay_default) FL_NOEXCEPT
	Configure handling of small frame delays.
const char *	fl::third_party::nsgif_str_disposal (enum nsgif_disposal disposal) FL_NOEXCEPT
	Convert a disposal method to a string.
const char *	fl::third_party::nsgif_strerror (nsgif_error err) FL_NOEXCEPT
	Convert an error code to a string.

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Class Documentation

fl::third_party::nsgif

struct fl::third_party::nsgif

Collaboration diagram for fl::third_party::nsgif:

Class Members
u32	aspect_ratio	image aspect ratio (ignored)
u32	bg_index	background index
nsgif_bitmap_cb_vt	bitmap	callbacks for bitmap functions
const u8 *	buf	pointer to GIF data
size	buf_len	total number of bytes of GIF data available
size	buf_pos	current index into GIF data
struct nsgif_colour_layout	colour_layout	Client's colour component order.
u32 *	colour_table	current colour table
u32	colour_table_size	size of global colour table (in entries)
bool	data_complete	Whether all the GIF data has been supplied, or if there may be more to come.
u32	decoded_frame	current frame decoded to bitmap
u16	delay_default	Frame delay to apply when delay is less than delay_min.
u16	delay_min	Minimum allowable frame delay.
u32	frame	current frame
u32	frame_count_partial	number of frames partially decoded
u32	frame_holders	current number of frame holders
nsgif_bitmap_t *	frame_image	currently decoded image; stored as bitmap from bitmap_create callback
nsgif_frame *	frames	decoded frames
u32	global_colour_table[NSGIF_MAX_COLOURS]	global colour table
struct nsgif_info	info
u32	local_colour_table[NSGIF_MAX_COLOURS]	local colour table
int	loop_count	number of animation loops so far
void *	lzw_ctx	LZW decode context.
void *	prev_frame	previous frame for NSGIF_FRAME_RESTORE
u32	prev_index	previous frame index
u32	rowspan	Row span of frame_image in pixels.

fl::third_party::nsgif_colour_layout

struct fl::third_party::nsgif_colour_layout

Class Members
u8	a	Byte offset within pixel to alpha component.
u8	b	Byte offset within pixel to blue component.
u8	g	Byte offset within pixel to green component.
u8	r	Byte offset within pixel to red component.

fl::third_party::nsgif_frame

struct fl::third_party::nsgif_frame

Collaboration diagram for fl::third_party::nsgif_frame:

Class Members
u32	colour_table_offset	offset to frame colour table
bool	decoded	whether the frame has previously been decoded.
u32	flags
size	frame_offset	offset (in bytes) to the GIF frame data
struct nsgif_frame_info	info
u32	lzw_data_length	Amount of LZW data found in scan.
bool	opaque	whether the frame is totally opaque
bool	redraw_required	whether a full image redraw is required
u32	transparency_index	the index designating a transparent pixel