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libwebsockets
Lightweight C library for HTML5 websockets
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libwebsockets
Lightweight C library for HTML5 websockets
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Go to the source code of this file.
Typedefs | |
| typedef struct lws_gif | lws_gif_t |
| LWS_VISIBLE LWS_EXTERN lws_gif_t * lws_gif_new | ( | void | ) |
lws_gif_new() - create a gif decode object
Returns a new gif decoding object, which should be destroyed with lws_gif_free() when done with, or NULL if OOM.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN void lws_gif_free | ( | lws_gif_t ** | gif | ) |
lws_gif_free() - destroy a gif decode object
| gif | pointer to the decode object pointer to destroy and set NULL |
This also frees any sub-allocations in the object, and releases the object's claim on the shared row buffer pool.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN void lws_gif_restart | ( | lws_gif_t * | gif | ) |
lws_gif_restart() - reset decode state, keeping allocations
| gif | the decode object |
Resets the parse, LZW and row state so the object expects a gif header again, for re-decoding retained input (eg, to reach a different row of an interlaced image). Allocations and the shared pool claim are kept.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t lws_gif_emit_next_line | ( | lws_gif_t * | gif, |
| const uint8_t ** | ppix, | ||
| int * | py, | ||
| const uint8_t ** | buf, | ||
| size_t * | len, | ||
| char | hold_at_metadata ) |
lws_gif_emit_next_line() - decode the next row
| gif | the decode object |
| ppix | set to the row's decoded palette indices on WANT_OUTPUT |
| py | set to the row's y position in the logical screen |
| buf | pointer to a const uint8_t array of gif input |
| len | pointer to the count of bytes available at *buf |
| hold_at_metadata | nonzero to stop consuming once the logical screen descriptor has parsed |
Make gif input available to the decoder so it can issue the next row. If the call consumed any input, *buf and *len are adjusted accordingly. The decoder is stateful so it is not sensitive to the chunk size of the input.
If hold_at_metadata is set, decoding stops once the logical screen descriptor has been parsed, even if further input is available at *buf, so image dimensions are known before committing to the decode allocations.
Returns LWS_SRET_WANT_OUTPUT if a row was produced, with *ppix pointing at logical-screen-width bytes of palette indices and *py set to the row's y; LWS_SRET_WANT_INPUT if the input so far was consumed and more is needed to progress; LWS_SRET_OK once the trailer has been reached, or a return with LWS_SRET_FATAL set if the gif is too broken to process. When input ends without a trailer, whatever rows decoded so far were issued and the retained state remains renderable.
For non-interlaced images rows are issued with y = 0, 1, 2... in order. For interlaced images they are issued in gif interlace order (pass 0 rows 0, 8, 16..., then 4, 12..., then 2, 6, 10..., then 1, 3, 5...) with py holding the row's true y position.
The row at *ppix lives in a buffer shared by every live gif object: it is valid only until the next call on any gif object. Decoding is single- threaded, like the display list it serves.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_width | ( | const lws_gif_t * | gif | ) |
lws_gif_get_width() - get the logical screen width in px
| gif | the decode object |
Returns the logical screen width in px once the logical screen descriptor has parsed, else 0.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_height | ( | const lws_gif_t * | gif | ) |
lws_gif_get_height() - get the logical screen height in px
| gif | the decode object |
As lws_gif_get_width(), but for the logical screen height.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN char lws_gif_get_interlaced | ( | const lws_gif_t * | gif | ) |
lws_gif_get_interlaced() - is the first image interlaced?
| gif | the decode object |
Returns nonzero if the first image's descriptor had the interlace flag set. This is only known once decoding has reached the image descriptor, ie, after input was fed without hold_at_metadata.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN const uint8_t * lws_gif_get_palette | ( | const lws_gif_t * | gif | ) |
lws_gif_get_palette() - get the active colour table
| gif | the decode object |
Returns a pointer to the active colour table entries as RGB byte triplets, or NULL if none has parsed yet. The active table is the first image's local colour table if it had one, else the global colour table.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_palette_count | ( | const lws_gif_t * | gif | ) |
lws_gif_get_palette_count() - number of entries in the active colour table
| gif | the decode object |
Returns the number of RGB triplets at the pointer given by lws_gif_get_palette(), a power of two up to 256, or 0 if none has parsed.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN int lws_gif_get_transparent_index | ( | const lws_gif_t * | gif | ) |
lws_gif_get_transparent_index() - transparent palette index of first frame
| gif | the decode object |
Returns the palette index the first image's graphic control extension (if any) declared transparent, or -1 if there is none. Rows still carry the index bytes; it is the compositor's business to treat them as transparent.
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_bpp | ( | const lws_gif_t * | gif | ) |
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_bitdepth | ( | const lws_gif_t * | gif | ) |
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_components | ( | const lws_gif_t * | gif | ) |
References LWS_EXTERN, and LWS_VISIBLE.
| LWS_VISIBLE LWS_EXTERN unsigned int lws_gif_get_pixelsize | ( | const lws_gif_t * | gif | ) |
1.18.0 