diff options
| -rw-r--r-- | include/nsgif.h | 31 | ||||
| -rw-r--r-- | src/gif.c | 10 |
2 files changed, 41 insertions, 0 deletions
diff --git a/include/nsgif.h b/include/nsgif.h index 03f9b16..a02597c 100644 --- a/include/nsgif.h +++ b/include/nsgif.h @@ -408,4 +408,35 @@ const nsgif_frame_info_t *nsgif_get_frame_info( const nsgif_t *gif, uint32_t frame); +/** + * Configure handling of small frame delays. + * + * Historically people created GIFs with a tiny frame delay, however the slow + * hardware of the time meant they actually played much slower. As computers + * sped up, to prevent animations playing faster than intended, decoders came + * to ignore overly small frame delays. + * + * By default a \ref nsgif_frame_prepare() managed animation will override + * frame delays of less than 2 centiseconds with a default frame delay of + * 10 centiseconds. This matches the behaviour of web browsers and other + * renderers. + * + * Both the minimum and the default values can be overridden for a given GIF + * by the client. To get frame delays exactly as specified by the GIF file, set + * \ref delay_min to zero. + * + * Note that this does not affect the frame delay in the frame info + * (\ref nsgif_frame_info_t) structure, which will always contain values + * specified by the GIF. + * + * \param[in] gif The \ref nsgif_t object to configure. + * \param[in] delay_min The minimum frame delay in centiseconds. + * \param[in] delay_default The delay to use if a frame delay is less than + * \ref delay_min. + */ +void nsgif_set_frame_delay_behaviour( + nsgif_t *gif, + uint16_t delay_min, + uint16_t delay_default); + #endif @@ -1450,6 +1450,16 @@ nsgif_error nsgif_create( return NSGIF_OK; } +/* exported function documented in nsgif.h */ +void nsgif_set_frame_delay_behaviour( + nsgif_t *gif, + uint16_t delay_min, + uint16_t delay_default) +{ + gif->delay_min = delay_min; + gif->delay_default = delay_default; +} + /** * Read GIF header. * |