nsgif__parse_logical_screen_descriptor()

static nsgif_error fl::third_party::nsgif__parse_logical_screen_descriptor ( struct nsgif * gif, const fl::u8 ** pos )

static

Read Logical Screen Descriptor.

7-byte Logical Screen Descriptor is:

+0 SHORT Logical Screen Width +2 SHORT Logical Screen Height +4 CHAR Packed Fields 1BIT Global Colour Table Flag 3BITS Colour Resolution 1BIT Sort Flag 3BITS Size of Global Colour Table +5 CHAR Background Colour Index +6 CHAR Pixel Aspect Ratio

Parameters

[in]	gif	The GIF object we're decoding.
[in,out]	pos	The current buffer position, updated on success.

Returns

NSGIF_OK on success, appropriate error otherwise.

Definition at line 1592 of file gif.cpp.hpp.

{
    const fl::u8 *data = *pos;
    fl::size len = gif->buf + gif->buf_len - data;
 
    if (len < 7) {
        return NSGIF_ERR_END_OF_DATA;
    }
 
    gif->info.width = data[0] | (data[1] << 8);
    gif->info.height = data[2] | (data[3] << 8);
    gif->info.global_palette = data[4] & NSGIF_COLOUR_TABLE_MASK;
    gif->colour_table_size = 2 << (data[4] & NSGIF_COLOUR_TABLE_SIZE_MASK);
    gif->bg_index = data[5];
    gif->aspect_ratio = data[6];
    gif->info.loop_max = 1;
 
    *pos += 7;
    return NSGIF_OK;
}

References FL_NOEXCEPT, NSGIF_COLOUR_TABLE_MASK, NSGIF_COLOUR_TABLE_SIZE_MASK, NSGIF_ERR_END_OF_DATA, NSGIF_OK, and pos.

Referenced by nsgif_data_scan().

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