lzw_decode_init_map()

lzw_result fl::third_party::lzw_decode_init_map	(	struct lzw_ctx *	ctx,
		fl::u8	minimum_code_size,
		fl::u32	transparency_idx,
		const fl::u32 *	colour_table,
		const fl::u8 *	input_data,
		fl::size	input_length,
		fl::size	input_pos )

Initialise an LZW decompression context for decoding to colour map values.

For transparency to work correctly, the given client buffer must have the values from the previous frame. The transparency_idx should be a value of 256 or above, if the frame does not have transparency.

Parameters

[in]	ctx	The LZW decompression context to initialise.
[in]	minimum_code_size	The LZW Minimum Code Size.
[in]	transparency_idx	Index representing transparency.
[in]	colour_table	Index to pixel colour mapping.
[in]	input_data	The compressed data.
[in]	input_length	Byte length of compressed data.
[in]	input_pos	Start position in data. Must be position of a size byte at sub-block start.

Returns

LZW_OK on success, or appropriate error code otherwise.

Definition at line 323 of file lzw.cpp.hpp.

{
    lzw_result res;
 
    if (colour_table == nullptr) {
        return LZW_BAD_PARAM;
    }
 
    res = lzw_decode_init(ctx, minimum_code_size,
            input_data, input_length, input_pos);
    if (res != LZW_OK) {
        return res;
    }
 
    ctx->has_transparency = (transparency_idx <= 0xFF);
    ctx->transparency_idx = transparency_idx;
    ctx->colour_map = colour_table;
 
    return LZW_OK;
}

References FL_NOEXCEPT, LZW_BAD_PARAM, lzw_decode_init(), and LZW_OK.

Referenced by nsgif__decode_simple().

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