api_reference.md

Specifications

Exported Functions

EncodeBGRAtoWebP

int EncodeBGRAtoWebP(
    const uint8_t* bgra,
    int width,
    int height,
    int stride,
    float quality,
    int lossless,
    uint8_t** output,
    size_t* outputSize);

• Encodes a BGRA format image into WebP.
• Set lossless = 1 for lossless encoding, and 0 for lossy encoding.
• The quality parameter is only applicable during lossy encoding (ranging from 0 to 100).
• Returns 1 on success, or 0 on failure.

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EncodeRGBAtoWebP

int EncodeRGBAtoWebP(
    const uint8_t* rgba,
    int width,
    int height,
    int stride,
    float quality,
    int lossless,
    uint8_t** output,
    size_t* outputSize);

• The RGBA format variant of the encoder.
• The functional specifications are identical to the BGRA version.

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FreeWebP

void FreeWebP(uint8_t* data);

• Frees the memory allocated by the encoding functions.
• CRITICAL: This function must always be called after processing to prevent memory leaks.

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Important Notes

• The output parameter is a pointer-to-pointer (e.g., out IntPtr in C#) used to receive the allocated memory address.
• The output buffer is allocated internally by the libwebp library.
• Ensure FreeWebP is always executed after usage to properly release memory.
• The stride parameter represents the data width of a single row in bytes.
• For 4-channel (RGBA/BGRA) images, the stride is typically calculated as width * 4.
• Providing an incorrect or mismatched pixel format will result in a corrupted output image.