Sets all image data to zero. But if color space is YCBCR, LAB or LUV, and data type is BYTE or USHORT, then
* data is initialized with 128 or 32768 accordingly. Alpha is initialized as transparent (0).
*
* \verbatim image:Clear() [in Lua 5] \endverbatim
* \ingroup imgclass
Sets all image data to zero. But if color space is YCBCR, LAB or LUV, and data type is BYTE or USHORT, then * data is initialized with 128 or 32768 accordingly. Alpha is initialized as transparent (0). * * \verbatim image:Clear() [in Lua 5] \endverbatim * \ingroup imgclass