The PHYS attachment (Physical Dimensions) defines the physical dimensions associated with the image in terms of the number of pixels per unit physical distance. This replaces image PPI mark-up and can be edited directly in the Layer Properties window in the user interface for Chasys Draw IES. The metadata consists of a host-defined structure of a fixed length:
#define META_PHYS_VERSION 0x0001
#define META_PHYS_UNIT_PPI 0x00 //pix per inch
#define META_PHYS_UNIT_PPCM 0x01 //pix per centimeter
#define META_PHYS_UNIT_PPM 0x02 //pix per meter
struct meta_PHYS_Obj
{
unsigned short version; //PHYS version
unsigned short unused_1; //unused, set to 0
unsigned long x; //value, x
unsigned long y; //value, y
unsigned char units; //units
unsigned char unused_2[3]; //unused, set to 0
};
The plug-in requests metadata of size sizeof(meta_PHYS_Obj). The plug-in then proceeds to fill the structure with the dimensions, the units of measure and the version of the structure.
