Online Help for Chasys Photo: SDK - Layer Attachments

Online Help for Chasys Photo: SDK - Layer Attachments - MARK

SDK - Layer Attachments - MARK

Using the MARK meta-type

The MARK attachment (Layer Mark-up) allows plug-ins to pass on descriptive information such as EXIF data. It is a null-terminated plain-text (UTF-8) segment consisting of keywords and values separated by the equals sign, e.g.:

image.bpp=32;
exif.artist=John Paul Chacha;
exif.software=Chasys Photo;
exif.GPS.version=2,2,0,0;
exif.GPS.latitude.pos=1.2833°;
exif.GPS.latitude.ref=S;
exif.GPS.longitude.pos=36.8167°;
exif.GPS.longitude.ref=E;
exif.GPS.altitude.pos=1661 m;
exif.GPS.altitude.ref=0 (above sea-level);

All keywords must take the form [namespace.parameter]. This is to avoid conflicts. For example, a blah plug-in could append the following mark-up to a layer:

blah.engine="OpenGL";
blah.import="mesh1.x";
blah.max_size=4096;

The terminating NULL character must be included for the attachment to be valid. This NULL must be included in metadata size calculations.

Sample Code

Here’s some sample code that creates MARK metadata:
TAGS: Chasys Photo Source Code, Attachment, Metadata, MARK

int dpi_x,dpi_y;
char markup[3072];

... ...

//insert MARK attachment
if(data->meta_write)
{
    StringCchPrintfA(markup,_countof(markup),"image.bpp=%i;\r\n",image.bits_per_pixel);
    data->meta_data=(unsigned char*)markup;
    data->meta_write(data,"MARK",strlen(markup)+1); //include terminating NULL
}