Sets an offset that is added to the device coordinates determined
by the CTM when drawing to surface. One use case for this function
is when we want to create a cairo_surface_t that redirects drawing
for a portion of an onscreen surface to an offscreen surface in a
way that is completely invisible to the user of the cairo
API. Setting a transformation via cairo_translate() isn't
sufficient to do this, since functions like
cairo_device_to_user() will expose the hidden offset.
Note that the offset affects drawing to the surface as well as
using the surface in a source pattern.
Sets an offset that is added to the device coordinates determined by the CTM when drawing to surface. One use case for this function is when we want to create a cairo_surface_t that redirects drawing for a portion of an onscreen surface to an offscreen surface in a way that is completely invisible to the user of the cairo API. Setting a transformation via cairo_translate() isn't sufficient to do this, since functions like cairo_device_to_user() will expose the hidden offset. Note that the offset affects drawing to the surface as well as using the surface in a source pattern.