Solved my own problem :-)
For future reference here is the solution:
class PycairoContext(Structure):
_fields_ = [("PyObject_HEAD", c_byte * object.__basicsize__),
("ctx", c_void_p),
("base", c_void_p)]
z = PycairoContext.from_address(id(ctx))
print z.ctx
where ctx is the python object
and PycairoContext is the C object of ctx
Full Code : ( simple rsvg / librsvg ctypes wrapper )
------------------------------------------
def WebColour(sCol):
#print sCol
ic = [int(sCol[i:i+2], 16)/255.0 for i in range(1, 7, 2)]
#print ic
return ic
from ctypes import *
l=CDLL('librsvg-2-2.dll')
g=CDLL('libgobject-2.0-0.dll')
print g.g_type_init()
import cairo
WIDTH, HEIGHT = 800, 800
# Setup Cairo
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, WIDTH, HEIGHT)
ctx = cairo.Context(surface)
error=''
handle1 = l.rsvg_handle_new_from_file('test.svg',error)
print error
print handle1
class PycairoContext(Structure):
_fields_ = [("PyObject_HEAD", c_byte * object.__basicsize__),
("ctx", c_void_p),
("base", c_void_p)]
z = PycairoContext.from_address(id(ctx))
print z.ctx
print '>>',l.rsvg_handle_render_cairo(handle1, z.ctx)
#add some cairo stuff on top
bg = WebColour('#FFFFFF')
ctx.set_source_rgb(bg[0],bg[1],bg[2])
# Set thickness of brush
ctx.set_line_width(15)
# Draw out the triangle using absolute coordinates
ctx.move_to(200, 100)
ctx.line_to(300, 300)
ctx.rel_line_to(-200, 0)
ctx.close_path()
# Apply the ink
ctx.stroke()
surface.write_to_png("test.png")
------------------------------------------
AngelBlaZe wrote:
> Can you access the c object of a python object directly? Can this be
> done in ctypes or directly throught python functions without reverting
> to forking the python module?
>
> scanario:
> I have pyctx object that i get in python like this:
>
> pyctx = cairo.Context(surface)
>
> defined in the python extension this:
>
> typedef struct {
> PyObject_HEAD
> cairo_t *ctx;
> PyObject *base; /* base object used to create context, or NULL */
> } PycairoContext;
>
> PyObject *
> PycairoContext_FromContext(cairo_t *ctx, PyTypeObject *type, PyObject
> *base)
> {
> PyObject *o;
>
> assert (ctx != NULL);
>
> if (Pycairo_Check_Status (cairo_status (ctx))) {
> cairo_destroy (ctx);
> return NULL;
> }
>
> if (type == NULL)
> type = &PycairoContext_Type;
> o = PycairoContext_Type.tp_alloc (type, 0);
> if (o) {
> ((PycairoContext *)o)->ctx = ctx;
> Py_XINCREF(base);
> ((PycairoContext *)o)->base = base;
> } else {
> cairo_destroy (ctx);
> }
> return o;
> }
>
> Now my question is:
> Is there any way to access/get a pointer to PycairoContext->ctx from
> python object (pyctx)?
>
> A long shot i know :-)
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