Python ctypes和librsvg出错
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我正在尝试使用ctypes来包装librsvg的基本功能，但是我遇到了段错误。
C：
// pycairo excerpt
typedef struct {
PyObject_HEAD
cairo_t *ctx;
PyObject *base; /* base object used to create context, or NULL */
} PycairoContext;
// librsvg excerpt
RsvgHandle * rsvg_handle_new_from_file (const gchar * file_name, GError ** error);
// ...
gboolean rsvg_handle_render_cairo (RsvgHandle * handle, cairo_t * cr);
from ctypes import *
from ctypes import util
librsvg = cdll.LoadLibrary(\'/brew/lib/librsvg-2.2.dylib\')
libgobject = cdll.LoadLibrary(\'/brew/lib/libgobject-2.0.dylib\')
libgobject.g_type_init()
class RSVGDimensionData(Structure):
_fields_ = (
(\'width\', c_int),
(\'height\', c_int),
(\'em\', c_double),
(\'ex\', c_double)
)
class PycairoContext(Structure):
_fields_ = (
(\'PyObject_HEAD\', c_byte * object.__basicsize__),
(\'ctx\', c_void_p),
(\'base\', c_void_p)
)
class RSVGHandle(object):
def __init__(self, path):
self.path = path
self.error = \'\'
self.handle = librsvg.rsvg_handle_new_from_file(self.path, self.error)
def render_cairo(self, context):
context.save()
z = PycairoContext.from_address(id(context))
librsvg.rsvg_handle_render_cairo(self.handle, z.ctx)
context.restore()
import cairo
h = RSVGHandle(\'bank.svg\')
s = cairo.ImageSurface(cairo.FORMAT_ARGB32, 100, 100)
ctx = cairo.Context(s)
# segmentation fault....
h.render_cairo(ctx)
没有找到相关结果
已邀请:
2 个回复
填盖
在适当的地方。然后，它（也）可以在OSX中以32位或64位工作。 但是，我发现增强基本包装更为有用，以便处理从文件创建句柄时可能出现的错误。以下是执行此操作的基本包装。它还以几乎相同的方式复制了标准“ 5”绑定的基本用法。from ctypes import CDLL, POINTER, Structure, byref, util from ctypes import c_bool, c_byte, c_void_p, c_int, c_double, c_uint32, c_char_p class _PycairoContext(Structure): _fields_ = [(\"PyObject_HEAD\", c_byte * object.__basicsize__), (\"ctx\", c_void_p), (\"base\", c_void_p)] class _RsvgProps(Structure): _fields_ = [(\"width\", c_int), (\"height\", c_int), (\"em\", c_double), (\"ex\", c_double)] class _GError(Structure): _fields_ = [(\"domain\", c_uint32), (\"code\", c_int), (\"message\", c_char_p)] def _load_rsvg(rsvg_lib_path=None, gobject_lib_path=None): if rsvg_lib_path is None: rsvg_lib_path = util.find_library(\'rsvg-2\') if gobject_lib_path is None: gobject_lib_path = util.find_library(\'gobject-2.0\') l = CDLL(rsvg_lib_path) g = CDLL(gobject_lib_path) g.g_type_init() l.rsvg_handle_new_from_file.argtypes = [c_char_p, POINTER(POINTER(_GError))] l.rsvg_handle_new_from_file.restype = c_void_p l.rsvg_handle_render_cairo.argtypes = [c_void_p, c_void_p] l.rsvg_handle_render_cairo.restype = c_bool l.rsvg_handle_get_dimensions.argtypes = [c_void_p, POINTER(_RsvgProps)] return l _librsvg = _load_rsvg() class Handle(object): def __init__(self, path): lib = _librsvg err = POINTER(_GError)() self.handle = lib.rsvg_handle_new_from_file(path.encode(), byref(err)) if self.handle is None: gerr = err.contents raise Exception(gerr.message) self.props = _RsvgProps() lib.rsvg_handle_get_dimensions(self.handle, byref(self.props)) def render_cairo(self, ctx): \"\"\"Returns True is drawing succeeded.\"\"\" z = _PycairoContext.from_address(id(ctx)) return _librsvg.rsvg_handle_render_cairo(self.handle, z.ctx)妒垮
注意，我将两个参数包装在c_void_p中，使它们成为void *指针。不理想，但似乎可行。