#---------------------------------------------------------------------- # Name: wx.lib.wxcairo # Purpose: Glue code to allow the pycairo package to be used # with a wx.DC as the cairo surface. # # Author: Robin Dunn # # Created: 3-Sept-2008 # Copyright: (c) 2008 by Total Control Software # Licence: wxWindows license # # Tags: phoenix-port, py3-port #---------------------------------------------------------------------- """ This module provides some glue code that allows the pycairo package to be used for drawing direclty on wx.DCs. In cairo terms, the DC is the drawing surface. The `CairoContextFromDC` function in this module will return an instance of the pycairo Context class that is ready for drawing, using the native cairo surface type for the current platform. This module requires the pycairo package, and makes use of ctypes for fetching the pycairo C API and also for digging into the cairo library itself. To use Cairo with wxPython you will need to have a few dependencies installed. On Linux and other unix-like systems you may already have them, or can easily get them with your system's package manager. Just check if libcairo and pycairo are installed. On Mac you can get Cairo from MacPorts or Fink. If you are also using MacPorts or Fink for your Python installation then you should be able to get pycairo the same way. Otherwise it's real easy to build and install pycairo for the Python framework installation. Just get the source tarball from http://pypi.python.org/pypi/pycairo and do the normal 'python setup.py install' dance. On Windows you can get a Cairo DLL from here: http://www.gtk.org/download/win32.php You'll also want to get the zlib and libpng binaries from the same page. Once you get those files extract the DLLs from each of the zip files and copy them to some place on your PATH. Finally, there is an installer for the pycairo pacakge here: http://wxpython.org/cairo/ """ # TODO: Support printer surfaces? import wx from wx.lib.six import PY3 import cairo import ctypes import ctypes.util #---------------------------------------------------------------------------- # A reference to the cairo shared lib via ctypes.CDLL cairoLib = None # A reference to the pycairo C API structure pycairoAPI = None # a convenience function, just to save a bit of typing below def voidp(ptr): """Convert a SIP void* type to a ctypes c_void_p""" if PY3: return ctypes.c_void_p(int(ptr)) else: return ctypes.c_void_p(long(ptr)) #---------------------------------------------------------------------------- def ContextFromDC(dc): """ Creates and returns a Cairo context object using the wxDC as the surface. (Only window, client, paint and memory DC's are allowed at this time.) """ if not isinstance(dc, wx.WindowDC) and not isinstance(dc, wx.MemoryDC): raise TypeError("Only window and memory DC's are supported at this time.") if 'wxMac' in wx.PlatformInfo: width, height = dc.GetSize() # use the CGContextRef of the DC to make the cairo surface cgc = dc.GetHandle() assert cgc is not None, "Unable to get CGContext from DC." cgref = voidp( cgc ) surfaceptr = voidp(surface_create(cgref, width, height)) # create a cairo context for that surface ctxptr = voidp(cairo_create(surfaceptr)) # Turn it into a pycairo context object ctx = pycairoAPI.Context_FromContext(ctxptr, pycairoAPI.Context_Type, None) # The context keeps its own reference to the surface cairoLib.cairo_surface_destroy(surfaceptr) elif 'wxMSW' in wx.PlatformInfo: # This one is easy, just fetch the HDC and use PyCairo to make # the surface and context. hdc = dc.GetHandle() # Ensure the pointer value is clampped into the range of a C signed long hdc = ctypes.c_long(hdc) surface = cairo.Win32Surface(hdc.value) ctx = cairo.Context(surface) elif 'wxGTK' in wx.PlatformInfo: # Get the GdkDrawable from the dc drawable = voidp( dc.GetHandle() ) # Call a GDK API to create a cairo context ctxptr = gdkLib.gdk_cairo_create(drawable) # Turn it into a pycairo context object ctx = pycairoAPI.Context_FromContext(ctxptr, pycairoAPI.Context_Type, None) else: raise NotImplementedError("Help me, I'm lost...") return ctx #---------------------------------------------------------------------------- def FontFaceFromFont(font): """ Creates and returns a cairo.FontFace object from the native information in a wx.Font. """ if 'wxMac' in wx.PlatformInfo: fontfaceptr = font_face_create(voidp(font.OSXGetCGFont())) fontface = pycairoAPI.FontFace_FromFontFace(fontfaceptr) elif 'wxMSW' in wx.PlatformInfo: fontfaceptr = voidp( cairoLib.cairo_win32_font_face_create_for_hfont( ctypes.c_ulong(font.GetHFONT())) ) fontface = pycairoAPI.FontFace_FromFontFace(fontfaceptr) elif 'wxGTK' in wx.PlatformInfo: # wow, this is a hell of a lot of steps... desc = voidp( font.GetPangoFontDescription() ) pcfm = voidp(pcLib.pango_cairo_font_map_get_default()) pctx = voidp(gdkLib.gdk_pango_context_get()) pfnt = voidp( pcLib.pango_font_map_load_font(pcfm, pctx, desc) ) scaledfontptr = voidp( pcLib.pango_cairo_font_get_scaled_font(pfnt) ) fontfaceptr = voidp(cairoLib.cairo_scaled_font_get_font_face(scaledfontptr)) cairoLib.cairo_font_face_reference(fontfaceptr) fontface = pycairoAPI.FontFace_FromFontFace(fontfaceptr) gdkLib.g_object_unref(pctx) else: raise NotImplementedError("Help me, I'm lost...") return fontface #---------------------------------------------------------------------------- # wxBitmap <--> ImageSurface def BitmapFromImageSurface(surface): """ Create a wx.Bitmap from a Cairo ImageSurface. """ format = surface.get_format() if format not in [cairo.FORMAT_ARGB32, cairo.FORMAT_RGB24]: raise TypeError("Unsupported format") width = surface.get_width() height = surface.get_height() stride = surface.get_stride() data = surface.get_data() if format == cairo.FORMAT_ARGB32: fmt = wx.BitmapBufferFormat_ARGB32 else: fmt = wx.BitmapBufferFormat_RGB32 bmp = wx.Bitmap(width, height, 32) bmp.CopyFromBuffer(data, fmt, stride) return bmp def ImageSurfaceFromBitmap(bitmap): """ Create an ImageSurface from a wx.Bitmap """ width, height = bitmap.GetSize() if bitmap.ConvertToImage().HasAlpha(): format = cairo.FORMAT_ARGB32 fmt = wx.BitmapBufferFormat_ARGB32 else: format = cairo.FORMAT_RGB24 fmt = wx.BitmapBufferFormat_RGB32 try: stride = cairo.ImageSurface.format_stride_for_width(format, width) except AttributeError: stride = width * 4 surface = cairo.ImageSurface(format, width, height) bitmap.CopyToBuffer(surface.get_data(), fmt, stride) surface.mark_dirty() return surface #---------------------------------------------------------------------------- # Only implementation helpers after this point #---------------------------------------------------------------------------- def _findCairoLib(): """ Try to locate the Cairo shared library and make a CDLL for it. """ global cairoLib if cairoLib is not None: return names = ['cairo', 'cairo-2', 'libcairo', 'libcairo-2'] # first look using just the base name for name in names: try: cairoLib = ctypes.CDLL(name) return except: pass # if that didn't work then use the ctypes util to search the paths # appropriate for the system for name in names: location = ctypes.util.find_library(name) if location: try: cairoLib = ctypes.CDLL(location) return except: pass # If the above didn't find it on OS X then we still have a # trick up our sleeve... if 'wxMac' in wx.PlatformInfo: # look at the libs linked to by the pycairo extension module import macholib.MachO m = macholib.MachO.MachO(cairo._cairo.__file__) for h in m.headers: for idx, name, path in h.walkRelocatables(): if 'libcairo' in path: try: cairoLib = ctypes.CDLL(path) return except: pass if not cairoLib: raise RuntimeError("Unable to find the Cairo shared library") #---------------------------------------------------------------------------- # For other DLLs we'll just use a dictionary to track them, as there # probably isn't any need to use them outside of this module. _dlls = dict() def _findHelper(names, key, msg): dll = _dlls.get(key, None) if dll is not None: return dll location = None for name in names: location = ctypes.util.find_library(name) if location: break if not location: raise RuntimeError(msg) dll = ctypes.CDLL(location) _dlls[key] = dll return dll def _findGDKLib(): return _findHelper(['gdk-x11-2.0'], 'gdk', "Unable to find the GDK shared library") def _findPangoCairoLib(): return _findHelper(['pangocairo-1.0'], 'pangocairo', "Unable to find the pangocairo shared library") def _findAppSvcLib(): return _findHelper(['ApplicationServices'], 'appsvc', "Unable to find the ApplicationServices Framework") #---------------------------------------------------------------------------- # Pycairo exports a C API in a structure via a PyCObject. Using # ctypes will let us use that API from Python too. We'll use it to # convert a C pointer value to pycairo objects. The information about # this API structure is gleaned from pycairo.h. class Pycairo_CAPI(ctypes.Structure): if cairo.version_info < (1,8): # This structure is known good with pycairo 1.6.4 _fields_ = [ ('Context_Type', ctypes.py_object), ('Context_FromContext', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object, ctypes.py_object)), ('FontFace_Type', ctypes.py_object), ('FontFace_FromFontFace', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('FontOptions_Type', ctypes.py_object), ('FontOptions_FromFontOptions', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Matrix_Type', ctypes.py_object), ('Matrix_FromMatrix', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Path_Type', ctypes.py_object), ('Path_FromPath', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Pattern_Type', ctypes.py_object), ('SolidPattern_Type', ctypes.py_object), ('SurfacePattern_Type', ctypes.py_object), ('Gradient_Type', ctypes.py_object), ('LinearGradient_Type', ctypes.py_object), ('RadialGradient_Type', ctypes.py_object), ('Pattern_FromPattern', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('ScaledFont_Type', ctypes.py_object), ('ScaledFont_FromScaledFont', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Surface_Type', ctypes.py_object), ('ImageSurface_Type', ctypes.py_object), ('PDFSurface_Type', ctypes.py_object), ('PSSurface_Type', ctypes.py_object), ('SVGSurface_Type', ctypes.py_object), ('Win32Surface_Type', ctypes.py_object), ('XlibSurface_Type', ctypes.py_object), ('Surface_FromSurface', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object)), ('Check_Status', ctypes.PYFUNCTYPE(ctypes.c_int, ctypes.c_int))] # This structure is known good with pycairo 1.8.4. # We have to also test for (1,10,8) because pycairo 1.8.10 has an # incorrect version_info value elif cairo.version_info < (1,9) or cairo.version_info == (1,10,8): _fields_ = [ ('Context_Type', ctypes.py_object), ('Context_FromContext', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object, ctypes.py_object)), ('FontFace_Type', ctypes.py_object), ('ToyFontFace_Type', ctypes.py_object), #** new in 1.8.4 ('FontFace_FromFontFace', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('FontOptions_Type', ctypes.py_object), ('FontOptions_FromFontOptions', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Matrix_Type', ctypes.py_object), ('Matrix_FromMatrix', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Path_Type', ctypes.py_object), ('Path_FromPath', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Pattern_Type', ctypes.py_object), ('SolidPattern_Type', ctypes.py_object), ('SurfacePattern_Type', ctypes.py_object), ('Gradient_Type', ctypes.py_object), ('LinearGradient_Type', ctypes.py_object), ('RadialGradient_Type', ctypes.py_object), ('Pattern_FromPattern', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object)), #** changed in 1.8.4 ('ScaledFont_Type', ctypes.py_object), ('ScaledFont_FromScaledFont', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Surface_Type', ctypes.py_object), ('ImageSurface_Type', ctypes.py_object), ('PDFSurface_Type', ctypes.py_object), ('PSSurface_Type', ctypes.py_object), ('SVGSurface_Type', ctypes.py_object), ('Win32Surface_Type', ctypes.py_object), ('XlibSurface_Type', ctypes.py_object), ('Surface_FromSurface', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object)), ('Check_Status', ctypes.PYFUNCTYPE(ctypes.c_int, ctypes.c_int))] # This structure is known good with pycairo 1.10.0. They keep adding stuff # to the middle of the structure instead of only adding to the end! elif cairo.version_info < (1,11): _fields_ = [ ('Context_Type', ctypes.py_object), ('Context_FromContext', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object, ctypes.py_object)), ('FontFace_Type', ctypes.py_object), ('ToyFontFace_Type', ctypes.py_object), ('FontFace_FromFontFace', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('FontOptions_Type', ctypes.py_object), ('FontOptions_FromFontOptions', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Matrix_Type', ctypes.py_object), ('Matrix_FromMatrix', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Path_Type', ctypes.py_object), ('Path_FromPath', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Pattern_Type', ctypes.py_object), ('SolidPattern_Type', ctypes.py_object), ('SurfacePattern_Type', ctypes.py_object), ('Gradient_Type', ctypes.py_object), ('LinearGradient_Type', ctypes.py_object), ('RadialGradient_Type', ctypes.py_object), ('Pattern_FromPattern', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object)), #** changed in 1.8.4 ('ScaledFont_Type', ctypes.py_object), ('ScaledFont_FromScaledFont', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)), ('Surface_Type', ctypes.py_object), ('ImageSurface_Type', ctypes.py_object), ('PDFSurface_Type', ctypes.py_object), ('PSSurface_Type', ctypes.py_object), ('SVGSurface_Type', ctypes.py_object), ('Win32Surface_Type', ctypes.py_object), ('Win32PrintingSurface_Type', ctypes.py_object), #** new ('XCBSurface_Type', ctypes.py_object), #** new ('XlibSurface_Type', ctypes.py_object), ('Surface_FromSurface', ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p, ctypes.py_object)), ('Check_Status', ctypes.PYFUNCTYPE(ctypes.c_int, ctypes.c_int))] def _loadPycairoAPI(): global pycairoAPI if pycairoAPI is not None: return if PY3: PyCapsule_GetPointer = ctypes.pythonapi.PyCapsule_GetPointer PyCapsule_GetPointer.argtypes = [ctypes.py_object, ctypes.c_char_p] PyCapsule_GetPointer.restype = ctypes.c_void_p ptr = PyCapsule_GetPointer(cairo.CAPI, b'cairo.CAPI') else: PyCObject_AsVoidPtr = ctypes.pythonapi.PyCObject_AsVoidPtr PyCObject_AsVoidPtr.argtypes = [ctypes.py_object] PyCObject_AsVoidPtr.restype = ctypes.c_void_p ptr = PyCObject_AsVoidPtr(cairo.CAPI) pycairoAPI = ctypes.cast(ptr, ctypes.POINTER(Pycairo_CAPI)).contents #---------------------------------------------------------------------------- # Load these at import time. That seems a bit better than doing it at # first use... _findCairoLib() _loadPycairoAPI() if 'wxMac' in wx.PlatformInfo: surface_create = cairoLib.cairo_quartz_surface_create_for_cg_context surface_create.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_int] surface_create.restype = ctypes.c_void_p cairo_create = cairoLib.cairo_create cairo_create.argtypes = [ctypes.c_void_p] cairo_create.restype = ctypes.c_void_p font_face_create = cairoLib.cairo_quartz_font_face_create_for_cgfont font_face_create.argtypes = [ctypes.c_void_p] font_face_create.restype = ctypes.c_void_p elif 'wxMSW' in wx.PlatformInfo: cairoLib.cairo_win32_font_face_create_for_hfont.restype = ctypes.c_void_p elif 'wxGTK' in wx.PlatformInfo: gdkLib = _findGDKLib() pcLib = _findPangoCairoLib() gdkLib.gdk_cairo_create.restype = ctypes.c_void_p pcLib.pango_cairo_font_map_get_default.restype = ctypes.c_void_p gdkLib.gdk_pango_context_get.restype = ctypes.c_void_p pcLib.pango_font_map_load_font.restype = ctypes.c_void_p pcLib.pango_cairo_font_get_scaled_font.restype = ctypes.c_void_p cairoLib.cairo_scaled_font_get_font_face.restype = ctypes.c_void_p #----------------------------------------------------------------------------