Hi, Le 18/02/2013 11:10, Rena a écrit : > Hi, just joined the mailing list, been using GTK and related projects > for a while now. Recently I've been developing a Game Boy emulator > that uses GtkDrawingArea and GdkPixbuf to display the game screen. > > In addition to the game output I want to also be able to draw text and > shapes on the display window, and Cairo seems to be the ideal way to > draw shapes. I'm already using Cairo to copy the Pixbuf to the > GtkDrawingArea, so that seems like a good sign that Cairo and > GdkPixbuf should interact nicely. > > However, it doesn't look like they should be able to interact at all, > as they don't seem to be able to agree on a pixel format: > http://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-Image-Data-in-Memory.html#gdk-pixbuf-new-from-data > "Currently only RGB images with 8 bits per sample are supported." > http://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-The-GdkPixbuf-Structure.html#image-data > "p[0] = red; p[1] = green; p[2] = blue; p[3] = alpha;" > That seems to suggest that GdkPixbuf supports only RGB (24-bit) and > RGBA (32-bit). But... > > http://www.cairographics.org/manual/cairo-Image-Surfaces.html#cairo-format-t > CAIRO_FORMAT_ARGB32 is ARGB ("each pixel is a 32-bit quantity, with > alpha in the upper 8 bits..."). CAIRO_FORMAT_RGB24 is xRGB ("each > pixel is a 32-bit quantity, with the upper 8 bits unused..."). Neither > of those are RGB or RGBA. So, how can Cairo operate on a surface > provided by GdkPixbuf?
I don't really get it. You say you already use Cairo to draw your pixbuf, but also that you can't see how to use a GdkPixbuf with Cairo? This seems contradictory to me. Anyway, what you want is gdk_cairo_set_source_pixbuf()[1] that does the appropriate conversions to create a Cairo pattern from a GdkPixbuf. Then you can use this pattern like any other Cairo pattern (e.g. cairo_paint()), and you're done. Hope it helps. Colomban [1] http://developer.gnome.org/gdk/stable/gdk-Cairo-Interaction.html#gdk-cairo-set-source-pixbuf _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org https://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
