Question

I’m developing an application that shall receive images from a camera device and display them in a GTK window.

The camera delivers raw RGB images (3 bytes per pixel, no alpha channel, fixed size) at a varying frame rate (1-50 fps).

I’ve already done all that hardware stuff and now have a callback function that gets called with every new image captured by the camera.

What is the easyest but fast enough way to display those images in my window?

Here’s what I already tried:

• using gdk_draw_rgb_image() on a gtk drawing area: basically worked, but rendered so slow that the drawing processes overlapped and the application crashed after the first few frames, even at 1 fps capture rate.

• allocating a GdkPixbuf for each new frame and calling gtk_image_set_from_pixbuf() on a gtk image widget: only displays the first frame, then I see no change in the window. May be a bug in my code, but don’t know if that will be fast enough.

• using Cairo (cairo_set_source_surface(), then cairo_paint()): seemed pretty fast, but the image looked striped, don’t know if the image format is compatible.

Currently I’m thinking about trying something like gstreamer and treating those images like a video stream, but I’m not sure whether this is like an overkill for my simple mechanism.

Thanks in advance for any advice!

Answer 1

The entire GdkRGB API seems to be deprecated, so that’s probably not the recommended way to solve this.

The same goes for the call to render a pixbuf. The documentation there points at Cairo, so the solution seems to be to continue investigating why your image looked incorrect when rendered by Cairo.