Linked by Thom Holwerda on Sat 28th Jun 2008 22:09 UTC, submitted by diegocg
X11, Window Managers "Maybe I'm just naive, but designing a graphics API such that all image data had to be sent over a socket to another process every time the image needed to be drawn seems like complete idiocy. Unfortunately, that is precisely what the X Window System forces a program to do, and exactly what Cairo does when drawing images in Linux - a full copy of the image data, send to another process, no less, every time it is drawn. One would think there would be some room for improvement. Unsurprisingly, others felt the same way about X, and decided to write an extension, Xlib Shm or XShm for short, that allows images to placed in a shared memory segment from which the X server reads which allows the program to avoid the memory copy. GTK already makes use of the XShm extension, and it seems like a good idea to see if Gecko couldn't do the same."
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RE[4]: Overstated conclusion
by dmantione on Sun 29th Jun 2008 09:39 UTC in reply to "RE[3]: Overstated conclusion"
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It sounds like you're thinking of VNC. I'm pretty sure that RDP only sends the *instructions* and raw image data (if needed) to draw the window on the client side.

So no, watching a DVD wouldn't be a full-screen update @ refresh rate.

Try it and watch the difference between Windows & Linux. Highly recommended.

The difference between VNC and RDP is that VNC captures the desktop and sends modified part, while RDP sits at the GDI level, it sends GDI drawing commands over the network. As the GDI has no "overlay" facilties, watching video on RDP falls back to sending RGB images over the network.

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