Linux 的窗口系统为什么这么慢？

choujs

相信大家都有感觉吧？Linux的窗口系统比Windows慢了很多很多。那么，有没有人考虑过这是为什么的？希望大家探讨一下。

raynorli

没研究过qt，只说说gtk
从系统上来说gtk的窗口其实并不慢，但窗口里有滚动条时，滚动的操作是很慢的，原因是gtk默认使用doublebuffer，是用来防止在同一位置画多张图片时屏幕闪烁的，对于要做动画是很方便的。但影响速度，对于只画一张图片时，没有作用，因此编程时可以尝试关闭它。
一般的程序使用gtk默认的设置，滚动时只产生要新画部分的event，gtk自己处理图片向上移动的操作，估计也使用了doublebuffer，导致速度降低。

powerme

那怎么紧止??

raynorli

gtk_widget_set_double_buffered ()
void        gtk_widget_set_double_buffered  (GtkWidget *widget,
                                             gboolean double_buffered);


Widgets are double buffered by default; you can use this function to turn off the buffering. "Double buffered" simply means that gdk_window_begin_paint_region() and gdk_window_end_paint() are called automatically around expose events sent to the widget. gdk_window_begin_paint() diverts all drawing to a widget's window to an offscreen buffer, and gdk_window_end_paint() draws the buffer to the screen. The result is that users see the window update in one smooth step, and don't see individual graphics primitives being rendered.

In very simple terms, double buffered widgets don't flicker, so you would only use this function to turn off double buffering if you had special needs and really knew what you were doing.



widget? a GtkWidget  
double_buffered? TRUE to double-buffer a widget