命令行XRandR与自己的代码之间的差异 [英] Discrepancy between command line XRandR and own code
问题描述
我需要以编程方式获取监视器的刷新率.
I need to programatically get the refresh rate of a monitor.
当我在命令行上输入 xrandr (1.4.1，opensuse 13)时，我得到:
When I type xrandr (1.4.1, opensuse 13) on the command line I get:
Screen 0: minimum 8 x 8, current 1920 x 1200, maximum 16384 x 16384
VGA-0 disconnected primary (normal left inverted right x axis y axis)
DVI-D-0 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 60.0*+
1920x1080 60.0
1680x1050 60.0
1600x1200 60.0
1280x1024 60.0
1280x960 60.0
1024x768 60.0
800x600 60.3
640x480 59.9
HDMI-0 disconnected (normal left inverted right x axis y axis)
除其他外， nvidia-settings -q RefreshRate 确认了此结果.
This result is confirmed by nvidia-settings -q RefreshRate, among other things.
但是... 当我运行以下代码(来源: https://github.com/raboof/xrandr/blob/master/xrandr.c )，使用g ++ 4.8.1编译(带有-lX11 -lXext -lXrandr):
But ... when I run the following code (origin: https://github.com/raboof/xrandr/blob/master/xrandr.c), compiled with g++ 4.8.1 (with -lX11 -lXext -lXrandr) :
int nsize;
int nrate;
short *rates;
XRRScreenSize *sizes;
Display *dpy = XOpenDisplay(NULL);
Window root = DefaultRootWindow(dpy);
XRRScreenConfiguration *conf = XRRGetScreenInfo(dpy, root);
printf ("Current rate: %d\n",XRRConfigCurrentRate(conf));
sizes = XRRConfigSizes(conf, &nsize);
printf(" SZ: Pixels Refresh\n");
for (int i = 0; i < nsize; i++) {
printf("%-2d %5d x %-5d", i, sizes[i].width, sizes[i].height);
rates = XRRConfigRates(conf, i, &nrate);
if (nrate)
printf(" ");
for (int j = 0; j < nrate; j++)
printf("%-4d", rates[j]);
printf("\n");
}
XRRFreeScreenConfigInfo(conf);
我得到:
Current rate: 50
SZ: Pixels Refresh
0 1920 x 1200 50
1 1920 x 1080 51
2 1680 x 1050 52
3 1600 x 1200 53
4 1280 x 1024 54
5 1280 x 960 55
6 1024 x 768 56
7 800 x 600 57
8 640 x 480 58
9 1440 x 900 59
10 1366 x 768 60
11 1280 x 800 61
12 1280 x 720 62
为什么我得到这个结果? 我在做什么错了?
Why am I getting this result? What I am doing wrong?
该软件将OpenGL与GLEW配合使用.这会产生影响吗? 我们确实调用了 glXQueryDrawable(dpy，drawable，GLX_SWAP_INTERVAL_EXT，& val)，但此后，我认为这不会产生任何影响.
The software uses OpenGL with GLEW. can this have any influence? We do call glXQueryDrawable(dpy, drawable, GLX_SWAP_INTERVAL_EXT, &val) but afterwards, and I do not think this should have any influence.
推荐答案
我找到了答案:
如果XRandR服务器支持协议的1.2版，则需要使用适当的功能(我计划通过复制
If the XRandR sever supports version 1.2 of the protocol, then the appropriate functions need to be used (wich I plan to do by copying snippets of code from https://github.com/raboof/xrandr/blob/master/xrandr.c where has_1_2 is true).
我在问题中的代码使用协议版本1.1的函数，因此仅返回元模式.
My code in the question uses functions for the version 1.1 of the protocol, and therefore only the metamodes are returned.
作为一个简单的检查，我尝试了以下两个命令:
As a simple check, I tried the following two commands:
xrandr --q1
xrandr --q12.
事实上，第一个给我的效果与我以编程方式得到的结果相同.
And indeed the 1st one gives me the same result I programatically get.
贷方进入 http://www .ogre3d.org/forums/viewtopic.php?f = 4& t = 65010& start = 200
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