在 C/Linux 中显示持续更新图像的简单方法 [英] Easy way to display a continuously updating image in C/Linux
问题描述
我是一名科学家,对 C 进行数值计算非常熟悉,但我需要一些帮助来显示结果.我希望能够在一个窗口中显示一个不断更新的位图,它是根据实时数据计算出来的.我希望能够非常快地更新图像(例如快于 1 帧/秒,最好是 100 fps).例如:
I'm a scientist who is quite comfortable with C for numerical computation, but I need some help with displaying the results. I want to be able to display a continuously updated bitmap in a window, which is calculated from realtime data. I'd like to be able to update the image quite quickly (e.g. faster than 1 frame/second, preferably 100 fps). For example:
char image_buffer[width*height*3];//rgb data
initializewindow();
for (t=0;t<t_end;t++)
{
getdata(data);//get some realtime data
docalcs(image_buffer, data);//process the data into an image
drawimage(image_buffer);//draw the image
}
在 linux (Ubuntu) 上执行此操作的最简单方法是什么?我应该为 initializewindow() 和 drawimage() 使用什么?
What's the easiest way to do this on linux (Ubuntu)? What should I use for initializewindow() and drawimage()?
推荐答案
如果您只想显示数据(即不需要 GUI),您可能需要查看 SDL:从您的像素数据创建一个表面,然后将其显示在屏幕上.
If all you want to do is display the data (ie no need for a GUI), you might want to take a look at SDL: It's straight-forward to create a surface from your pixel data and then display it on screen.
灵感来自 Artelius'回答,我还编写了一个示例程序:
Inspired by Artelius' answer, I also hacked up an example program:
#include <SDL/SDL.h>
#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#define WIDTH 256
#define HEIGHT 256
static _Bool init_app(const char * name, SDL_Surface * icon, uint32_t flags)
{
atexit(SDL_Quit);
if(SDL_Init(flags) < 0)
return 0;
SDL_WM_SetCaption(name, name);
SDL_WM_SetIcon(icon, NULL);
return 1;
}
static uint8_t * init_data(uint8_t * data)
{
for(size_t i = WIDTH * HEIGHT * 3; i--; )
data[i] = (i % 3 == 0) ? (i / 3) % WIDTH :
(i % 3 == 1) ? (i / 3) / WIDTH : 0;
return data;
}
static _Bool process(uint8_t * data)
{
for(SDL_Event event; SDL_PollEvent(&event);)
if(event.type == SDL_QUIT) return 0;
for(size_t i = 0; i < WIDTH * HEIGHT * 3; i += 1 + rand() % 3)
data[i] -= rand() % 8;
return 1;
}
static void render(SDL_Surface * sf)
{
SDL_Surface * screen = SDL_GetVideoSurface();
if(SDL_BlitSurface(sf, NULL, screen, NULL) == 0)
SDL_UpdateRect(screen, 0, 0, 0, 0);
}
static int filter(const SDL_Event * event)
{ return event->type == SDL_QUIT; }
#define mask32(BYTE) (*(uint32_t *)(uint8_t [4]){ [BYTE] = 0xff })
int main(int argc, char * argv[])
{
(void)argc, (void)argv;
static uint8_t buffer[WIDTH * HEIGHT * 3];
_Bool ok =
init_app("SDL example", NULL, SDL_INIT_VIDEO) &&
SDL_SetVideoMode(WIDTH, HEIGHT, 24, SDL_HWSURFACE);
assert(ok);
SDL_Surface * data_sf = SDL_CreateRGBSurfaceFrom(
init_data(buffer), WIDTH, HEIGHT, 24, WIDTH * 3,
mask32(0), mask32(1), mask32(2), 0);
SDL_SetEventFilter(filter);
for(; process(buffer); SDL_Delay(10))
render(data_sf);
return 0;
}
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