SDL  2.0
testdisplayinfo.c
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1 /*
2  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
3 
4  This software is provided 'as-is', without any express or implied
5  warranty. In no event will the authors be held liable for any damages
6  arising from the use of this software.
7 
8  Permission is granted to anyone to use this software for any purpose,
9  including commercial applications, and to alter it and redistribute it
10  freely.
11 */
12 
13 /* Program to test querying of display info */
14 
15 #include "SDL.h"
16 
17 #include <stdio.h>
18 #include <stdlib.h>
19 
20 static void
21 print_mode(const char *prefix, const SDL_DisplayMode *mode)
22 {
23  if (!mode)
24  return;
25 
26  SDL_Log("%s: fmt=%s w=%d h=%d refresh=%d\n",
27  prefix, SDL_GetPixelFormatName(mode->format),
28  mode->w, mode->h, mode->refresh_rate);
29 }
30 
31 int
32 main(int argc, char *argv[])
33 {
35  int num_displays, dpy;
36 
37  /* Enable standard application logging */
39 
40  /* Load the SDL library */
41  if (SDL_Init(SDL_INIT_VIDEO) < 0) {
42  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
43  return 1;
44  }
45 
46  SDL_Log("Using video target '%s'.\n", SDL_GetCurrentVideoDriver());
47  num_displays = SDL_GetNumVideoDisplays();
48 
49  SDL_Log("See %d displays.\n", num_displays);
50 
51  for (dpy = 0; dpy < num_displays; dpy++) {
52  const int num_modes = SDL_GetNumDisplayModes(dpy);
53  SDL_Rect rect = { 0, 0, 0, 0 };
54  float ddpi, hdpi, vdpi;
55  int m;
56 
58  SDL_Log("%d: \"%s\" (%dx%d, (%d, %d)), %d modes.\n", dpy, SDL_GetDisplayName(dpy), rect.w, rect.h, rect.x, rect.y, num_modes);
59 
60  if (SDL_GetDisplayDPI(dpy, &ddpi, &hdpi, &vdpi) == -1) {
61  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, " DPI: failed to query (%s)\n", SDL_GetError());
62  } else {
63  SDL_Log(" DPI: ddpi=%f; hdpi=%f; vdpi=%f\n", ddpi, hdpi, vdpi);
64  }
65 
66  if (SDL_GetCurrentDisplayMode(dpy, &mode) == -1) {
67  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, " CURRENT: failed to query (%s)\n", SDL_GetError());
68  } else {
69  print_mode("CURRENT", &mode);
70  }
71 
72  if (SDL_GetDesktopDisplayMode(dpy, &mode) == -1) {
73  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, " DESKTOP: failed to query (%s)\n", SDL_GetError());
74  } else {
75  print_mode("DESKTOP", &mode);
76  }
77 
78  for (m = 0; m < num_modes; m++) {
79  if (SDL_GetDisplayMode(dpy, m, &mode) == -1) {
80  SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, " MODE %d: failed to query (%s)\n", m, SDL_GetError());
81  } else {
82  char prefix[64];
83  SDL_snprintf(prefix, sizeof (prefix), " MODE %d", m);
84  print_mode(prefix, &mode);
85  }
86  }
87 
88  SDL_Log("\n");
89  }
90 
91  SDL_Quit();
92  return 0;
93 }
94 
95 /* vi: set ts=4 sw=4 expandtab: */
96 
SDL.h
SDL_GetError
#define SDL_GetError
Definition: SDL_dynapi_overrides.h:113
SDL_GetPixelFormatName
#define SDL_GetPixelFormatName
Definition: SDL_dynapi_overrides.h:277
SDL_GetDisplayMode
#define SDL_GetDisplayMode
Definition: SDL_dynapi_overrides.h:506
mode
GLenum mode
Definition: SDL_opengl_glext.h:1125
SDL_GetDisplayName
#define SDL_GetDisplayName
Definition: SDL_dynapi_overrides.h:502
dpy
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display dpy)
Definition: SDL_x11sym.h:44
SDL_GetDesktopDisplayMode
#define SDL_GetDesktopDisplayMode
Definition: SDL_dynapi_overrides.h:507
SDL_Rect::x
int x
Definition: SDL_rect.h:79
SDL_GetNumVideoDisplays
#define SDL_GetNumVideoDisplays
Definition: SDL_dynapi_overrides.h:501
SDL_LogError
#define SDL_LogError
Definition: SDL_dynapi_overrides.h:36
SDL_Rect::w
int w
Definition: SDL_rect.h:80
SDL_DisplayMode
The structure that defines a display mode.
Definition: SDL_video.h:54
SDL_Log
#define SDL_Log
Definition: SDL_dynapi_overrides.h:31
SDL_Rect::y
int y
Definition: SDL_rect.h:79
SDL_Rect::h
int h
Definition: SDL_rect.h:80
SDL_LOG_CATEGORY_APPLICATION
@ SDL_LOG_CATEGORY_APPLICATION
Definition: SDL_log.h:66
rect
SDL_Rect rect
Definition: testrelative.c:27
SDL_Quit
#define SDL_Quit
Definition: SDL_dynapi_overrides.h:58
SDL_GetDisplayBounds
#define SDL_GetDisplayBounds
Definition: SDL_dynapi_overrides.h:503
m
const GLfloat * m
Definition: SDL_opengl_glext.h:6095
SDL_INIT_VIDEO
#define SDL_INIT_VIDEO
Definition: SDL.h:80
SDL_LOG_PRIORITY_INFO
@ SDL_LOG_PRIORITY_INFO
Definition: SDL_log.h:106
SDL_GetCurrentVideoDriver
#define SDL_GetCurrentVideoDriver
Definition: SDL_dynapi_overrides.h:500
SDL_LogSetPriority
#define SDL_LogSetPriority
Definition: SDL_dynapi_overrides.h:236
SDL_snprintf
#define SDL_snprintf
Definition: SDL_dynapi_overrides.h:40
SDL_Rect
A rectangle, with the origin at the upper left (integer).
Definition: SDL_rect.h:78
print_mode
static void print_mode(const char *prefix, const SDL_DisplayMode *mode)
Definition: testdisplayinfo.c:21
SDL_GetCurrentDisplayMode
#define SDL_GetCurrentDisplayMode
Definition: SDL_dynapi_overrides.h:508
SDL_GetDisplayDPI
#define SDL_GetDisplayDPI
Definition: SDL_dynapi_overrides.h:504
SDL_Init
#define SDL_Init
Definition: SDL_dynapi_overrides.h:54
SDL_GetNumDisplayModes
#define SDL_GetNumDisplayModes
Definition: SDL_dynapi_overrides.h:505
main
int main(int argc, char *argv[])
Definition: testdisplayinfo.c:32