Why Control Window Position?

While letting the operating system handle window positioning works well for basic applications, there are several compelling reasons to take control of window positioning:

Many games and applications need precise window control for specific features:

• Split-screen modes where windows need to align perfectly
• Tool windows that dock to the main window
• Tutorial systems that position windows to highlight specific screen areas
• Multi-monitor game setups where specific windows need to appear on specific displays

Custom window positioning can significantly improve user experience:

1#include <SDL.h>
2#include "Window.h"
3
4int main(int argc, char** argv) {
5  SDL_Init(SDL_INIT_VIDEO);
6
7  // Create a main window centered on screen
8  SDL_Window* MainWindow{
9    SDL_CreateWindow(
10      "Main Window",
11      SDL_WINDOWPOS_CENTERED,
12      SDL_WINDOWPOS_CENTERED,
13      800, 600, 0
14    )
15  };
16
17  // Create a toolbar window that sits above
18  // the main window
19  int mainX, mainY;
20  SDL_GetWindowPosition(
21    MainWindow, &mainX, &mainY);
22
23  SDL_Window* ToolWindow{
24    SDL_CreateWindow(
25      "Tools",
26      // Position above main window
27      mainX, mainY - 100, 
28      800, 80, 0
29    )
30  };
31
32  SDL_Delay(5000);
33  SDL_Quit();
34  return 0;
35}

We can remember where users like their windows and restore those positions later:

1#include <SDL.h>
2#include <fstream>
3
4void SaveWindowPosition(
5  SDL_Window* Window, const char* Filename
6) {
7  int x, y;
8  SDL_GetWindowPosition(Window, &x, &y);
9
10  std::ofstream File{Filename};
11  File << x << ' ' << y;
12}
13
14void RestoreWindowPosition(
15  SDL_Window* Window, const char* Filename
16) {
17  std::ifstream File{Filename};
18  int x, y;
19  if (File >> x >> y) {
20    SDL_SetWindowPosition(Window, x, y);
21  }
22}

Control over window positioning helps create a more polished, professional feel:

• Ensuring dialog boxes appear centered over their parent window
• Preventing windows from opening in awkward positions
• Creating smooth transitions when reorganizing windows
• Maintaining consistent window layouts across sessions

While the operating system's default positioning is a good starting point, taking control of window positioning when needed can significantly enhance your application's usability and professional feel.