The following example tries to rudimentarily show how a console can be resized and then be changed to the original size.
Required steps
First, we need to store the HANDLE of the current console buffer so that we're able to go back to our console when we're done.
Then, our new console buffer needs to be created with CreateConsoleScreenBuffer().
The new console buffer is then activated with SetConsoleActiveScreenBuffer.
Since we want to resize the console, we need to specify the size of the window
and the size of the buffer (that stores the data that is displayed). The order is relevant:
- first
SetConsoleWindowInfo to change the size of the window
- then
SetConsoleScreenBufferSize to change the size of the buffer
Now, the console is resized. We can now write text into the buffer with SetConsoleCursorPosition and WriteConsole.
When we want to go back to our original buffer, we need to call SetConsoleScreenBufferInfoEx and SetConsoleActiveScreenBuffer, again in this order.
prog.c
// #define _CRT_SECURE_NO_WARNINGS
#include <windows.h>
#define NEW_WIDTH 100
#define NEW_HEIGHT 50
void error(const char *txt) {
char msg[200];
//
// StringCbPrintf should be used… however, I was unable
// to link it without CRT.
// StringCbPrintf(msg, 200, "%s: %d", txt, GetLastError());
//
wsprintfA(msg, "%s: %d", txt, GetLastError());
MessageBox(NULL, msg, "Error", 0);
}
int __stdcall go(void) {
HANDLE orig_con_h;
HANDLE repl_con_h;
CONSOLE_SCREEN_BUFFER_INFOEX orig_con_info;
COORD repl_con_buf_size;
SMALL_RECT repl_con_screen;
COORD cursor_pos;
orig_con_h = GetStdHandle(STD_OUTPUT_HANDLE);
orig_con_info.cbSize = sizeof(orig_con_info);
if (!GetConsoleScreenBufferInfoEx(orig_con_h, &orig_con_info)) {
MessageBox(NULL, "GetConsoleScreenBufferInfoEx", "Error", 0);
return 1;
}
//
// Check if we're able to create a console that fits
// our desired size:
//
if (NEW_WIDTH > orig_con_info.dwMaximumWindowSize.X ||
NEW_HEIGHT > orig_con_info.dwMaximumWindowSize.Y) {
MessageBox(NULL, "Requested width or height too large", "Error", 0);
goto back_to_orig_console;
}
repl_con_h = CreateConsoleScreenBuffer (GENERIC_READ | GENERIC_WRITE, 0, NULL, CONSOLE_TEXTMODE_BUFFER, NULL);
if (repl_con_h == INVALID_HANDLE_VALUE) {
error("CreateConsoleScreenBuffer");
goto back_to_orig_console;
}
//
// Switch to the »new« console
//
SetConsoleActiveScreenBuffer(repl_con_h);
//
// Change the new console's size
//
repl_con_screen.Left = 0;
repl_con_screen.Top = 0;
repl_con_screen.Right = NEW_WIDTH -1;
repl_con_screen.Bottom = NEW_HEIGHT -1;
if (!SetConsoleWindowInfo(repl_con_h, TRUE, &repl_con_screen)) {
error("SetConsoleWindowInfo");
goto back_to_orig_console;
}
//
// Change the new console's buffer size.
//
repl_con_buf_size.X = NEW_WIDTH ;
repl_con_buf_size.Y = NEW_HEIGHT;
if (!SetConsoleScreenBufferSize(repl_con_h, repl_con_buf_size)) {
error("SetConsoleScreenBufferSize");
goto back_to_orig_console;
}
//
// Show rudimentary coordinate system
//
for (cursor_pos.X = 10; cursor_pos.X < NEW_WIDTH ; cursor_pos.X += 10) {
for (cursor_pos.Y = 0; cursor_pos.Y < NEW_HEIGHT; cursor_pos.Y ++ ) {
if (!SetConsoleCursorPosition(repl_con_h, cursor_pos)) {
error("SetConsoleCursorPosition");
goto back_to_orig_console;
}
WriteConsole(repl_con_h, &"0123456789"[cursor_pos.Y %10], 1, NULL, NULL);
}}
for (cursor_pos.Y = 10; cursor_pos.Y < NEW_HEIGHT; cursor_pos.Y += 10) {
for (cursor_pos.X = 0; cursor_pos.X < NEW_WIDTH ; cursor_pos.X ++ ) {
if (!SetConsoleCursorPosition(repl_con_h, cursor_pos)) {
error("SetConsoleCursorPosition");
goto back_to_orig_console;
}
WriteConsole(repl_con_h, &"0123456789"[cursor_pos.X %10], 1, NULL, NULL);
}}
//
// Wait until the user chooses to quit the app.
//
MessageBoxA(0, "Finish app", "resize", MB_OK);
//
// Go back to original console
//
back_to_orig_console:
SetConsoleScreenBufferInfoEx(orig_con_h, &orig_con_info);
SetConsoleActiveScreenBuffer(orig_con_h);
return 0;
};