Change screen resolution to 320 x 200 ?

[superkat]

how is this possible, do I have to use direct X

Thanks

[Machaira]

You don't have to use DirectX, but it's very bad form to change the user's resolution if you're not running full-screen. Also, why would you ever want to use a resolution of 320 x 200?

[jmiller]

i don't think that today's monitors even support that low of a resolution; and i'm not sure if newer operating systems like xp do. In fact, i didn't think that it was even possible to run lower than 640x480 with win95

[CornedBee]

They do, but not via API. Windows won't accept any resolution lower than 640x480, you have to use DX for such low resolutions.

[CVMichael]

You can do it in C with interrupt 10h mode 13h

I used to program in 13h about 5 years ago...
Unfortunatelly in this mode you have to program everything, I mean to draw a line, you have to make your own function to draw that line, same with everything else.
here are some functions I used...

//pointer to graphic mode (pixelated)
unsigned char *vga    = (unsigned char *)MK_FP(0xA000, 0);

// mode for 300x200 is 0x13 (hex 13)
void vga_init(char mode)
{
//	union REGS inregs, outregs;

	asm mov ah, 0
	asm mov al, mode
	asm int 0x10

//	inregs.h.ah=0;
//	inregs.h.al=mode;
//	int86(0x10, &inregs, &outregs);
}

char vga_getmode()
{
	char mode;

	asm mov ah,0x0f
	asm int 0x10
	asm mov mode,al

	return mode;
}

void WaitRast()
{
	asm mov dx,0x3da
bra1:
	asm in  al,dx
	asm and al,8
	asm jnz bra1
bra2:
	asm in  al,dx
	asm and al,8
	asm jz bra2
}

int getpix(int x, int y, unsigned char far *v)
{
	int color = -1;
	if(x < 320 && x > -1 && y < 200 && y > -1)
		color = v[(y<<8) + (y<<6) + x];

	return color;
}

void putpix(int x, int y, unsigned char color, unsigned char far *v)
{
	if(x < 320 && x > -1 && y < 200 && y > -1)
		v[(y<<8) + (y<<6) + x] = color;

//	if(x < 640 && x > -1 && y < 480 && y > -1)
//	{	//v[(y<<9) + (y<<7) + x] = color;
//		v[(640*y)+x] = color;
//	}
	return;
}

#define uint  unsigned int
void putpixel(uint x, uint y, uchar col)
{
	uint width = 320;

	asm mov ax, 0xA000
	asm mov es, ax

	asm mov ax, width
	asm mov bx,[y]
	asm mul bx
	asm add ax,[x]
	asm mov di, ax

	asm mov al,[col]
	asm mov [es:di], al
}

[CornedBee]

WinNT/2k/XP will block that and immediatly kill your app most likely. Unless it's a real DOS application, then they even might let them do it. But then it's not a VB app.