mouse.c

一个跟踪鼠标位置并且把位置输出到屏幕的例子

/*====================================================================*/
/*                                                                    */
/*  NOTE: Ensure this program is compiled for LARGE model.            */
/*        Non-ANSI stuff is pertinent to Microsoft QuickC v2.5.       */
/*        Porting to another compiler should not be too hard!         */
/*                                                                    */
/*====================================================================*/

/*  What we are going to demonstrate here is the use of the mouse in    */
/*  video modes 0x13 (320x200x256) and 0x12 (640x480x16). In both we    */
/*  will simply display some text and allow the mouse to be moved. As   */
/*  the buttons are pressed and the mouse moved we will display the     */
/*  mouse position and button status. Use of the mouse is very simple   */
/*  as long as you obey certain rules:                                  */
/*                                                                      */
/*  1. Never draw to the screen when the mouse cursor is on. Always     */
/*     turn the mouse off before any drawing.                           */
/*  2. MouseOn() and MouseOff() are cummulative - i.e. 2 MouseOff()s    */
/*     will require 2 MouseOn()s before the cursor is visible again.    */
/*     However, once the mouse is on, many MouseOn()s will only require */
/*     one MouseOff() to make the cursor invisible.                     */
/*  3. Even if the cursor is off, the mouse is still 'working' and can  */
/*     be interrogated with MouseStatus().                              */
/*  4. For some strange reason, when 320x200x256 mode is on the x value */
/*     returned by the mouse driver needs to be divided by 2 (shifted   */
/*     right 1) to convert to actual screen pixel coordinates.          */
/*  5. If the video mode is changed, the mouse cursor is forced off.    */
/*                                                                      */
/*  As a final example, we will implement a third test that turns the   */
/*  mouse cursor off and simply tracks the cursor position so we can    */
/*  implement our OWN cursor. In this case, it will be just cross-hair  */
/*  type cursor. This last demo is only to demonstrate one method of    */
/*  implementing a cursor. What it doesn't do is actually do the job    */
/*  properly <g>. A true cursor would store a copy of what was being    */
/*  overwritten on screen so that it could be restored once the cursor  */
/*  has moved. This is highlighted by the fact that, 'cos the cursor is */
/*  alternately drawn in black and white, why it is possible to 'clear' */
/*  the text at the top of the screen. Any true cursor implementation   */
/*  should handle this problem which is easy to do     in mode 0x13 but */
/*  it's harder to deal with in mode 0x12 which is planar rather than   */
/*  linear. I'll leave that to you 'cos I can't be asked to do it now!  */

#include <stdio.h>
#include <stdlib.h>
#include <dos.h>
#include <string.h>
#include <memory.h>

#define FALSE         0
#define TRUE          1

typedef unsigned char BOOL;
typedef unsigned char BYTE;
typedef unsigned int  WORD;

/*=========================== Simple Support Functions ======================*/

BYTE    *pVideo=(BYTE *)0xA0000000L;       /*  Ptr to base of VGA video RAM  */

#define BLACK       0       /*  Colours from the std VGA palette  */
#define WHITE       15

void SetVideoMode( int nMode )
{
    /*  Simple routine to set the video mode using the BIOS video interrupt  */

    _asm    mov ah, 00H
    _asm    mov al, byte ptr nMode
    _asm    int 10H
}

void SetPixel( int x, int y, int colour )
{
    /*  Very simple (inefficient) way of setting a pixel colour  */

    *(pVideo+(unsigned)y*320U+(unsigned)x) = (BYTE)colour;
}

void DrawCross( int cx, int cy, int colour )
{
    /*  Simple function to draw a 'cross-hair' cursor.  */

#define XWTH    4       /*  Aspect ration in 320x200 is approx 3/4  */
#define YHT     3

    int     x, y;

    if ( cx>=0 && cx<320 )
    {
        for ( y=cy-YHT; y<=cy+YHT; y++ )
        {
            if ( y>=0 && y<200 ) SetPixel( cx,y,colour );
        }
    }

    if ( cy>=0 && cy<200 )
    {
        for ( x=cx-XWTH; x<=cx+XWTH; x++ )
        {
            if ( x>=0 && x<320 ) SetPixel(x,cy,colour);
        }
    }
}

void SetCursorPos( int col, int row )
{
    /*  Even though we will be in graphics mode we can ask the video BIOS  */
    /*  to set our cursor position for displaying text...                  */

    _asm    mov ah, 02H
    _asm    mov bh, 00H
    _asm    mov dl, byte ptr col
    _asm    mov dh, byte ptr row
    _asm    int 10H
}

/*============================= Mouse Routines ==============================*/

#define   MOUSE_INT     0x33
#define   L_BUTTON      0x01
#define   R_BUTTON      0x02

BOOL CheckMouse( void )
{
    /*  Checks to see if mouse/driver is present. Returns TRUE if found  */

    /*  TIP: Don't repeatedly call this function within your programs.   */
    /*  call it only once and assign it to your own flag. When the mouse */
    /*  driver receives this function call it does some time consuming   */
    /*  initialisation stuff. If you watch this program carefully when   */
    /*  you run it you'll notice a slight pause...                       */

    int     aa;

    _asm  mov    ax, 0000H
    _asm  int    MOUSE_INT
    _asm  mov    aa, ax

    return( (aa!=0?TRUE:FALSE) );
}

int MouseStatus( int *buttons, int *xpos, int *ypos )
{
    /*  Returns buttons pressed or 0  */

    int     x, y, b;

    _asm    mov    ax, 0003H
    _asm    int    MOUSE_INT
    _asm    and    bx, 03H
    _asm    mov    b,  bx
    _asm    mov    x,  cx
    _asm    mov    y,  dx

    *buttons = b;
    *xpos    = x;
    *ypos    = y;

    return( b );
}

void MouseOn( void )
{
    /*  Turn on the mouse cursor  */

    _asm    mov    ax, 0001H
    _asm    int    MOUSE_INT
}

void MouseOff( void )
{
    /*  Turns the mouse cursor off  */

    _asm    mov    ax, 0002H
    _asm    int    MOUSE_INT
}

void SetMousePos( int x, int y )
{
    /*  Set the position of the mouse cursor  */

    _asm    mov    ax, 0004H
    _asm    mov    cx, x
    _asm    mov    dx, y
    _asm    int    MOUSE_INT
}

/*========================= main program ====================================*/

void main( void )
{
    int     nDemo, x, y, b, lx, ly, lb, maxx, maxy, key;
    BOOL    bAbort=FALSE;
    char    szBuffer[32];

    printf( "\n\nMouse Demo\n==========\n\nPress ESCape to abort at any time.\nPress A Key..." );
    if ( getch()==27 ) exit( 1 );

    /*  Check for presence of mouse driver  */

    if ( !CheckMouse() )
    {
        printf( "\n\nSorry, you'll need a rodent for this!\n\n" );
        exit( 1 );
    }

    for ( nDemo=0; nDemo<3 && !bAbort; nDemo++ )
    {
        /*  Initialise items for this demo  */

        if ( nDemo==0 || nDemo==2 )
        {
            /*  Initialise stuff for 320x200x256  */

            SetVideoMode( 0x13 );
            maxx = 320;
            maxy = 200;
        }
        else
        {
            SetVideoMode( 0x12 );
            maxx = 640;
            maxy = 480;
        }

        /*  At this point the mouse will be off. We are safe to draw some stuff  */

        SetCursorPos( 0,0 );
        printf( "Press ESC to quit or N for next" );

        /*  Initialise our mouse so that it will be in the middle of the  */
        /*  screen and set last position indicators to cut down on redraw */
        /*  flicker...                                                    */

        x   = maxx/2;
        y   = maxy/2;
        b   = 0;
        lx  = -1;
        ly  = -1;
        lb  = 0;

        if ( maxx==320 ) x*=2;      /*  320x200 needs to have x doubled  */
        SetMousePos( x,y );

        /*  Okay, turn on the rodent unless we are going to use our OWN... */

        if ( nDemo!=2 ) MouseOn();

        while ( 1 )         /*  Keep on loopin...  */
        {
            /*  Look for a getout  */

            key=0;
            if ( kbhit() && (key=getch())==27 )
            {
                bAbort = TRUE;
                break;
            }

            /*  Next demo...  */

            if ( key=='n' || key=='N' ) break;

            /*  Get the mouse position and status, etc...  */

            MouseStatus( &b,&x,&y );

            /*  If in 320x200 mode, the x coordinate needs to be divided by 2  */

            if ( maxx==320 ) x/=2;

            /*  See if something has changed  */

            if ( lx!=x || ly!=y )
            {
                /*  Update the position counter  */

                sprintf( szBuffer,"%3d,%3d",x,y );
                if ( nDemo==2 )         /*  Our OWN mouse...         */
                {
                    /*  Remove last cursor  */

                    if ( lx!=-1 ) DrawCross( lx,ly,BLACK );
                }
                else
                {
                    MouseOff();         /*  Make sure not on screen  */
                }
                SetCursorPos( 0,1 );
                printf( szBuffer );
                if ( nDemo==2 )         /*  Our OWN mouse...          */
                {
                    /*  Draw at new position  */

                    DrawCross( x,y,WHITE );
                }
                else
                {
                    MouseOn();          /*  Okay, all drawing done... */
                }
                lx = x;
                ly = y;
            }

            if ( b!=lb )
            {
                /*  Update the button indicators  */

                if ( (b&L_BUTTON) != (lb&L_BUTTON) )
                {
                    MouseOff();
                    SetCursorPos( 0,3 );
                    printf( "%2s",(b&L_BUTTON?"B1":"") );
                    MouseOn();
                }
                if ( (b&R_BUTTON) != (lb&R_BUTTON) )
                {
                    MouseOff();
                    SetCursorPos( 4,3 );
                    printf( "%2s",(b&R_BUTTON?"B2":"") );
                    MouseOn();
                }
                lb = b;
            }
        }

        /*  Turn mouse off for completeness  */

        MouseOff();
    }

    SetVideoMode( 0x03 );

    printf( "\n\nMouse Demo Coded by CyberFrog 8:)\n\n" );
}