Level - Beginner
In this tutorial you will learn how to do mouse programming through C. Mouse Programming in C is simple and beginners can give it a shot if they undestand carry on otherwise read the basic tutorials first and then comeback and learn how to do Mouse Programming using C. Before we get our hands dirty we begin with a breif intro.
Mouse has revolutionized the Computer World . It was introduced with GUI which stands for Graphical User Interface.
It was a big step forward thrusting computer from command line execution to hot and happening menu driven applications that we see today. Many GUI were based on keyboards but they never outweighed thier opponents based on mouse reason is simple, just imagine your Windows or Linux to be keyboard driven. Nothing less than a nightmare it seems.
Mouse is simple input device which allows you to point and execute interface and is faster than keyboards many times. Mouse generally provide random interface on other hand keyboards provide sequential interface.
This article will act as a complete source of Mouse Programming in C and covers it all aspects. If we still miss something please inform us and we will try to cover it next revised edition.
Mouse Programming is a topic which every c programmer from begginer to professional needs to have in his toolbox to have a cutting edge.
Mouse Programming will be used almost everywhere. It will embeded in games programming to commerical valued applications. So if you aim to easily understand other tutorials in this website you must master this topics and believe me its very easy.
Contents -
1. Requirements
2. Fundamental Knowledge.
3. AX Register
4. Detecting Mouse
5. Showing & Hiding Mouse
6. Detecting Input
7. Mouse Coordinates
8. Restricting Mouse
9. What Next?
First and Formeost requirement which i believe will surely be satisfyied, you should have a mouse attached to your system.
This tutorial is written Turbo C++ 3.0 IDE and install in folder C:\TC. I recommend to use same IDE and settings to avoid any uncompatibility and even if you face any problem we provide an 24 X 7 Email Support to help you out.
You should have proper mouse driver for your hardware, this is also not a problem because almost 100% of operating System provide them through program MOUSE.COM or WITTYMS.COM.
That is all you need.
Before we start harcore programming we must first understand some principles on which mouse programming is based.
First thing you must know how to tell a mouse to do anything. In actual we doesnot communicate with mouse directly but through the driver provide. We use interrupts to get access to this driver. Each device provide by computer has its own port and more or less we access these ports.
Each device has a unique port which is a hexadecimal value and value is designed to be machine independent enhancing portability of program.
Mouse has port attached to it 0X33 and similarly keyboard has attach to it port 0X60. We restrict ourself only to mouse port in this tutorial but keyboard is also used extensively in other programs especially ones related to games programming.
We also make use of address registers. These are basically Union of type REGS defined in dos.h. You dont need further knowledge of them for programming. Just remember we use two register to communicate to a device driver using two registers one for input and one for output.
We send value to device driver through the input register and recieve information in it embedded in output register.
We can access various mouse functions using different values of AX input Register and passing those values to mouse port using a interrupt
The Functions are listed below - Here AX, BX, CX and DX are members of Union REGS and more or less integers.
Input Function Performed Returns
AX = 0 Get Mouse Status Output AX Value = FFFFh if mouse support is available.
Output AX Value = 0 if mouse support is not available.
AX = 1 Show Mouse Pointer Nothing
AX = 2 Hide Mouse Pointer Nothing
AX = 3 Mouse Position CX = Mouse X Coordinate
DX = Mouse Y Coordinate
Ax = 3 Mouse Button Press BX = 0 No Key Is Pressed
BX = 1 Left Button is Pressed
BX = 2 Right Button is Pressed
BX = 3 Centre Button is Pressed
Ax = 7 Set Horizontal Limit Nothing
CX = MaxX1
DX =MaxX2
Ax = 8 Set Vertical Limit Nothing
CX = MaxX1
DX =MaxX2
Now we step by step study each of these services in following sections and build up our combined code.
Before you start your embed mouse program you should always check wether the mouse programming is supported on not.
If some how mouse fails to initalise you should always make sure that either program terminates or employ a error handling approach that maybe shift to keyboard interface .
To do mouse programming you must include
To detect mouse we use a function name detectmouse which has following code -
#include
union REGS in, out;
void detectmouse ()
{
in.x.ax = 0;
int86 (0X33,&in,&out);
if (out.x.ax == 0)
printf ("\nMouse Fail To Initialize");
else
printf ("\nMouse Succesfully Initialize");
}
int main ()
{
detectmouse ();
getch ();
return 0;
} Now first we show mouse on screen .
Mouse works both in text mode and graphic mode.
In text mode it looks like a square while in graphics mode it looks like a pointer.
Here is a screen shot for text mode.
It was produced from adding a function showmousetext to above code so code becomes -
Here is a screen shot for graphic mode -
This is achieved using a function showmousegraphic added to above code while removing showmouse text from main.
#include union REGS in, out; void detectmouse () void showmousetext () void showmousegraphics () int main () { |
Next we do realtively simple task of hiding mouse using a function hidemouse as shown below -
#include union REGS in, out; void detectmouse () void showmousetext () void showmousegraphics () void hidemouse () int main () { |
We will now work on a important aspect of mouse programming detecting clicks.
We make use of an aditional function known as kbhit ( ). This functions returns zero till any keypress and when a key is press it returns 1.
We use kbhit to run a infinite while loop.
For detecting mouseclicks we use a function called detect which displays on screen the respective button clicked. Press any keyboad key to exit the loop.
#include union REGS in, out; void detectmouse () void showmousetext () void showmousegraphics () void hidemouse () void detect () { |
We can obtain the coordinates of the mouse using same service 3 but using different elments of the union .
This function has a prime use in games programming, application designing and GUI development. Different decisions are taken on same left button click, its the postion of click that matters.
BX element of output registers stores the X Coordinate of the postion of mouse at time of calling function.
CX element of output registers stores the Y Coordinate of the postion of mouse at time of calling function.
Now we demonstrate the use of this function by modifying detect function above to display x,y and y coordinates on screen when left click is pressed.
Code will be as followed -
#include union REGS in, out; void detectmouse () void showmousetext () void showmousegraphics () void hidemouse () void detect () int main () { |
We now restrict the mouse in particular rectangle .
We create a function called restrict which takes four paramters, two cartesian points each containing one x coordinate and one y coordinate.
First point mentions the top of the rectangle while second point mention the bottom bottom point of rectangle.
This service has limited uses but can be quite handy in special circumstances, for eg - if you want to restrict your mouse in one particular size window in GUI or In Games Programming.
Now i give you final code of the tutorial -
#include union REGS in, out; void restrict (int x1,int y1,int x2, int y2) { void detectmouse () void showmousetext () void showmousegraphics () void hidemouse () void detect () int main () { |
Now first thing you must do is congratulate yourself because you just added a super weapon to you arsenal.
Now there is no stopping you. Let your creativity flow and world class products come out of your computer.
To get you started here what you can do with mouse programming -
1. Games Programming
2. Commercial Applications Development.
3. Graphical User Interface
4. Utitlity Softwares such as Paint, Word Processors , Spread Sheets and so on....
Before you get your hands dirty we recommend you go through our game building and application building Tutorials. Most of them are based mouse programming.
Also if you still want to hone your mouse programming skills further go through our advance tutorials such as mouse cursors, mouse drawing, menu through mouse and more...