I don't know much about DarkGDK but I do have a suggestion for you if you know how to get the position of the mouse. Since you said you are using a .bmp for this you will know the (x,y) coordinates of the 'buttons' on the image. You will also know the height and width of the buttons. Create arrays for each button with the X coordinate first, then the Y coordinate second followed by the width and the height.
CODE
int myButton[] = { 100, 100, 100, 20 }; // Sample button
Once you have found out if the mouse coordinates there is a simple function I wrote that would check if the mouse was inside the 'button'. It takes the x coordinate of the mouse and checks to see if it is between the starting point and the starting point plus the width. If that succeeds it checks if the y coordinate is between the starting Y coordinate and the starting Y coordinate and the height.
CODE
bool checkInside(int button[], int x, int y)
{
if (x >= button[0] && x <= button[0] + button[2])
if ( y >= button[1] && y <= button[1] + button[3])
return true;
return false;
}
Alternatively you could use the four points and just check them.
CODE
int myButton[] = { 100, 100, 200, 120 };
bool checkInside(int button[], int x, int y)
{
if (x >= button[0] && x <= button[2])
if ( y >= button[1] && y <= button[3])
return true;
return false;
}
I don't think it is hard to find mouse clicks with DarkGDK but I could be wrong as I've never used it. Those would be the two easiest methods of finding out if the mouse is clicked in the area you want though.