I have an assigment to make an analog clock in C PIC18 starter kit. I need to draw all the hands of the clock, aka seconds, minutes and hours.
I have initialized all 60 points of the clock diamater in a 2D array with x and y values and have the values of the clock center.
In order to draw the hands I've been provided for this assigment with the DrawLine function, which looks like this:
void drawLine( BYTE x0, BYTE y0, BYTE x1, BYTE y1, LineWidth lw )
the x0, y0 are where the line starts, and x1,y1 are where the line ends.
the drawLine function works like a XOR, so if I call it again on the same values the line disappears from the screen.
the screen values when they're x=0,y=0 starts from the top-left corner of the screen.
I have built a function in order to draw the hour hand of the clock. I have an i value which increments by 1 for each coordinate of the clock, and it goes like this:
center[0][0]+(cord[i][0]-center[0][0])/2
But for some reason it only works on the 4th quadrant of the clock (aka when i is between 15 and 30), otherwise the lines it draws dosn't resemble an hand of a clock.
Below this is the full code for your understanding, but I would like to know what is wrong with my function, and what do I need to do in order of it to draw normally for the rest of thequadrants.
BYTE cord[60][2] = {
{67,0},{71,1},{74,2},{79,3},{81,4},
{82,5},{84,6},{88,9},{91,12},{92,14},
{93,16},{95,18},{96,21},{97,25},{98,29},
{98,32},{98,35},{97,39},{96,43},{95,45},
{93,47},{92,50},{89,53},{85,56},{84,58},
{82,58},{79,60},{76,61},{73,62},{70,63},
{67,63},{64,63},{60,62},{57,61},{54,60},
{51,58},{47,56},{45,54},{43,52},{41,50},
{40,47},{38,44},{37,41},{36,38},{35,35},
{35,32},{35,29},{36,26},{37,22},{38,18},
{40,16},{41,13},{44,10},{47,7},{49,6},
{51,5},{52,4},{54,3},{57,2},{61,1}};
void main(void)
{
BYTE xtemp, ytemp ;
BYTE i = 0;
BYTE center[1][2] = {{67,32}};
InitializeSystem();
while(1)
{
xtemp = center[0][0]+(cord[i][0]-center[0][0])/2;
ytemp = center[0][1]+(cord[i][1]-center[0][1])/2;
drawLine( center[0][0], center[0][1], xtemp, ytemp, thick ) ;
DelayMs(50);
drawLine( center[0][0], center[0][1], xtemp, ytemp, thick );
i++;
if(i>60)
i = 0;
}
}
There is no standard datatype BYTE included in C. I guess you have a typedef with an unsigned type.
When you do a signed calculation like:
xtemp = center[0][0]+(cord[i][0]-center[0][0])/2;
you need a signed signed type like int.