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action2003
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| glcd_bar don't work ??? |
 Posted: Mon Nov 08, 2004 3:35 am |
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I'm using a 18F452 for a inboard computer in my raid's car (see http://action2003.free.fr ! ).
I try to draw a needle as for an analogical tachometer.
All the code work perfectly, but I want to use the function glcd_bar to draw a 6 (or 7) pixel wide needle between the center and its end. But when I use glcd_bar instead of glcd_line, the result is not correct.
This code work fine, valeur_rpm is the speed motor in rpm, x_c and y_c is the coodinate af the dial'centre.
the needle result is like :
| Code: | void aff_aigui(int16 valeur_rpm,int8 x_c,y_c)
{
const int8 r3=40,r4=40,r5=49,r6=39; // distance between center and point
float angle;
int8 x3,x4,x5,x6,y3,y4,y5,y6;
angle = (float) valeur_rpm * ( PI / 6000); // exple 3000 rpm -> PI/2
x3 = (int8) calc_x_coord(angle + 0.1,r3,x_c);
x4 = (int8) calc_x_coord(angle - 0.1,r4,x_c);
// x3,y3,x4,y4,x5,y5 compute a triangle needle's end
x5 = (int8) calc_x_coord(angle,r5,x_c); // x needle's end.
x6 = (int8) calc_x_coord(angle,r6,x_c);
y3 = (int8) calc_y_coord(angle + 0.1,r3,y_c);
y4 = (int8) calc_y_coord(angle - 0.1,r4,y_c);
y5 = (int8) calc_y_coord(angle,r5,y_c); y needle's end
y6 = (int8) calc_y_coord(angle,r6,y_c);
glcd_line(x3,y3,x5,y5,ON);
glcd_line(x5,y5,x4,y4,ON);
glcd_line(x3,y3,x4,y4,ON);
glcd_line(x_c,y_c,x6,y6,ON);
}
//// ////
///////////////////////////////////////////////////////////////////////////////
//// ////
float calc_x_coord(float alpha,int8 rayon,x_offset)
{
float resul;
resul = ceil(x_offset - (rayon * cos(alpha)));
return(resul);
}
//// ////
///////////////////////////////////////////////////////////////////////////////
//// ////
float calc_y_coord(float alpha,int8 rayon,y_offset)
{
float resul;
resul = ceil(y_offset - (rayon * sin(alpha)));
return(resul);
}
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if i wrote glcd_bar(x_c,y_c,x6,y6,6,ON) for a 6 pixel wide needle instead glcd_line(x_c,y_c,x6,y6,ON);.... it doesn't draw the bar ! Why ???
Is glcd_bar function have a bug ???
Sorry for my poor english !! I'm living in Avignon - France
please help |
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treitmey
Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA
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| Posted: Mon Nov 08, 2004 9:41 am |
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Just from a quick look of the code, I think the bar can only be horizontal and vertical [--- or | ]
Its a bit more math to draw a line/bar at an angle. |
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action2003
Joined: 08 Nov 2004
Posts: 2
Location: Avignon - France
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| Posted: Tue Nov 09, 2004 7:57 am |
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| treitmey wrote: | Just from a quick look of the code, I think the bar can only be horizontal and vertical [--- or | ]
Its a bit more math to draw a line/bar at an angle. |
I don't think... Compare GLCD_LINE and GLCD_BAR code,.... it is same algorithm... (and GLCD_LINE work well for angle).
The difference is only for draw wide pixel... if you chose small x1-x2 and y1-y2, glcd_bar work a bit  and draw a strange dotted line 
I don't find the bug, but i solve my problem, a new GLCD_LINE_WIDE function with large pixel (5 pixel square instead 1 pixel). 
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Thierry - Avignon - France |
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