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libmemdraw: handle memarc() phi == 0 and phi <= -360, keep alpha in bounds

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This commit is contained in:
cinap_lenrek 2019-03-09 17:34:22 +01:00
parent c7b2ca5716
commit 5a724464d9
1 changed files with 16 additions and 11 deletions
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27
sys/src/libmemdraw/arc.c
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@ -40,13 +40,13 @@ memarc(Memimage *dst, Point c, int a, int b, int t, Memimage *src, Point sp, int
Point p, bnd[8];
Memimage *wedge, *figure, *mask;
if(a < 0)
a = -a;
if(b < 0)
b = -b;
w = t;
if(w < 0)
w = 0;
if(phi == 0)
return;
if(phi <= -360 || phi >= 360){
memellipse(dst, c, a, b, t, src, sp, op);
return;
}
alpha %= 360;
alpha = -alpha; /* compensate for upside-down coords */
phi = -phi;
beta = alpha + phi;
@ -56,10 +56,6 @@ memarc(Memimage *dst, Point c, int a, int b, int t, Memimage *src, Point sp, int
beta = tmp;
phi = -phi;
}
if(phi >= 360){
memellipse(dst, c, a, b, t, src, sp, op);
return;
}
while(alpha < 0)
alpha += 360;
while(beta < 0)
@ -70,6 +66,15 @@ memarc(Memimage *dst, Point c, int a, int b, int t, Memimage *src, Point sp, int
* icossin returns point at radius ICOSSCALE.
* multiplying by m1 moves it outside the ellipse
*/
if(a < 0)
a = -a;
if(b < 0)
b = -b;
w = t;
if(w < 0)
w = 0;
rect = Rect(-a-w, -b-w, a+w+1, b+w+1);
m = rect.max.x; /* inradius of bounding square */
if(m < rect.max.y)