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https://github.com/gnustep/libs-gui.git
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Fixes to appending an arc
git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@9252 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
Nicola Pero
parent
94fe65783b
commit
c76c32bc0f
1 changed files with 100 additions and 70 deletions
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@ -828,103 +828,132 @@ static Class NSBezierPath_concrete_class = nil;
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[self lineToPoint: points[i]];
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}
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- (void)appendBezierPathWithOvalInRect:(NSRect)aRect
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- (void) appendBezierPathWithOvalInRect: (NSRect)aRect
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{
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[self appendBezierPath: [isa bezierPathWithOvalInRect: aRect]];
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}
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- (void)appendBezierPathWithArcWithCenter:(NSPoint)center
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radius:(float)radius
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startAngle:(float)startAngle
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endAngle:(float)endAngle
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clockwise:(BOOL)clockwise
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/* startAngle and endAngle are in degrees, counterclockwise, from the
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x axis */
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- (void) appendBezierPathWithArcWithCenter: (NSPoint)center
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radius: (float)radius
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startAngle: (float)startAngle
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endAngle: (float)endAngle
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clockwise: (BOOL)clockwise
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{
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NSBezierPath *path = [isa bezierPath];
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float strtangrd, endangrd, diff;
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float startAngle_rad, endAngle_rad, diff;
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NSPoint p0, p1, p2, p3;
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while(startAngle < 0)
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while (startAngle < 0)
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startAngle = startAngle + 360;
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while(startAngle > 360)
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while (startAngle > 360)
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startAngle = startAngle - 360;
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while(endAngle < 0)
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while (endAngle < 0)
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endAngle = endAngle + 360;
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while(endAngle > 360)
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while (endAngle > 360)
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endAngle = endAngle - 360;
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strtangrd = PI * startAngle / 180;
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endangrd = PI * endAngle / 180;
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/* Convert the angles to radians */
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startAngle_rad = PI * startAngle / 180;
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endAngle_rad = PI * endAngle / 180;
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p0 = NSMakePoint(center.x + radius * cos(strtangrd), center.y + radius * sin(strtangrd));
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[path moveToPoint: p0];
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/* Start point */
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p0 = NSMakePoint (center.x + radius * cos (startAngle_rad),
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center.y + radius * sin (startAngle_rad));
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[self moveToPoint: p0];
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if (clockwise)
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{
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diff = -PI / 2;
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if (strtangrd < endangrd)
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strtangrd += 2 * PI;
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if (startAngle_rad < endAngle_rad)
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{
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startAngle_rad += 2 * PI;
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}
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}
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else
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{
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diff = PI / 2;
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if (strtangrd > endangrd)
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strtangrd -= 2 * PI;
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if (startAngle_rad > endAngle_rad)
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{
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startAngle_rad -= 2 * PI;
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}
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}
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while (strtangrd > endangrd)
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{
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if (strtangrd + diff >= endangrd)
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{
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float sin_sta = sin(strtangrd);
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float cos_sta = cos(strtangrd);
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// FIXME: Add a quarter circle, for clockwise the signs are not correct!
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p1 = NSMakePoint(center.x + radius * (cos_sta - KAPPA * sin_sta),
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center.y + radius * (sin_sta + KAPPA * cos_sta));
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p2 = NSMakePoint(center.x + radius * (KAPPA * cos_sta -sin_sta),
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center.y + radius * (cos_sta + KAPPA * sin_sta));
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p3 = NSMakePoint(center.x + radius * (-sin_sta),
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center.y + radius * cos_sta);
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[path curveToPoint: p3 controlPoint1: p1 controlPoint2: p2];
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strtangrd += diff;
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}
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else
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{
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float diff_ang = (endangrd - strtangrd) / 2;
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float cos_da = cos(diff_ang);
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float sin_da = sin(diff_ang);
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double x, y;
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float sin_sta = sin(strtangrd + diff_ang);
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float cos_sta = cos(strtangrd + diff_ang);
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x = (4 - cos_da) / 3;
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y = ((1- cos_da) * (cos_da - 3)) / (3 * sin_da);
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// FIXME: Add just the missing bit, for clockwise the signs are not correct!
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p1 = NSMakePoint(center.x + radius * (cos_sta * x - sin_sta * y),
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center.y + radius * (sin_sta * y + cos_sta * x));
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p2 = NSMakePoint(center.x + radius * (cos_sta * x + sin_sta * y),
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center.y + radius * (sin_sta * (-y) + cos_sta * x));
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p3 = NSMakePoint(center.x + radius * cos(endangrd),
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center.y + radius * sin(endangrd));
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[path curveToPoint: p3 controlPoint1: p1 controlPoint2: p2];
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break;
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}
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while ((clockwise) ? (startAngle_rad > endAngle_rad)
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: (startAngle_rad < endAngle_rad))
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{
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/* Add a quarter circle */
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if ((clockwise) ? (startAngle_rad + diff >= endAngle_rad)
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: (startAngle_rad + diff <= endAngle_rad))
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{
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float sin_start = sin (startAngle_rad);
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float cos_start = cos (startAngle_rad);
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float sign = (clockwise) ? -1.0 : 1.0;
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p1 = NSMakePoint (center.x
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+ radius * (cos_start - KAPPA * sin_start * sign),
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center.y
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+ radius * (sin_start + KAPPA * cos_start * sign));
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p2 = NSMakePoint (center.x
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+ radius * (-sin_start * sign + KAPPA * cos_start),
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center.y
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+ radius * (cos_start * sign + KAPPA * sin_start));
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p3 = NSMakePoint (center.x + radius * (-sin_start * sign),
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center.y + radius * cos_start * sign);
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[self curveToPoint: p3 controlPoint1: p1 controlPoint2: p2];
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startAngle_rad += diff;
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}
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else
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{
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/* Add the missing bit
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* We require that the arc be less than a semicircle.
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* The arc may go either clockwise or counterclockwise.
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* The approximation is a very simple one: a single curve
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* whose middle two control points are a fraction F of the way
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* to the intersection of the tangents, where
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* F = (4/3) / (1 + sqrt (1 + (d / r)^2))
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* where r is the radius and d is the distance from either tangent
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* point to the intersection of the tangents. This produces
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* a curve whose center point, as well as its ends, lies on
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* the desired arc.
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*/
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NSPoint ps = [self currentPoint];
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/* tangent is the tangent of half the angle */
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float tangent = tan ((endAngle_rad - startAngle_rad) / 2);
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/* trad is the distance from either tangent point to the
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intersection of the tangents */
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float trad = radius * tangent;
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/* pt is the intersection of the tangents */
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NSPoint pt = NSMakePoint (ps.x - trad * sin (startAngle_rad),
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ps.y + trad * cos (startAngle_rad));
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/* This is F - in this expression we need to compute
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(trad/radius)^2, which is simply tangent^2 */
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float f = (4.0 / 3.0) / (1.0 + sqrt (1.0 + (tangent * tangent)));
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p1 = NSMakePoint (ps.x + (pt.x - ps.x) * f, ps.y + (pt.y - ps.y) * f);
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p3 = NSMakePoint(center.x + radius * cos (endAngle_rad),
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center.y + radius * sin (endAngle_rad));
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p2 = NSMakePoint (p3.x + (pt.x - p3.x) * f, p3.y + (pt.y - p3.y) * f);
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[self curveToPoint: p3 controlPoint1: p1 controlPoint2: p2];
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break;
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}
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}
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}
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- (void)appendBezierPathWithArcWithCenter:(NSPoint)center
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radius:(float)radius
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startAngle:(float)startAngle
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endAngle:(float)endAngle
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- (void) appendBezierPathWithArcWithCenter: (NSPoint)center
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radius: (float)radius
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startAngle: (float)startAngle
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endAngle: (float)endAngle
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{
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[self appendBezierPathWithArcWithCenter: center radius: radius
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startAngle: startAngle endAngle: endAngle clockwise: NO];
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[self appendBezierPathWithArcWithCenter: center radius: radius
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startAngle: startAngle endAngle: endAngle clockwise: NO];
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}
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- (void)appendBezierPathWithArcFromPoint:(NSPoint)point1
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toPoint:(NSPoint)point2
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radius:(float)radius
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- (void) appendBezierPathWithArcFromPoint: (NSPoint)point1
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toPoint: (NSPoint)point2
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radius: (float)radius
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{
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// TODO
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}
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@ -1326,9 +1355,9 @@ typedef struct _PathElement
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INVALIDATE_CACHE();
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}
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- (void)curveToPoint:(NSPoint)aPoint
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controlPoint1:(NSPoint)controlPoint1
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controlPoint2:(NSPoint)controlPoint2
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- (void) curveToPoint: (NSPoint)aPoint
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controlPoint1: (NSPoint)controlPoint1
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controlPoint2: (NSPoint)controlPoint2
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{
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PathElement elem;
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@ -1666,3 +1695,4 @@ static void flatten(NSPoint coeff[], float flatness, NSBezierPath *path)
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[path lineToPoint: coeff[3]];
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}
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}
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