我想创建一个 NSBezierPath 代表这样的“弯曲”或“臃肿”正方形：
我正在努力想出正确的数学来使这个形状完全正确。我浏览了整个互联网，但谷歌搜索这个主题主要是“这就是你如何绘制圆角”，这不是我需要的。
谁能指出我可以用来放置这些曲线的控制点的公式？谢谢！
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好的; 经过多次试验和错误，我得到了一些有用的东西。下面的代码将绘制一个像这样的形状。（此图像对代码中的#define 语句使用以下值）：
#define SIDE_DEFLECTION 18.0f
#define CORNER_RAD 18.0f
#define KAPPA 0.55238f
#define CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION .10
#define SIDE_CENTER_CP_OFFSET 0.60
这些值，给定一个 500x500 像素的视图，将绘制这个形状：
绘图代码
在我的例子中，我在 NSButtonCell 子类中绘制这个形状。因为我知道这个单元格的框架永远不会在我的应用程序中调整大小，所以我可以做一些优化。具体来说，我将 NSBezierPath 存储为 iVar，因此我不必每次都通过 -drawImage 重新创建它...此外，我将 NSShadow 和 NSColor 存储为 iVar，因此也不必重新创建它们。
如果要在调整大小的视图中绘制此形状，则需要稍微调整代码。如果正方形的大小发生剧烈变化，则需要立即手动调整#define 语句的值（否则，拐角看起来不正确。侧曲线过渡到圆角曲线的压痕很少，等等）
下面的代码配置为在 52x52 像素的正方形中绘制相同的形状。一般的做法是设置你想要的“侧偏”和“拐角半径”，然后调整两个“偏移”定义语句（它们是百分比），直到拐角看起来完美。“kappa”的值永远不能改变——它取自我找到的一篇数学论文。
这是优化的绘图代码：
#import "LPProjectIconButtonCell.h"
#define SIDE_DEFLECTION 1.0f
#define CORNER_RAD 4.0f
// Distance (%) control points should be from curve start/end to form perfectly circular rounded corners
#define KAPPA 0.55238f
// Percentage offset (from perfectly circular rounded corner location) that the corner control points use to
// compensate for the fact that our sides are rounded. Without this, we get a rough transition between the
// curve of the side and the start of the corner curve
#define CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION .85
// As the curve approaches each side-center point, this is the percentage of the distance between the side endpoints
// and the side centerpoint where the control point for approaching the centerpoint is located. You are not expected
// to understand the preceeding sentence.
#define SIDE_CENTER_CP_OFFSET 0.60
@implementation LPProjectIconButtonCell
- (void) awakeFromNib
{
_shadow = [[NSShadow alloc] init];
[_shadow setShadowBlurRadius:1.0f];
[_shadow setShadowColor:[NSColor colorWithCalibratedWhite:1.0f alpha:0.2f]];
[_shadow setShadowOffset:NSMakeSize(0.0f, -1.0f)];
_borderColor = [[NSColor colorWithCalibratedWhite:0.13 alpha:1.0f] retain];
}
- (void) dealloc
{
[_path release];
_path = nil;
[_shadow release];
_shadow = nil;
[_borderColor release];
_borderColor = nil;
[super dealloc];
}
- (void) drawImage:(NSImage *)image withFrame:(NSRect)frame inView:(NSView *)controlView
{
NSGraphicsContext *currentContext = [NSGraphicsContext currentContext];
// The path never changes because this view never resizes. So we'll save it to be efficient
if (!_path)
{
NSRect rect = NSInsetRect(frame, 2.0f, 2.0f);
// Create the primary points -- 3 per side
NSPoint TCenter = NSMakePoint(rect.size.width/2.0f, rect.origin.y);
NSPoint TLeft = NSMakePoint(rect.origin.x + CORNER_RAD + SIDE_DEFLECTION, rect.origin.y + SIDE_DEFLECTION);
NSPoint TRight = NSMakePoint(rect.origin.x + rect.size.width - (CORNER_RAD + SIDE_DEFLECTION), rect.origin.y + SIDE_DEFLECTION);
NSPoint LTop = NSMakePoint(rect.origin.x + SIDE_DEFLECTION, rect.origin.y + CORNER_RAD + SIDE_DEFLECTION);
NSPoint LCenter = NSMakePoint(rect.origin.x, rect.size.height/2.0f);
NSPoint LBottom = NSMakePoint(rect.origin.x + SIDE_DEFLECTION, rect.origin.y + rect.size.height - CORNER_RAD - SIDE_DEFLECTION);
NSPoint BLeft = NSMakePoint(TLeft.x, rect.origin.y + rect.size.height - SIDE_DEFLECTION);
NSPoint BCenter = NSMakePoint(TCenter.x, rect.origin.y + rect.size.height);
NSPoint BRight = NSMakePoint(TRight.x, BLeft.y);
NSPoint RTop = NSMakePoint(rect.origin.x + rect.size.width - SIDE_DEFLECTION, LTop.y);
NSPoint RCenter = NSMakePoint(rect.origin.x + rect.size.width, LCenter.y);
NSPoint RBottom = NSMakePoint(RTop.x, LBottom.y);
// Create corner control points for rounded corners
// We don't want them to be perfectly circular, because our sides are curved. So we adjust them slightly to compensate for that.
NSPoint CP_TLeft = NSMakePoint(TLeft.x - (TLeft.x - LTop.x) * KAPPA, TLeft.y + SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION);
NSPoint CP_LTop = NSMakePoint(LTop.x + SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION, LTop.y - (LTop.y - TLeft.y) * KAPPA);
NSPoint CP_LBottom = NSMakePoint(LBottom.x + SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION, LBottom.y + (BLeft.y - LBottom.y) * KAPPA);
NSPoint CP_BLeft = NSMakePoint(BLeft.x - (BLeft.x - LBottom.x) * KAPPA, BLeft.y - SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION);
NSPoint CP_BRight = NSMakePoint(BRight.x + (RBottom.x - BRight.x) * KAPPA, BRight.y - SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION);
NSPoint CP_RBottom = NSMakePoint(RBottom.x - SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION, RBottom.y + (BRight.y - RBottom.y) * KAPPA);
NSPoint CP_RTop = NSMakePoint(RTop.x - SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION, RTop.y - (RTop.y - TRight.y) * KAPPA);
NSPoint CP_TRight = NSMakePoint(TRight.x + (RTop.x - TRight.x) * KAPPA, TRight.y + SIDE_DEFLECTION * CORNER_CP_OFFSET_FOR_SIDE_DEFLECTION);
// Create control points for the rounded sides. (The "duplicate" control points are here in case I ever tweak this in the future.)
NSPoint CP_DepartingTCenterForTLeft = NSMakePoint(TCenter.x - (TCenter.x - TLeft.x) * SIDE_CENTER_CP_OFFSET, TCenter.y);
NSPoint CP_ApproachingTLeft = TLeft;
NSPoint CP_DepartingLTopForLCenter = LTop;
NSPoint CP_ApproachingLCenterFromLTop = NSMakePoint(LCenter.x, LCenter.y - (LCenter.y - LTop.y) * SIDE_CENTER_CP_OFFSET);
NSPoint CP_DepartingLCenterForLBottom = NSMakePoint(LCenter.x, LCenter.y + (LBottom.y - LCenter.y) * SIDE_CENTER_CP_OFFSET);
NSPoint CP_ApproachingLBottom = LBottom;
NSPoint CP_DepartingBLeftForBCenter = BLeft;
NSPoint CP_ApproachingBCenter = NSMakePoint(BCenter.x - (BCenter.x - BLeft.x) * SIDE_CENTER_CP_OFFSET, BCenter.y);
NSPoint CP_DepartingBCenterForBRight = NSMakePoint(BCenter.x + (BRight.x - BCenter.x) * SIDE_CENTER_CP_OFFSET, BCenter.y);
NSPoint CP_ApproachingBRight = BRight;
NSPoint CP_DepartingRBottomForRCenter = RBottom;
NSPoint CP_ApproachingRCenterFromRBottom = NSMakePoint(RCenter.x, RCenter.y + (RBottom.y - RCenter.y) * SIDE_CENTER_CP_OFFSET);
NSPoint CP_DepartingRCenterForRTop = NSMakePoint(RCenter.x, RCenter.y - (RCenter.y - RTop.y) * SIDE_CENTER_CP_OFFSET);
NSPoint CP_ApproachingRTopFromRCenter = RTop;
NSPoint CP_DepartingTRightForTCenter = TRight;
NSPoint CP_ApproachingTCenterFromTRight = NSMakePoint(TCenter.x + (TRight.x - TCenter.x) * SIDE_CENTER_CP_OFFSET, TCenter.y);
// Draw the bloody square
NSBezierPath *p = [[NSBezierPath alloc] init];
[p moveToPoint:TCenter];
[p curveToPoint:TLeft controlPoint1:CP_DepartingTCenterForTLeft controlPoint2:CP_ApproachingTLeft];
[p curveToPoint:LTop controlPoint1:CP_TLeft controlPoint2:CP_LTop];
[p curveToPoint:LCenter controlPoint1:CP_DepartingLTopForLCenter controlPoint2:CP_ApproachingLCenterFromLTop];
[p curveToPoint:LBottom controlPoint1:CP_DepartingLCenterForLBottom controlPoint2:CP_ApproachingLBottom];
[p curveToPoint:BLeft controlPoint1:CP_LBottom controlPoint2:CP_BLeft];
[p curveToPoint:BCenter controlPoint1:CP_DepartingBLeftForBCenter controlPoint2:CP_ApproachingBCenter];
[p curveToPoint:BRight controlPoint1:CP_DepartingBCenterForBRight controlPoint2:CP_ApproachingBRight];
[p curveToPoint:RBottom controlPoint1:CP_BRight controlPoint2:CP_RBottom];
[p curveToPoint:RCenter controlPoint1:CP_DepartingRBottomForRCenter controlPoint2:CP_ApproachingRCenterFromRBottom];
[p curveToPoint:RTop controlPoint1:CP_DepartingRCenterForRTop controlPoint2:CP_ApproachingRTopFromRCenter];
[p curveToPoint:TRight controlPoint1:CP_RTop controlPoint2:CP_TRight];
[p curveToPoint:TCenter controlPoint1:CP_DepartingTRightForTCenter controlPoint2:CP_ApproachingTCenterFromTRight];
[p closePath];
_path = p;
}
// We want a slightly white drop shadow on the stroke and fill, giving our square some sense of depth.
[_shadow set];
[[NSColor blackColor] set];
[_path fill];
// Clip to the bezier path and draw a fill image inside of it.
[currentContext saveGraphicsState];
[_path addClip];
[image drawInRect:frame fromRect:NSZeroRect operation:NSCompositeCopy fraction:1.0f respectFlipped:YES hints:nil];
if (self.isHighlighted)
{
// If we're clicked, draw a 50% black overlay to show that
NSColor *overColor = [NSColor colorWithCalibratedWhite:0.0 alpha:0.5];
[overColor set];
[_path fill];
}
[currentContext restoreGraphicsState];
// Stroke the square to create a nice border with a drop shadow at top and bottom.
[_borderColor set];
[_path stroke];
}
@end
于 2013-02-17T09:54:46.313 回答