绘制多边形并填充

作者: 00d1ed2b53ae | 来源:发表于2018-11-02 16:34 被阅读6次

1.绘制矩形的一般方法
// Drawing with a white stroke color
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
// And drawing with a blue fill color
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
// Draw them with a 2.0 stroke width so they are a bit more visible.
CGContextSetLineWidth(context, 2.0);

// Add Rect to the current path, then stroke it
CGContextAddRect(context, CGRectMake(30.0, 30.0, 60.0, 60.0));
CGContextStrokePath(context);

// Stroke Rect convenience that is equivalent to above
CGContextStrokeRect(context, CGRectMake(30.0, 120.0, 60.0, 60.0));

// Stroke rect convenience equivalent to the above, plus a call to CGContextSetLineWidth().
CGContextStrokeRectWithWidth(context, CGRectMake(30.0, 210.0, 60.0, 60.0), 10.0);
// Demonstate the stroke is on both sides of the path.
CGContextSaveGState(context);
//red
CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0);
CGContextStrokeRectWithWidth(context, CGRectMake(30.0, 210.0, 60.0, 60.0), 2.0);
CGContextRestoreGState(context);

CGRect rects[] =
{
CGRectMake(120.0, 30.0, 60.0, 60.0),
CGRectMake(120.0, 120.0, 60.0, 60.0),
CGRectMake(120.0, 210.0, 60.0, 60.0),
};
// Bulk call to add rects to the current path.
CGContextAddRects(context, rects, sizeof(rects)/sizeof(rects[0]));
CGContextStrokePath(context);

// Create filled rectangles via two different paths.
// Add/Fill path
CGContextAddRect(context, CGRectMake(210.0, 30.0, 60.0, 60.0));
CGContextFillPath(context);
// Fill convienience.
CGContextFillRect(context, CGRectMake(210.0, 120.0, 60.0, 60.0));

注释：
CGContextAddRect(context, CGRectMake(30.0, 30.0, 60.0, 60.0));
CGContextStrokePath(context);
此两句绘制的是左上角的矩形，当CGContextStrokePath调用之后，current path会被清空。

CGContextStrokeRect(context, CGRectMake(30.0, 120.0, 60.0, 60.0));
上面的一条语句等价于上面的两条。

语句CGContextStrokeRectWithWidth(context, CGRectMake(30.0, 210.0, 60.0, 60.0), 10.0)等价与上面的语句在加上CGContextSetLineWidth(10.0)

下面的三条语句通过两种方法来fill矩形区域。
CGContextAddRect(context, CGRectMake(210.0, 30.0, 60.0, 60.0));
CGContextFillPath(context);
// Fill convienience.
CGContextFillRect(context, CGRectMake(210.0, 120.0, 60.0, 60.0));

结果如下图：

QuartZ例子（2）---绘制Polygons

2.绘制多边形（Polygon）

// Drawing with a white stroke color

CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);

// Drawing with a blue fill color

CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);

// Draw them with a 2.0 stroke width so they are a bit more visible.

CGContextSetLineWidth(context, 2.0);

CGPoint center;

// Add a star to the current path

center = CGPointMake(90.0, 90.0);

CGContextMoveToPoint(context, center.x, center.y + 60.0);

for(int i = 1; i < 5; ++i)

{

CGFloat x = 60.0 * sinf(i * 4.0 * M_PI / 5.0);

CGFloat y = 60.0 * cosf(i * 4.0 * M_PI / 5.0);

CGContextAddLineToPoint(context, center.x + x, center.y + y);

}

// And close the subpath.

CGContextClosePath(context);

// Now add the hexagon to the current path

center = CGPointMake(210.0, 90.0);

CGContextMoveToPoint(context, center.x, center.y + 60.0);

for(int i = 1; i < 6; ++i)

{

CGFloat x = 60.0 * sinf(i * 2.0 * M_PI / 6.0);

CGFloat y = 60.0 * cosf(i * 2.0 * M_PI / 6.0);

CGContextAddLineToPoint(context, center.x + x, center.y + y);

}

// And close the subpath.

CGContextClosePath(context);

// Now draw the star & hexagon with the current drawing mode.

CGContextDrawPath(context, drawingMode);

我们会根据drawingMode的五个常量讨论

[kCGPathFill](http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGPath/Reference/reference.html#//apple_ref/c/econst/kCGPathFill), [kCGPathEOFill](http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGPath/Reference/reference.html#//apple_ref/c/econst/kCGPathEOFill), [kCGPathStroke](http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGPath/Reference/reference.html#//apple_ref/c/econst/kCGPathStroke), [kCGPathFillStroke](http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGPath/Reference/reference.html#//apple_ref/c/econst/kCGPathFillStroke), or [kCGPathEOFillStroke](http://developer.apple.com/library/ios/documentation/GraphicsImaging/Reference/CGPath/Reference/reference.html#//apple_ref/c/econst/kCGPathEOFillStroke).

（1）kCGPathFill如下图：