cocos2dx图片精灵裁剪圆角矩形方法

在做项目中，需要对图片进行裁剪已统一所有图片的边角，在网上查找方法结合自己的项目，书写了一个专门做裁剪的函数，供大家参考；

本方法是对图片的边角进行像素点的裁剪，在使用中发现如果大料使用对图片的裁剪，对程序的性能还是有点影响的，会降低cocos2dx的帧率；

 ClippingNode* ccDrawRoundRect(cocos2d::Sprite *bgSprite, cocos2d::Vec2 origin, cocos2d::Vec2 destination, float radius, unsigned int segments){

Sprite *thisbg
4000
Sprite = bgSprite;

ClippingNode* pClip = ClippingNode::create();

pClip->setInverted(false);//设置是否反向，将决定画出来的圆是透明的还是黑色的

//    this->addChild(pClip);

pClip->setAnchorPoint(Point(0, 0));

pClip->setPosition(-7, -7);

//算出1/4圆

const float coef = 0.5f * (float)M_PI / segments;

Point * vertices = new Point[segments + 1];

Point * thisVertices = vertices;

for (unsigned int i = 0; i <= segments; ++i, ++thisVertices)

{

float rads = (segments - i)*coef;

thisVertices->x = (int)(radius * sinf(rads));

thisVertices->y = (int)(radius * cosf(rads));

}

//

Point tagCenter;

float minX = MIN(origin.x, destination.x);

float maxX = MAX(origin.x, destination.x);

float minY = MIN(origin.y, destination.y);

float maxY = MAX(origin.y, destination.y);

unsigned int dwPolygonPtMax = (segments + 1) * 4;

Point * pPolygonPtArr = new Point[dwPolygonPtMax];

Point * thisPolygonPt = pPolygonPtArr;

int aa = 0;

//左上角

tagCenter.x = minX + radius;

tagCenter.y = maxY - radius;

thisVertices = vertices;

for (unsigned int i = 0; i <= segments; ++i, ++thisPolygonPt, ++thisVertices)

{

thisPolygonPt->x = tagCenter.x - thisVertices->x;

thisPolygonPt->y = tagCenter.y + thisVertices->y;

// log("%f , %f", thisPolygonPt->x, thisPolygonPt->y);

++aa;

}

//右上角

tagCenter.x = maxX - radius;

tagCenter.y = maxY - radius;

thisVertices = vertices + segments;

for (unsigned int i = 0; i <= segments; ++i, ++thisPolygonPt, --thisVertices)

{

thisPolygonPt->x = tagCenter.x + thisVertices->x;

thisPolygonPt->y = tagCenter.y + thisVertices->y;

// log("%f , %f", thisPolygonPt->x, thisPolygonPt->y);

++aa;

}

//右下角

tagCenter.x = maxX - radius;

tagCenter.y = minY + radius;

thisVertices = vertices;

for (unsigned int i = 0; i <= segments; ++i, ++thisPolygonPt, ++thisVertices)

{

thisPolygonPt->x = tagCenter.x + thisVertices->x;

thisPolygonPt->y = tagCenter.y - thisVertices->y;

// log("%f , %f", thisPolygonPt->x, thisPolygonPt->y);

++aa;

}

//左下角

tagCenter.x = minX + radius;

tagCenter.y = minY + radius;

thisVertices = vertices + segments;

for (unsigned int i = 0; i <= segments; ++i, ++thisPolygonPt, --thisVertices)

{

thisPolygonPt->x = tagCenter.x - thisVertices->x;

thisPolygonPt->y = tagCenter.y - thisVertices->y;

// log("%f , %f", thisPolygonPt->x, thisPolygonPt->y);

++aa;

}

//设置参数

static Color4F red(1, 0, 0, 1);//顶点颜色设置为红色，参数是R,G,B,透明度

//注意不要将pStencil addChild

DrawNode *pStencil = DrawNode::create();

pStencil->drawPolygon(pPolygonPtArr, dwPolygonPtMax, red, 0, red);//绘制这个多边形

pStencil->setPosition(Point(0, 0));

pClip->setStencil(pStencil);

pClip->addChild(thisbgSprite, 1);

pClip->setContentSize(thisbgSprite->getContentSize());

CC_SAFE_DELETE_ARRAY(vertices);

CC_SAFE_DELETE_ARRAY(pPolygonPtArr);

          return pClip；

 }