anchorPoint:通過position來控制它的frame的位置,可以認為anchorPoint是用來移動圖層的把柄
一般來說anchorPoint:位于圖層的中心,但是圖層的anchorPoint可以被移動.

好了,將錨點之前,先來了解下坐標系
常見的三維坐標系分為兩種:左手坐標系和右手坐標系.當確定了x軸,y軸方向之后可以通過左手或右手來確定z軸的方向.

坐標系

iOS系統坐標

Sprite Kit坐標系

錨點的使用:錨點使用的是相對坐標,范圍是從0.0 ~1.0
默認值為0.5

錨點和position關于自身的使用

//anchorPoint = (0.5,0.5);
SKSpriteNode *spaceship = [[SKSpriteNode alloc] initWithColor:[UIColor orangeColor] size:CGSizeMake(100, 100)];
spaceship.position = CGPointMake(300, 300);
spaceship.anchorPoint = CGPointMake(0.5, 0.5);

[self addChild:spaceship];

錨點的使用

這種圖看的不是很清楚,使用坐標系創建

anchorPoint = (0.5,0.5),紅色的點代表(300,300)

//anchorPoint = (1,0.5)
SKSpriteNode *spaceship = [[SKSpriteNode alloc] initWithColor:[UIColor orangeColor] size:CGSizeMake(100, 100)];
spaceship.position = CGPointMake(300, 300);
spaceship.anchorPoint = CGPointMake(1, 0.5);

anchorPoint = (1,0.5)

//anchorPoint = (0.5,1)
SKSpriteNode *spaceship = [[SKSpriteNode alloc] initWithColor:[UIColor orangeColor] size:CGSizeMake(100, 100)];
spaceship.position = CGPointMake(300, 300);
spaceship.anchorPoint = CGPointMake(0.5, 1);
[self addChild:spaceship];

anchorPoint = (0.5,1)

父視圖上的錨點對子視圖的影響

-(SKSpriteNode *)makeRedBox:(CGSize )size{

return [[SKSpriteNode alloc] initWithColor:[UIColor redColor] size:size];
  }

-(SKSpriteNode *)makeGreenBox:(CGSize)size{

return [[SKSpriteNode alloc] initWithColor:[UIColor greenColor] size:size];
 }

-(SKSpriteNode *)makeBlueBox:(CGSize)size{

return [[SKSpriteNode alloc] initWithColor:[UIColor blueColor] size:size];

 }

pragma mark ---1

SKSpriteNode *box1 = [self makeRedBox:CGSizeMake(100, 100)];
box1.anchorPoint = CGPointMake(0, 0);
box1.position = CGPointMake(100, 100);

SKSpriteNode *box2 = [self makeBlueBox:CGSizeMake(50, 50)];
box2.anchorPoint = CGPointMake(0, 0);
box2.position = CGPointMake(0, 0);
[box1 addChild:box2];

SKSpriteNode *box3 = [self makeGreenBox:CGSizeMake(25, 25)];
box3.anchorPoint = CGPointMake(0, 0);
box3.position = CGPointMake(0, 0);
[box2 addChild:box3];

[self addChild:box1];

一

紅色的anchorPoint(0,0):說明紅色方塊的左下角在(100,100)點,紅色的坐標原點在左下角
藍色的anchorPoint(0,0),position(0,0):說明藍色的左下角在紅色的(0,0)點,坐標原點在藍色的左下角
綠色的anchorPoint(0,0),position(0,0):綠色的左下角在藍色的(0,0)點位置

pragma mark ---二

SKSpriteNode *box1 = [self makeRedBox:CGSizeMake(100, 100)];
box1.anchorPoint = CGPointMake(0.5, 0.5);
box1.position = CGPointMake(100, 100);

SKSpriteNode *box2 = [self makeBlueBox:CGSizeMake(50, 50)];
box2.anchorPoint = CGPointMake(0, 0);
box2.position = CGPointMake(0, 0);
[box1 addChild:box2];

SKSpriteNode *box3 = [self makeGreenBox:CGSizeMake(25, 25)];
box3.anchorPoint = CGPointMake(0, 0);
box3.position = CGPointMake(0, 0);
[box2 addChild:box3];

[self addChild:box1];

二

紅色的anchorPoint(0.5,0.5):說明紅色方塊的中心點在(100,100)點,紅色的坐標原點(0,0)在紅色的中心點
藍色的anchorPoint(0,0),position(0,0):說明藍色的左下角在紅色的(0,0)點,坐標原點在藍色的左下角
綠色的anchorPoint(0,0),position(0,0):綠色的左下角在藍色的(0,0)點位置

pragma mark----三

SKSpriteNode *box1 = [self makeRedBox:CGSizeMake(100, 100)];
box1.anchorPoint = CGPointMake(0.5, 0.5);
box1.position = CGPointMake(100, 100);

SKSpriteNode *box2 = [self makeBlueBox:CGSizeMake(50, 50)];
box2.anchorPoint = CGPointMake(0, 0);
box2.position = CGPointMake(25, 25);
[box1 addChild:box2];

SKSpriteNode *box3 = [self makeGreenBox:CGSizeMake(25, 25)];
box3.anchorPoint = CGPointMake(0, 0);
box3.position = CGPointMake(0, 0);
[box2 addChild:box3];

[self addChild:box1];

三

紅色的anchorPoint(0.5,0.5):說明紅色方塊的中心點在(100,100)點,紅色的坐標原點(0,0)在紅色的中心點
藍色的anchorPoint(0,0),position(25,25):說明藍色的左下角在紅色的(25,25)點,坐標原點在藍色的左下角
綠色的anchorPoint(0,0),position(0,0):綠色的左下角在藍色的(0,0)點位置

pragma mark ---四

SKSpriteNode *box1 = [self makeRedBox:CGSizeMake(100, 100)];
box1.anchorPoint = CGPointMake(0.5, 0.5);
box1.position = CGPointMake(100, 100);

SKSpriteNode *box2 = [self makeBlueBox:CGSizeMake(50, 50)];
box2.anchorPoint = CGPointMake(0.5, 0.5);
box2.position = CGPointMake(25, 25);
[box1 addChild:box2];

SKSpriteNode *box3 = [self makeGreenBox:CGSizeMake(25, 25)];
box3.anchorPoint = CGPointMake(0, 0);
box3.position = CGPointMake(0, 0);
[box2 addChild:box3];

[self addChild:box1];

四