- (void)willAnimateFirstHalfOfRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
if (toInterfaceOrientation == UIInterfaceOrientationPortrait)
{
b=YES;
self.view=mainvv;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(0));
self.view.bounds = CGRectMake(0.0, 0.0, 768.0, 1004.0);
}
else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft)
{
b=NO;
self.view = self.vv;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(-90));
self.view.bounds = CGRectMake(0.0, 0.0, 1024.0, 748.0);
}
else if (toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
b=YES;
self.view=mainvv;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(180));
self.view.bounds = CGRectMake(0.0, 0.0, 768.0, 1004.0);
}
else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight)
{
b=NO;
self.view = self.vv;
self.view.transform = CGAffineTransformIdentity;
self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(90));
self.view.bounds = CGRectMake(0.0, 0.0, 1024.0, 748.0);
}
}
3
Quartz轉換實現的原理:Quartz把繪圖分成兩個部分，
用戶空間，即和設備無關，
設備空間，
用戶空間和設備空間中間存在一個轉換矩陣 ： CTM
本章實質是講解CTM
Quartz提供的3大功能
移動，旋轉，縮放
演示如下，首先加載一張圖片
void CGContextDrawImage ( CGContextRef c, CGRect rect, CGImageRef image );
移動函數
CGContextTranslateCTM (myContext, 100, 50);
旋轉函數
include <math.h>
static inline double radians (double degrees) {return degrees * M_PI/180;}
CGContextRotateCTM (myContext, radians(–45.));
縮放
CGContextScaleCTM (myContext, .5, .75);
翻轉， 兩種轉換合成後的效果，先把圖片移動到右上角，然後旋轉180度
CGContextTranslateCTM (myContext, w,h);
CGContextRotateCTM (myContext, radians(-180.));
組合幾個動作CGContextTranslateCTM (myContext, w/4, 0);
CGContextScaleCTM (myContext, .25, .5);
CGContextRotateCTM (myContext, radians ( 22.));
CGContextRotateCTM (myContext, radians ( 22.));
CGContextScaleCTM (myContext, .25, .5);CGContextTranslateCTM (myContext, w/4, 0);
上面是通過直接修改當前的ctm實現3大效果，下面是通過創建Affine Transforms，然後連接ctm實現同樣的3種效果這樣做的好處是可以重用這個Affine Transforms應用Affine Transforms 到ctm的函數void CGContextConcatCTM ( CGContextRef c, CGAffineTransform transform );
Creating Affine Transforms移動效果CGAffineTransform CGAffineTransformMakeTranslation ( CGFloat tx, CGFloat ty );
CGAffineTransform CGAffineTransformTranslate ( CGAffineTransform t, CGFloat tx, CGFloat ty );
旋轉效果
CGAffineTransform CGAffineTransformMakeRotation ( CGFloat angle );
CGAffineTransform CGAffineTransformRotate ( CGAffineTransform t, CGFloat angle );
縮放效果
CGAffineTransform CGAffineTransformMakeScale ( CGFloat sx, CGFloat sy );
CGAffineTransform CGAffineTransformScale ( CGAffineTransform t, CGFloat sx, CGFloat sy );
反轉效果
CGAffineTransform CGAffineTransformInvert ( CGAffineTransform t );
只對局部產生效果
CGRect CGRectApplyAffineTransform ( CGRect rect, CGAffineTransform t );
判斷兩個AffineTrans是否相等
bool CGAffineTransformEqualToTransform ( CGAffineTransform t1, CGAffineTransform t2 );
獲得Affine Transform
CGAffineTransform CGContextGetUserSpaceToDeviceSpaceTransform ( CGContextRef c );
下面的函數只起到查看的效果，比如看一下這個用戶空間的點，轉換到設備空間去座標是多少
CGPoint CGContextConvertPointToDeviceSpace ( CGContextRef c, CGPoint point );
CGPoint CGContextConvertPointToUserSpace ( CGContextRef c, CGPoint point );
CGSize CGContextConvertSizeToDeviceSpace ( CGContextRef c, CGSize size );
CGSize CGContextConvertSizeToUserSpace ( CGContextRef c, CGSize size );
CGRect CGContextConvertRectToDeviceSpace ( CGContextRef c, CGRect rect );
CGRect CGContextConvertRectToUserSpace ( CGContextRef c, CGRect rect );
CTM真正的數學行爲
這個轉換矩陣其實是一個 3x3的 舉證
如下圖
下面舉例說明幾個轉換運算的數學實現
x y 是原先點的座標
下面是從用戶座標轉換到設備座標的計算公式
下面是一個identity matrix，就是輸入什麼座標，出來什麼座標，沒有轉換
最終的計算結果是 x=x，y=y，
bool CGAffineTransformIsIdentity ( CGAffineTransform t );
移動矩陣
縮放矩陣
旋轉矩陣
旋轉加移動矩陣
