检测CGAffineTransformed视图是否超出屏幕/ UIView的范围

我有几个视图，我可以拖动，旋转，缩放。我想做到这一点，他们不能药物，旋转或缩小屏幕。拖动似乎不是一个问题因为我没有使用变换来生成新位置并查看该新位置是否会将视图从屏幕上移开。当我旋转或缩放时，我使用CGAffineTransform（CGAffineTransformedRotate或CGAffineTransformScale）并且我似乎无法获得新帧的实际内容而不将其实际应用于我的视图。

CGRect  newElementBounds = CGRectApplyAffineTransform(element.bounds, CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]));


CGRect elementBoundsInSuperView = [element convertRect:newElementBounds toView:[element superview]];

elementBoundsInSuperView不是我期望它的Rect，它离开了。我也尝试先在SuperView中获取边界，然后将变换应用到它，这也不对。

CGRect elementBoundsInSuperView = [element convertRect:element.bounds toView:[element superview]];

CGRect  newElementBounds = CGRectApplyAffineTransform(newElementBounds, CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]));

[gestureRecognizer视图]应该与元素相同。

已邀请:

1 个回复

脖呐

我想出了一些可以工作的手势处理程序，这样你操作的视图就不会离开你指定的区域。 My View托盘由kscreenEditorSpace，2048定义。 Pan手势只调用calcCenterFromXposition：yPosition：fromBoundsInSuperView：方法设置其中心，如果中心超出界限，它只是调整并保持元素在边界内

//--------------------------------------------------------------------------------------------------------
//    handlePanGesture
//    Description: Called when scrollView got a DoubleFinger DoubleTap Gesture
//                 We want to Zoom out one ZOOM_STEP.               
//
//--------------------------------------------------------------------------------------------------------
- (void)handlePanGesture:(UIPanGestureRecognizer *)gestureRecognizer {

    UIView *element = [gestureRecognizer view];


    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan ) {
            [[self superview] bringSubviewToFront:self]; 
    }

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
            //Front and Center Mr Element! 

            // Find out where we are going
        CGPoint translation = [gestureRecognizer translationInView:[element superview]];
        CGRect elementBoundsInSuperView = [element convertRect:element.bounds toView:[element superview]];
        CGFloat xPosition = CGRectGetMidX(elementBoundsInSuperView) + translation.x;
        CGFloat yPosition = CGRectGetMidY(elementBoundsInSuperView) + translation.y;

        CGPoint newCenter = [self calcCenterFromXposition:xPosition yPosition:yPosition fromBoundsInSuperView:elementBoundsInSuperView];

            //Re position ourselves
        [element setCenter:newCenter];

            //set the translation back to 0 point
        [gestureRecognizer setTranslation:CGPointZero inView:[element superview]];
        [self setNeedsDisplay];
    }

    if ([gestureRecognizer state] == UIGestureRecognizerStateEnded ) {
    }

}

所以手柄的Pinch和Rotation非常相似。而不是直接调用calc Center，我们调用另一种方法来帮助确定我们是否在边界内。

//--------------------------------------------------------------------------------------------------------
//    handlePinchGesture
//    Description: Called when scrollView got a DoubleFinger DoubleTap Gesture
//                 We want to Zoom out one ZOOM_STEP.               
//
//--------------------------------------------------------------------------------------------------------

- (void)handlePinchGesture:(UIPinchGestureRecognizer *)gestureRecognizer {
    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan ) {

        [[self superview] bringSubviewToFront:self]; 
    }

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {



        BOOL aSelectedElementOffscreen = FALSE;
            if ([[gestureRecognizer view] pinchOffScreen:[gestureRecognizer scale]]) {
                aSelectedElementOffscreen = TRUE;
            }

        if (!aSelectedElementOffscreen) {

            [gestureRecognizer view].transform = CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]);

                //Update ourself
            [self contentSizeChanged];  
     }
             [gestureRecognizer setScale:1];
    }

    if ([gestureRecognizer state] == UIGestureRecognizerStateEnded) {

        if (![self becomeFirstResponder]) {
            NSLog(@" %@ - %@ - couldn't become first responder", INTERFACENAME, NSStringFromSelector(_cmd) );
            return;
        }
    }
}
}

夹紧屏幕方法

 //--------------------------------------------------------------------------------------------------------
//    pinchOffScreen
//    Description: Called to see if the Pinch Gesture will cause element to go off screen Gesture
//
//--------------------------------------------------------------------------------------------------------

- (BOOL)pinchOffScreen:(CGFloat)scale {

    // Save Our Current Transform incase we go off Screen
CGAffineTransform elementOrigTransform = [self transform];
    //Apply our Transform
self.transform = CGAffineTransformScale([self transform],  scale,  scale);
    // Get our new Bounds in the SuperView
CGRect newElementBoundsInSuperView = [self convertRect:self.bounds toView:[self superview]];

    //Find out where we are in the SuperView 
CGFloat xPosition = CGRectGetMidX( newElementBoundsInSuperView);
CGFloat yPosition = CGRectGetMidY( newElementBoundsInSuperView);

    //See if we are off the Screen
BOOL offScreen = [self calcOffEditorFromXposition:xPosition yPosition:yPosition fromBoundsInSuperView: newElementBoundsInSuperView];

    // We just wanted to Check. Revert to where we were
self.transform = elementOrigTransform;
return offScreen;

}

Handle Rotation与Pinch类似，我们有一个帮助方法，看看我们是否旋转屏幕。

//--------------------------------------------------------------------------------------------------------
//    handleRotationGesture
//    Description: Called when we get a rotation gesture
//                 toggle the scroll/zoom lock
//
//--------------------------------------------------------------------------------------------------------

- (void) handleRotationGesture:(UIRotationGestureRecognizer *)gestureRecognizer{
    UIView *element = [gestureRecognizer view];

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan ) {
                [[self superview] bringSubviewToFront:self]; 
    }

    if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {


        BOOL aSelectedElementOffscreen = FALSE;
            if ([element rotateOffScreen:[gestureRecognizer rotation]]) {
                aSelectedElementOffscreen = TRUE;
            }

        if (!aSelectedElementOffscreen) {

            [gestureRecognizer view].transform = CGAffineTransformRotate([element transform], [gestureRecognizer rotation]);


                //Update ourself
            [self contentSizeChanged];  

        }
        [gestureRecognizer setRotation:0];
    }
    if ([gestureRecognizer state] == UIGestureRecognizerStateEnded) {
    }
}
}

旋转屏幕外方法

//--------------------------------------------------------------------------------------------------------
//    rotateOffScreen
//    Description: Called to see if the Rotation Gesture will cause element to go off screen Gesture
//
//--------------------------------------------------------------------------------------------------------

- (BOOL)rotateOffScreen:(CGFloat)rotation {

    // Save Our Current Transform incase we go off Screen
CGAffineTransform elementOrigTransform = [self transform];
    //Apply our Transform
self.transform = CGAffineTransformRotate([self transform], rotation);
    // Get our new Bounds in the SuperView
CGRect newElementBoundsInSuperView = [self convertRect:self.bounds toView:[self superview]];

    //Find out where we are in the SuperVire 
CGFloat xPosition = CGRectGetMidX( newElementBoundsInSuperView);
CGFloat yPosition = CGRectGetMidY( newElementBoundsInSuperView);

    //See if we are off the Screen
BOOL offScreen = [self calcOffEditorFromXposition:xPosition yPosition:yPosition fromBoundsInSuperView: newElementBoundsInSuperView];

    // We just wanted to Check. Revert to where we were
self.transform = elementOrigTransform;

return offScreen;

}

Calc屏幕定位辅助方法

#pragma mark -
#pragma mark === Calc Screen Positioning  ===
#pragma mark
//--------------------------------------------------------------------------------------------------------
//    calcCenterFromXposition: yPosition: fromBoundsInSuperView:
//    Description: calculate the center point in the element's super view from x, y
//
//--------------------------------------------------------------------------------------------------------
-(CGPoint) calcCenterFromXposition: (CGFloat) xPosition yPosition:(CGFloat) yPosition fromBoundsInSuperView:(CGRect) elementBoundsInSuperView{


    // Ge the Height/width based on SuperView Bounds
CGFloat elementWidth = CGRectGetWidth(elementBoundsInSuperView); 
CGFloat elementHeight = CGRectGetHeight(elementBoundsInSuperView);

    //Determine our center.x from the new x
if (xPosition < elementWidth/2) {
    xPosition = elementWidth/2;
} else if (xPosition + elementWidth/2  > kscreenEditorSpace) {
    xPosition = kscreenEditorSpace - elementWidth/2;
}   
    //Determine our center.y from the new y
if (yPosition < elementHeight/2) {
    yPosition = elementHeight/2;
} else if (yPosition + elementHeight/2  > kscreenEditorSpace) {
    yPosition = kscreenEditorSpace - elementHeight/2;
} 
return (CGPointMake(xPosition, yPosition));
}

//--------------------------------------------------------------------------------------------------------
//    calcOffEditorFromXposition: yPosition: fromBoundsInSuperView:
//    Description: Determine if moving the element to x, y will it be off the editor screen
//
//--------------------------------------------------------------------------------------------------------
-(BOOL) calcOffEditorFromXposition: (CGFloat) xPosition yPosition:(CGFloat) yPosition fromBoundsInSuperView:(CGRect) elementBoundsInSuperView{

BOOL offScreen = NO;

    // Ge the Height/width based on SuperView Bounds
CGFloat elementWidth = CGRectGetWidth(elementBoundsInSuperView); 
CGFloat elementHeight = CGRectGetHeight(elementBoundsInSuperView);

    // Off Screen on Left
if (xPosition < elementWidth/2) {
    offScreen = YES;
} 
    //Off Screen Right
if (xPosition + elementWidth/2  > kscreenEditorSpace) {
    offScreen = YES;;
}

    // Off Screen Top
if (yPosition < elementHeight/2) {
    offScreen = YES;
} 

    //Off Screen Bottom
if (yPosition + elementHeight/2  > kscreenEditorSpace) {
    offScreen = YES;
}

return (offScreen);
}

要回复问题请先登录或注册

检测CGAffineTransformed视图是否超出屏幕/ UIView的范围

1 个回复

发起人

cgaffinetransform

bounds

问题状态

检测CGAffineTransformed视图是否超出屏幕/ UIView的范围

与内容相关的链接

1 个回复

发起人

cgaffinetransform

bounds

问题状态