How can I use pinch zoom(UIPinchGestureRecognizer) to change width of a UITextView?
I can get the UIPinchGestureRecognizer
handler to work with scaling an object but I don't want to scale I want to change the size. For example I have a UITextView
and I've attached a UIPinchGestureRecognizer
gesture to it and if the user pinches I want to change the width of the textview to match the pinch. I don't want to scale it so the UIT开发者_运维知识库extView
is larger(zooming).
I am doing the very same thing. I will update this post if I found how to do it.
Try this, it work for me (for UIView):
- (IBAction)handlePinchGesture:(UIGestureRecognizer *)sender {
static CGRect initialBounds;
UIView *_view = sender.view;
if (sender.state == UIGestureRecognizerStateBegan)
{
initialBounds = _view.bounds;
}
CGFloat factor = [(UIPinchGestureRecognizer *)sender scale];
CGAffineTransform zt = CGAffineTransformScale(CGAffineTransformIdentity, factor, factor);
_view.bounds = CGRectApplyAffineTransform(initialBounds, zt);
return;
}
You have to use in swift:
func pinchgsterAction(gesture:UIPinchGestureRecognizer){
if (gesture.state == UIGestureRecognizerState.Changed) {
let scale:CGFloat = gesture.scale
gesture.view.transform = CGAffineTransformScale(gesture.view.transform, scale, scale)
}
}
I think what you want to do is just multiplying the width of your textView's frame with the gesture recognizer's scale:
CGFloat scale = gestureRecognizer.scale;
CGRect newFrame = textView.frame;
newFrame.size = CGSizeMake(scale*newFrame.size.width, newFrame.size.height);
textView.frame = newFrame;
Or isn't this what you mean?
I have four routines that deal with pinching of a text field. The gesture recognizer is the core routine. It sees if the selected text field(s) are going to be Pinched off the Screen, I don't want that. If they are not, then I tell it to pinch itself with the scale from the gesture. If there are multiple selected I send a Notification for those that won't pinch off screen to Pinch themselves.
//--------------------------------------------------------------------------------------------------------
// pinchElement
// Description: Called to di the element scale, in our case, we are adjusting the length.
//
//--------------------------------------------------------------------------------------------------------
- (void)pinchElement:(CGFloat)scale {
//Grab how big we are now
CGRect textFieldBounds = textField.bounds;
//Multiple the Scale of the Pinch by the Width to get our new width.
CGFloat newWidth = textFieldBounds.size.width * scale;
CGFloat widthChange = newWidth - textFieldBounds.size.width;
CGRect newBounds = CGRectMake(0, 0, newWidth, textFieldBounds.size.height );
[textField setBounds: newBounds];
[textField setCenter: CGPointMake(textField.center.x + widthChange/2, textField.center.y)] ;
[self contentSizeChanged];
}
//--------------------------------------------------------------------------------------------------------
// pinchOffScreen
// Description: Called to see if the Pinch Gesture will cause element to go off screen Gesture
//
//--------------------------------------------------------------------------------------------------------
- (BOOL)pinchOffScreen:(CGFloat)scale {
//Grab how big we are now
CGRect textFieldBounds = textField.bounds;
//Multiple the Scale of the Pinch by the Width to get our new width.
CGFloat newWidth = textFieldBounds.size.width * scale;
//Figure out our Change in Width so we can calculate our new Zen Center
CGRect newElementBounds = CGRectMake(0, 0, newWidth+ kElementFrameOffset*2 + kElementContentFrameOffset*2, textFieldBounds.size.height + kElementFrameOffset*2 + kElementContentFrameOffset*2);
//We want to be sure that we dont size beyond our bounds, find our Parent Origin.
CGRect elementBoundsInSuperView = [self convertRect:newElementBounds toView:[self superview]];
CGFloat xPosition = CGRectGetMidX(elementBoundsInSuperView);
CGFloat yPosition = CGRectGetMidY(elementBoundsInSuperView);
BOOL offScreen = [self calcOffEditorFromXposition:xPosition yPosition:yPosition fromBoundsInSuperView:elementBoundsInSuperView];
return offScreen;
}
//--------------------------------------------------------------------------------------------------------
// handlePinchGesture
// Description: Called when we get a Pinch Gesture
// We want to override the default scaling and set the width.
//
//--------------------------------------------------------------------------------------------------------
- (void)handlePinchGesture:(UIPinchGestureRecognizer *)gestureRecognizer {
if (IoUIDebug & IoUIDebugSelectorNames) {
NSLog(@"%@ - %@", INTERFACENAME, NSStringFromSelector(_cmd) );
}
// UIView *element = [gestureRecognizer view];
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan ) {
//We are resizing, Select ourself
[self selectSelf];
}
if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
NSSet *selectedElements = [[(IoScreenEditorViewController *)UIAppDelegate.ioMainViewController.currentViewController editorContentViewController] selectedElements];
BOOL aSelectedElementOffscreen = FALSE;
for (IoUIScreenElement* element in selectedElements) {
if ([element pinchOffScreen:[gestureRecognizer scale]]) {
aSelectedElementOffscreen = TRUE;
break;
}
}
if (!aSelectedElementOffscreen) {
[self pinchElement:[gestureRecognizer scale]];
// Let others know they are moving if they are selected
// Setup our data for the Notification
NSMutableDictionary *theUserInfo = [[[NSMutableDictionary alloc] initWithCapacity:1] autorelease];
[theUserInfo setObject:self forKey:@"ElementWithGesture"];
NSNumber * scaleAsNumber = [[NSNumber alloc] initWithFloat:[gestureRecognizer scale]];
[theUserInfo setValue:scaleAsNumber forKey:@"GestureScale"];
[theUserInfo setObject:gestureRecognizer forKey:@"TheGestureRecognizer"];
[scaleAsNumber release];
// Post the Group Rotation Notification.
[[NSNotificationCenter defaultCenter] postNotificationName:kNCSEGroupPinchGesture
object:nil
userInfo:theUserInfo];
}
[gestureRecognizer setScale:1];
}
if ([gestureRecognizer state] == UIGestureRecognizerStateEnded ) {
}
}
//--------------------------------------------------------------------------------------------------------
// groupHandlePinchGesture:
// Description: For a groupPinch Notification. Move it! within bounds of course
//
//--------------------------------------------------------------------------------------------------------
- (void) groupHandlePinchGesture:(NSNotification*)notification{
if (IoUIDebug & IoUIDebugSelectorNames) {
NSLog(@"%@ - %@", INTERFACENAME, NSStringFromSelector(_cmd) );
}
IoUIScreenElement *element = (IoUIScreenElement *) [[notification userInfo] objectForKey:@"ElementWithGesture"];
//UIRotationGestureRecognizer *gestureRecognizer = (UIRotationGestureRecognizer *) [[notification userInfo] objectForKey:@"TheGestureRecognizer"];
NSNumber *scaleAsNumber = [[notification userInfo] valueForKey:@"GestureScale"];
CGFloat scale = [scaleAsNumber floatValue];
if (IOFNOTEQUAL(self, element) & [self isSelected]){
[self pinchElement: scale];
}
}
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