Pinch Zoom UITableView

We can give pinch zoom feature to UITableView using UIPinchGesture. Below is the subclass of UITableView which can be directly used to enable pinch zoom capability for your table view. Just you need to change the class of UITable in nib as shown below.

Just you need to add "PinchZoomTableView.h" and "PinchZoomTableView.m" to your project. Then change the class from UITableView to PinchZoomTableView in the nib file where UITable is used. You can download the sample project from https://github.com/sachithkadamba/PinchZoomUITableView.  Or You can copy paste PinchZoomTableView.h and PinchZoomTableView.m from below.

	//PinchZoomTableView.h
	//Created by Sachith on 14/01/11.
	/*Copyright 2011 Sachith Kadamba <sachithkadamba@gmail.com>
	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU  Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
	You should have received a copy of the GNU Lesser General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
	MA 02110-1301, USA.*/
	// For any Queries or suggestion contact me :sachithkadamba@gmail.com
	/*
	This works both for iPhone and iPad in all orientaions.
	For any bugs or improvements feel free to contact me.
	*/
	#import <UIKit/UIKit.h>
	@interface PinchZoomTableView : UITableView <UIGestureRecognizerDelegate>{
	CGRect originalFrame;
	CGFloat screenWidth;
	CGFloat screenHeight;
	CGFloat deltaY;
	}
	@property (nonatomic, readwrite) CGRect originalFrame;
	@property (nonatomic, readwrite) CGFloat screenWidth;
	@property (nonatomic, readwrite) CGFloat screenHeight;
	@property (nonatomic, readwrite) CGFloat deltaY;
	- (void) resetTable;
	- (void) addGesture;
	@end

view raw PinchZoomTableView.h hosted with ❤ by GitHub

	//PinchZoomTableView.m
	//Created by Sachith on 14/01/11.
	Copyright 2011 Sachith Kadamba <sachithkadamba@gmail.com>
	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU  Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.
	You should have received a copy of the GNU Lesser General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
	MA 02110-1301, USA.*/
	// For any Queries or suggestion contact me :sachithkadamba@gmail.com
	#import "PinchZoomTableView.h"
	#import <QuartzCore/QuartzCore.h>
	@implementation PinchZoomTableView
	@synthesize originalFrame;
	@synthesize screenWidth;
	@synthesize screenHeight;
	@synthesize deltaY;
	-(void)awakeFromNib {
	[self addGesture];
	CGRect wh = [[UIScreen mainScreen]bounds];
	screenWidth = wh.size.width;
	screenHeight = wh.size.height;
	/*
	For iPad i found deltaY as 120.. you can change this for your requirement
	*/
	if(screenWidth > 1000) {
	deltaY = 120;
	}
	else {
	deltaY = 50;
	}
	}
	- (void)addGesture {
	self.clipsToBounds = YES;
	UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(scalePiece:)];
	[pinchGesture setDelegate:self];
	[self addGestureRecognizer:pinchGesture];
	[pinchGesture release];
	}
	- (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer {
	if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {
	UIView *piece = gestureRecognizer.view;
	originalFrame.size.height = self.frame.size.height;
	self.originalFrame = self.frame;
	CGPoint locationInView = [gestureRecognizer locationInView:nil];
	CGPoint locationInSuperview = [gestureRecognizer locationInView:piece.superview];
	UIInterfaceOrientation orientaion = [[UIDevice currentDevice]orientation];
	/*some times Device gives unknown orientaion
	If Device orientaion is unkown check orientaion of status bar
	*/
	if( orientaion != UIInterfaceOrientationPortrait && orientaion != UIInterfaceOrientationPortraitUpsideDown &&orientaion != UIInterfaceOrientationLandscapeLeft && orientaion != UIInterfaceOrientationLandscapeRight) {
	orientaion = [[UIApplication sharedApplication] statusBarOrientation];
	}
	if( orientaion == UIInterfaceOrientationPortrait ) {
	}
	else if ( orientaion == UIInterfaceOrientationPortraitUpsideDown ) {
	locationInView.x = screenWidth - locationInView.x;
	locationInView.y = (screenHeight -20) - locationInView.y;
	}
	else if ( orientaion == UIInterfaceOrientationLandscapeLeft ) {
	float x = screenHeight - locationInView.y;
	float y = locationInView.x;
	locationInView.x = x;
	locationInView.y = y;
	}
	else if ( orientaion == UIInterfaceOrientationLandscapeRight ) {
	float y = locationInView.y;
	float x = screenWidth - locationInView.x;
	locationInView.x = y;
	locationInView.y = x;
	}
	piece.layer.anchorPoint = CGPointMake(locationInView.x / piece.bounds.size.width, (locationInView.y -deltaY) / piece.bounds.size.height);
	piece.center = locationInSuperview;
	}
	else if(gestureRecognizer.state == UIGestureRecognizerStateEnded) {
	[self resetTable];
	}
	}
	- (void)resetTable {
	[UIView beginAnimations:nil context:nil];
	[self setTransform:CGAffineTransformIdentity];
	self.frame = originalFrame;
	[UIView commitAnimations];
	}
	- (void)scalePiece:(UIPinchGestureRecognizer *)gestureRecognizer {
	[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];
	if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
	[gestureRecognizer view].transform = CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]);
	[gestureRecognizer setScale:1];
	}
	}
	- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
	return YES;
	}
	-(void)dealloc {
	[super dealloc];
	}
	@end

view raw PinchZoomTableView.m hosted with ❤ by GitHub

Please leave comments if this post helped you and also please share the code if you have fixed any bug or improved this code so that it helps others.