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PDFScrollView.m
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PDFScrollView.m
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/*
File: PDFScrollView.m
Abstract: Centers image within the scroll view and configures image sizing and display.
Version: 1.1
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
Inc. ("Apple") in consideration of your agreement to the following
terms, and your use, installation, modification or redistribution of
this Apple software constitutes acceptance of these terms. If you do
not agree with these terms, please do not use, install, modify or
redistribute this Apple software.
In consideration of your agreement to abide by the following terms, and
subject to these terms, Apple grants you a personal, non-exclusive
license, under Apple's copyrights in this original Apple software (the
"Apple Software"), to use, reproduce, modify and redistribute the Apple
Software, with or without modifications, in source and/or binary forms;
provided that if you redistribute the Apple Software in its entirety and
without modifications, you must retain this notice and the following
text and disclaimers in all such redistributions of the Apple Software.
Neither the name, trademarks, service marks or logos of Apple Inc. may
be used to endorse or promote products derived from the Apple Software
without specific prior written permission from Apple. Except as
expressly stated in this notice, no other rights or licenses, express or
implied, are granted by Apple herein, including but not limited to any
patent rights that may be infringed by your derivative works or by other
works in which the Apple Software may be incorporated.
The Apple Software is provided by Apple on an "AS IS" basis. APPLE
MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
Copyright (C) 2010 Apple Inc. All Rights Reserved.
*/
#import "PDFScrollView.h"
#import "PDFViewTiled.h"
@implementation PDFScrollView
@synthesize index;
- (id)initWithPage:(NSInteger)onPage frame:(CGRect)frame {
if (self = [self initWithFrame:frame]) {
self.index = onPage;
pdfView = [[PDFViewTiled alloc] initWithPage:onPage frame:frame];
[self addSubview:pdfView];
}
return self;
}
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame])) {
self.showsVerticalScrollIndicator = NO;
self.showsHorizontalScrollIndicator = NO;
self.bouncesZoom = YES;
self.decelerationRate = UIScrollViewDecelerationRateFast;
self.delegate = self;
[self setMaxMinZoomScalesForCurrentBounds];
self.contentSize = CGSizeMake(pdfView.bounds.size.width * 5, pdfView.bounds.size.height * 5);
self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
self.backgroundColor = [UIColor whiteColor];
}
return self;
}
- (void)resetZoomScale {
self.zoomScale = self.minimumZoomScale;
}
- (void)dealloc
{
[pdfView release];
[super dealloc];
}
#pragma mark -
#pragma mark Override layoutSubviews to center content
- (void)layoutSubviews
{
[super layoutSubviews];
// center the image as it becomes smaller than the size of the screen
CGSize boundsSize = self.bounds.size;
CGRect frameToCenter = pdfView.frame;
// center horizontally
if (frameToCenter.size.width < boundsSize.width)
frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
else
frameToCenter.origin.x = 0;
// center vertically
if (frameToCenter.size.height < boundsSize.height)
frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
else
frameToCenter.origin.y = 0;
pdfView.frame = frameToCenter;
// if ([pdfView isKindOfClass:[PDFViewTiled class]]) {
// // to handle the interaction between CATiledLayer and high resolution screens, we need to manually set the
// // tiling view's contentScaleFactor to 1.0. (If we omitted this, it would be 2.0 on high resolution screens,
// // which would cause the CATiledLayer to ask us for tiles of the wrong scales.)
// pdfView.contentScaleFactor = 1.0;
// }
}
#pragma mark -
#pragma mark UIScrollView delegate methods
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return pdfView;
}
- (void)willRotate
{
[pdfView willRotate];
}
- (void)didRotate
{
[pdfView didRotate];
// self.bounds = [self superview].bounds;
// self.contentSize = CGSizeMake(pdfView.bounds.size.width * 5, pdfView.bounds.size.height * 5);
// self.zoomScale = self.minimumZoomScale;
}
- (void)setMaxMinZoomScalesForCurrentBounds
{
CGSize boundsSize = self.bounds.size;
CGSize imageSize = CGSizeMake(pdfView.bounds.size.width * 5, pdfView.bounds.size.height * 5);
// calculate min/max zoomscale
CGFloat xScale = boundsSize.width / imageSize.width; // the scale needed to perfectly fit the image width-wise
CGFloat yScale = boundsSize.height / imageSize.height; // the scale needed to perfectly fit the image height-wise
CGFloat minScale = MIN(xScale, yScale); // use minimum of these to allow the image to become fully visible
// on high resolution screens we have double the pixel density, so we will be seeing every pixel if we limit the
// maximum zoom scale to 0.5.
CGFloat maxScale = 5.0 / [[UIScreen mainScreen] scale];
// don't let minScale exceed maxScale. (If the image is smaller than the screen, we don't want to force it to be zoomed.)
if (minScale > maxScale) {
minScale = maxScale;
}
// if (minScale < -5)
// minScale = -5;
self.maximumZoomScale = 5.0; //maxScale;
self.minimumZoomScale = 1.0; //minScale;
}
#pragma mark -
#pragma mark Methods called during rotation to preserve the zoomScale and the visible portion of the image
// returns the center point, in image coordinate space, to try to restore after rotation.
- (CGPoint)pointToCenterAfterRotation
{
CGPoint boundsCenter = CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));
return [self convertPoint:boundsCenter toView:pdfView];
}
// returns the zoom scale to attempt to restore after rotation.
- (CGFloat)scaleToRestoreAfterRotation
{
CGFloat contentScale = self.zoomScale;
// If we're at the minimum zoom scale, preserve that by returning 0, which will be converted to the minimum
// allowable scale when the scale is restored.
if (contentScale <= self.minimumZoomScale + FLT_EPSILON)
contentScale = 0;
return contentScale;
}
- (CGPoint)maximumContentOffset
{
CGSize contentSize = self.contentSize;
CGSize boundsSize = self.bounds.size;
return CGPointMake(contentSize.width - boundsSize.width, contentSize.height - boundsSize.height);
}
- (CGPoint)minimumContentOffset
{
return CGPointZero;
}
// Adjusts content offset and scale to try to preserve the old zoomscale and center.
- (void)restoreCenterPoint:(CGPoint)oldCenter scale:(CGFloat)oldScale
{
// Step 1: restore zoom scale, first making sure it is within the allowable range.
self.zoomScale = MIN(self.maximumZoomScale, MAX(self.minimumZoomScale, oldScale));
// Step 2: restore center point, first making sure it is within the allowable range.
// 2a: convert our desired center point back to our own coordinate space
CGPoint boundsCenter = [self convertPoint:oldCenter fromView:pdfView];
// 2b: calculate the content offset that would yield that center point
CGPoint offset = CGPointMake(boundsCenter.x - self.bounds.size.width / 2.0,
boundsCenter.y - self.bounds.size.height / 2.0);
// 2c: restore offset, adjusted to be within the allowable range
CGPoint maxOffset = [self maximumContentOffset];
CGPoint minOffset = [self minimumContentOffset];
offset.x = MAX(minOffset.x, MIN(maxOffset.x, offset.x));
offset.y = MAX(minOffset.y, MIN(maxOffset.y, offset.y));
self.contentOffset = offset;
}
@end