(I already read this page, but it didn't help me CALayer not displaying)
I have a class called Image that has this field data:
uint8_t *data;
I already use this data to display this Image on a CALayer that I got gathering code from the internet.
I saw how to create another windows in my application, and I put a NSView inside it to display an Image using the method, I intend to display the histogram latter, but now I'm just trying to display again the same image:
-(void)wrapImageToCALayer: (CALayer*) layer{
if(!layer) return;
CGColorSpaceRef grayColorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef context = CGBitmapContextCreate(data, width, height, 8, step, grayColorSpace, kCGImageAlphaNone);
CGImageRef dstImage = CGBitmapContextCreateImage(context);
dispatch_sync(dispatch_get_main_queue(), ^{
layer.contents = (__bridge id)dstImage;
});
CGImageRelease(dstImage);
CGContextRelease(context);
CGColorSpaceRelease(grayColorSpace);
}
And this is my Window Controler:
#implementation HistogramControllerWindowController
#synthesize display;
- (id)initWithWindow:(NSWindow *)window{
self = [super initWithWindow:window];
if (self) {
// Initialization code here.
}
return self;
}
- (void)windowDidLoad
{
// Implement this method to handle any initialization after your window controller's window has been loaded from its nib file.
[super windowDidLoad];
histogramDisplayLayer = [CALayer layer];
[histogramDisplayLayer setContentsGravity:AVLayerVideoGravityResizeAspectFill];
histogramDisplayLayer.position = CGPointMake(display.frame.size.width/2., display.frame.size.height/2.);
[histogramDisplayLayer setNeedsDisplay];
[display.layer addSublayer: histogramDisplayLayer];
}
#end
And I'm calling this way:
[frame wrapImageToCALayer:histogramDisplayLayer];
Note that histogramDisplayLayer is an external (CALayer *)
Your histogramDisplayLayer have no size defined, you just set a position but not its size. So init its frame, and this should fix your problem.
Just insert:
[display setWantsLayer:YES]; // view's backing store is using a Core Animation Layer
Before:
[display.layer addSublayer: histogramDisplayLayer];
[ Best way to change the background color for an NSView ]
Related
This is what I did:
#implementation BGUIActivityIndicator
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
[self customInitialize];
return self;
}
-(id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
[self customInitialize];
return self;
}
-(void)customInitialize
{
UIView * theImageView= [self findASubViewforClass:[UIImageView class]];//
UIImageView * theImageView1 = (UIImageView *) theImageView;
theImageView1.image = [UIImage imageNamed:#"spinner_blue"];
[theImageView1.image saveScreenshot];
while (false) ;
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
// Drawing code
}
*/
#end
Everything seems perfect. [theImageView1.image saveScreenshot]; jot down both the old and new view perfectly.
However, nothing changes. Why?
I am not exactly asking how to change the image of UIActivityIndicator. There are tons of it already. I want to use it by subclassing UIActivityIndicator because I think it's the most elegant solution. I can't seem to do that.
In particular, I am asking why my approach, which works for changing background of search controller, for example, doesn't work for this.
According to the UIActivityIndicatorView Class Reference ,there is no way/ chance to change the image through sub-classing.
However you can change its activityIndicatorViewStyle , color of the activity indicator,UIActivityIndicatorStyle etc..
I think, without sub-classing, the class class UIImageView provides a very useful and simple way to implement such a thing. The only thing you have to do is to:
1.Provide a number of images that reflect your indicator animation.
2.Create a new UIImageView instance and set images and animation duration.
3.Position your custom activity indicator within your current view.
SAMPLE CODE:
//Create the first status image and the indicator view
UIImage *statusImage = [UIImage imageNamed:#"status1.png"];
UIImageView *activityImageView = [[UIImageView alloc]
initWithImage:statusImage];
//Add more images which will be used for the animation
activityImageView.animationImages = [NSArray arrayWithObjects:
[UIImage imageNamed:#"status1.png"],
[UIImage imageNamed:#"status2.png"],
[UIImage imageNamed:#"status3.png"],
[UIImage imageNamed:#"status4.png"],
[UIImage imageNamed:#"status5.png"],
[UIImage imageNamed:#"status6.png"],
[UIImage imageNamed:#"status7.png"],
[UIImage imageNamed:#"status8.png"],
nil];
//Set the duration of the animation (play with it
//until it looks nice for you)
activityImageView.animationDuration = 0.8;
//Position the activity image view somewhere in
//the middle of your current view
activityImageView.frame = CGRectMake(
self.view.frame.size.width/2
-statusImage.size.width/2,
self.view.frame.size.height/2
-statusImage.size.height/2,
statusImage.size.width,
statusImage.size.height);
//Start the animation
[activityImageView startAnimating];
//Add your custom activity indicator to your current view
[self.view addSubview:activityImageView];
See the full details Here
My question is same as mentioned at here. I'm also using two images in my app and all I need is to erase a top image by touch. Then un-erase (if required) the erased part by touch. I'm using following code to erase the the top image. There is also a problem in this approach. Which is that the images are big and I'm using Aspect Fit content mode to properly display them. When I touch on the screen, it erase in the corner not the touched place. I think the touch point calculation is required some fix. Any help will be appreciated.
Second problem is that how to un-erase the erased part by touch?
UIGraphicsBeginImageContext(self.imgTop.image.size);
[self.imgTop.image drawInRect:CGRectMake(0, 0, self.imgTop.image.size.width, self.imgTop.image.size.height)];
self.frame.size.width, self.frame.size.height)];
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
GContextSetLineWidth(UIGraphicsGetCurrentContext(), pinSize);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0, 0, 0, 1.0);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
CGContextBeginPath(UIGraphicsGetCurrentContext());
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
self.imgTop.contentMode = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Your code is quite ambiguous: you're creating a context with imgTop inside, then blending with kCGBlendModeCopy the black color? This would cause the black color to be copied onto imgTop. I assume you wanted to set the layer's contentproperty then?
Anyway this class does what you need. There are only a few interesting methods (they're at the top), the others are only properties or init... routines.
#interface EraseImageView : UIView {
CGContextRef context;
CGRect contextBounds;
}
#property (nonatomic, retain) UIImage *backgroundImage;
#property (nonatomic, retain) UIImage *foregroundImage;
#property (nonatomic, assign) CGFloat touchWidth;
#property (nonatomic, assign) BOOL touchRevealsImage;
- (void)resetDrawing;
#end
#interface EraseImageView ()
- (void)createBitmapContext;
- (void)drawImageScaled:(UIImage *)image;
#end
#implementation EraseImageView
#synthesize touchRevealsImage=_touchRevealsImage, backgroundImage=_backgroundImage, foregroundImage=_foregroundImage, touchWidth=_touchWidth;
#pragma mark - Main methods -
- (void)createBitmapContext
{
// create a grayscale colorspace
CGColorSpaceRef grayscale=CGColorSpaceCreateDeviceGray();
/* TO DO: instead of saving the bounds at the moment of creation,
override setFrame:, create a new context with the right
size, draw the previous on the new, and replace the old
one with the new one.
*/
contextBounds=self.bounds;
// create a new 8 bit grayscale bitmap with no alpha (the mask)
context=CGBitmapContextCreate(NULL,
(size_t)contextBounds.size.width,
(size_t)contextBounds.size.height,
8,
(size_t)contextBounds.size.width,
grayscale,
kCGImageAlphaNone);
// make it white (touchRevealsImage==NO)
CGFloat white[]={1., 1.};
CGContextSetFillColor(context, white);
CGContextFillRect(context, contextBounds);
// setup drawing for that context
CGContextSetLineCap(context, kCGLineCapRound);
CGContextSetLineJoin(context, kCGLineJoinRound);
CGColorSpaceRelease(grayscale);
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch=(UITouch *)[touches anyObject];
// the new line that will be drawn
CGPoint points[]={
[touch previousLocationInView:self],
[touch locationInView:self]
};
// setup width and color
CGContextSetLineWidth(context, self.touchWidth);
CGFloat color[]={(self.touchRevealsImage ? 1. : 0.), 1.};
CGContextSetStrokeColor(context, color);
// stroke
CGContextStrokeLineSegments(context, points, 2);
[self setNeedsDisplay];
}
- (void)drawRect:(CGRect)rect
{
if (self.foregroundImage==nil || self.backgroundImage==nil) return;
// draw background image
[self drawImageScaled:self.backgroundImage];
// create an image mask from the context
CGImageRef mask=CGBitmapContextCreateImage(context);
// set the current clipping mask to the image
CGContextRef ctx=UIGraphicsGetCurrentContext();
CGContextSaveGState(ctx);
CGContextClipToMask(ctx, contextBounds, mask);
// now draw image (with mask)
[self drawImageScaled:self.foregroundImage];
CGContextRestoreGState(ctx);
CGImageRelease(mask);
}
- (void)resetDrawing
{
// draw black or white
CGFloat color[]={(self.touchRevealsImage ? 0. : 1.), 1.};
CGContextSetFillColor(context, color);
CGContextFillRect(context, contextBounds);
[self setNeedsDisplay];
}
#pragma mark - Helper methods -
- (void)drawImageScaled:(UIImage *)image
{
// just draws the image scaled down and centered
CGFloat selfRatio=self.frame.size.width/self.frame.size.height;
CGFloat imgRatio=image.size.width/image.size.height;
CGRect rect={0.,0.,0.,0.};
if (selfRatio>imgRatio) {
// view is wider than img
rect.size.height=self.frame.size.height;
rect.size.width=imgRatio*rect.size.height;
} else {
// img is wider than view
rect.size.width=self.frame.size.width;
rect.size.height=rect.size.width/imgRatio;
}
rect.origin.x=.5*(self.frame.size.width-rect.size.width);
rect.origin.y=.5*(self.frame.size.height-rect.size.height);
[image drawInRect:rect];
}
#pragma mark - Initialization and properties -
- (id)initWithCoder:(NSCoder *)aDecoder
{
if ((self=[super initWithCoder:aDecoder])) {
[self createBitmapContext];
_touchWidth=10.;
}
return self;
}
- (id)initWithFrame:(CGRect)frame
{
if ((self=[super initWithFrame:frame])) {
[self createBitmapContext];
_touchWidth=10.;
}
return self;
}
- (void)dealloc
{
CGContextRelease(context);
[super dealloc];
}
- (void)setBackgroundImage:(UIImage *)value
{
if (value!=_backgroundImage) {
[_backgroundImage release];
_backgroundImage=[value retain];
[self setNeedsDisplay];
}
}
- (void)setForegroundImage:(UIImage *)value
{
if (value!=_foregroundImage) {
[_foregroundImage release];
_foregroundImage=[value retain];
[self setNeedsDisplay];
}
}
- (void)setTouchRevealsImage:(BOOL)value
{
if (value!=_touchRevealsImage) {
_touchRevealsImage=value;
[self setNeedsDisplay];
}
}
#end
Some notes:
This class retains the two images you need. It has a touchRevealsImage property to set the mode to drawing or erasing, and you can set the width of the line.
At the initialization, it creates a CGBitmapContextRef, grayscale, 8bpp, no alpha, of the same size of the view. This context is used to store a mask, that will be applied to the foreground image.
Every time you move a finger on the screen, a line is drawn on the CGBitmapContextRef using CoreGraphics, white to reveal the image, black to hide it. In this way we're storing a b/w drawing.
The drawRect: routine simply draws the background, then creates a CGImageRef from the CGBitmapContextRef and applies it to the current context as a mask. Then draws the foreground image. To draw images it uses - (void)drawImageScaled:(UIImage *)image, which just draws the image scaled and centered.
If you're planning to resize the view, you should implement a method to copy or to recreate the mask with new size, overriding - (void)setFrame:(CGRect)frame.
The - (void)reset method simply clears the mask.
Even if the bitmap context hasn't any alpha channel, the grayscale color space used has alpha: that's why every time a color is set, I had to specify two components.
I have a UIView that I set up to respond to pinch gestures and change its size, except, once you enlarge it and then try and pinch it again, it jumps to its original size (which just so happens to be 100x200). Here is the code:
#implementation ChartAxisView
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
// do gesture recognizers
UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(onPinch:)];
[self addGestureRecognizer:pinch];
[pinch release];
}
return self;
}
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorRef redColor = [UIColor colorWithRed:1.0 green:0.0 blue:0.0 alpha:1.0].CGColor;
CGContextSetFillColorWithColor(context, redColor);
CGContextFillRect(context, self.bounds);
}
- (void)onPinch: (UIPinchGestureRecognizer*) gesture {
self.transform = CGAffineTransformMakeScale(gesture.scale, gesture.scale);
}
- (void)dealloc {
[super dealloc];
}
#end
Any thoughts?
So there are two types of Scale (or, transform in general) functions: CGAffineTransformMakeScale and CGAffineTransformScale
The first one, CGAffineTransformMakeScale which you are using, always transforms with respect to the image's original size. And that is why you see the jump to its original size before the scaling happens.
The second one, CGAffineTransformScale, transforms from the image's current position. This is what you need. For this, it requires an additional 'transform' arg. The 'transform' arg in your case represents the enlarged image.
Read this very informative blog post about transformations.
- (void)onPinch: (UIPinchGestureRecognizer*) gesture {
if ([gesture state] == UIGestureRecognizerStateBegan)
{
curTransform = self.transform;
}
self.transform = CGAffineTransformScale(curTransform,gesture.scale, gesture.scale);
}
use CGAffineTransformScale instead of CGAffineTransformMakeScale
you will need a member -> CGAffineTransform curTransform;
;)
you can set transform with following code:
ivClone setTransform:CGAffineTransformMakeScale(scale, scale)];
and you can get current transform with following coee:
newV.transform.a //x scale
newV.transform.d // y scale
Is is possible to stop CATiledLayer to draw (drawLayer:inContext)?
It draws asynchronously and when i try to release CGPDFDocumentRef, which is used by CATiledLayer, the app crashes (EXC_BAD_ACCESS).
That's my view:
#implementation TiledPDFView
- (id)initWithFrame:(CGRect)frame andScale:(CGFloat)scale{
if ((self = [super initWithFrame:frame])) {
CATiledLayer *tiledLayer = (CATiledLayer *)[self layer];
tiledLayer.levelsOfDetail = 4;
tiledLayer.levelsOfDetailBias = 4;
tiledLayer.tileSize = CGSizeMake(512.0, 512.0);
myScale = scale;
}
return self;
}
// Set the layer's class to be CATiledLayer.
+ (Class)layerClass {
return [CATiledLayer class];
}
- (void)stopDrawing{
CATiledLayer *tiledLayer = (CATiledLayer *)[self layer];
[tiledLayer removeFromSuperlayer];
tiledLayer.delegate = nil;
}
// Set the CGPDFPageRef for the view.
- (void)setPage:(CGPDFPageRef)newPage
{
CGPDFPageRelease(self->pdfPage);
self->pdfPage = CGPDFPageRetain(newPage);
//self->pdfPage = newPage;
}
-(void)drawRect:(CGRect)r
{
}
// Draw the CGPDFPageRef into the layer at the correct scale.
-(void)drawLayer:(CALayer*)layer inContext:(CGContextRef)context
{
// First fill the background with white.
CGContextSetRGBFillColor(context, 1.0,1.0,1.0,1.0);
CGContextFillRect(context,self.bounds);
CGContextSaveGState(context);
// Flip the context so that the PDF page is rendered
// right side up.
CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// Scale the context so that the PDF page is rendered
// at the correct size for the zoom level.
CGContextScaleCTM(context, myScale,myScale);
CGContextDrawPDFPage(context, pdfPage);
CGContextRestoreGState(context);
}
// Clean up.
- (void)dealloc {
CGPDFPageRelease(pdfPage);
[super dealloc];
}
And this is where i try to stop and release PDF in view controller:
v is instance of TiledPDFView
-(void) stopDwaring {
[v stopDrawing];
[v removeFromSuperview];
[v release];
[self.view removeFromSuperview];
self.view = nil;
CGPDFDocumentRelease(pdf);
}
this post helped me solving my own trouble with CATiledLayer. I used TiledPDFview.m from Apple's documentation as example.
Since I need to redraw the entire view and all tiles at some point, I use a CATiledLayer as property.
When exiting and deallocating the viewcontroller, it crashed with [CATiledLayer retain]: Message sent to deallocated instance.
Here is my dealloc method of the view controller:
- (void)dealloc {
self.tiledLayer.contents=nil;
self.tiledLayer.delegate=nil;
[self.tiledLayer removeFromSuperlayer];
// note: releasing the layer still crashes-
// I guess removeFromSuperlayer releases it already,
// but couldn't find documentation so far.
// So that's why it's commented out:
// [self.tiledLayer release], self.tiledLayer=nil;
//release the other viewcontroller stuff...
[super dealloc];
}
That works for me. Hope it helps someone.
Remove the CATiledLayer from its superlayer before releasing the CGPDFDocumentRef.
[yourTiledLayer removeFromSuperlayer];
Dont forget to set it's delegate to nil too.
yourTiledLayer.delegate = nil;
After that, you can safely release your CGPDFDocumentRef.
Edit after OP adds code:
Did you get pdfPage using CGPDFDocumentGetPage()? If so, you shouldn't release it, it is an autoreleased object.
Regarding how to add it as sublayer:
You don't actually need TiledPDFView. In your view controller, you can simply do this:
CATiledLayer *tiledLayer = [CATiledLayer layer];
tiledLayer.delegate = self; //sets where tiledLayer will look for drawLayer:inContext:
tiledLayer.tileSize = CGSizeMake(512.0f, 512.0f);
tiledLayer.levelsOfDetail = 4;
tiledLayer.levelsOfDetailBias = 4;
tiledLayer.frame = CGRectIntegral(CGRectMake(0.0f, 0.0f, 512.0f, 512.0f));
[self.view.layer addSublayer:tiledLayer];
Then move your drawLayer:inContext: implementation to your view controller.
Then in your view controller's dealloc, release it as:
[tiledLayer removeFromSuperlayer];
tiledLayer.delegate = nil;
CGPDFDocumentRelease(pdf);
Note that you can't do this on a UIView subclass, as the drawLayer:inContext: will conflict with the UIView's main layer.
object.layer.contents = Nil
This should wait for the thread to finish. It helped in my case.
TiledPDFView *pdfView;
In dealloc of pdfView's superview class, write below line of codes.
- (void)dealloc {
if (nil != self.pdfView.superview) {
self.pdfView.layer.delegate = nil;
[self.pdfView removeFromSuperview];
}
}
This works for me. Hope it will help.
I've had a similar problem.
I ended up setting a float variable "zoom" in my TiledPDFView which I set as the zoomScale of PDFScrollView in the UIScrollview Delegate method: scrollViewDidZoom
Then in my drawLayer method inside TiledPDFView I only called the contents of that method if the float variable "zoom" was above 2.
This fixes any issues of someone leaving the view without zooming. It may not be ideal for your case as this error still occurs if someone zooms above 2 then releases the viewcontroller quickly, but you might be able to find a similar technique to cover all bases.
It looks like you're doing the same thing I am, which is borrowing the ZoomingPDFView code and integrating it into your project. If your UIScrollView delegate methods in PDFScrollView are unchanged, you can solve your problem by just commenting both lines of your dealloc method (in TiledPDFView). That stuff should only be happening when you kill the parent view, anyway.
I am stuck with parsing a PDF file. Please guide me how to do this.
Header file.
//PDFViewer.h
#interface PDFViewer : UIView
{
CGPDFDocumentRef pdf;
}
-(void)drawInContext:(CGContextRef)context;
#end
Implementation file
//PDFViewer.m
#implementation PDFViewer
- (id)initWithFrame:(CGRect)frame
{
if ((self = [super initWithFrame:frame]))
{
// Initialization code
if(self != nil)
{
CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), CFSTR("WR1MayJun1S08.pdf"), NULL, NULL);
pdf = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
CFRelease(pdfURL);
}
}
return self;
}
-(void)drawInContext:(CGContextRef)context
{
// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
// before we start drawing.
CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// Grab the first PDF page
CGPDFPageRef page = CGPDFDocumentGetPage(pdf, 1);
// We're about to modify the context CTM to draw the PDF page where we want it, so save the graphics state in case we want to do more drawing
CGContextSaveGState(context);
// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
// base rotations necessary to display the PDF page correctly.
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
// Finally, we draw the page and restore the graphics state for further manipulations!
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
// Drawing code
}
*/
- (void)dealloc
{
CGPDFDocumentRelease(pdf);
[super dealloc];
}
#end
Now I am adding this class (PDFViewer.h) to my MainViewController.
//MainViewController.m
CGRect frame = CGRectMake(0, 200, 300, 500);
PDFViewer *pdfViewer = [[PDFViewer alloc] initWithFrame:frame];
CGContextRef context = UIGraphicsGetCurrentContext();
[pdfViewer drawInContext:context];
[self.view addSubview:pdfViewer];
It shows nothing. I get the following errors/warnings:
local MultiView[2850] <Error>: CGContextTranslateCTM: invalid context
local MultiView[2850] <Error>: CGContextScaleCTM: invalid context
local MultiView[2850] <Error>: CGContextSaveGState: invalid context
local MultiView[2850] <Error>: CGContextConcatCTM: invalid context
local MultiView[2850] <Error>: CGContextRestoreGState: invalid context
What am I missing?
Regards.
UIGraphicsGetCurrentContext does not return a context if there isn't one, obviously.
You try to get the context at view initialization, at that time there is no context available. A valid context gets pushed onto the stack just before -[UIView drawRect:] is being called. This should work:
//PDFViewer.m
#implementation PDFViewer
- (void)drawRect:(CGRect)rect {
[self drawInContext:UIGraphicsGetCurrentContext()];
}
#end
EDIT
Eventhough I don't like to give anyone copy-and-paste-ready-code, I don't think there is another option left if you didn't understand my latest comment. I don't know what you've tried, but if you try to understand what I'm really saying, this is the only thing you can come up with:
//PDFViewer.m
#implementation PDFViewer
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame])
{
CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), CFSTR("WR1MayJun1S08.pdf"), NULL, NULL);
pdf = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL);
CFRelease(pdfURL);
}
return self;
}
-(void)drawInContext:(CGContextRef)context
{
// PDF page drawing expects a Lower-Left coordinate system, so we flip the coordinate system
// before we start drawing.
CGContextTranslateCTM(context, 0.0, self.bounds.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
// Grab the first PDF page
CGPDFPageRef page = CGPDFDocumentGetPage(pdf, 1);
// We're about to modify the context CTM to draw the PDF page where we want it, so save the graphics state in case we want to do more drawing
CGContextSaveGState(context);
// CGPDFPageGetDrawingTransform provides an easy way to get the transform for a PDF page. It will scale down to fit, including any
// base rotations necessary to display the PDF page correctly.
CGAffineTransform pdfTransform = CGPDFPageGetDrawingTransform(page, kCGPDFCropBox, self.bounds, 0, true);
// And apply the transform.
CGContextConcatCTM(context, pdfTransform);
// Finally, we draw the page and restore the graphics state for further manipulations!
CGContextDrawPDFPage(context, page);
CGContextRestoreGState(context);
}
- (void)drawRect:(CGRect)rect {
[self drawInContext:UIGraphicsGetCurrentContext()];
}
- (void)dealloc
{
CGPDFDocumentRelease(pdf);
[super dealloc];
}
#end
—
//MainViewController.m
CGRect frame = CGRectMake(0, 200, 300, 500);
PDFViewer *pdfViewer = [[PDFViewer alloc] initWithFrame:frame];
[self.view addSubview:pdfViewer];
I got another simple way to parse PDF for iPhone/iPad:
1.Take one UIwebView (name:pdfView).
2.Give IBoutlet connection to it & Delegate it to FilesOwner
3.In Viewdidload
[self.pdfView loadRequest:[NSURLRequest requestWithURL:[NSURL
fileURLWithPath:[[NSBundle mainBundle]
pathForResource:#"ObjC" ofType:#"pdf"]]]];
4.ObjC.pdf should be in resource folder..