While I think it is a basic question, I didn't manage to find a response that works yet. I am creating a PDF file by stroking paths to a PDF context, and I want different areas on the drawing to be hyperlinks to outside contents (http://bla.bla). I'd be happy even with areas that are non-intersecting rectangles. Anyone knows how to do that?
check the answer to this question it works:Embed hyperlink in PDF using Core Graphics on iOS.
- (void) drawTextLink:(NSString *) text inFrame:(CGRect) frameRect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform ctm = CGContextGetCTM(context);
// Translate the origin to the bottom left.
// Notice that 842 is the size of the PDF page.
CGAffineTransformTranslate(ctm, 0.0, 842);
// Flip the handedness of the coordinate system back to right handed.
CGAffineTransformScale(ctm, 1.0, -1.0);
// Convert the update rectangle to the new coordiante system.
CGRect xformRect = CGRectApplyAffineTransform(frameRect, ctm);
NSURL *url = [NSURL URLWithString:text];
UIGraphicsSetPDFContextURLForRect( url, xformRect );
CGContextSaveGState(context);
NSDictionary *attributesDict;
NSMutableAttributedString *attString;
NSNumber *underline = [NSNumber numberWithInt:NSUnderlineStyleSingle];
attributesDict = #{NSUnderlineStyleAttributeName : underline, NSForegroundColorAttributeName : [UIColor blueColor]};
attString = [[NSMutableAttributedString alloc] initWithString:url.absoluteString attributes:attributesDict];
[attString drawInRect:frameRect];
CGContextRestoreGState(context);
}
Related
I am making a pdf in an iPad app. Now i can make the pdf however want to add a picture with a rounded corner border. For example to achieve the effect i want on the border on a simple view item i use the following code.
self.SaveButtonProp.layer.cornerRadius=8.0f;
self.SaveButtonProp.layer.masksToBounds=YES;
self.SaveButtonProp.layer.borderColor=[[UIColor blackColor]CGColor];
self.SaveButtonProp.layer.borderWidth= 1.0f;
With the pdf i am using the following method to add the picture with the border to the pdf.
CGContextRef currentContext = UIGraphicsGetCurrentContext();
UIImage * demoImage = [UIImage imageWithData : Image];
UIColor *borderColor = [UIColor blackColor];
CGRect rectFrame = CGRectMake(20, 125, 200, 200);
[demoImage drawInRect:rectFrame];
CGContextSetStrokeColorWithColor(currentContext, borderColor.CGColor);
CGContextSetLineWidth(currentContext, 2);
CGContextStrokeRect(currentContext, rectFrame);
How do i round the corners?
Thanks
While drawing you can set clipping masks. For example, it's relatively easy to create a Bezier path with the shape of a rounded rectangle and apply that as clipping mask to your graphics context. Everything subsequently drawn will be clipped.
If you want remove the clipping mask later (for example because you have an image with rounded corners but follow that by other elements) you'll have to save the graphic state first, then apply your clipping mask and restore the graphics state when you're done with your rounded corners.
You can see actual code that comes pretty close to what I think you need here:
UIImage with rounded corners
You can use a method to get any UIView/UIImageView to PDF NSData:
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
NSData *data = [self makePDFfromView:imageView];
Method:
- (NSData *)makePDFfromView:(UIView *)view
{
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, view.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[view.layer renderInContext:pdfContext];
UIGraphicsEndPDFContext();
return pdfData;
}
Maybe you can change or use this code to help you with your problem.
Is there any way in Objective-c/cocoa (OSX) to crop an image without changing the quality of the image?
I am very near to a solution, but there are still some differences that I can detect in the color. I can notice it when zooming into the text. Here is the code I am currently using:
NSImage *target = [[[NSImage alloc]initWithSize:panelRect.size] autorelease];
target.backgroundColor = [NSColor greenColor];
//start drawing on target
[target lockFocus];
[NSGraphicsContext saveGraphicsState];
[[NSGraphicsContext currentContext] setImageInterpolation:NSImageInterpolationNone];
[[NSGraphicsContext currentContext] setShouldAntialias:NO];
//draw the portion of the source image on target image
[source drawInRect:NSMakeRect(0,0,panelRect.size.width,panelRect.size.height)
fromRect:NSMakeRect(panelRect.origin.x , source.size.height - panelRect.origin.y - panelRect.size.height, panelRect.size.width, panelRect.size.height)
operation:NSCompositeCopy
fraction:1.0];
[NSGraphicsContext restoreGraphicsState];
//end drawing
[target unlockFocus];
//create a NSBitmapImageRep
NSBitmapImageRep *bmpImageRep = [[[NSBitmapImageRep alloc]initWithData:[target TIFFRepresentation]] autorelease];
//add the NSBitmapImage to the representation list of the target
[target addRepresentation:bmpImageRep];
//get the data from the representation
NSData *data = [bmpImageRep representationUsingType: NSJPEGFileType
properties: imageProps];
NSString *filename = [NSString stringWithFormat:#"%#%#.jpg", panelImagePrefix, panelNumber];
NSLog(#"This is the filename: %#", filename);
//write the data to a file
[data writeToFile:filename atomically:NO];
Here is a zoomed-in comparison of the original and the cropped image:
(Original image - above)
(Cropped image - above)
The difference is hard to see, but if you flick between them, you can notice it. You can use a colour picker to notice the difference as well. For example, the darkest pixel on the bottom row of the image is a different shade.
I also have a solution that works exactly the way I want it in iOS. Here is the code:
-(void)testMethod:(int)page forRect:(CGRect)rect{
NSString *filePath = #"imageName";
NSData *data = [HeavyResourceManager dataForPath:filePath];//this just gets the image as NSData
UIImage *image = [UIImage imageWithData:data];
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], rect);//crop in the rect
UIImage *result = [UIImage imageWithCGImage:imageRef scale:0 orientation:image.imageOrientation];
CGImageRelease(imageRef);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
[UIImageJPEGRepresentation(result, 1.0) writeToFile:[documentsDirectoryPath stringByAppendingPathComponent::#"output.jpg"] atomically:YES];
}
So, is there a way to crop an image in OSX so that the cropped image does not change at all? Perhaps I have to look into a different library, but I would be surprised if I could not do this with Objective-C...
Note, This is a follow up question to my previous question here.
Update I have tried (as per the suggestion) to round the CGRect values to whole numbers, but did not notice a difference. Here is the code in case I used:
[source drawInRect:NSMakeRect(0,0,(int)panelRect.size.width,(int)panelRect.size.height)
fromRect:NSMakeRect((int)panelRect.origin.x , (int)(source.size.height - panelRect.origin.y - panelRect.size.height), (int)panelRect.size.width, (int)panelRect.size.height)
operation:NSCompositeCopy
fraction:1.0];
Update I have tried mazzaroth code and it works if I save it as a png, but if I try and save it as a jpeg, the image loses quality. So close, but not close enough. Still hoping for a complete answer...
use CGImageCreateWithImageInRect.
// this chunk of code loads a jpeg image into a cgimage
// creates a second crop of the original image with CGImageCreateWithImageInRect
// writes the new cropped image to the desktop
// ensure that the xy origin of the CGRectMake call is smaller than the width or height of the original image
NSURL *originalImage = [NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:#"lockwood" ofType:#"jpg"]];
CGImageRef imageRef = NULL;
CGImageSourceRef loadRef = CGImageSourceCreateWithURL((CFURLRef)originalImage, NULL);
if (loadRef != NULL)
{
imageRef = CGImageSourceCreateImageAtIndex(loadRef, 0, NULL);
CFRelease(loadRef); // Release CGImageSource reference
}
CGImageRef croppedImage = CGImageCreateWithImageInRect(imageRef, CGRectMake(200., 200., 100., 100.));
CFURLRef saveUrl = (CFURLRef)[NSURL fileURLWithPath:[#"~/Desktop/lockwood-crop.jpg" stringByExpandingTildeInPath]];
CGImageDestinationRef destination = CGImageDestinationCreateWithURL(saveUrl, kUTTypeJPEG, 1, NULL);
CGImageDestinationAddImage(destination, croppedImage, nil);
if (!CGImageDestinationFinalize(destination)) {
NSLog(#"Failed to write image to %#", saveUrl);
}
CFRelease(destination);
CFRelease(imageRef);
CFRelease(croppedImage);
I also made a gist:
https://gist.github.com/4259594
Try to change the drawInRect orign to 0.5,0.5. Otherwise Quartz will distribute each pixel color to the adjacent 4 fixels.
Set the color space of the target image. You might be having a different colorspace causing to to look slightly different.
Try the various rendering intents and see which gets the best result, perceptual versus relative colorimetric etc. There are 4 options I think.
You mention that the colors get modified by the saving of JPEG versus PNG.
You can specify the compression level when saving to JPEG. Try with something like 0.8 or 0.9. you can also save JPEG without compression with 1.0, but ther PNG has a distinct advantage. You specify the compression level in the options dictionary for CGImageDesinationAddImage.
Finally - if nothing her helps - you should open a TSI with DTS, they can certainly provide you with the guidance you seek.
The usual problem is that cropping sizes are float, but image pixels are integer.
cocoa interpolates it automatically.
You need to floor, round or ceil the size and coordinates to be sure that they are integer.
This may help.
I am doing EXIF deleting of JPG files and I think I caught the reason:
All losses and changes come from the re-compress of your image during saving to file.
You may notice the change too if you just to save the whole image again.
What I am to do is to read the original JPG and re-compress it to a quality that take equivalent file size.
I am trying to render Arabic text in my iOS app with custom TTF font (scheherazade) using core-text, which works for the most part - however certain glyphs at the edge of the CTFrame are dropped.
When I adjust the frame-size to make the dropped-glyphs appear in the interior of the frame, they display corretly, which leads me believe something is going wrong in inside CTFrameDraw. Below is the code I'm using to render the Arabic-text:
CGContextRef context = UIGraphicsGetCurrentContext();
// Flip the coordinate system
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, 0, v.textFrame.size.height);
CGContextScaleCTM(context, 1.0, -1.0);
CGMutablePathRef path = CGPathCreateMutable(); //1
CGPathAddRect(path, NULL, v.textFrame );
CGFloat minLineHeight = 60.0;
CGFloat maxLineHeight = 60.0;
CTTextAlignment paragraphAlignment = kCTRightTextAlignment;
CTLineBreakMode lineBrkMode = kCTLineBreakByWordWrapping;
CTParagraphStyleSetting setting[4] = {
{kCTParagraphStyleSpecifierAlignment, sizeof(CTTextAlignment), ¶graphAlignment},
{kCTParagraphStyleSpecifierMinimumLineHeight, sizeof(CGFloat), &minLineHeight},
{kCTParagraphStyleSpecifierMaximumLineHeight, sizeof(CGFloat), &maxLineHeight},
{kCTParagraphStyleSpecifierLineBreakMode, sizeof(CTLineBreakMode), &lineBrkMode}
};
CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(setting, 4);
NSDictionary *attr = [NSDictionary dictionaryWithObjectsAndKeys:
(id)v.arabicFont, (id)kCTFontAttributeName,
paragraphStyle, (id)kCTParagraphStyleAttributeName,
nil];
CFRelease(paragraphStyle);
NSAttributedString* attString = [[[NSAttributedString alloc]
initWithString:v.verseText attributes:attr] autorelease]; //2
CTFramesetterRef framesetter =
CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attString); //3
CTFrameRef frame =
CTFramesetterCreateFrame(framesetter,
CFRangeMake(0, [attString length]), path, NULL);
CTFrameDraw(frame, context); //4
CFRelease(frame); //5
CFRelease(path);
CFRelease(framesetter);
Also attached are the screenshots showing the problem I face. Any help would be much appreciated. Thanks.
invalid: http://stellarbeacon.com.au/invalid.png
valid : http://stellarbeacon.com.au/valid.png
There are some bugs in CoreText related to determining the correct frame size. Some of these where fixed in iOS 6, e.g. http://www.cocoanetics.com/2012/02/radar-coretext-line-spacing-bug/
If your problem still exists there then you should file a Radar with the specifics. Also you should open a call with Apple DTS which can probably provide you with a workaround. Often - if your problem is indeed a bug - then you get your DTS call credited back.
PS: try to display your text with my DTCoreText views which do manual layouting and display and see if the problem can be reproduced there. If not then you have your workaround.
Generate PDF from UIView by rendering looses quality iOS
I have a custom UIView called TTT_WantsToBeRazorSharpView.
This view does nothing, but draw a text with
NSString*txtPleaseHelp = NSLocalizedString(#"Hello, am I blurry again?",#"");
CGContextShowTextAtPoint(ctx, 10, 50, [txtPleaseHelp cStringUsingEncoding:NSMacOSRomanStringEncoding], [txtPleaseHelp length]);
Now the View is drawn three times to an UIViewController (one time in IB) and two times in code with these lines (compare to image below):
TTT_WantsToBeRazorSharpView *customViewSharp = [[TTT_WantsToBeRazorSharpView alloc] initWithFrame:CGRectMake(10,250, 300, 80)];
[self.view addSubview:customViewSharp];
TTT_WantsToBeRazorSharpView *customViewBlurryButIKnowWhy = [[TTT_WantsToBeRazorSharpView alloc] initWithFrame:CGRectMake(361.5, 251.5, 301.5, 80.5)];
[self.view addSubview:customViewBlurryButIKnowWhy];
the first code drawn view is razorsharp, while the second isn't, but that is ok, because of rect's comma values (361.5, 251.5, 301.5, 80.5).
See this picture:
But my problem is now, if I render the view into an pdf document it is blurry!
And don't know why, see here:
and the PDF file itself Test.pdf
https://raw.github.com/florianbachmann/GeneratePDFfromUIViewButDontWantToLooseQuality/master/Test.pdf
and the lines to render the view into the pdf:
//this is blurry, but why? it can't be the comma coordinates
CGRect customFrame1 = CGRectMake(10,50, 300, 80);
TTT_WantsToBeRazorSharpView *customViewSharp = [[TTT_WantsToBeRazorSharpView alloc] initWithFrame:customFrame1];
CGContextSaveGState(context);
CGContextSetTextMatrix(context, CGAffineTransformIdentity);
CGContextTranslateCTM(context, (int)customFrame1.origin.x, (int)customFrame1.origin.y);
[customViewSharp.layer renderInContext:context];
CGContextRestoreGState(context);
So why is the renderInContext:context text blurry?
I appreciate all your hints and help, I even made an GitHub project for the brave of you (with source): https://github.com/florianbachmann/GeneratePDFfromUIViewButDontWantToLooseQuality
Try this:
- (void)initValues {
UIColor *gray = [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.3f];
CALayer *l = [self layer];
l.masksToBounds = YES;
l.cornerRadius = 10.0f;
l.borderWidth = 3.0f;
self.backgroundColor = gray;
l.backgroundColor = gray.CGColor;
l.borderColor = gray.CGColor;
}
- (void)drawRect:(CGRect)rect {
NSLog(#"TTT_WantsToBeRazorSharpView drawRect[%3.2f,%3.2f][%3.2f,%3.2f]",rect.origin.x,rect.origin.y,rect.size.width,rect.size.height);
// get the graphic context
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetShouldSmoothFonts(ctx,YES);
CGColorRef colorWhite = CGColorRetain([UIColor redColor].CGColor);
CGContextSetFillColorWithColor(ctx, colorWhite);
CGContextSelectFont(ctx, "Helvetica-Bold", 24, kCGEncodingMacRoman);
CGAffineTransform tranformer = CGAffineTransformMakeScale(1.0, -1.0);
CGContextSetTextMatrix(ctx, tranformer);
//why is this sucker blurry?
NSString*txtPleaseHelp = NSLocalizedString(#"Hello, am I blurry again?",#"");
CGContextShowTextAtPoint(ctx, 10, 50, [txtPleaseHelp cStringUsingEncoding:NSMacOSRomanStringEncoding], [txtPleaseHelp length]);
CGColorRelease(colorWhite);
}
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx {
if (!layer.shouldRasterize && !CGRectIsEmpty(UIGraphicsGetPDFContextBounds())) {
[self drawRect:self.bounds];
}
else {
[super drawLayer:layer inContext:ctx];
}
}
I had to change the text color to red to make it visible. Because the text is written first, then the transparent grey button is placed over it, it would make the white text disappear. When adding the drawLayer method, everything that does not need to be rasterized is written as vector to pdf, making the text also selectable.
The text in the view is rendered as bitmap in the PDF and not as vector graphics and this causes the blurry appearance. My guess is iOS rendering engine draws the text on an intermediary bitmap (for color composition purposes I think) and then this bitmap is rendered on the target context.
I have used the following command to fix blurry text:
self.frame = CGRectIntegral(self.frame);
The reason for blurry text was that alignment was not ideal, i.e. fraction values in the point coordinates, so the text appear blurry due to excessive antialiasing.
I am trying to add text to t a PDFPage. Specifically, I want to add it to the header/footer of the pdf document. I have looked everywhere for an example of doing this but I can't find it. If someone can point to a tutorial or give a quick example of how I can add text to PDFPage it would be really helpful. Thanks.
You can do it using Quartz 2D - PDF Document Creation, Viewing, and Transforming. This code will help you to write into file:
[someString drawAtPoint:CGPointMake(100, 200) withFont:[NSFont systemFontOfSize:20.0f]];
The short answer is to subclass PDFPage and override the drawing methods. There's a description here.
The answers here are incomplete, after putting various pieces together, here is complete sample code (Objective-C):
// Need to create pdf Graphics context for Drawing text
CGContextRef pdfContextRef = NULL;
CFURLRef writeFileUrl = (CFURLRef)[NSURL fileURLWithPath:writeFilePath];
if(writeFileUrl != NULL){
pdfContextRef = CGPDFContextCreateWithURL(writeFileUrl, NULL, NULL);
}
// Start page in PDF context
CGPDFContextBeginPage(pdfContextRef, NULL);
NSGraphicsContext* pdfGraphicsContext = [NSGraphicsContext graphicsContextWithCGContext:pdfContextRef flipped:false];
[NSGraphicsContext saveGraphicsState];
// Need to set the current graphics context
[NSGraphicsContext setCurrentContext:pdfGraphicsContext];
NSDictionary *attributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSFont fontWithName:#"Helvetica" size:26], NSFontAttributeName,[NSColor blackColor], NSForegroundColorAttributeName, nil];
NSAttributedString * currentText=[[NSAttributedString alloc] initWithString:#"Write Something" attributes: attributes];
// [currentText drawInRect: CGRectMake(0, 300, 500, 100 )];
[currentText drawAtPoint:NSMakePoint(100, 100)];
[NSGraphicsContext restoreGraphicsState];
// Close all the created pdf Contexts
CGPDFContextEndPage(pdfContextRef);
CGPDFContextClose(pdfContextRef);