CODEWITHSUNDEEP
iosobjective-c
Yomo
Yomo

Reputation: 175

Putting text over an image programmatically in Objective-C

I want to add text on an image programmatically, but I can't seem to find how to do it. I've found one solution on here, but a lot of things are deprecated so it doesn't work...

Please help!

EDIT:

Here's my code:

UIImage *backgroundImage = image;

NSMutableDictionary *stringAttributes = [NSMutableDictionary dictionary];

[stringAttributes setObject: [UIFont fontWithName:@"Helvetica" size:20] forKey: NSFontAttributeName];
[stringAttributes setObject: [UIColor whiteColor] forKey: NSForegroundColorAttributeName];
[stringAttributes setObject: [NSNumber numberWithFloat: 2.0] forKey: NSStrokeWidthAttributeName];
[stringAttributes setObject: [UIColor blackColor] forKey: NSStrokeColorAttributeName];

[backgroundImage drawInRect:CGRectMake(0, 0, backgroundImage.size.width, backgroundImage.size.height)];

NSString *myString = [NSString stringWithFormat:@"Yolo"];

[myString drawInRect:CGRectMake(0, 0, 200, 50) withAttributes:stringAttributes];

UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.imageView.image = result;

NEW EDIT:

I'd like to clearify some things to understand the question better. My app lets the user send a photo that they have taken themselves via text messaging or by email, and I want to add some pre-written text from strings, on the photo.

So my question is: How do I get the text from the strings, on to the photo?

Upvotes: 1

Views: 1740

Answers (3)

Yomo
Yomo

Reputation: 175

It took forever, but I figured it out.

Code:

NSMutableDictionary *stringAttributes = [NSMutableDictionary dictionary];

[stringAttributes setObject: [UIFont fontWithName:@"Avenir Book" size:250] forKey: NSFontAttributeName];
[stringAttributes setObject: [UIColor whiteColor] forKey: NSForegroundColorAttributeName];

NSString *placeString = [NSString stringWithFormat:@"Text here."];

CGSize size = [placeString sizeWithAttributes:stringAttributes];
//Create a bitmap context into which the text will be rendered.
UIGraphicsBeginImageContext(size);
//Render the text.
[placeString drawAtPoint:CGPointMake(0.0, 0.0) withAttributes:stringAttributes];
//Retrieve the image.
UIImage *imagene = UIGraphicsGetImageFromCurrentImageContext();

UIImage *mergedImage = _imageView.image;

CGSize newSize = image.size;
UIGraphicsBeginImageContext(newSize);

//Use existing opacity as is.
[mergedImage drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];

//Apply supplied opacity if applicable.
CGRect drawingRect = (CGRect) {.size = size};
drawingRect.origin.x = (newSize.width - size.width) * 0.01;
drawingRect.origin.y = (newSize.height - size.height) * 0.03;
[imagene drawInRect:drawingRect blendMode:kCGBlendModeNormal alpha:1];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

[_imageView setImage:newImage];
self.imageView.image = newImage;

Upvotes: 1

Duncan C
Duncan C

Reputation: 131398

Simply place a UILabel on top of a UIImageView in IB and position them as desired using constraints. Then set the text into the label as desired.

EDIT:

Now that I know you want to be able to save I'd suggest using UIGraphicsBeginImageContextWithOptions to create an off-screen graphics context. I find that easier to deal with than CGContext and Core Graphics calls.

Draw into the context and the fetch and image from it.

Make the context the size of your image, and pass in a scale of 0 to use the device's native scale.

Your code might look something like this:

//Create an off-screen graphics context for drawing.
CGSize imageSize = myImage.size;
UIGraphicsBeginImageContextWithOptions(imageSize, false, 0);

//draw your image using drawAtPoint(CGPointmake(0,0));
//draw your string using one of the drawAtPoint or drawInRect methods
//available in NSString UIKit additions

//Fetch the resulting image from the context.
UIImage *maskImage = UIGraphicsGetImageFromCurrentImageContext();

//End the off-screen context
UIGraphicsEndImageContext();

Upvotes: 0

Mitchell Currie
Mitchell Currie

Reputation: 2809

Here's a general approach, code is likely missing but it gives you the important bits. 

 CGContextRef ctx = CGBitmapContextCreate(...)
 CGContextDrawImage (gtx, myContextRect, myimage);

 CGContextSelectFont(ctx, "Helvetica", 10.0, kCGEncodingMacRoman);
 CGContextSetCharacterSpacing(ctx, 1.7);
 CGContextSetTextDrawingMode(ctx, kCGTextFill);
 CGContextShowTextAtPoint(ctx, 100.0, 100.0, "SOME TEXT", 9);

 CGImageRef imageRef = CGBitmapContextCreateImage(ctx);
 UIImage *finalImage = [UIImage imageWithCGImage:imageRef];

This will give you an image you can put in a view, or share via UIActivityViewController. I'm sure you can work out the bits. The approach is: 1) Create bitmap context. 2) Render image 3) Add text 4) Save context to image

Upvotes: 0

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