Nsimage Getting Resized When I Draw Text on It

NSImage Getting Resized when I draw Text on it

This is a different approach using a temporary NSView to draw the image and the text and cache the result in a new image (code is Swift 4). The benefit it you don't need to deal with pixels

class ImageView : NSView  {

    var image : NSImage
    var text : String

    init(image: NSImage, text: String)
    {
        self.image = image
        self.text = text
        super.init(frame: NSRect(origin: NSZeroPoint, size: image.size))
    }

    required init?(coder decoder: NSCoder) { fatalError() }

    override func draw(_ dirtyRect: NSRect) {
        let font = NSFont.boldSystemFont(ofSize: 18)
        let textRect = CGRect(x: 5, y: 5, width: image.size.width - 5, height: image.size.height - 5)
        image.draw(in: dirtyRect)
        text.draw(in: textRect, withAttributes: [.font: font, .foregroundColor: NSColor.white])
    }

    var outputImage : NSImage  {
        let imageRep = bitmapImageRepForCachingDisplay(in: frame)!
        cacheDisplay(in: frame, to:imageRep)
        let tiffData = imageRep.tiffRepresentation!
        return NSImage(data : tiffData)!
    }
}

To use it, initialize a view

let image = ... // get some image
let view = ImageView(image: image, text: "Sample Text")

and get the new image

let imageWithText = view.outputImage

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Note:

The paragraph style is not used at all, but if you want to create a mutable paragraph style just write

let textStyle = NSMutableParagraphStyle()

How to resize NSImage?

Edit:
Since this answer is still the accepted answer, but was written without Retina screens in mind, I will straight up link to a better solution further down the thread: Objective-C Swift 4

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Because the method of Paresh is totally correct but deprecated since 10.8 I'll post the working 10.8 code below. All credit to Paresh's answer though.

- (NSImage *)imageResize:(NSImage*)anImage newSize:(NSSize)newSize {
    NSImage *sourceImage = anImage;
    [sourceImage setScalesWhenResized:YES];
    
    // Report an error if the source isn't a valid image
    if (![sourceImage isValid]){
        NSLog(@"Invalid Image");
    } else {
        NSImage *smallImage = [[NSImage alloc] initWithSize: newSize];
        [smallImage lockFocus];
        [sourceImage setSize: newSize];
        [[NSGraphicsContext currentContext] setImageInterpolation:NSImageInterpolationHigh];
        [sourceImage drawAtPoint:NSZeroPoint fromRect:CGRectMake(0, 0, newSize.width, newSize.height) operation:NSCompositingOperationCopy fraction:1.0];
        [smallImage unlockFocus];
        return smallImage;
    }
    return nil;
}

Resized NSImageView not redrawing

So I found a way around this, however it is fairly hackish.

As mentioned in the edit, this bug only occurs with ImageFrameStyle set to NSImageFrameNone. When I set the ImageFrameStyle to something else, then resize it, then set it to NSImageFrameNone again after resizing, things work fine:

[coverImage setImageFrameStyle: NSImageFramePhoto];
coverImage.frame = CGRectMake((1280 - 869) / 2, 0, 869 * percentage, 800);
[coverImage setImageFrameStyle: NSImageFrameNone];

This works but isn't very pretty. Thus I'll leave the question open for a couple more days in hope to find a better answer.

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