Retrieving an NSImage from an SVGView - no sample code for Cocoa

[jcnolan]

I'm working w/Macaw and making very good progress but am trying to sort out one last detail for my app which is to render an SVG into an NSImage for display ( specifically in the icon portion of a "Image & Text Table Cell View" in an NSTable View - we're using custom SVGs as standard icons in our tableview)

I found the iOS version of the sample here #382 (comment) but the required UIGraphicsContext functions are not available in Cocoa. I also noticed the MGraphicsContext functions down in MacawView but have had no success accessing them.

Any hints for getting an NSImage out of standard functions in the Macaw library? Also, I'm unable to find any support forum / support group for Macaw - hope it's ok to post questions here.

[amarunko]

Hi, @jcnolan, you can try following code:

import Foundation
import AppKit

func svgToImage(resourceName: String, size: CGSize) -> NSImage? {
    let rootNode = SVGParser.parse(path: resourceName)
    let macawView = MacawView(node: rootNode, frame: CGRect(origin: CGPoint.zero, size: size))
    macawView.wantsLayer = true
    let image = NSImage(size: macawView.bounds.size)
    image.lockFocus()
    if let ctx = NSGraphicsContext.current?.graphicsPort {
        macawView.layer?.render(in: ctx)
    }
    image.unlockFocus()
    return image
}

[jcnolan]

Brilliant, thanks for that... almost perfect, a couple tweaks and it appears to be working for Swift4/Cocoa (on the main thread at least)

    func svgToNSImage(resourceName: String, size: CGSize) -> NSImage? {
        
       if let rootNode = try? SVGParser.parse(path: resourceName) {

            let macawView = MacawView(node: rootNode, frame: CGRect(origin: CGPoint.zero, size: size))
            macawView.wantsLayer = true
        
            let image = NSImage(size: macawView.bounds.size)
            image.lockFocus()
        
            //        if let ctx = NSGraphicsContext.current?.graphicsPort {
            if let ctx = NSGraphicsContext.current?.cgContext {
                // image is drawing upside down, invert it and render
                ctx.translateBy(x: 0, y: size.height)
                ctx.scaleBy(x: 1.0, y: -1.0)
                macawView.layer?.render(in: ctx)
            }
            image.unlockFocus()
            return image
        } else {
           return nil
        }
    }

[jcnolan]

Greetings all,

I'm back peeking at that project I inquired about a couple years back and it seems that this render function is no longer working. I always get an empty NSImage (just white, I believe). Can you see anything obvious in the solution we worked out that needs to be changed with your current version?

Thanks,
JC

[ystrot]

Hi @jcnolan,

Now there is Node.toNativeImage function which should work properly.

[jcnolan]

Perfect... that's got it fixed, thanks!