1 Reply
      Latest reply on Oct 18, 2019 6:33 AM by Nickkk
      KGraus Level 1 Level 1 (0 points)

        We have some code that draws text to an NSImage, and the converts it to a NSBitmapImageRep so we can grab the data and use it as a texture.  This has worked fine for many years and on thousands of customers machines:


        image = [[NSImage alloc] initWithSize:size];
        [image lockFocus];
        //Do drawing
        bitmap = [[NSBitmapImageRep alloc] initWithFocusedViewRect:rect];
        [image unlockFocus];
        //Generate texture using [bitmap bitmapData];


        We now have a customer with a 2019 MacBook that is showing a corrupted texture.  We were able to track it down to the NSBitmapImageRep being created with floating point samples.  I see there's an option to initialize the NSBitmapImageRep with the exact format we need.  Once we do that, how to we get the data from the NSImage into it?  Or is there a way to convert the NSImage directly into the format we need?

        • Re: Converting NSImage to Texture
          Nickkk Level 1 Level 1 (0 points)

          I had the same problem when trying to draw a String into a texture. This code works for me on macOS 10.14 and macOS 10.15:


          // let rect: NSRect
          // let frameSize: NSSize
          let backingScaleFactor = NSScreen.main!.backingScaleFactor
          let bitmap = NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: Int(frameSize.width * backingScaleFactor), pixelsHigh: Int(frameSize.height * backingScaleFactor), bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true, isPlanar: false, colorSpaceName: .calibratedRGB, bytesPerRow: Int(frameSize.width * backingScaleFactor) * 4, bitsPerPixel: 32)!
          bitmap.size = frameSize
          let ctx = NSGraphicsContext(bitmapImageRep: bitmap)!
          NSGraphicsContext.current = ctx
          let image = NSImage()
          image.draw(in: rect)