Gradient effect with UInt32 Colors?

Question

Hey I am new in programming and I want to know if it's possible to create a gradient effect having 2 colors (red and blue for example) of type UInt32. Any suggestions? Thanks

ADDITION TO QUESTION

The idea is that I have only pixels informations:

        func fillRegion(pixelX: Int, pixelY: Int, withColor color: UIColor) {

    var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
    color.getRed(&red, green: &green, blue: &blue, alpha: &alpha)

    let newColor = (UInt32)(alpha*255)<<24 | (UInt32)(red*255)<<16 | (UInt32)(green*255)<<8 | (UInt32)(blue*255)<<0

    let pixelColor = regionsData.advanced(by: (pixelY * imageHeight) + pixelX).pointee

    if pixelColor == blackColor { return }

    var pointerRegionsData: UnsafeMutablePointer<UInt32> = regionsData
    var pointerImageData: UnsafeMutablePointer<UInt32> = imageData

    var pixelsChanged = false

    for i in 0...(imageHeight * imageHeight - 1) {
        if pointerRegionsData.pointee == pixelColor {
            pointerImageData = imageData.advanced(by: i)
            if pointerImageData.pointee != newColor {
                pointerImageData.pointee = newColor
                pixelsChanged = true
            }
        }
        pointerRegionsData = pointerRegionsData.successor()
    }

    if pixelsChanged {
        self.image = UIImage(cgImage: imageContext.makeImage()!)
        DispatchQueue.main.async {
            CATransaction.setDisableActions(true)
            self.layer.contents = self.image.cgImage
            self.onImageDraw?(self.image)
        }
        self.playTapSound()
    }
}

now it's filling with simple color, but I need to set a gradient somehow, I do not have a proper form, and I can't manage to set CAShapeLayer... as I have only pixel number information, and his color, though I am able to change the color here :

if pointerImageData.pointee != newColor {
                pointerImageData.pointee = newColor
                pixelsChanged = true
            }

But I don't know how to make a smooth changing of color, to make gradient effect, or to identify somehow the perimeter and set up a layer, dunno, any ideas will be as gold.

@Larme color of type: var newColor = (UInt32)(alpha*255)<<24 | (UInt32)(red*255)<<16 | (UInt32)(green*255)<<8 | (UInt32)(blue*255)<<0 — Dumitru Rogojinaru, Jan 25 '17 at 11:10
To do a gradient, you need an array of CGColor, if I remember correctly, so you need to convert your colorClass into UIColor, then into CGColor. — Larme, Jan 25 '17 at 11:11
@Larme i need to make gradient Effect, as I can not use Gradient Layers... I have no other choice... — Dumitru Rogojinaru, Jan 25 '17 at 11:16
To make that gradient effects, what kind of objects/parameters do you need? Because the iOS system usually use UIColor or CGColor, so it's unclear. It's all about conversions into the one you want. — Larme, Jan 25 '17 at 11:19
I know how to make that with UIColor and CGColor, but now I am using UnsafeMutablePointer for regions, and I change the color of every pixel in the region I need, it works good with simple color, but I need to set up a gradient, the form of the area is not proper and differs all the time, check my answer, I posted some coding and a description. @Larme — Dumitru Rogojinaru, Jan 25 '17 at 11:23

score 0 · Answer 1 · answered Jan 25 '17 at 11:15

Yes it possible using CoreGraphics or CALayer.
To simplify, you can override the layer of a view returning a CAGradientLayer.
This is an implementation:

@implementation PGSGradientView

+ (Class)layerClass {
    return [CAGradientLayer class];
}

- (instancetype) initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self initializeGradient];
    }
    return self;
}

- (instancetype) initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        [self initializeGradient];
    }
    return self;
}

- (void) initializeGradient {
    [(CAGradientLayer*)self.layer setLocations:locations];
    [(CAGradientLayer*)self.layer setColors:colors];

}

@end

Imagine that you have 2 arrays as properties, one is locations and the other one are the colors that you want to add in the gradindient.
locations represents:

the starting location for each color. Also, and that’s important, those numbers should mandatorily range from 0.0 to 1.0. and is paired with the colors arrays.

Gradient effect with UInt32 Colors?

1 Answers1