how to erase the colour of particular pixel and pixel area covered with the same colour.I am able to get the particular pixel colour using below swift code but I am not able to get surrounding area which has same colour pixel and unable to erase it.
import UIKit
class ColorOfImage: UIImageView {
var lastColor:UIColor? = nil
/*
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
// Drawing code
}
*/
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
if self.isHidden == true {
self.next?.touchesEnded(touches, with: event)
return
}
let touch: UITouch = touches.first!
var point:CGPoint = touch.location(in: self)
self.lastColor = self.getPixelColorAtLocation(point:point)
}
public func createARGBBitmapContext(inImage: CGImage) -> CGContext {
var bitmapByteCount = 0
var bitmapBytesPerRow = 0
//Get image width, height
let pixelsWide = inImage.width
let pixelsHigh = inImage.height
// Declare the number of bytes per row. Each pixel in the bitmap in this
// example is represented by 4 bytes; 8 bits each of red, green, blue, and
// alpha.
bitmapBytesPerRow = Int(pixelsWide) * 4
bitmapByteCount = bitmapBytesPerRow * Int(pixelsHigh)
// Use the generic RGB color space.
let colorSpace = CGColorSpaceCreateDeviceRGB()
// Allocate memory for image data. This is the destination in memory
// where any drawing to the bitmap context will be rendered.
let bitmapData = malloc(bitmapByteCount)
// Create the bitmap context. We want pre-multiplied ARGB, 8-bits
// per component. Regardless of what the source image format is
// (CMYK, Grayscale, and so on) it will be converted over to the format
// specified here by CGBitmapContextCreate.
let context = CGContext(data: bitmapData, width: pixelsWide, height: pixelsHigh, bitsPerComponent: 8, bytesPerRow: bitmapBytesPerRow, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)
// Make sure and release colorspace before returning
return context!
}
public func getPixelColorAtLocation( point:CGPoint) -> UIColor {
// Create off screen bitmap context to draw the image into. Format ARGB is 4 bytes for each pixel: Alpa, Red, Green, Blue
var point = point
var context:CGContext? = nil
context = self.createARGBBitmapContext(inImage: (self.image?.cgImage)!)
if context == nil {
return UIColor.white
}
var pixelsWide = (self.image?.cgImage)!.width
var pixelsHigh = (self.image?.cgImage)!.height
var rect = CGRect(x:0, y:0, width:Int(pixelsWide), height:Int(pixelsHigh))
var xScale:CGFloat = CGFloat(pixelsWide)/self.frame.size.width
var yScale:CGFloat = CGFloat(pixelsHigh)/self.frame.size.height
point.x = point.x * xScale
point.y = point.y * yScale
var x:CGFloat = 1.0
if (self.image?.responds(to: #selector(getter: self.image?.scale)))! {
x = ( self.image!.scale)
}
//Clear the context
context?.clear(rect)
// Draw the image to the bitmap context. Once we draw, the memory
// allocated for the context for rendering will then contain the
// raw image data in the specified color space.
context?.draw((self.image?.cgImage)!, in: rect)
// Now we can get a pointer to the image data associated with the bitmap
// context.
let data = context?.data
// let dataType = UnsafePointer<UInt8>(data)
var color:UIColor? = nil
if data != nil {
let dataType = data?.assumingMemoryBound(to: UInt8.self)
let offset = 4*((Int(pixelsWide) * Int(point.y)) + Int(point.x))
let alpha = dataType?[offset]
let red = dataType?[offset+1]
let green = dataType?[offset+2]
let blue = dataType?[offset+3]
color = UIColor(red: CGFloat(red!)/255.0, green: CGFloat(green!)/255.0, blue: CGFloat(blue!)/255.0, alpha: CGFloat(alpha!)/255.0)
}
else
{
}
// Free image data memory for the context
free(data)
return color!;
}
}For example if i touch on UIImage and at particular coordinates then it has to get the colour and erase that pixel and surrounding pixels which has same colour and all those have to erase.Can one please help me on this.