如何擦除特定像素的颜色以及覆盖相同颜色的像素区域。我可以使用以下Swift代码获取特定像素颜色，但我无法获取周围具有相同颜色像素的区域，也无法擦除它。
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!;
}
}