如何擦除用相同颜色覆盖的特定像素和像素区域的颜色。我能够使用下面的快速代码获得特定的像素颜色但是我无法获得具有相同颜色像素的周围区域并且无法擦掉它。
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!;
}
}
例如，如果我触摸UIImage并在特定坐标处，则必须获取颜色并擦除该像素和周围像素，这些像素具有相同的颜色，并且所有这些都必须擦除。可以请一位帮助我。
答案 0 :(得分：1)
几个月前，我在一个应用程序中工作，你得到一个图像，你不得不交换颜色...我不知道它是否对你有用。 我为它制作了一个UIImage类别。
无论如何这里是Objective-C中的代码：
#import <UIKit/UIKit.h>
@interface UIImage (YPKInterface)
+ (UIImage *)swapImage:(UIImage *)image color:(UIColor *)originalColor withColor:(UIColor *)swappedColor andThreshold:(float)threshold;
@end
#import "UIImage+YPKInterface.h"
@implementation UIImage (YPKInterface)
+ (UIImage *)swapImage:(UIImage *)image color:(UIColor *)originalColor withColor:(UIColor *)swappedColor andThreshold:(float)threshold {
int count = image.size.width*image.size.height;
// Convert image in raw data
CGImageRef imageRef = [image CGImage];
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char *rawData = (unsigned char*) calloc(height * width * 4, sizeof(unsigned char));
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData, width, height, bitsPerComponent, bytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
// Scan all the pixels
NSUInteger byteIndex = 0;
for (int i = 0 ; i < count ; ++i)
{
CGFloat alpha = ((CGFloat) rawData[byteIndex + 3] ) / 255.0f;
CGFloat red = ((CGFloat) rawData[byteIndex] ) / alpha;
CGFloat green = ((CGFloat) rawData[byteIndex + 1] ) / alpha;
CGFloat blue = ((CGFloat) rawData[byteIndex + 2] ) / alpha;
// Change the color
// RGBA of the colors
float origR = CGColorGetComponents(originalColor.CGColor)[0] * 255;
float origG = CGColorGetComponents(originalColor.CGColor)[1] * 255;
float origB = CGColorGetComponents(originalColor.CGColor)[2] * 255;
//float origA = CGColorGetComponents(originalColor.CGColor)[3];
float swapR = CGColorGetComponents(swappedColor.CGColor)[0] * 255;
float swapG = CGColorGetComponents(swappedColor.CGColor)[1] * 255;
float swapB = CGColorGetComponents(swappedColor.CGColor)[2] * 255;
//float swapA = CGColorGetComponents(swappedColor.CGColor)[3];
if (red >= origR - threshold && red <= origR + threshold &&
green >= origG - threshold && green <= origG + threshold &&
blue >= origB - threshold && blue <= origB + threshold) {
rawData[byteIndex + 3] = alpha * 255;
rawData[byteIndex ] = swapR * alpha;
rawData[byteIndex + 1] = swapG * alpha;
rawData[byteIndex + 2] = swapB * alpha;
}
byteIndex += bytesPerPixel;
}
CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, rawData, width*height*4, NULL);
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo =
kCGBitmapByteOrderDefault | kCGImageAlphaLast;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef imageRef2 = CGImageCreate(width, height, 8, 32, 4*width,colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent);
UIImage *newImage = [UIImage imageWithCGImage:imageRef2];
return newImage;
}
@end