相关疑难解决方法(0)

我收到'kCGImageAlphaPremultipliedLast'的未解决的标识符错误.斯威夫特找不到它.这可以在Swift中使用吗？

var gc = CGBitmapContextCreate(&pixelData, width: width, height: height, bitsPerComponent: 8, bytesPerRow: width*4, imageCS, bitmapInfo: kCGImageAlphaPremultipliedLast);

我正在开发一个将彩色图像更改为灰色图像的应用程序.但是,有些图片如何出错.我不知道代码有什么问题.也许我输入的参数是错误请帮忙.

 UIImage *c = [UIImage imageNamed:@"downRed.png"];
 CGImageRef cRef = CGImageRetain(c.CGImage);

 NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(cRef));

 size_t w = CGImageGetWidth(cRef);
 size_t h = CGImageGetHeight(cRef);

 unsigned char* pixelBytes = (unsigned char *)[pixelData bytes];

 unsigned char* greyPixelData = (unsigned char*) malloc(w*h);

 for (int y = 0; y < h; y++) {
 for(int x = 0; x < w; x++){

 int iter = 4*(w*y+x);
 int red = pixe lBytes[iter];
 int green = pixelBytes[iter+1];
 int blue = pixelBytes[iter+2];
 greyPixelData[w*y+x] = (unsigned char)(red*0.3 + green*0.59+ blue*0.11); …

我最初在Obj-C中编写了这个App(GitHub),但是需要将它转换为Swift.在转换时,我一直无法获得创建位图的上下文.

错误信息:

Whiteboard[2833] <Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 24 bits/pixel; 3-component color space; kCGImageAlphaNone; 1500 bytes/row.

本来我有这个:

self.cacheContext = CGBitmapContextCreate (self.cacheBitmap, size.width, size.height, 8, bitmapBytesPerRow, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst);

现在我有:

self.cacheContext = CGBitmapContextCreate(self.cacheBitmap!, UInt(size.width), UInt(size.height), 8, bitmapBytesPerRow, CGColorSpaceCreateDeviceRGB(), CGBitmapInfo.ByteOrder32Little);

我相信这个问题与CGBitmapInfo.ByteOrder32Little我有关,但我不知道该通过什么.有没有办法通过kCGImageAlphaNoneSkipFirst的CGBitmapInfo？

完整来源:

//
//  WhiteBoard.swift
//  Whiteboard
//

import Foundation
import UIKit


class WhiteBoard: UIView {

    var hue: CGFloat
    var cacheBitmap: UnsafeMutablePointer<Void>?
    var cacheContext: CGContextRef?


    override init(frame: CGRect) {
        self.hue = 0.0; …