在objective-c cocoa app中将颜色设置为屏幕上的一个像素

#import <Cocoa/Cocoa.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSRect screenRect = [[NSScreen mainScreen] frame];
        NSBitmapImageRep *bitmapRep = [[NSBitmapImageRep alloc] initWithFocusedViewRect:screenRect];
        
        // 获取指定位置的像素颜色
        NSColor *pixelColor = [bitmapRep colorAtX:100 y:100];
        NSLog(@"Pixel color at (100, 100): %@", pixelColor);
        
        // 设置指定位置的像素颜色
        NSColor *newColor = [NSColor redColor];
        [bitmapRep setColor:newColor atX:100 y:100];
        
        // 将修改后的位图图像表示对象绘制到屏幕上
        NSImage *image = [[NSImage alloc] initWithSize:screenRect.size];
        [image addRepresentation:bitmapRep];
        [image drawAtPoint:NSZeroPoint fromRect:screenRect operation:NSCompositeSourceOver fraction:1.0];
        
        // 保存修改后的位图图像表示对象到文件
        NSData *imageData = [bitmapRep representationUsingType:NSPNGFileType properties:@{}];
        [imageData writeToFile:@"/path/to/save/image.png" atomically:YES];
    }
    return NSApplicationMain(argc, argv);
}