我正在尝试创建一个简单的Mac绘图应用程序.在iOS上,我使用UIGraphicsGet
ImageFromCurrentImageContext在touchesMoved时更新UIImageView的图像.我现在正试图激活同样的东西,但在Mac应用程序上,我想做：
myNSImageView.image = UIGraphicsGetImageFromCurrentImageContext();
但是这个函数只存在于cocoa-touch而不存在于cocoa框架中,关于在Cocoa中可以找到类似函数的地方的任何提示？
谢谢.
更新
一些额外的完整性代码.
- (void)mouseDragged:(NSEvent *)event
{
NSInteger width = canvasView.frame.size.width;
NSInteger height = canvasView.frame.size.height;
NSGraphicsContext * graphicsContext = [NSGraphicsContext currentContext];
CGContextRef contextRef = (CGContextRef) [graphicsContext graphicsPort];
CGContextRef imageContextRef = CGBitmapContextCreate(0,width,height,8,width*4,[NSColorSpace genericRGBColorSpace].CGColorSpace,kCGImageAlphaPremultipliedFirst);
NSPoint currentPoint = [event locationInWindow];
CGContextSetRGBStrokeColor(contextRef,49.0/255.0,147.0/255.0,239.0/255.0,1.0);
CGContextSetLineWidth(contextRef,1.0);
CGContextBeginPath(contextRef);
CGContextMoveToPoint(contextRef,lastPoint.x,lastPoint.y);
CGContextAddLineToPoint(contextRef,currentPoint.x,currentPoint.y);
CGContextDrawPath(contextRef,kCGPathStroke);
CGImageRef imageRef = CGBitmapContextCreateImage(imageContextRef);
NSImage* image = [[NSImage alloc] initWithCGImage:imageRef size:NSMakeSize(width,height)];
canvasView.image = image;
CFRelease(imageRef);
CFRelease(imageContextRef);
lastPoint = currentPoint;
}
我现在得到的结果是,这幅画在视图的上半部分工作正常,但其余部分则是僵尸.就像在这个图像上(红色部分应该是canvasView)：
解决方法
NSInteger width = 1024; NSInteger height = 768; CGContextRef contextRef = CGBitmapContextCreate(0,kCGImageAlphaPremultipliedFirst); CGContextSetRGBStrokeColor(contextRef,1.0); CGContextFillRect(contextRef,CGRectMake(0.0f,0.0f,height)); CGImageRef imageRef = CGBitmapContextCreateImage(contextRef); NSImage* image = [[NSImage alloc] initWithCGImage:imageRef size:NSMakeSize(width,height)]; CFRelease(imageRef); CFRelease(contextRef);