如何绘制圆形的NSImage

本文介绍了如何绘制圆形的NSImage的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在尝试在 NSTableView内创建带有圆角的 NSImage 或 NSImageCell 。我什么都不能工作。这是迄今为止我自定义的 NSCell 中最好的：

I am trying to create a NSImage or NSImageCell with rounded corners inside a NSTableView. I can't get anything to work. Here is the best I have so far inside my custom NSCell:

- (void)drawInteriorWithFrame:(NSRect)frame inView:(NSView *)controlView {
  if (thumbnailLink) {
    NSURL *url = [NSURL URLWithString:thumbnailLink];
    if (url) {
        NSRect imageFrame = [self _imageFrameForInteriorFrame:frame];
        NSImage *image = [[NSImage alloc] initWithContentsOfURL:url];
        [image setScalesWhenResized:YES];
        [image setSize:NSMakeSize(IMAGE_HEIGHT, IMAGE_WIDTH)];

        [NSGraphicsContext saveGraphicsState];
        imageFrame = NSInsetRect(imageFrame, 1, 1);
        NSBezierPath *clipPath = [NSBezierPath bezierPathWithRoundedRect:imageFrame cornerRadius:5.0];
        [clipPath setWindingRule:NSEvenOddWindingRule];
        [clipPath addClip];
        [NSGraphicsContext restoreGraphicsState];
        [image drawInRect:imageFrame fromRect:NSMakeRect(0, 0, 0, 0) operation:NSCompositeSourceIn fraction:1.0];
        [image release];
    }
}
...

关于如何

推荐答案

绘制图像时需要保持剪辑设置，然后恢复上下文。另外，如果您只是想正常绘制图像而不考虑目标不透明度，那么我不希望使用输入合成，而是使用覆盖合成。尝试类似的操作：

You need to keep the clip set when drawing your image, and restore the context after instead. Also I don't think you want to be using "in" compositing but rather "over" if you just want to draw your image normally without taking the destination opacity in consideration. Try something like:

[NSGraphicsContext saveGraphicsState];

NSBezierPath *path = [NSBezierPath bezierPathWithRoundedRect:imageFrame
                                                     xRadius:5
                                                     yRadius:5];
[path addClip];

[image drawInRect:imageFrame
         fromRect:NSZeroRect
        operation:NSCompositeSourceOver
         fraction:1.0];

[NSGraphicsContext restoreGraphicsState];

这篇关于如何绘制圆形的NSImage的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！