objective-c - 如何在 NSView (Mac OS X) 上显示徽章

Question

要在 Dock 中向应用程序添加徽章很简单，只需调用 [NSDockTile setBadgeLabel] 即可。但我想向通用 NSView 添加徽章。有什么办法可以做到这一点吗？或者如果做不到这一点，您如何绘制一个，使其看起来与系统 UI 的其余部分保持一致？

Answer 1

没有内置方法可以在 NSView 上绘制徽章，因此您应该自己绘制它。这是我绘制徽章的代码:

- (void)drawBadgeImageWithText:(NSString*)text atPoint:(NSPoint)point
{
    NSSize badgeSize = [self badgeSizeForString:text];
    NSRect badgeRect = NSMakeRect(point.x - badgeSize.width, point.y - badgeSize.height, badgeSize.width, badgeSize.height);

    [NSGraphicsContext saveGraphicsState];

    // Set a shadow
    NSShadow* shadow = [[NSShadow alloc] init];
    shadow.shadowColor = [[NSColor blackColor] colorWithAlphaComponent:0.4];
    shadow.shadowBlurRadius = 1;
    shadow.shadowOffset = NSMakeSize(0, -1);
    [shadow set];

    // Draw white border
    NSBezierPath* path = [NSBezierPath bezierPathWithRoundedRect:badgeRect xRadius:badgeSize.height / 2.0 yRadius:badgeSize.height / 2.0];
    [[NSColor whiteColor] setFill];
    [path fill];

    [NSGraphicsContext restoreGraphicsState];

    // Fill the background with red gradient 
    badgeRect = NSInflateRect(badgeRect, -1.5, -1.5);
    path = [NSBezierPath bezierPathWithRoundedRect:badgeRect xRadius:badgeSize.height / 2.0 yRadius:badgeSize.height / 2.0];
    [[NSColor colorWithCalibratedRed:192.0 / 255.0 green:0.0 blue:0.0 alpha:1.0] setFill];
    [path fill];

    NSGradient* gradient = [[NSGradient alloc] initWithStartingColor:[NSColor colorWithCalibratedRed:241.0 / 255.0 green:113.0 / 255.0 blue:115.0 / 255.0 alpha:1.0]
                                                         endingColor:[NSColor colorWithCalibratedRed:192.0 / 255.0 green:0.0 blue:0.0 alpha:1.0]];
    [gradient drawInBezierPath:path angle:-90.0];

    // Draw the text
    NSMutableParagraphStyle* paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setAlignment:NSCenterTextAlignment];

    NSDictionary* textAttributes = @{NSForegroundColorAttributeName:[NSColor whiteColor], NSParagraphStyleAttributeName:paragraphStyle};

    [text drawInRect:badgeRect withAttributes:textAttributes];
}

- (NSSize)badgeSizeForString:(NSString*)string
{
    NSDictionary* attributes = [NSDictionary dictionaryWithObject:[NSFont systemFontOfSize:13] forKey: NSFontAttributeName];
    NSSize size = [string sizeWithAttributes:attributes];

    // Paddings
    size.height += 2.0;
    size.width += 12.0;

    return size;
}