如何填充NSScrollView的右下角？

Question

我想改变它的颜色，但我不确定是否要继承 NSScrollView 或 NSClipView 的子类。或者是否可以将角作为常规 NSView 插入。

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我不知道不需要代码。只是提示如何操作。

Answer 1

mekentosj 已经在 stackoverflow 上的其他地方回答了。子类是 NSScrollView。

@interface MyScrollView : NSScrollView {
}
@end


@implementation MyScrollView

- (void)drawRect:(NSRect)rect{
    [super drawRect: rect];

    if([self hasVerticalScroller] && [self hasHorizontalScroller]){
        NSRect vframe = [[self verticalScroller]frame];
        NSRect hframe = [[self horizontalScroller]frame];
        NSRect corner;
        corner.origin.x = NSMaxX(hframe);
        corner.origin.y = NSMinY(hframe);
        corner.size.width = NSWidth(vframe);
        corner.size.height = NSHeight(hframe);

        // your custom drawing in the corner rect here
        [[NSColor redColor] set];
        NSRectFill(corner);
    }
}
@end

Answer 2

有点奇怪，但只是子类化 NSScrollView 并使用 super.drawRect() 覆盖绘制，使我的 NSScrollView （不）用白色填充那个角落。我测试了两次以确定，因为它没有多大意义。

import Cocoa

class ThemedScrollView: NSScrollView {
    override func drawRect(dirtyRect: NSRect) {
        super.drawRect(dirtyRect)
    }
}

这也是原始答案的 Swift 变体：

import Cocoa

class ThemedScrollView: NSScrollView {

    override func drawRect(dirtyRect: NSRect) {
        super.drawRect(dirtyRect)

        if hasVerticalScroller && hasHorizontalScroller {
            guard verticalScroller != nil && horizontalScroller != nil else { return }

            let vFrame = verticalScroller!.frame
            let hFrame = horizontalScroller!.frame
            let square = NSRect(origin: CGPoint(x: hFrame.maxX, y: vFrame.maxY), size: CGSize(width: vFrame.width, height: hFrame.height))

            let path = NSBezierPath(rect: square)
            let fillColor = NSColor.redColor()
            fillColor.set()
            path.fill()
        }
    }
}

Answer 3

更新了 Austin 答案的 Swift 5.2 版本

class Themed: NSScrollView {

    override func draw(_ dirtyRect: NSRect) {
        super.draw(dirtyRect)

        if hasVerticalScroller && hasHorizontalScroller {
            guard verticalScroller != nil && horizontalScroller != nil else { return }

            let vFrame = verticalScroller!.frame
            let hFrame = horizontalScroller!.frame
            let square = NSRect(origin: CGPoint(x: hFrame.maxX, y: vFrame.maxY), size: CGSize(width: vFrame.width, height: hFrame.height))

            let path = NSBezierPath(rect: square)
            let fillColor = NSColor.red
            fillColor.set()
            path.fill()
        }
    }
}