如何让NSScrollView在10.9及更高版本中居中文档视图？

Question

有很多关于如何让NSScrollView集中其文档视图的例子.这里有两个例子(它们是如此相似,以至于有人在没有归属的情况下复制某人,但关键是如何.) http://www.bergdesign.com/developer/index_files/88a764e343ce7190c4372d1425b3b6a3-0.html https:// github的.com/devosoft/avida /斑点/主/应用/观察者的MacOS/SRC /主/ CenteringClipView.h

这通常通过子类化NSClipView并覆盖来完成:

- (NSPoint)constrainScrollPoint:(NSPoint)newOrigin;

但是在Mac OS X 10.9 +中不推荐使用此方法

我们现在能做什么？哦不!〜

Answer 1

嗯,答案很简单,没有那么臃肿.无论如何,这些都不适用于双击放大.

这样做.它只是有效.您还可以根据需要自定义调整.

在@implementation中,您只需要实现constrainBoundsRect的覆盖:

- (NSRect)constrainBoundsRect:(NSRect)proposedClipViewBoundsRect {

    NSRect constrainedClipViewBoundsRect = [super constrainBoundsRect:proposedClipViewBoundsRect];

    // Early out if you want to use the default NSClipView behavior.
    if (self.centersDocumentView == NO) {
        return constrainedClipViewBoundsRect;
    }

    NSRect documentViewFrameRect = [self.documentView frame];

    // If proposed clip view bounds width is greater than document view frame width, center it horizontally.
    if (proposedClipViewBoundsRect.size.width >= documentViewFrameRect.size.width) {
        // Adjust the proposed origin.x
        constrainedClipViewBoundsRect.origin.x = centeredCoordinateUnitWithProposedContentViewBoundsDimensionAndDocumentViewFrameDimension(proposedClipViewBoundsRect.size.width, documentViewFrameRect.size.width);
    }

    // If proposed clip view bounds is hight is greater than document view frame height, center it vertically.
    if (proposedClipViewBoundsRect.size.height >= documentViewFrameRect.size.height) {

        // Adjust the proposed origin.y
        constrainedClipViewBoundsRect.origin.y = centeredCoordinateUnitWithProposedContentViewBoundsDimensionAndDocumentViewFrameDimension(proposedClipViewBoundsRect.size.height, documentViewFrameRect.size.height);
    }

    return constrainedClipViewBoundsRect;
}


CGFloat centeredCoordinateUnitWithProposedContentViewBoundsDimensionAndDocumentViewFrameDimension
(CGFloat proposedContentViewBoundsDimension,
 CGFloat documentViewFrameDimension )
{
    CGFloat result = floor( (proposedContentViewBoundsDimension - documentViewFrameDimension) / -2.0F );
    return result;
}

在@interface中只需添加一个属性.这允许您不使用居中.可以想象,有时可能会出现条件逻辑.

@property BOOL centersDocumentView;

此外,请务必将此设置BOOL为YES或NO覆盖

initWithFrame 和 initWithCoder:

所以你将拥有一个已知的默认值.

(记住小孩, initWithCoder:允许你做必要的事情并在笔尖中设置视图的类.不要忘记在你的东西之前打电话给super!)

当然,如果你需要支持10.9之前的任何东西,你需要实现其他的东西.

(虽然可能没有其他人那么多......)

Answer 2

这里是swift的工人阶级

class CenteredClipView:NSClipView
{
    override func constrainBoundsRect(proposedBounds: NSRect) -> NSRect {

        var rect = super.constrainBoundsRect(proposedBounds)
        if let containerView = self.documentView as? NSView {

            if (rect.size.width > containerView.frame.size.width) {
                rect.origin.x = (containerView.frame.width - rect.width) / 2
            }

            if(rect.size.height > containerView.frame.size.height) {
                rect.origin.y = (containerView.frame.height - rect.height) / 2
            }
        }

        return rect
    }
}