cocoa - 未在 PDFView 子类上调用 drawRect

Question

我有一个自定义的PDFView子类，并覆盖了-mouseDown、-mouseDragged等以在 View 上绘制一个矩形。这是我正在使用的代码:

@implementation MyPDFView {
    NSPoint clickLocation;
    NSRect selection;
}

- (void)mouseDown:(NSEvent *)theEvent {
    NSPoint clickLocationOnWindow = [self.window mouseLocationOutsideOfEventStream];
    clickLocation = [self convertPoint:clickLocationOnWindow fromView:nil];

    NSLog(@"%@", NSStringFromPoint(clickLocation));
}

- (void)mouseDragged:(NSEvent *)theEvent {
    NSPoint mouseLocationOnWindow = [self.window mouseLocationOutsideOfEventStream];
    NSPoint currentLocation = [self convertPoint:mouseLocationOnWindow fromView:nil];

    CGFloat lowerX = fmin(clickLocation.x, currentLocation.x);
    CGFloat lowerY = fmin(clickLocation.y, currentLocation.y);
    CGFloat upperX = fmax(clickLocation.x, currentLocation.x);
    CGFloat upperY = fmax(clickLocation.y, currentLocation.y);

    selection = NSMakeRect(lowerX, lowerY, upperX-lowerX, upperY-lowerY);

    [self setNeedsDisplay:YES];

    NSLog(@"%@", NSStringFromRect(selection));
}

- (void)drawRect:(NSRect)dirtyRect
{
    // Drawing code here.
    NSLog(@"drawRect");

    NSBezierPath *bp = [NSBezierPath bezierPathWithRect:selection];
    [[NSColor blueColor] set];
    [bp fill];
}

@end

NSRect 计算正确，但是当我调用 [self setNeedsDisplay] 时，-drawRect 永远不会被调用，并且矩形也永远不会被调用绘制。

有什么原因导致 PDFView 子类永远不会调用 -drawRect 吗？

Answer 1

我有一个类似的用例。根据文档，请重写 PDFView 的 drawPage 方法。继续在 PDFView 上调用 setNeedsDisplay。它有效，但有点慢。现在正在努力覆盖 View 。