自定义NSSliderCell

Question

我有点实现了一个自定义滑块单元,可以使用滚动条和旋钮的图像进行绘制.现在唯一的障碍就是这个,当我快速拖动旋钮时,图像变得混乱.我发布了一个屏幕截图.

这是代码:

#import "customSliderCell.h"
@implementation customSliderCell
- (void)drawKnob:(NSRect)knobRect {

    NSImage * knob = knobImage;
 [[self controlView] lockFocus];
 [knob
 compositeToPoint:NSMakePoint(knobRect.origin.x,knobRect.origin.y+knobRect.size.height)
 operation:NSCompositeSourceOver];

[[self controlView] unlockFocus];
}
- (void)drawBarInside:(NSRect)rect flipped:(BOOL)flipped {
rect.size.height = 8;

    NSRect leftRect = rect;
    leftRect.origin.x=0;
    leftRect.origin.y=2;
    leftRect.size.width = knobrect.origin.x + (knobrect.size.width);
    [leftBarImage setSize:leftRect.size];
    [leftBarImage drawInRect:leftRect fromRect: NSZeroRect operation: NSCompositeSourceOver fraction:1];

    NSRect rightRect = rect;
    rightRect.origin.x=0;
    rightRect.origin.y=2;
    rightRect.origin.x = knobrect.origin.x;
    [rightBarImage setSize:rightRect.size];
    [rightBarImage drawInRect:rightRect fromRect: NSZeroRect operation: NSCompositeSourceOver fraction:1];
}

啊,我很亲密.关于为什么会发生这种情况以及如何解决它的任何帮助将不胜感激,谢谢!

Answer 1

好的,所以它已经弄清楚了.显然,滑块试图变得聪明,只能在旋钮的位置画画.所以显然我必须通过覆盖滑块类中的setNeedsDisplayInRect来使rect一直无效.

#import "customSlider.h"

@implementation customSlider
-(void)setNeedsDisplayInRect:(NSRect)invalidRect{
    [super setNeedsDisplayInRect:[self bounds]];
}
@end