我已经完成了一个自定义 slider 单元格的实现,该单元格可以使用滚动条和旋钮的图像进行绘制。现在唯一的障碍是,当我快速拖动旋钮时,图像会变得困惑。我已经发布了一个屏幕截图。
代码如下:
#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,我太接近了。任何关于为什么会发生这种情况以及如何解决它的帮助将不胜感激,谢谢!
最佳答案
好的,所以它想通了。显然, slider 试图变得聪明,只在旋钮所在的位置绘制。所以显然我必须通过覆盖 slider 类中的 setNeedsDisplayInRect 来始终使矩形无效。
#import "customSlider.h"
@implementation customSlider
-(void)setNeedsDisplayInRect:(NSRect)invalidRect{
[super setNeedsDisplayInRect:[self bounds]];
}
@end
关于objective-c - 自定义 NSSliderCell,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3985816/