Objective c 如何将scrollWheel:处理程序更改为放大WithEvent:调用？

第一个帖子在这里

我有一个NSScrollView子类。我希望鼠标的选项滚轮事件能够导致与轨迹板收缩缩放相同的缩放。我尝试了下面的简单解决方案，但这只会导致大量断言，可能是因为scroll事件的类型错误，并且没有放大事件所需的数据。我看不到用于创建放大事件的便捷的NSEvent类方法，比如它们为鼠标、按键、输入/退出和其他事件提供的方法

-(void) scrollWheel:(NSEvent*)event
{
    if(event.modifierFlags & NSAlternateKeyMask)
        [self magnifyWithEvent:event];
    else
        [super scrollWheel:event];
}

错误输出：

2018-01-18 11:35:59.509 BoF[71240:2227373] -_continuousScroll is deprecated for NSScrollWheel. Please use -hasPreciseScrollingDeltas.
2018-01-18 11:35:59.509 BoF[71240:2227373] -deviceDeltaX is deprecated for NSScrollWheel. Please use -scrollingDeltaX.
2018-01-18 11:35:59.509 BoF[71240:2227373] -deviceDeltaY is deprecated for NSScrollWheel. Please use -scrollingDeltaY.
2018-01-18 11:35:59.509 BoF[71240:2227373] *** Assertion failure in -[NSEvent magnification], /SourceCache/AppKit/AppKit-1348.17/AppKit.subproj/NSEvent.m:1890
2018-01-18 11:35:59.509 BoF[71240:2227373] Invalid message sent to event "NSEvent: type=ScrollWheel loc=(371,197) time=80177.1 flags=0x80120 win=0x6180001f8000 winNum=3959 ctxt=0x0 deltaX=0.000000 deltaY=0.400024 deltaZ=0.000000 deviceDeltaX=0.000000 deviceDeltaY=3.000000 deviceDeltaZ=0.000000 count:0 phase=Changed momentumPhase=None"
2018-01-18 11:35:59.643 BoF[71240:2227373] (
    0   CoreFoundation                      0x00007fff90c6e03c __exceptionPreprocess + 172
    1   libobjc.A.dylib                     0x00007fff8282176e objc_exception_throw + 43
    2   CoreFoundation                      0x00007fff90c6de1a +[NSException raise:format:arguments:] + 106
    3   Foundation                          0x00007fff8632897b -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 195
    4   AppKit                              0x00007fff8f96c8c2 -[NSEvent magnification] + 182
    5   AppKit                              0x00007fff8f96c488 -[NSScrollView magnifyWithEvent:] + 395
    6   BoF                      0x000000010002ceb3 -[ComicScrollView scrollWheel:] + 99
    7   AppKit                              0x00007fff8f7c4cfb forwardMethod + 126
    8   AppKit                              0x00007fff8f8f5d00 -[NSView scrollWheel:] + 507
    9   AppKit                              0x00007fff8f7c4cfb forwardMethod + 126
    10  AppKit                              0x00007fff8f8f5d00 -[NSView scrollWheel:] + 507
    11  AppKit                              0x00007fff8fe3b6cc -[NSWindow _reallySendEvent:isDelayedEvent:] + 6941
    12  AppKit                              0x00007fff8f7ccc86 -[NSWindow sendEvent:] + 470
    13  AppKit                              0x00007fff8f7c9137 -[NSApplication sendEvent:] + 2285
    14  AppKit                              0x00007fff8f6f2b68 -[NSApplication run] + 711
    15  AppKit                              0x00007fff8f66f244 NSApplicationMain + 1832
    16  BoF                      0x000000010000f232 main + 34
    17  libdyld.dylib                       0x00007fff848f95c9 start + 1
    18  ???                                 0x0000000000000003 0x0 + 3
)

---

好吧，它没有使用标准的放大WithEvent:code path，但它可以像这样伪造它，假设乘数将滚动量转换为放大量

-(void) scrollWheel:(NSEvent*)event
{
    if(event.modifierFlags & NSAlternateKeyMask) {
        NSPoint         pt = [self.documentView convertPoint:event.locationInWindow fromView:nil];
        CGFloat         by = event.scrollingDeltaY * 0.001; // The smallest pinch-zoom amount seems to be about 0.002, but that was a bit too coarse.

        if(!event.hasPreciseScrollingDeltas)
            by *= self.verticalLineScroll;

        [self setMagnification:self.magnification + by centeredAtPoint:pt];
    }
    else
        [super scrollWheel:event];
}

---

好吧，它没有使用标准的放大WithEvent:code path，但它可以像这样伪造它，假设乘数将滚动量转换为放大量

-(void) scrollWheel:(NSEvent*)event
{
    if(event.modifierFlags & NSAlternateKeyMask) {
        NSPoint         pt = [self.documentView convertPoint:event.locationInWindow fromView:nil];
        CGFloat         by = event.scrollingDeltaY * 0.001; // The smallest pinch-zoom amount seems to be about 0.002, but that was a bit too coarse.

        if(!event.hasPreciseScrollingDeltas)
            by *= self.verticalLineScroll;

        [self setMagnification:self.magnification + by centeredAtPoint:pt];
    }
    else
        [super scrollWheel:event];
}

---

一个可能的Swift 5版本，最好使用二次放大：

使用事件NSEvent覆盖func ScrollWheels{ if！event.momentumPhase.isEmpty | |！event.phase.isEmpty{ //魔力触控板或魔力鼠标 super.scrollWheelwith:事件 }否则，如果event.modifierFlags.contains.option{ //传统鼠标 如果让centerPoint=documentView？.convertevent.locationInWindow，则从：nil{ 设linearVal=CGFloatlog2magnification 变量linearDeltaY=event.scrollingDeltaY*0.01 if！event.hasPreciseScrollingDelta{ linearDeltaY*=垂直卡林斯克罗尔 } 设置放大倍数CgFloatPow2，linearVal+linearDeltaY，中心点：中心点 } } }

---

一个可能的Swift 5版本，最好使用二次放大：

使用事件NSEvent覆盖func ScrollWheels{ if！event.momentumPhase.isEmpty | |！event.phase.isEmpty{ //魔力触控板或魔力鼠标 super.scrollWheelwith:事件 }否则，如果event.modifierFlags.contains.option{ //传统鼠标 如果让centerPoint=documentView？.convertevent.locationInWindow，则从：nil{ 设linearVal=CGFloatlog2magnification 变量linearDeltaY=event.scrollingDeltaY*0.01 if！event.hasPreciseScrollingDelta{ linearDeltaY*=垂直卡林斯克罗尔 } 设置放大倍数CgFloatPow2，linearVal+linearDeltaY，中心点：中心点 } } }