drawRect 没有被调用以使用 NSView 进行图层支持绘图
drawRect not getting called for layer backed drawing with NSView
我正在尝试将我的 Opengl 应用程序迁移到 Metal,并且我正在使用 CAMetalLayer
作为 Metal 实现。
我在继承的 NSView
class 对象上设置了以下属性:
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
[self setWantsLayer:YES];
我已经检查了关于 SO 的其他答案,例如 NSView subclass - drawRect: not called
所以,我尝试按照上面的答案中的建议分配委托,就像这样
[self.layer setDelegate:self];
我得到以下编译错误:
Cannot initialize a parameter of type 'id<CALayerDelegate> _Nullable' with an lvalue of type 'MyNSView *'
此外,我还在 https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreAnimation_guide/SettingUpLayerObjects/SettingUpLayerObjects.html 看到了设置图层对象的文档,其中指出:
For layer-backed views with custom content, you should continue to
override the view’s methods to do your drawing. A layer-backed view
automatically makes itself the delegate of its layer and implements
the needed delegate methods, and you should not change that
configuration. Instead, you should implement your view’s drawRect:
method to draw your content.
因此,据此,我什至不必在我的案例中设置委托,我已经在 MyNSView
中实现了 drawRect
函数。仍然没有被调用。
还有什么需要做的吗?
谢谢!
编辑:
因此,我通过让我的层遵循协议 CALayerDelegate
来修复编译错误,但我仍然没有收到任何对 drawLayer
或 drawRect
.
的调用
制作背景图层
- (CALayer*)makeBackingLayer
{
id <MTLDevice> device = MTLCreateSystemDefaultDevice();
CAMetalLayer *backingLayer = [CAMetalLayer layer];
backingLayer.opaque = YES;
backingLayer.device = device;
backingLayer.pixelFormat = MTLPixelFormatBGRA8Unorm;
backingLayer.framebufferOnly = YES;
// [backingLayer setDelegate:self]; //Tried setting the delegate
//here as well
return backingLayer;
}
初始化函数
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
[self setWantsLayer:YES];
[self.layer setDelegate:self];
绘制函数
- (void)displayLayer:(CALayer *)layer
{
[self drawRect:self.bounds];
}
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx {
[self drawRect:self.bounds];
}
-(void) drawRect: (NSRect) dirtyRect
{
[super drawRect:dirtyRect];
}
我已经实现了所有绘制函数以检查是否有任何函数被击中,但我没有收到任何这些函数的调用。
为了将内容绘制到 NSView,我绘制到屏幕外资源并从 NSView 的 CALayer 获取 drawable
并在提交 commandBuffer
之前调用 presentDrawable
。
由于这里没有太多我可以调试以找到引入错误的地方,所以我开始研究指令的执行顺序。事实证明,您调用的顺序:
[self setWantsLayer:YES];
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
导致了这个问题。交换这两个语句后,我开始收到对 displayLayer
函数的调用。我仍然无法弄清楚为什么 drawRect
没有被层支持的 NSView 调用。
张贴这个以防万一这个交换也解决了其他人的问题。
我正在尝试将我的 Opengl 应用程序迁移到 Metal,并且我正在使用 CAMetalLayer
作为 Metal 实现。
我在继承的 NSView
class 对象上设置了以下属性:
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
[self setWantsLayer:YES];
我已经检查了关于 SO 的其他答案,例如 NSView subclass - drawRect: not called
所以,我尝试按照上面的答案中的建议分配委托,就像这样
[self.layer setDelegate:self];
我得到以下编译错误:
Cannot initialize a parameter of type 'id<CALayerDelegate> _Nullable' with an lvalue of type 'MyNSView *'
此外,我还在 https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreAnimation_guide/SettingUpLayerObjects/SettingUpLayerObjects.html 看到了设置图层对象的文档,其中指出:
For layer-backed views with custom content, you should continue to override the view’s methods to do your drawing. A layer-backed view automatically makes itself the delegate of its layer and implements the needed delegate methods, and you should not change that configuration. Instead, you should implement your view’s drawRect: method to draw your content.
因此,据此,我什至不必在我的案例中设置委托,我已经在 MyNSView
中实现了 drawRect
函数。仍然没有被调用。
还有什么需要做的吗?
谢谢!
编辑:
因此,我通过让我的层遵循协议 CALayerDelegate
来修复编译错误,但我仍然没有收到任何对 drawLayer
或 drawRect
.
制作背景图层
- (CALayer*)makeBackingLayer
{
id <MTLDevice> device = MTLCreateSystemDefaultDevice();
CAMetalLayer *backingLayer = [CAMetalLayer layer];
backingLayer.opaque = YES;
backingLayer.device = device;
backingLayer.pixelFormat = MTLPixelFormatBGRA8Unorm;
backingLayer.framebufferOnly = YES;
// [backingLayer setDelegate:self]; //Tried setting the delegate
//here as well
return backingLayer;
}
初始化函数
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
[self setWantsLayer:YES];
[self.layer setDelegate:self];
绘制函数
- (void)displayLayer:(CALayer *)layer
{
[self drawRect:self.bounds];
}
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx {
[self drawRect:self.bounds];
}
-(void) drawRect: (NSRect) dirtyRect
{
[super drawRect:dirtyRect];
}
我已经实现了所有绘制函数以检查是否有任何函数被击中,但我没有收到任何这些函数的调用。
为了将内容绘制到 NSView,我绘制到屏幕外资源并从 NSView 的 CALayer 获取 drawable
并在提交 commandBuffer
之前调用 presentDrawable
。
由于这里没有太多我可以调试以找到引入错误的地方,所以我开始研究指令的执行顺序。事实证明,您调用的顺序:
[self setWantsLayer:YES];
self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
导致了这个问题。交换这两个语句后,我开始收到对 displayLayer
函数的调用。我仍然无法弄清楚为什么 drawRect
没有被层支持的 NSView 调用。
张贴这个以防万一这个交换也解决了其他人的问题。