我正在尝试使用 LibvnccClient
在 Swift 中实现一个简单的VNC client
。
我创建了一个NSView
子类。我创建了一个CGContext
并将数据指针传递给库以用作framebuffer
。libvncclient 随着屏幕内容的变化更新帧缓冲,并调用我提供的回调。
这是相关代码
class VNCClient {
var localClient: rfbClient
var view: NSView
init(view: NSView) {
guard let client_ptr = rfbGetClient(8, 3, 4) else {
fatalError("Trouble")
}
self.view = view
self.localClient = client_ptr.pointee
localClient.MallocFrameBuffer = resize
localClient.GotFrameBufferUpdate = update
let fbPointer = UnsafeMutablePointer<UInt8>(OpaquePointer((view as! RFBView).buffer))
localClient.frameBuffer = fbPointer
rfbClientSetClientData(&localClient, &viewTag, &self.view)
var argc: Int32 = 0
let b = rfbInitClient(&localClient, &argc, nil)
if b == RFB_TRUE {
print("Connected!")
}
Timer.scheduledTimer(withTimeInterval: 0.001, repeats: true) {_ in
if WaitForMessage(&self.localClient, 1) > 0 {
HandleRFBServerMessage(&self.localClient)
}
}
}
func update(client: UnsafeMutablePointer<rfbClient>?, x: Int32, y: Int32, w: Int32, h: Int32) -> Void {
let cl = client!.pointee
let view_ptr = rfbClientGetClientData(client, &viewTag)
let view = view_ptr?.assumingMemoryBound(to: RFBView.self).pointee
view?.setNeedsDisplay(NSRect(x: Int(x), y: Int(y), width: Int(w), height: Int(h)))
}
class RFBView: NSView {
let ctx = CGContext(data: nil, width: 800, height: 600, bitsPerComponent: 8, bytesPerRow: 4 * 800, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGImageAlphaInfo.noneSkipLast.rawValue)!
var buffer: UnsafeMutableRawPointer? {
return ctx.data
}
override func draw(_ dirtyRect: NSRect) {
let image = ctx.makeImage()
NSGraphicsContext.current()?.cgContext.draw(image!, in: frame)
}
它可以工作,但显示不流畅。服务器在 VM 中的同一台计算机上运行,因此没有网络问题。
我正在为每个更新重绘整个图像,我认为这是问题的原因。那么如何只重绘更新的帧缓冲部分呢?
CoreGraphics
足够快还是我应该使用NSOpenGLView
?
我假设如果有更新,HandleRFBServerMessage
每次迭代都会调用update
函数一次。但事实并非如此。
我用打印到控制台的存根替换了update
,并注意到当屏幕上有很多活动时,它被调用了一千多次。
然而,随着setNeedsDisplay
的呼叫update
,它只被调用了几百次。由于它花费了太多时间渲染,因此错过了中间的几帧。
我将绘图代码移到Timer
内,现在它运行良好。
localClient.GotFrameBufferUpdate = { _, _, _, _, _ in needs_update = true }
Timer.scheduledTimer(withTimeInterval: 0.016, repeats: true) {_ in
if needs_update {
view.display()
needs_update = false
}
if WaitForMessage(&self.localClient, 1) > 0 {
HandleRFBServerMessage(&self.localClient)
}
}