Delphi RawInput WinAPI:GetRawInputBuffer()和消息处理
为什么Delphi RawInput WinAPI:GetRawInputBuffer()和消息处理,delphi,messaging,raw-input,Delphi,Messaging,Raw Input,为什么 我正在尝试从条形码扫描仪获取输入到我的(视觉)应用程序。我希望忽略来自其他设备的输入,即使应用程序失去焦点也能获得输入。为了实现这一点,我在SO和其他地方找到了推荐的RawInputAPI 我的重点是读取输入,因为我预计每秒扫描2次,每次扫描都会触发700个事件(按键向下/按键向上)(假设扫描仪用作键盘)。文档中提到使用GetRawInputBuffer()“用于能够产生大量原始输入的设备”。我不知道上面的内容是否符合 问题 我已经成功地收到了输入数据,但我一定是做错了什么(可能是根本的
我正在尝试从条形码扫描仪获取输入到我的(视觉)应用程序。我希望忽略来自其他设备的输入,即使应用程序失去焦点也能获得输入。为了实现这一点,我在SO和其他地方找到了推荐的RawInputAPI 我的重点是读取输入,因为我预计每秒扫描2次,每次扫描都会触发700个事件(按键向下/按键向上)(假设扫描仪用作键盘)。文档中提到使用GetRawInputBuffer()“用于能够产生大量原始输入的设备”。我不知道上面的内容是否符合 问题
我已经成功地收到了输入数据,但我一定是做错了什么(可能是根本的…),因为我无法找到一个好方法来获得一致的结果。原始数据似乎很快就“消失”了,而且我经常得不到任何数据。关于GetRawInputBuffer()也存在类似的问题,但这些问题到目前为止还没有解决。。。一些注意事项:
- 我使用来自的“unRawInput.pas”
- 我使用AllocateHwnd()创建一个窗口句柄,并将其注册为原始输入
如何/何时(正确地)在可视化应用程序中调用GetRawInputBuffer()以获得一致的结果,例如,自上次调用以来的所有关键事件?或者:如何/为什么事件似乎在调用之间被“丢弃”,我如何防止它 代码
下面的代码是一个64位控制台应用程序,展示了我迄今为止尝试过的3种方法及其问题(如主begin-end.-块的代码注释中所述的取消注释/注释掉方法)
- 方法#1:在输入发生时执行Sleep(),然后立即读取缓冲区。我从中得到了Sleep()的想法,它工作得非常好,因为它似乎可以获得所有的输入,但我认为这并不实用,因为我的应用程序需要保持响应李>
- 方法#2:使用GetMessage()-通常,这不会产生任何数据,除非您非常快速地键入(例如,mash键),即使如此,它也可能占输入的50%,最多
- 方法3:使用peek message()和PM#u NOREMOVE-这似乎可以非常一致地获得输入,但会使线程最大化李>
程序读取缓冲区;
{$APPTYPE控制台}
{$R*.res}
使用
WinAPI.Windows,
WinAPI.Messages,
系统,班级,,
System.SysUtils,
URawInput输入“..\URawInput.pas”;//发件人:https://github.com/lhengen/RawInput
类型
TGetInput=class
严格保密
fRawInputStructureSize:UINT;
fRawInputHeaderSize:UINT;
fRawInputBufferSize:基数;
fRawInputDevice:RAWINPUTDEVICE;
fRawInputBuffer:PravinPut;
程序RawInputWndProc(var-aMsg:TMessage);
公众的
FrawinPutHND:HWND;
函数ReadInputBuffer():字符串;
构造函数Create();
析构函数Destroy();推翻
结束;
构造函数TGetInput.Create();
开始
继承;
fRawInputStructureSize:=SizeOf(RAWINPUT);
fRawInputHeaderSize:=SizeOf(RAWINPUTHEADER);
//创建缓冲区
fRawInputBufferSize:=40*16;
GetMem(fRawInputBuffer,fRawInputBufferSize);
//为原始(键盘)输入创建句柄和寄存器
fRawInputWindowHnd:=AllocateHWnd(RawInputWndProc);
fRawInputDevice.UsuseSagePage:=$1;
fRawInputDevice.usage:=6美元;
fRawInputDevice.dwFlags:=RIDEV_INPUTSINK;
fRawInputDevice.hwndTarget:=fRawInputWindowHnd;
如果注册了WinputDevices(@fRawInputDevice,1,SizeOf(RAWINPUTDEVICE)),则
WriteLn('已注册设备;开始键入…')
其他的
WriteLn('注册设备时出错:'+GetLastError().ToString());
结束;
析构函数TGetInput.Destroy();
开始
如果已分配(fRawInputBuffer),则
FreeMem(fRawInputBuffer);
DeallocateHWnd(FrawinPutHnd);
继承;
结束;
函数TGetInput.ReadInputBuffer():字符串;
变量
pcbSizeT,pcbSizeT:UINT;
numberOfStructs:UINT;
pRI:PRAWINPUT;
开始
结果:=字符串。空;
PCB尺寸:=0;
pcbSizeT:=0;
numberOfStructs:=GetRawInputBuffer(零、pcbSize、fRawInputHeaderSize);
如果(numberOfStructs=0),则
开始
//docs.microsoft.com对“nil”调用说:“以字节为单位的所需最小缓冲区以*pcbSize为单位返回”
//虽然可能是多余的,但我想检查一下也无妨:
如果(fRawInputBufferSize0)和(numberOfStructs<900000)),则
开始
{$POINTERMATH ON}
pRI:=fRawInputBuffer;
对于变量i:=0到(numberOfStructs-1)do
开始
如果(pRI.keyboard.Flags=RI\u KEY\u MAKE),则
结果:=Result+pRI.keyboard.VKey.ToHexString()+#32;
pRI:=NEXTRAWINPUTBLOCK(pRI);
结束;
{$POINTERMATH OFF}
//DefRawInputProc();//什么都不做?http://blog.airesoft.co.uk/2014/04/defrawinputproc-rastinating-away/
结束
其他的
打破
直到错误;
结束
结束;
程序TGetInput.RawInputWndProc(var-aMsg:TMessage);
开始
//注释掉Sleep()方法的案例块;保留最后一行DefWindowProc()
//为GetMessage()/PeekMessage()-方法保留案例块;注释掉最后一行DefWindowProc()
//案例aMsg.Msg
//WM_输入:
//开始
//写入(ReadInputBuffer(),“-”);
//aMsg.结果:=0;
//结束
//否则
//aMsg.Result:=DefWindowProc(fRawInputWindowHnd,aMsg.Msg,aMsg.WParam,aMsg.LParam);
//结束;
//注释掉GetMessage()/PeekMessage()-方法
aMsg.Result:=deffwindowp
program readrawbuffer;
{$APPTYPE CONSOLE}
{$R *.res}
uses
WinAPI.Windows,
WinAPI.Messages,
System.Classes,
System.SysUtils,
URawInput in '..\URawInput.pas'; // from: https://github.com/lhengen/RawInput
type
TGetInput = class
strict private
fRawInputStructureSize: UINT;
fRawInputHeaderSize: UINT;
fRawInputBufferSize: Cardinal;
fRawInputDevice: RAWINPUTDEVICE;
fRawInputBuffer: PRAWINPUT;
procedure RawInputWndProc(var aMsg: TMessage);
public
fRawInputWindowHnd: HWND;
function ReadInputBuffer(): String;
constructor Create();
destructor Destroy(); override;
end;
constructor TGetInput.Create();
begin
inherited;
fRawInputStructureSize := SizeOf(RAWINPUT);
fRawInputHeaderSize := SizeOf(RAWINPUTHEADER);
// create buffer
fRawInputBufferSize := 40 * 16;
GetMem(fRawInputBuffer, fRawInputBufferSize);
// create handle and register for raw (keyboard) input
fRawInputWindowHnd := AllocateHWnd(RawInputWndProc);
fRawInputDevice.usUsagePage := $1;
fRawInputDevice.usUsage := $6;
fRawInputDevice.dwFlags := RIDEV_INPUTSINK;
fRawInputDevice.hwndTarget := fRawInputWindowHnd;
if RegisterRawInputDevices(@fRawInputDevice, 1, SizeOf(RAWINPUTDEVICE)) then
WriteLn('device(s) registered; start typing...')
else
WriteLn('error registering device(s): ' + GetLastError().ToString());
end;
destructor TGetInput.Destroy();
begin
if Assigned(fRawInputBuffer) then
FreeMem(fRawInputBuffer);
DeallocateHWnd(fRawInputWindowHnd);
inherited;
end;
function TGetInput.ReadInputBuffer(): String;
var
pcbSize, pcbSizeT: UINT;
numberOfStructs: UINT;
pRI: PRAWINPUT;
begin
Result := String.Empty;
pcbSize := 0;
pcbSizeT := 0;
numberOfStructs := GetRawInputBuffer(nil, pcbSize, fRawInputHeaderSize);
if (numberOfStructs = 0) then
begin
// docs.microsoft.com says for 'nil'-call: "minimum required buffer, in bytes, is returned in *pcbSize"
// though probably redundant, I guess it can't hurt to check:
if (fRawInputBufferSize < pcbSize) then
begin
fRawInputBufferSize := pcbSize * 16;
ReallocMem(fRawInputBuffer, fRawInputBufferSize);
end;
repeat
pcbSizeT := fRawInputBufferSize;
numberOfStructs := GetRawInputBuffer(fRawInputBuffer, pcbSizeT, fRawInputHeaderSize);
if ((numberOfStructs > 0) and (numberOfStructs < 900000)) then
begin
{$POINTERMATH ON}
pRI := fRawInputBuffer;
for var i := 0 to (numberOfStructs - 1) do
begin
if (pRI.keyboard.Flags = RI_KEY_MAKE) then
Result := Result + pRI.keyboard.VKey.ToHexString() + #32;
pRI := NEXTRAWINPUTBLOCK(pRI);
end;
{$POINTERMATH OFF}
// DefRawInputProc(); // doesn't do anything? http://blog.airesoft.co.uk/2014/04/defrawinputproc-rastinating-away/
end
else
Break;
until False;
end
end;
procedure TGetInput.RawInputWndProc(var aMsg: TMessage);
begin
// comment-out case block for Sleep() approach; leave last DefWindowProc() line
// leave case block for GetMessage() / PeekMessage() -approaches; comment-out last DefWindowProc() line
// case aMsg.Msg of
// WM_INPUT:
// begin
// Write(ReadInputBuffer(), '-');
// aMsg.Result := 0;
// end
// else
// aMsg.Result := DefWindowProc(fRawInputWindowHnd, aMsg.Msg, aMsg.WParam, aMsg.LParam);
// end;
// comment-out for GetMessage() / PeekMessage() -approaches
aMsg.Result := DefWindowProc(fRawInputWindowHnd, aMsg.Msg, aMsg.WParam, aMsg.LParam);
end;
var
getInput: TGetInput;
lpMsg: tagMSG;
begin
getInput := TGetInput.Create();
////////////////////////////////////////////////////////////////////////////////
// approach #1: Sleep()
// >> comment-out other aproaches; comment-out case block in RawInputWndProc(), leave last DefWindowProc() line
repeat
WriteLn('sleeping, type now...');
Sleep(3000);
WriteLn('VKeys read: ', getInput.ReadInputBuffer());
until False;
////////////////////////////////////////////////////////////////////////////////
// approach #2: GetMessage()
// >> comment-out other approaches; comment-out last DefWindowProc() line in RawInputWndProc(), leave case block
// repeat
// // docs.microsoft.com: "Use WM_INPUT here and in wMsgFilterMax to specify only the WM_INPUT messages."
// if GetMessage(lpMsg, getInput.fRawInputWindowHnd, WM_INPUT, WM_INPUT) then
// DispatchMessage(lpMsg);
// until False;
////////////////////////////////////////////////////////////////////////////////
// approach #3: PeekMessage()
// >> comment-out other approaches; comment-out last DefWindowProc() line in RawInputWndProc(), leave case block
// repeat
// if PeekMessage(lpMsg, getInput.fRawInputWindowHnd, WM_INPUT, WM_INPUT, PM_NOREMOVE) then
// DispatchMessage(lpMsg);
//
// if PeekMessage(lpMsg, 0, 0, 0, PM_REMOVE) then
// DispatchMessage(lpMsg);
// until False;
getInput.Free();
end.
repeat
TThread.Sleep(10);
while True do
begin
if (Not PeekMessage(lpMsg, 0, 0, WM_INPUT - 1, PM_NOYIELD or PM_REMOVE)) then System.Break;
DefWindowProc(lpMsg.hwnd, lpMsg.message, lpMsg.wParam, lpMsg.lParam);
end;
while True do
begin
if (Not PeekMessage(lpMsg, 0, WM_INPUT + 1, High(Cardinal), PM_NOYIELD or PM_REMOVE)) then System.Break;
DefWindowProc(lpMsg.hwnd, lpMsg.message, lpMsg.wParam, lpMsg.lParam);
end;
ReadRawInputBuffer(); // shown below; essentially reads out all queued-up input
until SomeCondition;
procedure ReadInputBuffer();
var
// ...
begin
// this returns the minimum required buffer size in ```pcbSize```
numberOfStructs := GetRawInputBuffer(nil, pcbSize, rawInputHeaderSize);
if (numberOfStructs = 0) then
begin
// read out all queued-up data
repeat
// ... allocate pBuffer as needed
numberOfStructs := GetRawInputBuffer(pBuffer, pcbSize, rawInputHeaderSize);
if ((numberOfStructs > 0) and (numberOfStructs < 900000)) then
// do something with pBuffer / its data
// I use a TThreadedQueue<T>; the items/data is worked off outside this thread
else
System.Break;
until False;
end
end;