I can confirm this behavior with Lazarus 1.6 (gtk2) / FPC 3.0 on Xubuntu 16.04.
Typing keys rapidly (even by hand with a normal keyboard) will make it lose keypress events occasionally, using a barcode reader (it emulates an USB-Keyboard) through the KeyPress event is virtually impossible with Gtk2-LCL. No problems on Windows. Bypassing the LCL and binding a handler directly to the gtk signal proves that gtk will fire events for *all* keys, no matter how rapidly the keyboard will send them, its just LCL that is missing some of them :-( 2013-03-25 14:17 GMT+01:00 byungho jeon <bas...@softfac.co.kr>: > I'm using CodeTyphon 4.10 on ubuntu mint 14 desktop (x86-64) > - CodeTyphon 4.10 = FPC 2.7.1, Lazarus 2013-03-25 SVN 40461CT > x86_64-linux-gtk2 > > Barcode reader is MOTOROLA DS3578 with FIPS model (configed HID Keyboard > Emulation, USB Type) > > I make reader code using TForm.KeyPreview property. > > 1. There is main form. (Keypreview := True) > 2. Make OnKeyPress event handler > 3. Read a sample QRCode ( http://localhost/qrcode/Test_2012/A001 ) > 4. OnKeyPress missing some characters. > -> Readed -> http://localhost/qrcode/est2012/001 > -> Missed capital character(T, A) and under bar character(_) > -> Lower case character is no problem. > > When I read barcode(qrcode) focus to text editor like pluma, qrcode data is > inserted correctly without missing characters. > > Here is test project main form unit source code: > > //----------------------------------- SAMPLE CODE > unit Unit1; > > {$mode objfpc}{$H+} > > interface > > uses > Classes, SysUtils, FileUtil, ubarcodes, Forms, Controls, Graphics, > Dialogs, > StdCtrls, LCLType; > > type > { TForm1 } > TForm1 = class(TForm) > Button1: TButton; > Button2: TButton; > procedure Button1Click(Sender: TObject); > procedure Button2Click(Sender: TObject); > procedure FormCreate(Sender: TObject); > procedure FormKeyPress(Sender: TObject; var Key: char); > private > FBuffer: string; > public > { public declarations } > end; > > var > Form1: TForm1; > > implementation > > {$R *.lfm} > > { TForm1 } > > procedure TForm1.FormCreate(Sender: TObject); > begin > KeyPreview := True; > end; > > procedure TForm1.FormKeyPress(Sender: TObject; var Key: char); > begin > FBuffer += Key; > end; > > procedure TForm1.Button1Click(Sender: TObject); > begin > ShowMessage(FBuffer); > end; > > procedure TForm1.Button2Click(Sender: TObject); > begin > FBuffer := ''; > end; > > end. > > > > -- > _______________________________________________ > Lazarus mailing list > Lazarus@lists.lazarus.freepascal.org > http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus > -- _______________________________________________ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
