Issue with Display of wxFrame

[cotede2]

Hello I face an issue when I use codeblocks and create a wxFrame. http://yfrog.com/2ftroublerj

Look, on my design view it looks okai http://yfrog.com/5eokaij

Here is my code . any ideas?

Code Select Expand

#include "MainFrame.h"

//(*InternalHeaders(MainFrame)
#include <wx/intl.h>
#include <wx/string.h>
//*)

//(*IdInit(MainFrame)
const long MainFrame::ID_TEXTCTRL2 = wxNewId();
const long MainFrame::ID_TEXTCTRL1 = wxNewId();
const long MainFrame::ID_STATICTEXT3 = wxNewId();
const long MainFrame::ID_STATICTEXT2 = wxNewId();
const long MainFrame::ID_BUTTON1 = wxNewId();
const long MainFrame::ID_PANEL1 = wxNewId();
//*)

BEGIN_EVENT_TABLE(MainFrame,wxFrame)
//(*EventTable(MainFrame)
//*)
END_EVENT_TABLE()

MainFrame::MainFrame(wxWindow* parent,wxWindowID id,const wxPoint& pos,const wxSize& size)
{
//(*Initialize(MainFrame)
Create(parent, wxID_ANY, wxEmptyString, wxDefaultPosition, wxDefaultSize, wxDEFAULT_FRAME_STYLE, _T("wxID_ANY"));
Panel1 = new wxPanel(this, ID_PANEL1, wxPoint(56,24), wxDefaultSize, wxTAB_TRAVERSAL, _T("ID_PANEL1"));
TextCtrl2 = new wxTextCtrl(Panel1, ID_TEXTCTRL2, _("Text"), wxPoint(144,128), wxDefaultSize, 0, wxDefaultValidator, _T("ID_TEXTCTRL2"));
TextCtrl1 = new wxTextCtrl(Panel1, ID_TEXTCTRL1, _("Text"), wxPoint(144,168), wxDefaultSize, 0, wxDefaultValidator, _T("ID_TEXTCTRL1"));
StaticText3 = new wxStaticText(Panel1, ID_STATICTEXT3, _("Identifiant"), wxPoint(64,136), wxDefaultSize, 0, _T("ID_STATICTEXT3"));
StaticText2 = new wxStaticText(Panel1, ID_STATICTEXT2, _("Mot De Passe"), wxPoint(64,168), wxDefaultSize, 0, _T("ID_STATICTEXT2"));
Button1 = new wxButton(Panel1, ID_BUTTON1, _("Valider"), wxPoint(144,208), wxDefaultSize, 0, wxDefaultValidator, _T("ID_BUTTON1"));

Connect(ID_BUTTON1,wxEVT_COMMAND_BUTTON_CLICKED,(wxObjectEventFunction)&MainFrame::OnButton1Click);
Panel1->Connect(ID_PANEL1,wxEVT_PAINT,(wxObjectEventFunction)&MainFrame::OnPanel1Paint,0,this);
//*)
}

MainFrame::~MainFrame()
{
//(*Destroy(MainFrame)
//*)
}


void MainFrame::OnPanel1Paint(wxPaintEvent& event)
{
}

void MainFrame::OnButton1Click(wxCommandEvent& event)
{
}


[seb_seb0]

Well, your topic will be locked because it is a wxWidgets question, and not a CodeBlocks question

Your problem comes certainly from the panel paint handler

Code Select Expand

void MainFrame::OnPanel1Paint(wxPaintEvent& event)

and from the event connector:

Code Select Expand

Panel1->Connect(ID_PANEL1,wxEVT_PAINT,(wxObjectEventFunction)&MainFrame::OnPanel1Paint,0,this);

There are 2 mistakes in these 2 lines:
 1 - the wxEVT_PAINT handling is not needed - wxPanel manages it internally
 2 - you are doing nothing in the event handler (empty function). On windows (I assume you are on Windows, seeing your screenshots), you MUST create a wxPaintDC object in the paint handler, even if you do not use it. Otherwise, Windows will keep asking to update the panel, making an infinite loop. I bet that when you run your program, your CPU usage is near 100%
       this infinite loop prevents the child window from the panel being repainted - hence you have 4 nice black rectangles on your window.

Everything is in the wxWidgets doc. You should read them.

Regards,

Sebastien

[oBFusCATed]

seb_seb0, by reading your explanation, I conclude that this is a wxSmith bug.

It should generate wxPaintDC dc(this); in the on_paint handler, so the user knows that this object is needed.

[seb_seb0]

seb_seb0, by reading your explanation, I conclude that this is a wxSmith bug.

It should generate wxPaintDC dc(this); in the on_paint handler, so the user knows that this object is needed.

This is needed only on Windows platform, as far as I know.
Perhaps it can be added, but we should be cautious: there can be scenarios where creating a wxPaintDC is not desired.
I think it is better to let the wxSmith user decide.

Here is the related part of wxWidgets doc (2.9.0 version, but applies to 2.8.xx as well - in the wxPaintDC entry)

A wxPaintDC must be constructed if an application wishes to paint on the client area of a window from within an EVT_PAINT() event handler.
This should normally be constructed as a temporary stack object; don't store a wxPaintDC object. If you have an EVT_PAINT() handler, you must create a wxPaintDC object within it even if you don't actually use it.

So perhaps you are right. I prefer to let the programmer decide.

Sebastien

[Jenna]

So perhaps you are right. I prefer to let the programmer decide.

If someone wants to use wxwidgets as toolkit, he/she should read the documentation, even if he/she uses a gui-designer like wxsmith.

By the way, I just looked into the wxwidgets code: changing the behaviour of wxwidgets in this case is not so easy.
See: wxsEventsEditor::CreateNewFunction (wxseventseditor.cpp:395).

[Englishuk]

Well, your topic will be locked because it is a wxWidgets question, and not a CodeBlocks question

Your problem comes certainly from the panel paint handler

Code Select Expand

void MainFrame::OnPanel1Paint(wxPaintEvent& event)

and from the event connector:

Code Select Expand

Panel1->Connect(ID_PANEL1,wxEVT_PAINT,(wxObjectEventFunction)&MainFrame::OnPanel1Paint,0,this);

There are 2 mistakes in these 2 lines:
 1 - the wxEVT_PAINT handling is not needed - wxPanel manages it internally
 2 - you are doing nothing in the event handler (empty function). On windows (I assume you are on Windows, seeing your screenshots), you MUST create a wxPaintDC object in the paint handler, even if you do not use it. Otherwise, Windows will keep asking to update the panel, making an infinite loop. I bet that when you run your program, your CPU usage is near 100%
       this infinite loop prevents the child window from the panel being repainted - hence you have 4 nice black rectangles on your window.

Everything is in the wxWidgets doc. You should read them.

Regards,

Sebastien

You Sir are a star!

I installed code::blocks on Ubuntu, got a helloworld app going with wxsmith. Setup code::blocks for cross compile for win32 using mingw32 (which I must say is not easy to do for a newbie).

Compiled my program for win32, and was seeing 100% cpu usage using wine and also on native Windows.

For anyone else who is using the wxsmith helloworld tutorial, I commented out the following line:

//Panel1->Connect(wxEVT_PAINT,(wxObjectEventFunction)&HelloApp2Frame::OnPanel1Paint,0,this);

Located in Main.cpp

Further down, I commented out the following block of code:

//void HelloApp2Frame::OnPanel1Paint(wxPaintEvent& event)
//{
//   wxPaintDC dc(this);
//}

Many thanks to the original poster for asking the question and for Sebastien who correctly identified how this issue presents itsself in Windows.

The only issue now is every time I change by frame/panel, the first line above is uncommented and I have to re-comment it before compiling.

Why am I posting? Just in case it helps someone else resolve the same issue...........