Need help on drawing a line

[John502]

Hi, I need some help on drawing a line, i am able to draw vertical line on dialog box, But whenever i have opened othe application on the dialog box, the line is getting erasing.... I am using below code snippet for drawing line.. dc.SetROP2(R2_NOTXORPEN); dc.MoveTo(old_x1,old_y1); dc.LineTo(old_x2,old_y2); dc.MoveTo(start); dc.LineTo(end); Can any one help me regrading why the line is getting erasing..? as it is very urgent requirement for me..

[_Superman_]

Put those lines in the OnPaint method of the dialog.

«_Superman_» I love work. It gives me something to do between weekends.

[Hamid Taebi]

Where do you use of this code? WM_PAINT

Of one Essence is the human race thus has Creation put the base One Limb impacted is sufficient For all Others to feel the Mace (Saadi )

[_AnsHUMAN_]

in which function do you try to do this?

You need to google first, if you have "It's urgent please" mentioned in your question. ;-)_AnShUmAn_

[CPallini]

Windows is event driven (well, message driven...): drawing should happen inside the WM_PAINT message handler, that is CDialog::OnPaint method for an MFC application. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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[John502]

Yes, I have written that code snippet in OnPaint function only...

[John502]

I have written that code snippet in OnPaint function only...

[John502]

In OnPaint function... , I have already done with google, but i don't get any correct help... So Could you please help me regarding this...?

[_AnsHUMAN_]

did you debug to check if variables contain the same values as they did before other window was moved over your dialog.

You need to google first, if you have "It's urgent please" mentioned in your question. ;-)_AnShUmAn_

[John502]

yes i have debugged, iam getting all the variables are in correct manner.

[Hamid Taebi]

Does your code like this? void CTestDlg::OnPaint() { if (IsIconic()) { CPaintDC dc(this); // device context for painting SendMessage(WM_ICONERASEBKGND, reinterpret_cast(dc.GetSafeHdc()), 0); // Center icon in client rectangle int cxIcon = GetSystemMetrics(SM_CXICON); int cyIcon = GetSystemMetrics(SM_CYICON); CRect rect; GetClientRect(&rect); int x = (rect.Width() - cxIcon + 1) / 2; int y = (rect.Height() - cyIcon + 1) / 2; // Draw the icon dc.DrawIcon(x, y, m_hIcon); } else { CPaintDC dc(this); // device context for painting dc.SetROP2(R2_NOTXORPEN); dc.MoveTo(100,100); dc.LineTo(100,200); dc.MoveTo(200,205); dc.LineTo(200,305); CDialog::OnPaint(); } }

Of one Essence is the human race thus has Creation put the base One Limb impacted is sufficient For all Others to feel the Mace (Saadi )

[John502]

Hi Saadi, Thanks for your help on this.., I am able to draw the constant line if i have opened other window on dialog box, but here in my application the line will move from left to right in between two sliders along with the slider positions. while the line is moving, if i have opened any window on dialog box, the previous line is not getting erasing. I thought of it is losting the previous line pixels information.. Can you please tell me how i have to achive this..? thanks in advance..

[Hamid Taebi]

Hi John Well Im not Saadi (poet)[^]. Your answer is easy if you want to clear previous lines you can draw on it again for example you have this code: dc.SetROP2(R2_NOTXORPEN); dc.MoveTo(100,100); dc.LineTo(100,200); dc.MoveTo(200,205); dc.LineTo(200,305); if you use of this code again you clear previous line. dc.SetROP2(R2_NOTXORPEN); dc.MoveTo(100,100); dc.LineTo(100,200); dc.MoveTo(200,205); dc.LineTo(200,305);

Of one Essence is the human race thus has Creation put the base One Limb impacted is sufficient For all Others to feel the Mace (Saadi )