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Gradient Progress control

Posted by Matt Weagle on January 24th, 1999

Gradient Progress Control (7961 bytes)  Download Source Code and Example

Development Environment: VC5, 95

This is a simple class to display a gradient fill progress control.  It works just like the normal progress control. The main enhancements are that you can customize the colors and toggle the percentage caption's visibility. 

The control can be incorporated into a project like any other CProgressCtrl derived control. Either create the control manually, subclass an existing CProgressCtrl, or use ClassWizard to DDX_control it.  The actual code for the progress control is located in GradientProgressCtrl.h and GradientProgressCtrl.cpp. I haven't fully tested it's robustness, although I don't suspect that it will fail miserably.  Most of the work happens in the DrawGradient(...) function, which also uses Keith Rule's MemDC class.  The sample project also uses Chris Maunder's ColourPicker.  Both of these classes are included in the sample project and can be downloaded elsewhere at this site.

It is derived from CProgressCtrl so all standard CProgressCtrl functions are available.  Additional functions are listed below.

I hope someone gives it a good home :).  Please let me know of any problems or improvements.  Thanks and good luck.

Member Set Functions 

	void SetTextColor(COLORREF color)           // Set the percentage text color
	void SetBkColor(COLORREF color)             // Set background color
	void SetStartColor(COLORREF color)          // Set starting color
	void SetEndColor(COLORREF color)            // Set ending color
	void ShowPercent(BOOL bShowPercent = TRUE)  // Show the percent caption?

Member Get Functions 

	COLORREF GetTextColor(void)		    
	COLORREF GetBkColor(void)	
	COLORREF GetStartColor(void)	
	COLORREF GetEndColor(void)

 

Last updated: 18 May 1998

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Comments

  • GetPercent of CGradientProgressCtrl

    Posted by Legacy on 12/16/2003 12:00am

    Originally posted by: Micket

    CString CGradientProgressCtrl::GetPercent()
    {
    CString percent;
    percent.Format("%.0f%%", 100.0f*(float)m_nCurrentPosition/(float)m_nUpper);

    return percent;
    }

    Reply

  • Error using OffsetPos

    Posted by Legacy on 03/23/2001 12:00am

    Originally posted by: Daniel Bayer

    Be aware of using OffsetPos instead of SetPos with this implementation of CGradiantProgressCtrl. Bugfix should be really simple, but i used the easy way an replaced OffsetPos by using SetPos. Thats it folks! Keep on improving Windows GUI and bring pleasure to the eyes of the world!

    Reply

  • Vertical?

    Posted by Legacy on 07/27/1999 12:00am

    Originally posted by: john

    Anyway to make it work vertical also?

    Reply

  • Update To the code that outputs the text

    Posted by Legacy on 07/15/1999 12:00am

    Originally posted by: Murali Soundararajan

    This code should replace the "Show percent indicator if needed" code in CGradientProgressCtrl::OnPaint(). It draws the text using colors that force the text to stand out regardless of the Gradient start & stop you choose.

    if (m_bShowPercent)
    {
    CMemDC memDC(&dc);
    CDC dcMask;
    CDC dc2;

    // Create a place to work on our inverted text...
    VERIFY(dcMask.CreateCompatibleDC(&dc));
    VERIFY(dc2.CreateCompatibleDC(&dc));

    // Certain types of bitmap operations require WORD aligned buffers
    CRect rectEven;
    ::SetRect(&rectEven,
    0, // Upper left X
    0, // Upper left Y
    ((rectClient.Width()+7)*16)/16-1, // Lower right X
    ((rectClient.Height()+7)*16)/16-1); // Lower right Y


    // Create the text mask
    CBitmap bmShadow;
    VERIFY(bmShadow.CreateBitmap( rectEven.Width(),rectEven.Height(), 1, 1, NULL ) );

    CBitmap* pOldBitmap = dcMask.SelectObject(&bmShadow);

    CString percent;
    if (m_strOutput.IsEmpty())
    percent.Format("%3.0f %%", 100.0f*(float)nDrawPosition/(float)m_nUpper);
    else
    percent = m_strOutput;

    RECT rectFill; // Rectangle for filling band
    ::SetRect(&rectFill,
    0, // Upper left X
    0, // Upper left Y
    rectClient.Width()-1, // Lower right X
    rectClient.Height())-1; // Lower right Y

    // Blank the mask bitmap
    VERIFY(dcMask.BitBlt(0,0,rectEven.Width(),rectEven.Height(),NULL,rectClient.top,rectClient.left,BLACKNESS));

    // Print The text in white text on the mask
    dcMask.SetTextColor(RGB(255,255,255));
    dcMask.SetBkMode(TRANSPARENT);
    dcMask.DrawText(percent, &rectFill, DT_VCENTER | DT_CENTER | DT_SINGLELINE); // write out text

    // Create the invert color
    CBitmap bmInvertColor;
    bmInvertColor.CreateCompatibleBitmap(&dc,rectEven.Width(), rectEven.Height());
    CBitmap* pOldBitmapDC2 = dc2.SelectObject(&bmInvertColor);
    // copy get a copy of the screen
    VERIFY(dc2.BitBlt(0,0,rectEven.Width(),rectEven.Height(),&dc,rectClient.top,rectClient.left,NOTSRCCOPY));
    // invert the colors in the copy
    // taken care of in NOTSRCCOPY VERIFY(dc2.BitBlt(0,0,rectClient.Width(),rectClient.Height(),NULL,0,0,DSTINVERT));
    // AND the "White" text mask to the Invert Colors => this produces our inverted color text
    VERIFY(dc2.BitBlt(0,0,rectEven.Width(),rectEven.Height(),&dcMask,0,0,SRCAND));

    // Now invert the text mask
    VERIFY(dcMask.BitBlt(0,0,rectEven.Width(),rectEven.Height(),NULL,0,0,DSTINVERT));
    // Prepare screen - Apply inverted text mask to screen, ie erase data on screen we are going to replace
    VERIFY(memDC.BitBlt(rectClient.top,rectClient.left,rectClient.Width(),rectClient.Height(),&dcMask,0,0,SRCAND));

    // Now fill in the area we cleared using the "inverted text mask" by copying "inverted color text" to the screen
    VERIFY(memDC.BitBlt(rectClient.top,rectClient.left,rectClient.Width(),rectClient.Height(),&dc2,0,0,SRCPAINT));

    dcMask.SelectObject(pOldBitmap);
    dcMask.DeleteDC();
    dc2.SelectObject(pOldBitmapDC2);
    dc2.DeleteDC();
    }

    Reply

  • Percent string badly computed !

    Posted by Legacy on 05/10/1999 12:00am

    Originally posted by: Fabrice GIRARDOT

    The displayed percent string is badly evaluated.

    To fix it, use such formula :

    float percent = 100.0f;
    percent *= (float)(m_nCurrentPosition-m_nLower);
    percent /= (float)(m_nUpper-m_nLower);

    It may display value <0 or >100 if out of range !

    Anyway, this is a *GREAT* control !
    Thanks a lot.

    Regards.
    Fabrice.

    Reply

  • Bug fix for Gradient Progress Control

    Posted by Legacy on 04/08/1999 12:00am

    Originally posted by: Rajesh Bobade 

    Comment : Doesn't work when the start and end colors are same because the color 

    differences r,g,b workout to zero when the start and end colors are same.Consequently 

    the value of nSteps(which is the max of r,g and b) also becomes zero.This ultimately 

    used to miscalcutate the values for the width of each band(Step) and the step size for 

    each color(rStep, gStep, and bStep).The Listing below shows the 

    CGradientProgressCtrl::DrawGradient() function with the necesssary changes.


    

    void CGradientProgressCtrl::DrawGradient(CPaintDC *pDC, const RECT& rectClient, const int&
nMaxWidth)

    {

    	RECT rectFill;	// Rectangle for filling band

    	float fStep;	// How wide is each band?

    	CBrush brush;	// Brush to fill in the bar		

    	

    	CMemDC memDC(pDC);


    	//First find out the largest color distance between the start and 

    	//end colors.This distance will determine how many steps we use to 

    	//carve up the client region and the size of each gradient rect.

    	

    	int r, g, b;		// First distance, then starting value

    	float rStep, gStep, bStep;	// Step size for each color

    	BOOL  bSameColor = FALSE;

    	int nSteps;


    	// Get the color differences

    	r = (GetRValue(m_clrEnd) - GetRValue(m_clrStart));

    	g = (GetGValue(m_clrEnd) - GetGValue(m_clrStart));

    	b =  (GetBValue(m_clrEnd) - GetBValue(m_clrStart));

    	

    	if((r == 0) && (g == 0) && (b == 0))

    	{

    		bSameColor = TRUE;

    		//{{ADDED BY RAJESH

    		//Added the three lines below to fix the drawing 

    		//problem which used to occur when both the start 

    		//and end colors are same.

    		r = GetRValue(m_clrStart);

    		g = GetGValue(m_clrStart);

    		b = GetBValue(m_clrStart);

    		//}}ADDED BY RAJESH

    	}

    	

    	// Make the number of steps equal to the greatest distance	

    	//{{MODIFIED BY RAJESH

    	//To fix the drawing problem which used to occur when 

    	//both the start and end colors are RGB(0,0,0).

    	if(bSameColor && m_clrStart == 0)

    		nSteps = 255;//Select max. possible value for nSteps

    	else

    		nSteps = max(abs(r), max(abs(g), abs(b)));	

    	//Determine how large each band should be in order to cover the

    	//client with nSteps bands (one for every color intensity level)

    	//}}MODIFIED BY RAJESH

    	fStep = (float)rectClient.right / (float)nSteps;

    	

    	//Calculate the step size for each color

    	rStep = r/(float)nSteps;

    	gStep = g/(float)nSteps;

    	bStep = b/(float)nSteps;

    	

    	//Reset the colors to the starting position

    	r = GetRValue(m_clrStart);

    	g = GetGValue(m_clrStart);

    	b = GetBValue(m_clrStart);

    	

    	// Start filling bands

    	for (int iOnBand = 0; iOnBand < nSteps; iOnBand++) 

    	{		

    		::SetRect(&rectFill,(int)(iOnBand * fStep),0,

    			(int)((iOnBand+1) * fStep),rectClient.bottom + 1);

    	

    		//CDC::FillSolidRect is faster, but it does not handle 

    		//8-bit color depth	

    		if(bSameColor) VERIFY(brush.CreateSolidBrush(m_clrStart));

    		else

    			VERIFY(brush.CreateSolidBrush(RGB(r+rStep * iOnBand,

    			g + gStep * iOnBand, b + bStep * iOnBand)));


    		memDC.FillRect(&rectFill,&brush);

    		VERIFY(brush.DeleteObject());

    		

    		//If we are past the maximum for the current position we 

    		//need to get out of the loop.Before we leave,we repaint the 

    		//remainder of the client area with the background color.

    		if(rectFill.right > nMaxWidth)

    		{

    			::SetRect(&rectFill,rectFill.right,0,

    				rectClient.right, rectClient.bottom);

    			VERIFY(brush.CreateSolidBrush(m_clrBkGround));

    			memDC.FillRect(&rectFill,&brush);

    			VERIFY(brush.DeleteObject());

    			return;

    		}

    	}

    }

    Reply

  • VC 6 - SetRange32

    Posted by Legacy on 02/23/1999 12:00am

    Originally posted by: Greg


    I thought I would point out in VC6 the CProgressCtrl has a SetRange and SetRange32 function. SetRange32 must have been added between VC5 and VC6, so you will need to override this function in the CGradientProgressCtrl class.

    Otherwise, this class works great! Thanks.


    Reply

  • An Oddity

    Posted by Legacy on 02/18/1999 12:00am

    Originally posted by: Rick York

    I noticed an oddity with this control. At least, I think
    it's oddity - it is apparently by design. When the value
    of the progress hits its maximum the bar goes away.
    The reason this seems to be an oddity is that the standard
    progress bar does not exhibit this behavior.
    Luckily the fix for this is simple : on line 83 change
    the greater than or equal to just a greater than.
    It could be argued that if the value exceeds the maximum
    then just consider it to be AT the maximum but that is
    probably picking at nits.

    Nit-picking aside, this is a very nice control, thanks a lot !
    I am using it in an app I hope to be posting here soon :)

    Reply
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