C++ BView::DrawString方法代码示例

void
IconSpewer::DrawSomeOld()
{
#if 0
	if (!oldIconCacheInited)
		BIconCache::InitIconCaches();

	target->Lock();
	target->SetTitle("old cache");
	BView* view = target->FindView("iconView");
	ASSERT(view);

	BRect bounds(target->Bounds());
	view->SetHighColor(Color(255, 255, 255));
	view->FillRect(bounds);

	view->SetHighColor(Color(0, 0, 0));
	char buffer[256];
	if (cycleTime) {
		sprintf(buffer, "last cycle time %Ld ms", cycleTime/1000);
		view->DrawString(buffer, BPoint(20, bounds.bottom - 20));
	}
	if (numDrawn) {
		sprintf(buffer, "average draw time %Ld us per icon",
			watch.ElapsedTime() / numDrawn);
		view->DrawString(buffer, BPoint(20, bounds.bottom - 30));
	}
	sprintf(buffer, "directory: %s", currentPath.Path());
	view->DrawString(buffer, BPoint(20, bounds.bottom - 40));

	target->Unlock();

	for (int32 row = 0; row < kRowCount; row++) {
		for (int32 column = 0; column < kColumnCount; column++) {
			BEntry entry(NextRef());
			BModel model(&entry, true);

			if (!target->Lock())
				return;

			if (model.IsDirectory())
				entry.GetPath(&currentPath);

			BIconCache::LockIconCache();
			BIconCache* iconCache
				= BIconCache::GetIconCache(&model, kIconSize);
			iconCache->Draw(view, BPoint(column * (kIconSize + 2),
				row * (kIconSize + 2)), B_NORMAL_ICON, kIconSize, true);
			BIconCache::UnlockIconCache();

			target->Unlock();
			numDrawn++;
		}
	}
#endif
}

void CounterView::Draw (BRect updateRect)
{
  BRect MovingRect (
    m_MovingDotPoint.x,
    m_MovingDotPoint.y,
    m_MovingDotPoint.x + m_MovingDotSize,
    m_MovingDotPoint.y + m_MovingDotSize);
  char TempString [40];

  if (m_BackingBitmap != NULL)
  {
    m_BackingBitmap->Lock ();
    m_BackingView.SetHighColor (60, 60, 255, 8);
    m_BackingView.FillRect (m_BndRect);
    m_BackingView.SetHighColor (255, 255, 0, 255);
    m_BackingView.MovePenTo (m_TextStartPoint);
    sprintf (TempString, "%d", m_CurrentCount);
    m_BackingView.DrawString (TempString);
    m_BackingView.FillRect (MovingRect);
    m_BackingView.Sync ();
    m_BackingBitmap->Unlock ();
    MovePenTo (0, 0);
    DrawBitmap (m_BackingBitmap);
  }
}

void wxStatusBarBeOS::DrawStatusBar()
{

	int i=0;
	int leftPos=0;
	wxArrayInt widthsAbs;
	wxString text;

	m_view->Clear();
	BRect bounds(m_view->bounds());
	BView * drawview = m_view->GetBack();
	if(drawview->LockLooper())
	{	
		rgb_color clr;
		drawview->PushState();
		clr = drawview->ViewColor();
		clr.red-=50; clr.green-=50; clr.blue-=50;
		drawview->SetHighColor(clr);
		drawview->StrokeLine(BPoint(bounds.left, bounds.top), BPoint(bounds.right, bounds.top));
		clr.red+=100; clr.green+=100; clr.blue+=100;
		drawview->SetHighColor(clr);
		drawview->StrokeLine(BPoint(bounds.left, bounds.top+1), BPoint(bounds.right, bounds.top+1));
		drawview->PopState();
		
		if(m_nFields>0)
			widthsAbs = CalculateAbsWidths(bounds.IntegerWidth() - 2*(m_nFields - 1));
		
		drawview->SetDrawingMode(B_OP_OVER);
		for(i=0;i<m_nFields;i++)
		{
			text = GetStatusBufferText(i);
			drawview->DrawString(text, BPoint(leftPos, bounds.bottom-2));
			leftPos+=widthsAbs[i]+2;
		}
		
		drawview->UnlockLooper();
	}
	m_view->flush();
}

BBitmap *DragonView::_MakeNoneImage( void )
{
	// Draw an "empty" bitmap to represent "no image"; we'll use one
	// that tells the user what to do.
	BBitmap *bitmap = new BBitmap( BRect( 0, 0, 319, 199 ),
								   BScreen().ColorSpace(),
								   true );
	BView *view = new BView( bitmap->Bounds(),
							 "not a bitmap",
							 B_FOLLOW_ALL_SIDES, 0 );
	bitmap->AddChild( view );

	DragonApp *app = dynamic_cast<DragonApp *>( be_app );
	
	rgb_color White = { 255, 255, 255, 0 };
	rgb_color Black = { 0, 0, 0, 0 };
	
	bitmap->Lock();

	view->SetLowColor( White );
	view->SetViewColor( White );
	view->SetHighColor( Black );
	view->SetDrawingMode( B_OP_OVER );
	view->FillRect( view->Bounds(), B_SOLID_LOW );

	// Excercise for the reader here:  Read the old newsletter articles
	// about how to use the font metrics to find out how large a font is,
	// then center to font in the window dynamically no matter what font
	// settings the user has.

	view->SetFont( be_plain_font );
	view->MovePenTo( 5, 100 );
	view->DrawString( app->rsrc_strings->FindString( RSRC_Drop_an_image ) );
	view->Sync();
	
	bitmap->Unlock();

	return bitmap;
}

// MouseMoved
void
ObjectView::MouseMoved(BPoint where, uint32 transit,
					   const BMessage* dragMessage)
{
//	BRect dirty(where, where);
//	dirty.InsetBy(-10, -10);
//	Invalidate(dirty);
	
if (dragMessage) {
//printf("ObjectView::MouseMoved(BPoint(%.1f, %.1f)) - DRAG MESSAGE\n", where.x, where.y);
//Window()->CurrentMessage()->PrintToStream();
} else {
//printf("ObjectView::MouseMoved(BPoint(%.1f, %.1f))\n", where.x, where.y);
}

	if (fScrolling) {
		BCursor cursor(kGrabCursor);
		SetViewCursor(&cursor);
	
		BPoint offset = fLastMousePos - where;
		ScrollBy(offset.x, offset.y);
		fLastMousePos = where + offset;
	} else if (fInitiatingDrag) {
		BPoint offset = fLastMousePos - where;
		if (sqrtf(offset.x * offset.x + offset.y * offset.y) > 5.0) {
			BMessage newDragMessage('drag');
			BBitmap* dragBitmap = new BBitmap(BRect(0, 0, 40, 40), B_RGBA32,
				true);
			if (dragBitmap->Lock()) {
				BView* helper = new BView(dragBitmap->Bounds(),
					"offscreen view", B_FOLLOW_ALL, B_WILL_DRAW);
				dragBitmap->AddChild(helper);
				helper->SetDrawingMode(B_OP_ALPHA);
				helper->SetBlendingMode(B_CONSTANT_ALPHA, B_ALPHA_COMPOSITE);

				BRect r(helper->Bounds());
				helper->SetHighColor(0, 0, 0, 128);
				helper->StrokeRect(r);

				helper->SetHighColor(200, 200, 200, 100);
				r.InsetBy(1, 1);
				helper->FillRect(r);

				helper->SetHighColor(0, 0, 0, 255);
				const char* text = B_TRANSLATE("Test");
				float pos = (r.Width() - helper->StringWidth(text)) / 2;
				helper->DrawString(text, BPoint(pos, 25));
				helper->Sync();
			}
			
			DragMessage(&newDragMessage, dragBitmap, B_OP_ALPHA, B_ORIGIN,
				this);
			fInitiatingDrag = false;
		}
	} else {
		BCursor cursor(kMoveCursor);
		SetViewCursor(&cursor);
	
		if (fState && fState->IsTracking()) {
			BRect before = fState->Bounds();
	
			fState->MouseMoved(where);
	
			BRect after = fState->Bounds();
			BRect invalid(before | after);
			Invalidate(invalid);
		}
	}
//	SetViewCursor();
}

//.........这里部分代码省略.........
				rgb_color oldColor = offscreen->HighColor();
				offscreen->SetHighColor(color);

				if (code == RP_STROKE_RECT_1PX_COLOR) {
					float oldSize = PenSize();
					offscreen->SetPenSize(1);
					offscreen->StrokeRect(rect);
					offscreen->SetPenSize(oldSize);
				} else
					offscreen->FillRect(rect);

				offscreen->SetHighColor(oldColor);
				invalidRegion.Include(rect);
				break;
			}

			case RP_DRAW_STRING:
			{
				BPoint point;
				size_t length;
				char *string;
				bool hasDelta;

				message.Read(point);
				message.ReadString(&string, length);
				if (message.Read(hasDelta) != B_OK) {
					free(string);
					continue;
				}

				if (hasDelta) {
					escapement_delta delta[length];
					message.ReadList(delta, length);
					offscreen->DrawString(string, point, delta);
				} else
					offscreen->DrawString(string, point);

				free(string);
				reply.Start(RP_DRAW_STRING_RESULT);
				reply.Add(token);
				reply.Add(offscreen->PenLocation());
				reply.Flush();

				font_height height;
				offscreen->GetFontHeight(&height);

				BRect bounds(point, offscreen->PenLocation());
				bounds.top -= height.ascent;
				bounds.bottom += height.descent;
				invalidRegion.Include(bounds);
				break;
			}

			case RP_DRAW_STRING_WITH_OFFSETS:
			{
				size_t length;
				char *string;
				message.ReadString(&string, length);
				int32 count = UTF8CountChars(string, length);

				BPoint offsets[count];
				if (message.ReadList(offsets, count) != B_OK) {
					free(string);
					continue;
				}

void MonthWindowView::DrawMonth()
{
 Bmp->Lock();
 
 float y=yearStringView->Frame().bottom+h_cell;
 float x=0;
 
 if(NewMonth)
 {
  BmpView->SetHighColor(VIEW_COLOR);
  BmpView->FillRect(BRect(0,y+1,
                    BmpView->Bounds().right,todayStringView->Frame().top-6));
  BmpView->SetHighColor(0,0,0,0);
  NewMonth=false;
 }
 
 int byear=cyear; // base year
 if(tyear<byear) byear=tyear;
  
 int day1=0, m=0, k=byear;
 
 while(k<cyear)
 {
  day1++;

  if(k%4==0) // leap year?
   if((k%100!=0) || (k%400==0)) day1++; // yes
  
  k++;
 }
 while(++m<cmonth)
 {
  day1+=(monthDays[m-1]-28);
  if(m==2) if((cyear%4)==0) if((cyear%100!=0) || (cyear%400==0)) day1++;
 }
 day1++; // day1 is number of 1st day of chosen month in chosen year
 day1=day1%7;
 
 int day2=0;
 m=0;
 k=byear;
 while(k<tyear)
 {
  day2++;
  if((k%4)==0) if((k%100!=0) || (k%400==0)) day2++;
  k++;
 }
 while(++m<tmonth)
 {
  day2+=(monthDays[m-1]-28);
  if(m==2) if((tyear%4)==0) if((tyear%100!=0) || (tyear%400==0)) day2++;
 }
 day2+=tday; // day2 - number of today's day in today's year
 day2=day2%7;
 
 k=(twday==0) ? 6 : twday-1;
 
 k=k-day2+day1;
 while(k<0) k+=7;
 k=k%7;
 cwday1=k;
 
 x=w_cell*k+1;
 y+=h_cell;
 
 int qu_days=monthDays[cmonth-1]; // quantity of days in month
 
 if(cmonth==2) if(cyear%4==0) if((cyear%100!=0) || (cyear%400==0)) qu_days=29;
 
 BString s;
 int t=0;
 while(t<qu_days)
 {
  t++;
  
  s<<t;
  
  if(cyear==tyear) if(cmonth==tmonth) if(t==tday) BmpView->SetHighColor(200,0,0,0);
  BmpView->DrawString(s.String(),BPoint(x+(w_cell-StringWidth(s.String()))/2,y));
  if(cyear==tyear) if(cmonth==tmonth) if(t==tday) BmpView->SetHighColor(0,0,0,0);
  
  if(t==cday)
  {
   cwday=k;
   if(which_focused==2) BmpView->SetHighColor(ACTIVE_COLOR);
   else BmpView->SetHighColor(NOACTIVE_COLOR);
   cursor.Set(x,y-h_cell+5,x+w_cell-1,y+4);
   BmpView->StrokeRect(cursor);
   BmpView->SetHighColor(0,0,0,0);
  }
  
  x+=w_cell;
  k++;
  s.SetTo("");
  
  if(k==7)
  {
   k=0;
   y+=h_cell;
   x=1;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
 
 monthStringView=new BStringView(BRect(10,10,100,100),"monthStringViewAViX",
                                 monthNames[8]);
 monthStringView->SetAlignment(B_ALIGN_CENTER);
 AddChild(monthStringView);
 monthStringView->ResizeToPreferred();
 monthStringView->SetText(monthNames[cmonth-1]);
 monthStringView->SetViewColor(VIEW_COLOR);
 
 s.SetTo("");
 if(cyear<10) s.Append("000");
 else if(cyear<100) s.Append("00");
 else if(cyear<1000) s.Append("0");
 s<<cyear;
 
 yearStringView=new BStringView(BRect(10,10,100,100),"yearStringViewAViX",
                                "0000");
 AddChild(yearStringView);
 yearStringView->ResizeToPreferred();
 yearStringView->SetText(s.String());
 yearStringView->SetViewColor(VIEW_COLOR);
 
 ResizeTo(w_cell*7+1,h_cell*7+3+16+yearStringView->Bounds().bottom+todayStringView->Bounds().bottom);
 Window()->ResizeTo(Bounds().right, Bounds().bottom);
 
 yearMStringView[0]=new MouseSenseStringView(new BMessage('YEA0'),msng,
                                             BRect(10,10,100,100),
                                             "yearMStringViewAViX0",
                                             "<<");
 AddChild(yearMStringView[0]);
 yearMStringView[0]->ResizeToPreferred();
 yearMStringView[0]->SetViewColor(VIEW_COLOR);
 
 yearMStringView[1]=new MouseSenseStringView(new BMessage('YEA1'),msng,
                                             BRect(10,10,100,100),
                                             "yearMStringViewAViX1",
                                             ">>");
 AddChild(yearMStringView[1]);
 yearMStringView[1]->ResizeToPreferred();
 yearMStringView[1]->SetViewColor(VIEW_COLOR);
 
 monthMStringView[0]=new MouseSenseStringView(new BMessage('MON0'),msng,
                                              BRect(10,10,100,100),
                                              "monthMStringViewAViX0",
                                              "<<");
 AddChild(monthMStringView[0]);
 monthMStringView[0]->ResizeToPreferred();
 monthMStringView[0]->SetViewColor(VIEW_COLOR);
 
 monthMStringView[1]=new MouseSenseStringView(new BMessage('MON1'),msng,
                                              BRect(10,10,100,100),
                                              "monthMStringViewAViX1",
                                              ">>");
 AddChild(monthMStringView[1]);
 monthMStringView[1]->ResizeToPreferred();
 monthMStringView[1]->SetViewColor(VIEW_COLOR);
 
 todayStringView->MoveTo((Bounds().right-todayStringView->Bounds().right)/2,
                         Bounds().bottom-todayStringView->Bounds().bottom-2);
 if(tyear<first_year || tyear>last_year) todayStringView->SetHighColor(NOACTIVE_COLOR);
  
 yearMStringView[1]->MoveTo(Bounds().right-yearMStringView[1]->Bounds().right,5);
 yearStringView->MoveTo(yearMStringView[1]->Frame().left-yearStringView->Bounds().right,5);
 yearMStringView[0]->MoveTo(yearStringView->Frame().left-yearMStringView[0]->Bounds().right,5);
 
 
 monthStringView->MoveTo((yearMStringView[0]->Frame().left-monthStringView->Bounds().right)/2,5);
 monthMStringView[0]->MoveTo(monthStringView->Frame().left-monthMStringView[0]->Bounds().right,5);
 monthMStringView[1]->MoveTo(monthStringView->Frame().right,5);
 
 which_focused=2; // days of month
 
 
 Bmp=new BBitmap(BRect(Frame()),B_RGB32,true);
 BmpView=new BView(Bmp->Bounds(),"BV",0,B_WILL_DRAW);
 Bmp->AddChild(BmpView);
 
 Bmp->Lock();
 BmpView->SetHighColor(VIEW_COLOR);
 BmpView->FillRect(BmpView->Frame());
 
 BmpView->SetHighColor(LINE_COLOR);
 BmpView->StrokeLine(BPoint(3,todayStringView->Frame().top-5),
                     BPoint(Bounds().right-3,todayStringView->Frame().top-5));
 BmpView->StrokeLine(BPoint(3,yearStringView->Frame().bottom+2),
                     BPoint(Bounds().right-3,yearStringView->Frame().bottom+2));
 BmpView->SetHighColor(0,0,0,0);
 
 float y=yearStringView->Frame().bottom+h_cell;
 float x=0;
 for(int i=0;i<7;i++)
 {
  BmpView->DrawString(weekdayNames[i],BPoint(x+(w_cell-StringWidth(weekdayNames[i]))/2,y));
  x+=w_cell;
 }
 
 BmpView->Sync();
 Bmp->Unlock();
 DrawMonth();
}

void CalcoloKtView::Draw(BRect)
{
	
	BView *iconView;
    iconView = (BView *)FindView("iconView");
         	
	iconView->SetHighColor(0, 0, 0);	
	
	BPoint	p1, p2;
	
	// Dimensioni della BView iconView 130 x 60 pixels
	
	float x_origin;
	float y_origin;
	float l_tot;
	float h_tot;
	
	// .:: Dimensioni principali dell'icona ::.
	
	x_origin = 25;
	y_origin = 5;
	l_tot = 90;
	h_tot = 52;
	
	// .:: Sezione Sx ::.
	
	p1.x = x_origin;
	p1.y = y_origin;
	p2.x = x_origin + l_tot * 5 / 9;
	p2.y = y_origin;
	
	iconView->StrokeLine(p1, p2, B_SOLID_HIGH);

	p1.x = x_origin;
	p1.y = y_origin + h_tot;
	p2.x = x_origin + l_tot * 5 / 9;
	p2.y = y_origin + h_tot;
	
	iconView->StrokeLine(p1, p2, B_SOLID_HIGH);

	p1.x = x_origin + l_tot * 5 / 9;
	p1.y = y_origin;
	p2.x = x_origin + l_tot * 5 / 9;
	p2.y = y_origin + h_tot;
	
	iconView->StrokeLine(p1, p2, B_SOLID_HIGH);
	
	// .:: Quota Sx ::.
	
	p1.x = x_origin + (l_tot * 5 / 9)/2;
	p1.y = y_origin;
	p2.x = x_origin + (l_tot * 5 / 9)/2;
	p2.y = y_origin + h_tot;
	
	iconView->StrokeLine(p1, p2, B_SOLID_HIGH);
	
	// .:: Freccie quota Sx ::.
	
	float largfreccie;
	BPoint p3;
	
	largfreccie = h_tot * 3 / 52;
	
	p1.x = x_origin + (l_tot * 5 / 9)/2;
	p1.y = y_origin;
	p2.x = p1.x - largfreccie / 2;
	p2.y = p1.y + largfreccie * 2;
	p3.x = p1.x + largfreccie / 2;
	p3.y = p1.y + largfreccie * 2;
	
	iconView->FillTriangle(p1, p2, p3, B_SOLID_HIGH);
	
	p1.x = x_origin + (l_tot * 5 / 9)/2;
	p1.y = y_origin + h_tot;
	p2.x = p1.x - largfreccie / 2;
	p2.y = p1.y - largfreccie * 2;
	p3.x = p1.x + largfreccie / 2;
	p3.y = p1.y - largfreccie * 2;
	
	iconView->FillTriangle(p1, p2, p3, B_SOLID_HIGH);
	
	// .:: Testo quota Sx ::.
	
	BPoint dimtext;
	BFont font(be_plain_font); 
	
	float fontsize;
	
	fontsize = h_tot * 7 / 52;
	
	font.SetSize(fontsize);
	iconView->SetFont(&font);

	dimtext.x = x_origin + (l_tot * 5 / 9)/2 + l_tot * 5 / 90;
	dimtext.y = y_origin + h_tot / 2 + fontsize / 2;
	
	iconView->MovePenTo(dimtext);
   	iconView->DrawString("D");
	
	// .:: Sezione Dx ::.
//.........这里部分代码省略.........

// This function returns the number of pixels of the text that
// were clipped if the text does not fit into the clipping rect.
// If the text all fit, it returns 0.
int
BeOSCanvas::RenderText( int iFontHeight, Rect& oClipRect,
                        string& oText, AlignEnum eAlign,
                        Font* pFont, const Color& oColor,
                        bool bBold, bool bItalic, bool bUnderline )
{
    Erase( oClipRect );

    BView* v = m_pBufferBitmap->OffscreenView();
    if ( !v ) return 0;

    BBitmap* bitmap = m_pBufferBitmap->GetBBitmap();
    assert( bitmap );

    BFont font;
    font_height fontHeight;
    BRect clipRect( float(oClipRect.x1), float(oClipRect.y1),
                    float(oClipRect.x2-1), float(oClipRect.y2-1) );
    BRegion clipRegion;
    clipRegion.Set( clipRect );

    if ( !bitmap->Lock() )
    {
        puts( "lock failed" );
        return 0;
    }

    v->ConstrainClippingRegion( &clipRegion );
    v->SetDrawingMode( B_OP_OVER );
    if ( bBold )
    {
        v->SetFont( be_bold_font );
    }
    else
    {
        v->SetFont( be_plain_font );
    }
    v->SetFontSize( (float)iFontHeight - 1 );
    v->GetFont( &font );
    font.GetHeight( &fontHeight );
    
    float width = v->StringWidth(oText.c_str(), oText.size());
    
    if(eAlign == eCenter)
        v->MovePenTo( float(oClipRect.x1) +
                      (float(oClipRect.x2 - oClipRect.x1) - width)/2,
                      float(oClipRect.y2-fontHeight.descent) );	
    else if (eAlign == eRight)
        v->MovePenTo( float(oClipRect.x2) - width,
                      float(oClipRect.y2-fontHeight.descent) );
    else
        v->MovePenTo( float(oClipRect.x1),
                      float(oClipRect.y2-fontHeight.descent) );

    v->DrawString( oText.c_str() );
    v->Sync();

    bitmap->Unlock();

    Invalidate( oClipRect );

    return (width < oClipRect.Width()) ? 0 : int(width - oClipRect.Width());
}

void URLView::DoPersonDrag() {
	// Handle all of the bookmark dragging.  This includes setting up
	// the drag message and drawing the dragged bitmap.
	
	// Set up the drag message to support both BTextView dragging (using
	// the e-mail address) and file dropping (to Tracker).
	BMessage *dragMessage = new BMessage( B_MIME_DATA );
	dragMessage->AddInt32( "be:actions", B_COPY_TARGET );
	dragMessage->AddString( "be:types", "application/octet-stream" );
	dragMessage->AddString( "be:filetypes", "application/x-person" );
	dragMessage->AddString( "be:type_descriptions", "person" );
	dragMessage->AddString( "be:clip_name", Text() );
	
	// This allows the user to drag the e-mail address into a
	// standard BTextView.
	BString email = GetImportantURL();
	dragMessage->AddData( "text/plain", B_MIME_DATA, email.String(),
						  email.Length() + 1 );
	
	// Query for the system's icon for bookmarks.
	BBitmap *personIcon = new BBitmap( BRect( 0, 0, iconSize - 1,
									   iconSize - 1 ), B_CMAP8 );
	#ifdef ZETA
		BMimeType mime( "application/x-vnd.Be-PEPL" );
	#else
		BMimeType mime( "application/x-person" );
	#endif
	if( iconSize == 16 ) mime.GetIcon( personIcon, B_MINI_ICON );
	else mime.GetIcon( personIcon, B_LARGE_ICON );
	
	// Find the size of the bitmap to drag.  If the text is bigger than the
	// icon, use that size.  Otherwise, use the icon's.  Center the icon
	// vertically in the bitmap.
	BRect rect = GetTextRect();
	rect.right += iconSize + 4;
	if( (rect.bottom - rect.top) < iconSize ) {
		int adjustment = (int) ((iconSize - (rect.bottom - rect.top)) / 2) + 1;
		rect.top -= adjustment;
		rect.bottom += adjustment;
	}
	
	// Make sure the rectangle starts at 0,0.
	rect.bottom += 0 - rect.top;
	rect.top = 0;
	
	// Create the bitmap to draw the dragged image in.
	BBitmap *dragBitmap = new BBitmap( rect, B_RGBA32, true );
	BView *dragView = new BView( rect, "Drag View", 0, 0 );
	dragBitmap->Lock();
	dragBitmap->AddChild( dragView );
	
	BRect frameRect = dragView->Frame();
	
	// Make the background of the dragged image transparent.
	dragView->SetHighColor( B_TRANSPARENT_COLOR );
	dragView->FillRect( frameRect );

	// We want 'g's, etc. to go below the underline.  When the BeOS can
	// do underlining of any font, this code can be removed.
	font_height height;
	GetFontHeight( &height );
	float descent = height.descent;

	// Find the vertical center of the view so we can vertically
	// center everything.
	int centerPixel = (int) ((frameRect.bottom - frameRect.top) / 2);
	int textCenter  = (int) (descent + underlineThickness) + centerPixel;

	// We want to draw everything only half opaque.
	dragView->SetDrawingMode( B_OP_ALPHA );
	dragView->SetHighColor( 0.0, 0.0, 0.0, 128.0 );
	dragView->SetBlendingMode( B_CONSTANT_ALPHA, B_ALPHA_COMPOSITE );

	// Center the icon in the view.
	dragView->MovePenTo( BPoint( frameRect.left,
								 centerPixel - (iconSize / 2) ) );
	dragView->DrawBitmap( personIcon );

	// Draw the text in the same font (size, etc.) as the link view.
	// Note:  DrawString() draws the text at one pixel above the pen's
	//		  current y coordinate.
	BFont font;
	GetFont( &font );
	dragView->SetFont( &font );
	dragView->MovePenTo( BPoint( frameRect.left + iconSize + 4, textCenter ) );
	dragView->DrawString( Text() );
	
	// Be sure to flush the view buffer so everything is drawn.
	dragView->Flush();
	dragBitmap->Unlock();
	
	// The Person icon adds some width to the bitmap that we are
	// going to draw.  So horizontally offset the bitmap proportionally
	// to where the user clicked on the link.
	float horiz = dragOffset.x / GetTextRect().Width();
	dragOffset.x = horiz * frameRect.right;

	DragMessage( dragMessage, dragBitmap, B_OP_ALPHA,
				 BPoint( dragOffset.x,
				 		 (rect.Height() + underlineThickness) / 2 + 2), this );
//.........这里部分代码省略.........

void
ColorStepView::Draw(BRect updateRect)
{
	BView *view = NULL;
	if(fOffScreenView){
		view = fOffScreenView;
	}
	else{
		view = this;
	}

	if (!fOffScreenBitmap || !fOffScreenBitmap->Lock())
		return;
	view->SetLowColor(ui_color(B_PANEL_BACKGROUND_COLOR));

	view->SetHighColor(ui_color(B_PANEL_BACKGROUND_COLOR));
	view->FillRect(updateRect);

	BRect colorBarRect =  fSlider->BarFrame();
	colorBarRect.top = 0;
	colorBarRect.bottom = kColorBarHeight;
	colorBarRect.OffsetTo(colorBarRect.left, fSlider->Frame().bottom);

	float pos = 0.0;
	for (int i = fPerformanceList->CountItems() - 1; i >= 0 ; i--) {
		performance_step* perfState = fPerformanceList->ItemAt(i);

		float nextPos = perfState->cpu_usage;
		float width = colorBarRect.Width();

		BRect subRect(colorBarRect);
		subRect.left += pos * width;
		subRect.right = colorBarRect.left + nextPos * width;

		view->SetHighColor(perfState->color);
		view->FillRect(subRect);

		pos = nextPos;
	}
	// draw label
	if (IsEnabled()) {
		view->SetHighColor(0, 0, 0);
	} else {
		view->SetHighColor(tint_color(LowColor(), B_DISABLED_LABEL_TINT));
	}

	font_height fontHeight;
	GetFontHeight(&fontHeight);
	float totalFontHeight = fontHeight.descent + fontHeight.ascent;

	view->DrawString(fMinFrequencyLabel.String(),
						BPoint(0.0,
								colorBarRect.bottom + totalFontHeight + 5));

	view->DrawString(fMaxFrequencyLabel.String(),
						BPoint(Bounds().right
								- StringWidth(fMaxFrequencyLabel.String()),
								colorBarRect.bottom	+ totalFontHeight + 5));

	// blit bitmap
	view->Sync();
	fOffScreenBitmap->Unlock();
	DrawBitmap(fOffScreenBitmap, B_ORIGIN);

	BView::Draw(updateRect);
}