Camelot: Conv32to8 Class Reference

Constructor & Destructor Documentation

Conv32to8::Conv32to8	(	UINT32	Width,
		LPLOGPALETTE	Palette,
		UINT32	DitherType
	)

Constructor.

Author:: Andy_Pennell (Xara Group Ltd) <camelotdev@xara.com>?

Date:: 29/06/96

Definition at line 485 of file dibconv.cpp.

00486 {
00487     ERROR3IF(Palette == NULL,"Conv32to8 null palette specified");
00488 
00489     SourceHeader.biPlanes = 1;
00490     SourceHeader.biBitCount = 32;
00491     SourceHeader.biWidth = Width;
00492     SourceHeader.biClrUsed = 0;
00493 
00494     DestHeader.biPlanes = 1;
00495     DestHeader.biBitCount = 8;
00496     DestHeader.biWidth = Width;
00497     DestHeader.biClrUsed = 256;
00498 
00499     DestPalette = Palette;
00500 
00501     // Remember which dithering to use
00502     Dither = DitherType;
00503 
00504     // lets use this palette for the conversion
00505     GDrawContext *GDC = GetConvertContext();
00506 
00507     GDC->SetupBitmap(Width, 16, 8, NULL);
00508 
00509     // This should return a palette plus tell it what dithering we require
00510     // 0 = ordered dither, not 0 for error diffusion or no dithering.
00511 
00512     pcLOGPALETTE lpPalette = GDC->SelectPalette((Dither == XARADITHER_SIMPLE ||
00513                                                  Dither == XARADITHER_ERROR_DIFFUSION ||
00514                                                  Dither == XARADITHER_NONE) ? 1 : 0 );
00515     if (lpPalette == NULL)
00516     {
00517         ENSURE(lpPalette, "Didnt get a palette for export");
00518     }
00519 
00520 
00521     // Graeme (25/9/00) - Removed to prevent a problem with creating a bitmap copy of an
00522     // existing bitmap.
00523 /*
00524     // Added by Craig Hamilton 15/9/00.
00525     // This section of code will replace any flag value with null if it is not a valid value.
00526     INT32 i;
00527 
00528     for(i=0;i<DestPalette->palNumEntries;i++)
00529     {
00530         if(DestPalette->palPalEntry[i].peFlags != NULL && DestPalette->palPalEntry[i].peFlags != PC_EXPLICIT &&
00531             DestPalette->palPalEntry[i].peFlags != PC_NOCOLLAPSE && DestPalette->palPalEntry[i].peFlags != PC_RESERVED)
00532         {
00533             DestPalette->palPalEntry[i].peFlags = NULL;
00534         }
00535     }
00536     // End added.
00537 */
00538 
00539     GDC->InitialiseWithPalette(DestPalette);
00540 }

Conv32to8::~Conv32to8

(

)

Definition at line 542 of file dibconv.cpp.

00543 {
00544 }

Member Function Documentation

BOOL Conv32to8::Convert	(	LPBYTE	Input,
		LPBYTE	Output,
		UINT32	Height,
		BOOL	FirstStrip
	)	`[virtual]`

Implements DIBConvert.

Definition at line 546 of file dibconv.cpp.

00547 {
00548     SourceHeader.biHeight = Height;
00549       DestHeader.biHeight = Height;
00550 
00551     //  If we are converting to 8 bit, and the bitmap has less than 256 colours, then
00552     //  it is better to avoid the GDraw conversion function, and do our own instead.
00553 PORTNOTE("other","Removed GRenderOptPalette usage")
00554 #ifndef EXCLUDE_FROM_XARALX
00555     if( GRenderOptPalette::DoGDrawConversion && !GRenderOptPalette::UseOldPalette )
00556     {
00557         // GAT
00558         RGBQUAD aFastPalette[0x100] ;
00559         BYTE aIndex[0x100] ;
00560         UINT32 nEntries = 0 ;
00561 
00562         //  Go through the supplied bitmap strip.
00563         RGBQUAD* InputBytes = (RGBQUAD*)Input ;
00564         BYTE*   OutputBytes = Output ;
00565         UINT32 Width = SourceHeader.biWidth ;
00566         //  Need an offset if the width of the bitmap is not a multiple of 4.
00567         INT32 OffsetValue = Width % 4 ;
00568         if( OffsetValue > 0 )
00569             OffsetValue = 4 - OffsetValue ;
00570 
00571         for( UINT32 j=0 ; j<Height ; j++ )
00572         {
00573             for( UINT32 i=0 ; i<Width ; i++ )
00574             {
00575                 // Get the RGB value for the current pixel.
00576                 // Mask out the alpha channel.
00577                 RGBQUAD rgb = *InputBytes++ ;
00578                 (DWORD&)rgb &= 0xFFFFFF ;
00579                 // Search through the palette to try and find this colour.
00580                 // This code assumes that it will definitely not be more
00581                 // than 256 colours in the palette.
00582                 for( UINT32 k=0 ; k<nEntries ; k++ )
00583                     if( (DWORD&)aFastPalette[k]==(DWORD&)rgb )
00584                     {
00585                         *OutputBytes++ = aIndex[k] ;
00586                         goto done ;     // Use goto for efficiency.
00587                     }
00588                 // Pixel not found so add to tables.
00589                 {
00590                     PALETTEENTRY pe = {rgb.rgbRed,rgb.rgbGreen,rgb.rgbBlue,0} ;
00591                     *OutputBytes++ = aIndex[nEntries] = PaletteManager::FindIndexOfNearestColour( pe, DestPalette ) ;
00592                     aFastPalette[nEntries++] = rgb ;
00593                     ASSERT(nEntries<=256) ;
00594                 }
00595         done:   ;
00596             }
00597             //  After the current row has been done, then apply any 'filler' bytes
00598             //  necessary.
00599             OutputBytes += OffsetValue ;
00600         }
00601         //  Finished now.
00602         return TRUE;
00603     }
00604     else
00605 #endif
00606     {
00607         //  Go here if we have an optimised palette
00608         DWORD DitherWord = Dither;
00609         TRACEUSER( "Andy?", _T("Convert32to8, Strip = %d, dither = %d\n"), FirstStrip, Dither);
00610 
00611         if (Dither == XARADITHER_SIMPLE || Dither == XARADITHER_ERROR_DIFFUSION)
00612         {
00613             // We are using some form of error diffusion ....
00614 
00615             // Set second byte to 255 if this is the First strip,
00616             // so that the error buffer is cleared
00617             DitherWord |= (( FirstStrip ? 0 : 255 ) << 8);
00618         }
00619 
00620         GDrawContext *GDC = GetConvertContext();
00621         const BOOL res = GDC->ConvertBitmap( &SourceHeader, Input, &DestHeader, Output, DitherWord);
00622 
00623         if (!res)
00624             TRACE( _T("GColour_ConvertBitmap did error %x\n"), GetLastError() );
00625 
00626         return TRUE;
00627     }
00628 }

Member Data Documentation

Generated on Sat Nov 10 03:53:10 2007 for Camelot by

1.4.4

Conv32to8 Class Reference

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation


Public Member Functions
	Conv32to8 (UINT32, LPLOGPALETTE, UINT32)
	Constructor.
	~Conv32to8 ()
BOOL	Convert (LPBYTE Input, LPBYTE Output, UINT32 Height, BOOL FirstStrip)
Private Attributes
BITMAPINFOHEADER	SourceHeader
BITMAPINFOHEADER	DestHeader
LPLOGPALETTE	DestPalette
UINT32	Dither