Erwin, Once again you provide invaluable assistance. I always feel that I am taking advantage of other people's knowledge in situations like this and that I am somehow lazy, but this kind of stuff takes me days to work out.
I shall try this out once I get my machine back operational. Back soon, Darren -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Erwin Haid Sent: 06 April 2005 01:02 To: Borland's Delphi Discussion List Subject: RE: Working with bitmaps Hi Darren, copying a bitmap line by line is the same for monochrome and for color bitmaps. First you have to calculate the size of a line in bytes LineSize = Width * 3; // 3 bytes per pixel for pixelformat pf24bit then you have to calculate the pitch (linesize aligned by 2 bytes) Pitch = AlignWord(LineSize); you can calculate the source pointer for scanline y pSrc = pImageDataSrc + y * Pitch the destination pointer is the scanline of the bitmap pDst = bmpDest.Scanline[y]; then you can copy the whole scanline CopyMemory(pDst,pSrc,LineSize); Here is a small example you can play with, just create a new application in delphi and drop an image and a button on the form: ---------------------------------------------------------- function AlignWord(const x: Integer): Integer; begin Result := (x + 1) and not 1; end; procedure WriteToColourBitmap(dstBitmap: TBitmap; const ImageData: PChar; const Width, Height: Integer); var y, pitch, linesize: Integer; pSrcScanline,pDstScanline: PChar; begin linesize := Width * 3; // 3 bytes per pixel for pf24bit pitch := AlignWord(linesize); for y := 0 to Height-1 do begin pSrcScanline := ImageData + y * pitch; pDstScanline := dstBitmap.Scanline[y]; CopyMemory(pDstScanline,pSrcScanline,linesize); end; end; procedure TForm1.Button1Click(Sender: TObject); const IMG_WIDTH = 543; IMG_HEIGHT = 345; BYTES_PER_PIXEL = 3; // 24 bit image LINE_SIZE = IMG_WIDTH * BYTES_PER_PIXEL; // size of line in bytes LINE_PITCH = (LINE_SIZE + 1) and not 1; // 2-byte aligned var ImageData: array[0..IMG_HEIGHT*LINE_PITCH-1] of byte; x,y: Integer; bmp: TBitmap; begin // fill buffer with some image data FillMemory(@ImageData[0],SizeOf(ImageData),0); for y := 0 to IMG_HEIGHT-1 do begin for x := 0 to IMG_WIDTH-1 do begin with PRGBTriple(@ImageData[y*LINE_PITCH+x*BYTES_PER_PIXEL])^ do begin rgbtBlue := Byte(x and not 15); rgbtGreen := Byte(y and not 15); rgbtRed := Byte(rgbtBlue+rgbtGreen); end; end; end; // Write ImageData to bitmap bmp := TBitmap.Create; try bmp.Width := IMG_WIDTH; bmp.Height := IMG_HEIGHT; bmp.PixelFormat := pf24Bit; WriteToColourBitmap(bmp,PChar(@ImageData[0]),IMG_WIDTH,IMG_HEIGHT); Image1.Picture.Bitmap.Assign(bmp); finally bmp.Free; end; end; > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Darren McBride > Sent: Wednesday, March 30, 2005 11:32 AM > To: 'Borland's Delphi Discussion List' > Subject: Working with bitmaps > > > Folks, > > Unfortunately I don't know enough about pointers and the like, but I'm > trying to learn. People like Erwin Haid have provided me with HUGE > help in the past, so I'm hoping someone can come to my aid again. It > might only take someone with knowledge on this list a few minutes to > fix what would otherwise take me days. > > Considering the following two routines, the WriteToMonochromeBitmap > function writes the data far faster than the colour function because > it writes the image data to the new image line by line, not pixel by > pixel. In the WriteToColourBitmap function the target file is 24-bit - > how do I replicate the scanline by scanline method in this function ? > > procedure WriteToColourBitmap(const ImageData: PChar; const Width, Height: > Integer); > var > x, y, z, w, p: Integer; > sl: PChar; > pc: PRGBTriple; > begin > { get pixel co-ordinate } > p := AlignWord(Width * 3); > > { create bitmap } > if Assigned(gbBitmap) then > begin > { write band } > z := Height - 1; > for y := 0 to z do > begin > sl := ImageData + y * p; > w := Width - 1; > for x := 0 to w do > begin > pc := PRGBTriple(sl + x * 3); > gbBitmap.Canvas.Pixels[x, gbImageHeight + y] := > RGB(pc.rgbtBlue, pc.rgbtGreen, pc.rgbtRed); > end; > end; > end; > end; > > procedure WriteToMonochromeBitmap(const ImageData: PChar; const Width, > Height: Integer); > var > x, y, z, w: Integer; > sl: PChar; > r: PByteArray; > begin > { check bitmap } > if Assigned(gbBitmap) then > begin > { calculate scanline length } > w := Trunc(Width / 8); > > { write band } > z := Height - 1; > for y := 0 to z do > begin > sl := ImageData + (y * w); > r := PByteArray(gbBitmap.Scanline[y]); > for x := 0 to (w - 1) do > r[x] := Byte(sl[x]); > end; > end; > end; > > Many, many thanks in advance, > Darren > > -- > No virus found in this outgoing message. > Checked by AVG Anti-Virus. > Version: 7.0.308 / Virus Database: 266.8.5 - Release Date: 29/03/2005 > > > > _______________________________________________ > Delphi mailing list -> [email protected] > http://www.elists.org/mailman/listinfo/delphi > _______________________________________________ Delphi mailing list -> [email protected] http://www.elists.org/mailman/listinfo/delphi _______________________________________________ Delphi mailing list -> [email protected] http://www.elists.org/mailman/listinfo/delphi
