Hello all,
I have loaded the pixel data of my image into an array of Bytes. I now need to load these pixels into a TBitmap object and I would like to do this the fastest way possible. The array is height x width x 4 (bytes per pixel) and these images can be somewhat large (desktop sizes 1024x780 etc)RGBP.
I am using Delphi 7.
Thank you.
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1) Create an instance of Bitmap: TBitmap.
2) Set its width and height via Bitmap.Height and Bitmap.Width (byte array dimensions)
3) Use Bitmap.ScanLine[row] to write 4 bytes at a time (1 pixel).
If you provide more details regarding the structure of your array of bytes (e.g. in which order have the pixels have been copied, by scanline?), then I will be able to give you more help.
I am curious why you copied it to an array of bytes to begin with... Understanding that would help me to understand your situation and perhaps give you better adviice. Copying to an array of bytes undoes some of the TBitmaps ability to handle varying color depths for you, etc. If you would like me to look into it further, give me as much information as you can, please.
Would anyone be able to provide me with a working example using SetDIBits and GetDIBits APIs? Could these be the fastest way to do this task?
I am sorry for not being more specific. I have been tasked with providing a function that gets an array of bytes (representing pixel data) that then gets loaded into a TBitmap object.
Thank you
Below are 2 procedures which quickly copy Bitmap to Bytes Array, and Bytes Array to Bitmap:
--------------------------
type
TMyByteArray = array of Byte;
var
MyBytes: TMyByteArray;
function BytesPerPixel(APixelFormat
begin
Result := -1;
case APixelFormat of
pf8bit: Result := 1;
pf16bit: Result := 2;
pf24bit: Result := 3;
pf32bit: Result := 4;
end;
end;
procedure BitmapToBytes(Bitmap: TBitmap; out Bytes: TMyByteArray);
var
BytesPerLine: Integer;
Row, Col, BPP: Integer;
PPixels, PBytes: Pointer;
begin
BPP := BytesPerPixel(Bitmap.Pixel
if BPP < 1 then
raise Exception.Create('Unknown pixel format');
SetLength(Bytes, Bitmap.Width * Bitmap.Height * BPP);
BytesPerLine := Bitmap.Width * BPP;
for Row := 0 to Bitmap.Height-1 do
begin
PBytes := @Bytes[Row * BytesPerLine];
PPixels := Bitmap.ScanLine[Row];
CopyMemory(PBytes, PPixels, BytesPerLine);
end;
end;
procedure BytesToBitmap(const Bytes: TMyByteArray; Bitmap: TBitmap;
APixelFormat: TPixelFormat; AWidth, AHeight: Integer);
var
BytesPerLine: Integer;
Row, Col, BPP: Integer;
PPixels, PBytes: Pointer;
begin
BPP := BytesPerPixel(APixelFormat
if BPP < 1 then
raise Exception.Create('Unknown pixel format');
if (AWidth * AHeight * BPP) <> Length(Bytes) then
raise Exception.Create('Bytes do not match image properties');
Bitmap.Width := AWidth;
Bitmap.Height := AHeight;
Bitmap.PixelFormat := APixelFormat;
BytesPerLine := Bitmap.Width * BPP;
for Row := 0 to Bitmap.Height-1 do
begin
PBytes := @Bytes[Row * BytesPerLine];
PPixels := Bitmap.ScanLine[Row];
CopyMemory(PPixels, PBytes, BytesPerLine);
end;
end;
--------------------------
Here is sample usage:
--------------------------
procedure TForm1.Button1Click(Sender
begin
BitmapToBytes(Image1.Pictu
BytesToBitmap(MyBytes, Image2.Picture.Bitmap,
Image1.Picture.Bitmap.Pixe
Image1.Picture.Bitmap.Widt
Image1.Picture.Bitmap.Heig
end;
--------------------------
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by: imitchiePosted on 2007-11-08 at 16:23:44ID: 20246830
look at the free Graphics32 package. full source code included