Broken example "Creating and drawing a transparent bitmap for a TImage" in Linux

[KodeZwerg]

Many years ago, I've written a little program to look inside the bitmaps header, where the data are ok

This is how I would fetch amazing fast the needed info:
This demonstration does not do any kind of checking, it just try to do its job done by assuming all is cool.

Code: Pascal  [Select][+][-]

1. program project1;
2.  
3. {$IfDef Windows}
4. {$AppType Console}
5. {$EndIf Windows}
6.  
7. uses
8.   SysUtils, Classes, BMPcomn;
9.  
10. type
11.   TFullBitmapHeader = packed record
12.     BitMapFileHeader: TBitMapFileHeader;
13.     BitMapInfoHeader: TBitMapInfoHeader;
14.   end;
15.  
16. function GetBitmapHeader(const AFilename: string): TFullBitmapHeader;
17. var
18.   FileStream: TFileStream;
19. begin
20.   FileStream := TFileStream.Create(AFilename, fmOpenRead);
21.   try
22.     FillChar(Result, SizeOf(Result), 0);
23.     FileStream.Position := 0;
24.     FileStream.Read(Result.BitMapFileHeader.bfType, SizeOf(Result.BitMapFileHeader.bfType));
25.     FileStream.Read(Result.BitMapFileHeader.bfSize, SizeOf(Result.BitMapFileHeader.bfSize));
26.     FileStream.Read(Result.BitMapFileHeader.bfReserved, SizeOf(Result.BitMapFileHeader.bfReserved));
27.     FileStream.Read(Result.BitMapFileHeader.bfOffset, SizeOf(Result.BitMapFileHeader.bfOffset));
28.     FileStream.Read(Result.BitMapInfoHeader.Size, SizeOf(Result.BitMapInfoHeader.Size));
29.     FileStream.Read(Result.BitMapInfoHeader.Width, SizeOf(Result.BitMapInfoHeader.Width));
30.     FileStream.Read(Result.BitMapInfoHeader.Height, SizeOf(Result.BitMapInfoHeader.Height));
31.     FileStream.Read(Result.BitMapInfoHeader.Planes, SizeOf(Result.BitMapInfoHeader.Planes));
32.     FileStream.Read(Result.BitMapInfoHeader.BitCount, SizeOf(Result.BitMapInfoHeader.BitCount));
33.     FileStream.Read(Result.BitMapInfoHeader.Compression, SizeOf(Result.BitMapInfoHeader.Compression));
34.     FileStream.Read(Result.BitMapInfoHeader.SizeImage, SizeOf(Result.BitMapInfoHeader.SizeImage));
35.     FileStream.Read(Result.BitMapInfoHeader.XPelsPerMeter, SizeOf(Result.BitMapInfoHeader.XPelsPerMeter));
36.     FileStream.Read(Result.BitMapInfoHeader.YPelsPerMeter, SizeOf(Result.BitMapInfoHeader.YPelsPerMeter));
37.     FileStream.Read(Result.BitMapInfoHeader.ClrUsed, SizeOf(Result.BitMapInfoHeader.ClrUsed));
38.     FileStream.Read(Result.BitMapInfoHeader.ClrImportant, SizeOf(Result.BitMapInfoHeader.ClrImportant));
39.   finally
40.     FileStream.Free;
41.   end;
42. end;
43.  
44. var
45.   BitmapHeader: TFullBitmapHeader;
46. begin
47.   WriteLn('Quick Bitmap Info by KodeZwerg.');
48.   if FileExists(ParamStr(1)) then
49.     begin
50.       BitmapHeader := GetBitmapHeader(ParamStr(1));
51.       WriteLn('Type: ' + IntToHex(Swap(BitmapHeader.BitMapFileHeader.bfType), SizeOf(BitmapHeader.BitMapFileHeader.bfType)));
52.       WriteLn('Filesize: ' + IntToStr(BitmapHeader.BitMapFileHeader.bfSize));
53.       WriteLn('Reserved: ' + IntToHex(Swap(BitmapHeader.BitMapFileHeader.bfReserved), SizeOf(BitmapHeader.BitMapFileHeader.bfReserved)));
54.       WriteLn('Offset: ' + IntToStr(BitmapHeader.BitMapFileHeader.bfOffset));
55.       WriteLn('Structure Size: ' + IntToStr(BitmapHeader.BitMapInfoHeader.Size));
56.       WriteLn('Width: ' + IntToStr(BitmapHeader.BitMapInfoHeader.Width));
57.       WriteLn('Height: ' + IntToStr(BitmapHeader.BitMapInfoHeader.Height));
58.       WriteLn('Planes: ' + IntToStr(BitmapHeader.BitMapInfoHeader.Planes));
59.       WriteLn('Bits Per Pixel: ' + IntToStr(BitmapHeader.BitMapInfoHeader.BitCount));
60.       WriteLn('Compression Method: ' + IntToStr(BitmapHeader.BitMapInfoHeader.Compression));
61.       WriteLn('Image Size: ' + IntToStr(BitmapHeader.BitMapInfoHeader.SizeImage));
62.       WriteLn('Horizontal Resolution: ' + IntToStr(BitmapHeader.BitMapInfoHeader.XPelsPerMeter));
63.       WriteLn('Vertical Resolution: ' + IntToStr(BitmapHeader.BitMapInfoHeader.YPelsPerMeter));
64.       WriteLn('Colors Used: ' + IntToStr(BitmapHeader.BitMapInfoHeader.ClrUsed));
65.       WriteLn('Colors Important: ' + IntToStr(BitmapHeader.BitMapInfoHeader.ClrImportant));
66.     end
67.   else
68.     WriteLn('Usage: ' + ExtractFileName(ParamStr(0)) + ' "image.bmp"');
69.   WriteLn('');
70.   WriteLn('Done.');
71.   {$IfDef Windows}
72.   ReadLn;
73.   {$EndIf Windows}
74. end.

[jipété]

Good evening,

One month later, I come back here because nothing is moving forward...

A few minute before, I started with  the two files kindly provided by me on May 27 (src32.bmp) and by KodeZwerg on May 27 also (test.zip), the first one has a BITMAPHEADER version 4 when the second has version 1, and I always used this code from the wiki :
TLazIntfImage.LoadFromFile https://wiki.freepascal.org/Developing_with_Graphics#TLazIntfImage.LoadFromFile

Here is an example how to load an image directly into a TLazIntfImage. It initializes the TLazIntfImage to a 32bit RGBA format. Keep in mind that this is probably not the native format of your screen.

Code: Pascal  [Select][+][-]

1. uses LazLogger, Graphics, IntfGraphics, GraphType;
2. procedure TForm1.FormCreate(Sender: TObject);
3. var
4.   AImage: TLazIntfImage;
5.   lRawImage: TRawImage;
6. begin
7.   // create a TLazIntfImage with 32 bits per pixel, alpha 8bit, red 8 bit, green 8bit, blue 8bit,
8.   // Bits In Order: bit 0 is pixel 0, Top To Bottom: line 0 is top
9.   lRawImage.Init;
10.   lRawImage.Description.Init_BPP32_A8R8G8B8_BIO_TTB(0,0);
11.   lRawImage.CreateData(false);
12.   AImage := TLazIntfImage.Create(0,0);
13.   try
14.     AImage.SetRawImage(lRawImage);
15.     // Load an image from disk.
16.     // It uses the file extension to select the right registered image reader.
17.     // The AImage will be resized to the width, height of the loaded image.
18. //    AImage.LoadFromFile('lazarus/examples/openglcontrol/data/texture1.png');
19.     AImage.LoadFromFile(openpicturedialog1.FileName);
20.     debugln(['TForm1.FormCreate ',AImage.Width,' ',AImage.Height]);
21.   finally
22.     AImage.Free;
23.   end;
24. end;

and just before the finally line I added the command below after changing the last word :

Loading a TLazIntfImage into a TImage

The pixel data of a TImage is the TImage.Picture property, which is of type TPicture. TPicture is a multi format container containing one of several common image formats like Bitmap, Icon, Jpeg or PNG . Usually you will use the TPicture.Bitmap to load a TLazIntfImage:

Code: Pascal  [Select][+][-]

1.     Image1.Picture.Bitmap.LoadFromIntfImage(IntfImg);

becomes

Code: Pascal  [Select][+][-]

1.     Image1.Picture.Bitmap.LoadFromIntfImage(AImage);

Result, it only works with the v1 file, with v4 nothing is displayed while the preview image in the OpenPictureDialog is fine...