problems using GetDataLineStart of tlazintfimage with 24bits tbitmap
in linux
lazarus / 39-Graphics

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dcelso · 2013-01-28 14:37

Hello to all,
I have another problem in linux.
When I convert a Bitmat in lazintfimage, the color depth is
automatically converted in 32 bits, so when I try to use
getdatalinestart to run it 3 bytes by 3 bytes, to change it directly
my program fails.

In windows It run correctly, the conversion to a lazinftfimage does
not change the color deph.

So, this kind of problems, do mys applications 0% portables bettwen
linux and windows , .

My example is the next
Code: [Select]unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
ExtCtrls,
  StdCtrls, Buttons, IntfGraphics;

type

  { TForm1 }

  TForm1 = class(TForm)
    BitBtn1: TBitBtn;
    Image1: TImage;
    Label1: TLabel;
    Memo1: TMemo;
    procedure BitBtn1Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.BitBtn1Click(Sender: TObject);
var
  bmp : TBitmap;
  lazBmp : TLazIntfImage;
  pointer : PByteArray;
  i,j : integer;
  tmpStr : String;
  value : byte;
begin
  bmp:= TBitmap.Create;
  bmp.PixelFormat:=pf24bit;
  bmp.SetSize(4,4);
  bmp.canvas.Brush.Color:=clRed;
  bmp.Canvas.FillRect(0,0,4,1);
  bmp.canvas.Brush.Color:=clLime;
  bmp.Canvas.FillRect(0,1,4,2);
  bmp.canvas.Brush.Color:=clYellow;
  bmp.Canvas.FillRect(0,2,4,3);
  bmp.canvas.Brush.Color:=clBlue;
  bmp.Canvas.FillRect(0,3,4,4);
  Image1.Picture.Assign(bmp);
  tmpStr:='';
  lazBmp := bmp.CreateIntfImage;
  for j:=0 to lazBmp.Height -1 do
  begin
    pointer:= lazBmp.GetDataLineStart(j);
    for i:=0 to lazBmp.Width -1  do
    begin
        value:=pointer^[i*3];
        tmpStr:=tmpStr+IntToHex(value,2);
        value:=pointer^[i*3+1];
        tmpStr:=tmpStr+IntToHex(value,2);
        value:=pointer^[i*3+2];
        tmpStr:=tmpStr+IntToHex(value,2);
        tmpStr:=tmpStr+',';
    end;
    Memo1.Lines.Add(tmpStr);
    tmpStr:='';
  end;
  label1.Caption:=inttostr(lazBMP.DataDescription.BitsPerPixel);
  lazBMP.free;
end;

end.

and the form
Code: [Select]object Form1: TForm1
  Left = 352
  Height = 240
  Top = 264
  Width = 320
  Caption = 'Form1'
  ClientHeight = 240
  ClientWidth = 320
  LCLVersion = '1.1'
  object Image1: TImage
    Left = 8
    Height = 111
    Top = 8
    Width = 127
    Stretch = True
  end
  object BitBtn1: TBitBtn
    Left = 191
    Height = 30
    Top = 47
    Width = 75
    Caption = 'BitBtn1'
    OnClick = BitBtn1Click
    TabOrder = 0
  end
  object Memo1: TMemo
    Left = 12
    Height = 98
    Top = 128
    Width = 276
    TabOrder = 1
  end
  object Label1: TLabel
    Left = 201
    Height = 15
    Top = 95
    Width = 34
    Caption = 'Label1'
    ParentColor = False
  end
end