[Gnavi-discuss] Create_Bitmap mystery

[Gautier de M. <gd...@ho...>]

Hello everybody,
The following code causes some trouble to me. Perhaps someone has an idea what is wrong.
    bmp.Create_Bitmap(      Width          => bitmap.width,      Height         => bitmap.height,      Planes         => 1,      Bits_Per_Pixel => 24,      Bits           => bitmap.data(0)'Address    );
bitmap.data is of type p_Byte_Array defined below.
  type Byte is mod 2**8;  type Byte_Array is array(Integer range <>) of aliased Byte;  type p_Byte_Array is access Byte_Array;
Problem is: the call to Create_Bitmap seems to create an empty bitmap into variable bmp.Any clue ?
If I set bmp with bmp.Load_Bitmap_From_File("screenshot.bmp");, the bitmap is displayed correctly.
bitmap.width, bitmap.height and bitmap.data are correct, I can display them with:
    procedure Slow_display is      i: Integer:= 0;    begin      for y in reverse 1..bitmap.height loop        for x in 1..bitmap.width loop          on.Drawing_Canvas.Point(x-1+coords.p1.x, y-1+coords.p1.y,             Color_Type(bitmap.data(i+2))+            Color_Type(bitmap.data(i+1))*256+            Color_Type(bitmap.data(i  ))*65536           ) ;          i:= i + 3;        end loop;        while i mod 4 > 0 loop -- padding          i:= i + 1;        end loop;      end loop;    end Slow_display;
TIAGautier