How to get width and height of an image in PB

Question

I'm using PB8.0 and I want to get the width and height of a picture to resize my picture in DW. Do you know how to get it?

I search an example to get width and height of a bitmap file. It seems correct with bitmap file but not for other such as .jpg, .gif

Please help me

//Getting a Bitmaps Width and Height 
int     li_job
blob    b
string  ls_ext

ls_ext = lower(Right(as_filename, 3))
CHOOSE CASE ls_ext
  CASE 'bmp'
    li_job = FileOpen( "filename.bmp", StreamMode!, Read! )
    IF li_job > 0 THEN
      FileRead( li_job, b )

      arl_Width  = Long(Integer( BlobMid( b, 19, 2 ) ), &
                   Integer( BlobMid( b, 21, 2) ) )
      arl_Height = Long(Integer( BlobMid( b, 23, 2 ) ), &
                   Integer( BlobMid( b, 25, 2) ) )
      FileClose( li_job )
    ELSE
      RETURN -1
    END IF
  CASE ELSE
    RETURN -1
END CHOOSE
RETURN 1

Thanks

Answer 1

Here are the code to get the width and height of JPG:

//JPG

li_file = FileOpen(as_file_name, StreamMode!, Read! )
If li_file = -1 Then Return 0

li_read = FileRead (li_file, lb_data)  

If String (BlobMid (lb_Data, 1,3)) = Char (255) + Char (216) + Char (255) Then //JPG

    ll_DataLen = Len(lb_Data)   
    ll_DataPos = 3
    ll_FilePos = 3
    lb_LoopFlag = true
    Do While lb_LoopFlag
        ll_DataPos = ll_DataPos + 1
        ll_FilePos = ll_FilePos + 1
        li_Char1 = Asc (String (BlobMid(lb_Data, ll_DataPos, 1)))
        li_Char2 = Asc (String (BlobMid(lb_Data, ll_DataPos + 1, 1)))

        If li_Char1 = 255 And li_Char2 <> 255 Then
            If li_Char2 >= 192 And li_Char2 <= 195 Then
                al_width = Asc (String (BlobMid (lb_Data, ll_DataPos + 7,1))) * 256 + Asc (String (BlobMid (lb_Data, ll_DataPos + 8,1)))
                al_height= Asc (String (BlobMid (lb_Data, ll_DataPos + 5,1))) * 256 + Asc (String (BlobMid (lb_Data, ll_DataPos + 6,1))) 
                lb_LoopFlag= False
            Else   
                ll_FilePos = ll_FilePos + Asc (String (BlobMid(lb_Data, ll_DataPos + 3, 1))) + Asc (String (BlobMid(lb_Data, ll_DataPos + 2, 1))) + 1
                If ll_FilePos > ll_FileLength Then   
                    Exit   
                Else
                    FileSeek(li_file, ll_FilePos)   
                    FileRead(li_file, lb_Data)   
                    ll_DataLen = Len(lb_Data)   
                    ll_DataPos = 0   
                End If   
            End If   
        End If

        If ll_DataPos = ll_DataLen - 9 And lb_LoopFlag = True Then   
            ll_FilePos = ll_FilePos - 9   
            FileSeek(li_file, ll_FilePos)   
            FileRead(li_file, lb_Data)   
            ll_DataLen = Len(lb_Data)   
            ll_DataPos = 0   
        End If
        If ll_FilePos >= ll_FileLength Then   
            lb_LoopFlag = False   
        End If   
    Loop
End If

For GIF:

al_width = Asc(String (BlobMid (lb_Data, 7,1))) + Asc (String (BlobMid (lb_Data, 8,1))) * 256
al_height = Asc (String (BlobMid (lb_Data, 9,1))) + Asc (String (BlobMid (lb_Data, 10,1))) * 256