How to get width and height of an image in PB - height

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

The offset of the image size depends on the file format. The values that your are using are valid for the BMP format, but will be different for another format.
You need to search separately for any of the file formats you need to handle. Some infos are available here. A similar example for VB to handle JPEG, GIF, BMP, & PNG is available here.
Also, you could get some info via the Windows image API, but I have no example available.

Answer 2

One way is to add a Picture control to a window with visible property unchecked and OriginalSize checked.
Set the picture name to load the image and Height and Width will be available to do your processing.
// p_1 is not visible
p_1.PictureName = "c:\temp\pbHowTo.jpg"
MessageBox("height", p_1.height)
MessageBox("width", p_1.width)
You may need to convert the values in pixel since they are in PbUnit.
height_pixel = UnitsToPixels(p_1.height, YUnitsToPixels!)
width_pixel = UnitsToPixels(p_1.width, XUnitsToPixels!)
The Picture control supports .BMP, GIF, .JPG and PNG files.

Answer 3

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