GET/PUT image header example

FreeBASIC

GET/PUT image header example
 
Example showing the two different headers used for image buffers.
Note: ImageInfo is provided as a simpler alternative to reading the image structures directly.

'' fbgfx.bi contains the necessary structures and constants for working
'' directly with image headers
#include "fbgfx.bi"

'' in lang fb, structures and constants are contained in the FB namespace
#if __FB_LANG__ = "fb"
Using FB
#endif


'' function to show info on an image
Sub show_image_info( ByVal image As Any Ptr )
    Dim As PUT_HEADER Ptr header
    Dim As Integer w, h, bpp, pitch

    header = image
    If( header->Type = PUT_HEADER_NEW ) Then

        Print "New style header"

        w = header->Width
        h = header->height
        bpp = header->bpp
        pitch = header->pitch

    Else

        Print "Old style header"

        w = header->old.width
        h = header->old.height
        bpp = header->old.bpp
        pitch = w * bpp

    End If

    Print "Image dimensions are " & w & "*" & h
    Print "Image uses " & bpp & " bytes for each pixel"
    Print "A row of image pixels takes " & pitch & " bytes"

End Sub


Dim As Any Ptr picture

ScreenRes 320, 200, 32

picture = ImageCreate( 10, 10, RGB(128, 192, 255) )

Put( 40, 40 ), picture, PSet

show_image_info( picture )

ImageDestroy picture

Sleep


NOTE: To use this code with an array, pass your array to the function, like this:

show_image_info( VarPtr( myarray( L ) ) )

where L is the lower bound of myarray().