Re: fli and DIB graphics

Hi John,

I wrote some code that interfaced with the raw win32 api hoping to get
more GDI support.  I was succesful, though it is nowhere near complete.

Here is an example of creating a DIB from a raw array of bytes from a bitmap file (see
bitmap-tests.lisp).  The raw bits have to converted using a HDC from a window, I think
gp:read-external-image just returns an array of the bmp file.

(defun create-dib-bitmap (hdc raw-bitmap)
  (fli:with-dynamic-foreign-objects ()
    (let* ((size (bitmap-file-size raw-bitmap))
           (offset-bits (bitmap-offset-bits raw-bitmap))
           (c-raw-bitmap (fli:allocate-dynamic-foreign-object :type :byte :nelems size))
           (bitmap-bits (fli:copy-pointer c-raw-bitmap))
           (info (fli:copy-pointer c-raw-bitmap)))
      (loop for byte from 0 below size
            do
            (setf (fli:dereference c-raw-bitmap :index byte) (aref raw-bitmap byte)))
      (fli:incf-pointer bitmap-bits offset-bits)
      (fli:incf-pointer info +offset-info-header+)
      (winapi:|CreateDIBitmap| hdc info winapi::CBM_INIT bitmap-bits info
winapi::DIB_RGB_COLORS))))

My LWW-GDI stuff can be found at

http://www3.telus.net/public/whumeniu/gdi.zip

Enjoy

Wade


----- Original Message -----
From: "John DeSoi" <desoi@icx.net>
To: <lisp-hug@xanalys.com>
Sent: Tuesday, July 30, 2002 7:26 PM
Subject: fli and DIB graphics


| Hi,
|
| The docs seem to indicate that the gp:read-external-image represents
| the image as a Windows DIB. Questions:
|
| Is the vector in the data slot of the external image really a DIB? I
| have a DLL that accepts a DIB pointer. I tried to copy the vector to
| a foreign pointer and then call the DLL, but it crashes.
|
| Is there a way copy a Lisp array to a foreign array other than
| looping over each byte? I could not find anything in the FLI.
|
| Ideas and examples greatly appreciated,
|
| John DeSoi, Ph.D.
|