Excellent work Tom..
Hopefully this can help hamish get something new into the repositries for
the Debian based stuff.
Tony Hunt VK5AH
-- Original Message -----
Date: Fri, 4 Dec 2009 12:03:56 -0700
From: Tom Russo <[email protected]>
To: Xastir - APRS client software discussion <[email protected]>
Cc: [email protected], [email protected]
Subject: [Xastir] GraphicsMagick/ImageMagick QuantumDepth issue fixed.
Re: [OZAPRS] XASTIR - maps (fwd)
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
Xastir has long had the problem that it will display jpeg images (through
.geo
files) incorrectly if ImageMagick or GraphicsMagick have been compiled
with
QuantumDepth=8. They would display as completely black.
None of my systems (FreeBSD, Ubuntu 8.04) have the problem, so it took me
a
while to get around to looking into it. I built a VirtualBox virtual
machine
with Ubuntu 9.10 and dove in last night. The issue was trivial, and
amounted
to a single function call where there was an incorrect assumption of
type-equivalence between a Quantum and the red/green/blue components of an
XColor. The function pixel_pack_bits was being called with Quantums as
arguments. When QuantumDepth was 8, these were up-cast to unsigned
shorts,
which had 0 for the upper 8 bits and the value of the quantum for the
lower
8 bits. Thing is, pixel_pack_bits strips the upper 8 bits of the r,g, and
b
provided and packs them into a 24 bit quantity for the X display. That
meant that it always returned 0x000000 for every pixel.
This problem was only present for images that were not color mapped. GIF,
PNG, XBM, etc were not a problem, but jpg certainly were.
I just committed a fix for this. As of today, CVS Xastir will work
properly
with images through ImageMagick or GraphicsMagick irrespective of
QuantumDepth=16 or QuantumDepth=8.
I have not addressed the HDRI issue. HDRI is considered "experimental" in
ImageMagick, and at this point Xastir does not compile with versions of IM
for which this experimental feature is turned onn.
On Tue, Nov 24, 2009 at 02:24:59PM -0800, we recorded a bogon-computron
collision of the <[email protected]> flavor, containing:
Response from Hamish, for those that are following this thread.
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