[Xastir] Xastir Digest, Vol 49, Issue 6

[Tony Hunt]

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 <russo at bogodyn.org>
> To: Xastir - APRS client software discussion <xastir at lists.xastir.org>
> Cc: hamish at cloud.net.au, xastir at xastir.org
> Subject: [Xastir] GraphicsMagick/ImageMagick QuantumDepth issue fixed.
> Re: [OZAPRS] XASTIR - maps (fwd)
> Message-ID: <20091204190356.GA40037 at bogodyn.org>
> 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 <archer at eskimo.com> flavor, containing:
>>
>> Response from Hamish, for those that are following this thread.