Re: [Algorithms] OT: How to read a bitmap of arbitrary size?

[Ray G. <ra...@da...>]

Sounds like you need to take the
rowbytes-per-scanline into consideration.

Ray Gardener
Daylon Graphics Ltd.
http://www.daylongraphics.com/products/leveller
"heightfield modeling perfected"



-----Original Message-----
From: Pai-Hung Chen <pa...@ac...>
To: gda...@li...
<gda...@li...>
Date: Sunday, August 13, 2000 10:10 AM
Subject: [Algorithms] OT: How to read a bitmap of arbitrary size?


>Hi,
>
>I have been frustratingly bugged for hours and I decide to resort to the
>list.  I want to read a 24-bit bitmap heightfield.  I can correctly read it
>as long as the dimension of the bitmap file is in 2's power such as 4x4,
>8x8, 16x16, etc.  (But 2x2 doesn't work?!)  In these _normal_ cases, the
>*biSizeImage* field of the BITMAPINFOHEADER structure gives me the correct
>size of image in bytes.  However, if I create a bitmap of non-2's-power
>dimension such as 5x5, 6x6, 7x7, etc., the *biSizeImage* field gives me
some
>bogus number.  For example, 5x5 yields 80 bytes (5x5x3 = 75 bytes); 6x6
>yields 120 bytes (6x6x3 = 108 bytes); 7x7 yields 168 bytes (7x7x3 = 147
>bytes).  Could somebody tell me what happened?
>
>Thanks in advance,
>
>Pai-Hung Chen
>
>
>
>_______________________________________________
>GDAlgorithms-list mailing list
>GDA...@li...
>http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list
>