From: Paul Eggert <eggert@cs.ucla.edu>
To: "Nicolas Léveillé" <nicolas@uucidl.com>
Cc: 17519@debbugs.gnu.org
Subject: bug#17519: [PATCH] take into account QuantumScale when reading imagemagick images
Date: Mon, 19 May 2014 13:04:12 -0700 [thread overview]
Message-ID: <537A63BC.5090408@cs.ucla.edu> (raw)
In-Reply-To: <C6926551-6A17-42FF-8A41-D365BFAF7CB8@uucidl.com>
[-- Attachment #1: Type: text/plain, Size: 229 bytes --]
Thanks for reporting this. Does the attached simpler patch fix the
problem for you? Dividing by QuantumRange instead of multiplying by
QuantumScale avoids potential double-rounding problems in future
versions of ImageMagick.
[-- Attachment #2: imagemagick.patch --]
[-- Type: text/x-patch, Size: 919 bytes --]
=== modified file 'src/image.c'
--- src/image.c 2014-05-04 18:51:32 +0000
+++ src/image.c 2014-05-19 19:47:21 +0000
@@ -8388,6 +8388,7 @@
#endif /* HAVE_MAGICKEXPORTIMAGEPIXELS */
{
size_t image_height;
+ double color_scale = 65535.0 / QuantumRange;
/* Try to create a x pixmap to hold the imagemagick pixmap. */
if (!image_create_x_image_and_pixmap (f, img, width, height, 0,
@@ -8428,9 +8429,9 @@
PixelGetMagickColor (pixels[x], &pixel);
XPutPixel (ximg, x, y,
lookup_rgb_color (f,
- pixel.red,
- pixel.green,
- pixel.blue));
+ color_scale * pixel.red,
+ color_scale * pixel.green,
+ color_scale * pixel.blue));
}
}
DestroyPixelIterator (iterator);
next prev parent reply other threads:[~2014-05-19 20:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-17 13:25 bug#17519: [PATCH] take into account QuantumScale when reading imagemagick images Nicolas Léveillé
2014-05-19 20:04 ` Paul Eggert [this message]
2014-05-20 7:37 ` Nicolas Léveillé
2014-05-20 8:07 ` Paul Eggert
2014-05-21 19:31 ` Nicolas Léveillé
2014-05-21 19:54 ` Paul Eggert
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