Search found 102 matches

by Jason S
2012-08-12T11:28:38-07:00
Forum: Bugs
Topic: Multiple issues with BMPv5 colorimetry
Replies: 1
Views: 3056

Multiple issues with BMPv5 colorimetry

I'm using IM 6.7.8-9. I've made some sample BMP files that may be of use, available here . The g/pal8v5.bmp and g/pal8v4.bmp files are relevant. (I can't be sure these files are correctly formed. Please tell me if you think they're not.) Here's the main BMP documentation I'm using. Test case: Create...
by Jason S
2012-07-25T12:25:48-07:00
Forum: Bugs
Topic: XMP corrupt after convert
Replies: 4
Views: 6908

Re: XMP corrupt after convert

Right. Apparently, some applications can't parse multiple XMP packets in the same JPEG/XMP segment, and ignore the whole segment that case. I looked at the XMP spec , and my assessment is that both files are invalid: All of the XMP about a resource should be stored in a single XMP packet. The XMP Sp...
by Jason S
2012-07-25T09:47:59-07:00
Forum: Bugs
Topic: XMP corrupt after convert
Replies: 4
Views: 6908

Re: XMP corrupt after convert

The original file has 15 separate blocks of XMP text, each stored in its own JPEG file segment. In the result file, all the XMP text has been concatenated together into a single JPEG file segment. The characters you see between the blocks of XMP text in the original file are part of the JPEG file in...
by Jason S
2012-06-06T11:08:09-07:00
Forum: Developers
Topic: BiCubic Interpolation does not match any known filter!
Replies: 90
Views: 113745

Re: BiCubic Interpolation does not match any known filter!

Did you get nonsense results when you used bilinear on the alpha with another filter on the colour channels? My point is to use a "safer" (monotone, tight support...) filter on the alpha. I don't recall, and I don't have a good example at the moment. It might be that it's only a significant problem...
by Jason S
2012-06-06T09:18:45-07:00
Forum: Developers
Topic: BiCubic Interpolation does not match any known filter!
Replies: 90
Views: 113745

Re: BiCubic Interpolation does not match any known filter!

Transparency outside of [0,1] makes absolutely no sense to me . Consider two ways you could process an image: 1. Apply a background color to the image, then resize it. 2. Resize the image, then apply a background color to it. Do you expect to get the same result in both cases? If you allow the inte...
by Jason S
2012-05-17T13:31:47-07:00
Forum: Bugs
Topic: Some PNG images get corrupted
Replies: 7
Views: 12192

Re: Some PNG images get corrupted

I was using an old version version of libpng and zlib in that case (because I used what was provided by the Ubuntu distribution managers). Sorry for the lack of details, but I didn't expect this to be hard for others to reproduce. I've had a chance to try it with the latest libpng, and it didn't hel...
by Jason S
2012-05-16T17:41:39-07:00
Forum: Bugs
Topic: Some PNG images get corrupted
Replies: 7
Views: 12192

Re: Some PNG images get corrupted

Using valgrind, I get dozens of "uninitialised value" warnings that I don't get with other types of PNG images. For example, Use of uninitialised value of size 8 at 0x4C2A291: memcpy (mc_replace_strmem.c:635) by 0x5296466: ??? (in /lib/x86_64-linux-gnu/libz.so.1.2.3.4) by 0x5296937: ??? (in /lib/x86...
by Jason S
2012-05-13T21:04:40-07:00
Forum: Bugs
Topic: Some PNG images get corrupted
Replies: 7
Views: 12192

Re: Some PNG images get corrupted

There is some unknown factor that determines whether this problem occurs, so I don't expect everyone to be able to reproduce it. But if you're suggesting the two images in my report are visually identical to you, I don't really know what to say. Note that 'compare' appears to also be affected by the...
by Jason S
2012-05-13T18:15:24-07:00
Forum: Bugs
Topic: Some PNG images get corrupted
Replies: 7
Views: 12192

Some PNG images get corrupted

Here's a small 16-bit RGB PNG image with binary transparency: http://entropymine.com/jason/temp/ctest.png Run it through "convert", with no options. Using the Cygwin 6.7.6-3 release, the top row gets corrupted: http://entropymine.com/jason/temp/ctest-cygwin-6.7.6-3.png With 6.7.6-9 on Cygwin, I get ...
by Jason S
2012-04-30T16:48:33-07:00
Forum: Developers
Topic: BMP "CSType" field
Replies: 0
Views: 3205

BMP "CSType" field

If I run "convert logo: test.bmp", IM writes a version 5 BMP file, and sets the "bV5CSType" (color space type) field to 1. My question is, what does the 1 mean? The IM source code in bmp.c has this: (void) WriteBlobLSBLong(image,0x00000001U); /* CSType==Calib. RGB */ But my Windows SDK tells me that...
by Jason S
2012-04-26T15:09:59-07:00
Forum: Users
Topic: How to Convert *jpg/png/24bmp/etc/anything to 16bit-bitmap
Replies: 4
Views: 13284

Re: How to Convert *jpg/png/24bmp/etc/anything to 16bit-bitm

ImageMagick doesn't support writing 16 bits/pixel BMP images.

(I do know of another program, that can do that.)
by Jason S
2012-02-24T10:50:51-07:00
Forum: Users
Topic: Converting 12bit Tiff from Photron Highspeed camera.
Replies: 10
Views: 18122

Re: Converting 12bit Tiff from Photron Highspeed camera.

Unfortunately, I think the image is damaged, and probably cannot be recovered in an automated way. For example, here's a binary representation of a run of blue samples near the start of the image: ... 010001111001 010001110011 010000111111 010000011001 011111111100 011111101110 010000011010 01000011...
by Jason S
2012-02-24T08:02:42-07:00
Forum: Users
Topic: Converting 12bit Tiff from Photron Highspeed camera.
Replies: 10
Views: 18122

Re: Converting 12bit Tiff from Photron Highspeed camera.

Portable = something that ImageMagick can read.
by Jason S
2012-02-23T17:32:19-07:00
Forum: Users
Topic: Converting 12bit Tiff from Photron Highspeed camera.
Replies: 10
Views: 18122

Re: Converting 12bit Tiff from Photron Highspeed camera.

I examined the file, but I'm having trouble making sense of it. It does not seem to be a simple byte/nibble ordering problem.

If you could provide samples of a single image saved in both the 12-bit format, and in a portable format, that might help.
by Jason S
2011-12-04T14:14:48-07:00
Forum: Users
Topic: Emulating a resize algorithm
Replies: 2
Views: 5159

Re: Emulating a resize algorithm

I figured out a way to make the box filter work. I'd assumed I could distort both dimensions at once, but it only works if I separate them. convert Rings1.gif \ -filter box -define filter:blur=0.707 \ +distort SRT "0,0 0.8,1.0 0 0.3999,0.0" -crop 800x1000+0+0 \ +distort SRT "0,0 1.0,0.8 0 0.0,0.3999...