Search found 1147 matches

by glennrp
2017-06-10T09:00:31-07:00
Forum: Kudos and Rants
Topic: Why is there an off-topic add at the top of each imagemagick.org page?
Replies: 13
Views: 31177

Re: Why is there an off-topic add at the top of each imagemagick.org page?

I see them if I visit as guest but not while logged in. Lately the ad has contained a huge green DOWNLOAD button which installs some sort of crapware, not ImageMagick.
by glennrp
2017-06-10T08:58:45-07:00
Forum: Users
Topic: identify and cr2 raw takes ages
Replies: 12
Views: 6720

Re: identify and cr2 raw takes ages

Have you tried using a Q16 build instead of Q32?
by glennrp
2017-06-07T12:22:57-07:00
Forum: Users
Topic: Apply standard brightness/saturation/contrast
Replies: 9
Views: 9400

Re: Apply standard brightness/saturation/contrast

Here are comments by me and fmw42 on the StackOverflow instance of this question: Have you tried the "-normalize" option of ImageMagick? There are more complex methods that produce better results, but you might like the result as a first cut at fixing them. – Glenn Randers-Pehrson yesterday Just to ...
by glennrp
2017-05-31T14:13:04-07:00
Forum: Developers
Topic: PNG eXIF chunk proposal
Replies: 9
Views: 12716

Re: PNG eXIF chunk proposal

Thanks for the feedback. We're proceeding with the eXIf chunk proposal, keeping the thumbnail if it's present.
by glennrp
2017-05-29T13:31:23-07:00
Forum: Developers
Topic: PNG eXIF chunk proposal
Replies: 9
Views: 12716

Re: PNG eXIF chunk proposal

I know what you mean about the jpg thumbnail being out of sink. Out of interest how would a create private chunk in imagemagick? Look at the "caNv" chunk support in coders/png.c; this is a fairly simple example of using a user read function to understand a private chunk. There's also code in coders...
by glennrp
2017-05-29T10:26:53-07:00
Forum: Developers
Topic: PNG eXIF chunk proposal
Replies: 9
Views: 12716

Re: PNG eXIF chunk proposal

The troublesome part is maintaining the thumbnail when the image is edited. We dealt with that in the chunk proposal by mentioning that the thumbnail might be out of sync with the main image. Specifically, the current draft says "While encoders may choose to update them, there is no expectation that...
by glennrp
2017-05-29T08:10:07-07:00
Forum: Users
Topic: Help me to understand below CLI
Replies: 3
Views: 4290

Re: Help me to understand below CLI

I was saving image as jpeg using first CLI so it would remove transparency. That's not a great way of removing transparency, due to the lossy conversion to JPEG. There are ways of removing transparency via "-alpha " options, but if you like the simplicity of converting to an opaque image format, us...
by glennrp
2017-05-28T09:01:12-07:00
Forum: Developers
Topic: PNG eXIF chunk proposal
Replies: 9
Views: 12716

PNG eXIF chunk proposal

During January and February 2017 the PNG Development Group discussed a proposed eXIf chunk for storing the Exif profile. See http://www.simplesystems.org/png-group/proposals/eXIf/ The PNG group discussion has lapsed without action on the proposal. The proposal was pretty simplistic: just copy whatev...
by glennrp
2017-05-24T07:41:42-07:00
Forum: Bugs
Topic: macOS, PNG conversion gives "Abort trap: 6"
Replies: 2
Views: 3939

Re: macOS, PNG conversion gives "Abort trap: 6"

Are you sure you are running ImageMagick's "convert"? With version 7.0.5 it's "magick" or "magick convert" instead.
by glennrp
2017-05-20T17:18:21-07:00
Forum: Developers
Topic: MozJPEG library in ImageMagick build
Replies: 3
Views: 13888

Re: MozJPEG library in ImageMagick build

What does MozJPEG offer that libjpeg doesn't? As far as I know, MozJPEG is just a fork of libjpeg.
by glennrp
2017-05-18T10:10:14-07:00
Forum: Bugs
Topic: PNG32/PNG64 has broken.
Replies: 4
Views: 6114

Re: PNG32/PNG64 has broken.

Confirmed that this bug exists in 7.0.5-0 and as far back as 7.0.1-0.
Version 6.9.8-5 produces a correct png32 but a fully transparent png64.
by glennrp
2017-04-30T08:22:18-07:00
Forum: Users
Topic: "Optimized" image heavier (bigger file size) than the original
Replies: 14
Views: 10218

Re: "Optimized" image heavier (bigger file size) than the original

Your original file, according to "identify -verbose" has "Quality 69 (approximate)".
The "approximate" means that the quantization tables used weren't exactly those
used by ImageMagick, so the recompression won't be exactly the same. It's not
a mistake but simply a fact of life.
by glennrp
2017-04-28T12:55:50-07:00
Forum: Users
Topic: "Optimized" image heavier (bigger file size) than the original
Replies: 14
Views: 10218

Re: "Optimized" image heavier (bigger file size) than the original

Is there any way to preserve de multiplicity? I mean, trim in "8x8 blocks" steps, to avoid to do new blocks. I don't mind trim a little less pixels if the file size will be better. I don't know of a really simple way, but I've done it lots of times, for this very reason. It involves some bookkeepin...
by glennrp
2017-04-27T11:43:41-07:00
Forum: Users
Topic: "Optimized" image heavier (bigger file size) than the original
Replies: 14
Views: 10218

Re: "Optimized" image heavier (bigger file size) than the original

Also bear in mind that when the -trim operation doesn't cut off an exact multiple of 8 columns or 8 rows, the image gets re-quantized into new 8x8 blocks (or 16x16 blocks, if sub-sampling), which can cause new colors to be created (by default, sub-sampling happens when the requested quality is less ...
by glennrp
2017-04-14T07:35:50-07:00
Forum: Bugs
Topic: Corrupt input may lead to crash
Replies: 3
Views: 7402

Re: Corrupt PNG leads to SIGABRT

The test file actually contains a corrupt PPM file with the .png extension. studio> od -c corrupt.png | head 0000000 P 6 \n # S A N E d a t a f 0000020 o l l o w s \n 2 7 5 2 4 6 0 4 0000040 \n 2 5 5 \n 377 377 377 377 377 377 377 377 377 377 377 0000060 377 377 377 377 377 377 377 377 377 377 377 3...