Search found 1163 matches

by glennrp
2017-10-31T12:57:08-07:00
Forum: Bugs
Topic: PNG -> PDF-Conversion results in corrupted image
Replies: 5
Views: 563

Re: PNG -> PDF-Conversion results in corrupted image

I When either version converts to PNG, I get that warning. I think it's simply a warning, that someone (GlennRP?) thinks grayscale PNG files shouldn't have colour profiles. But it does put the profile in the file. (Glenn knows far more about PNG than I do.) The PNG speciification for the iCCP chunk...
by glennrp
2017-09-30T08:46:39-07:00
Forum: Users
Topic: optimizing 'convert' speed
Replies: 4
Views: 1467

Re: optimizing 'convert' speed

When the output is PNG, the "quality" does not affect image appearance; it only affects the amount of compression. For your task, try "-quality 50" or "-quality 40", then adjust until you are happy with the compression speed and filesize (put this option at the end, just before "result.png" on your ...
by glennrp
2017-09-27T12:47:51-07:00
Forum: Bugs
Topic: PNG iCCP included in stripped image
Replies: 1
Views: 1224

Re: PNG iCCP included in stripped image

Thanks, fixed in IM7. Bug didn't exist in IM6.
by glennrp
2017-09-16T18:08:10-07:00
Forum: Bugs
Topic: Possible bug related to convert corrupted png file
Replies: 1
Views: 1005

Re: Possible bug related to convert corrupted png file

Not sure what else it could tell you. libpng was attempting to read a chunk (most likely IDAT) and some of it was missing. You can get more info by adding "-debug coder -log %e" to your commandline (put it right after "convert").
by glennrp
2017-09-13T17:57:10-07:00
Forum: Bugs
Topic: Possible bug related to the ‘geometry’ property
Replies: 7
Views: 1501

Re: Possible bug related to the ‘geometry’ property

Confirmed the behavior you observed. You can get the result you expected by adding "+repage" to the third line: convert 2.png -resize 3 +repage 3.png The recorded offset is interfering somehow with the conversion. You can also get the result you expected by using PPM instead of PNG for the files (PP...
by glennrp
2017-09-09T13:43:36-07:00
Forum: Users
Topic: Error "Got 2576-byte ICC profile not recognized as sRGB"
Replies: 3
Views: 1078

Re: Error "Got 2576-byte ICC profile not recognized as sRGB"

Get rid of the iCCP profile and replace it with the sRGB chunk or with a valid sRGB profile. The complaint is ocming from libpng16. The simplest way is to use the -strip option, if you haven't got any other valuable metadata that you want to preserve (by the way, the -debug option should appear earl...
by glennrp
2017-09-05T17:08:48-07:00
Forum: Bugs
Topic: Posible bug - surprisingly huge icon
Replies: 4
Views: 1387

Re: Posible bug - surprisingly huge icon

Not sure but "pngcheck -v file.ico" might help us figure out what's going on.
by glennrp
2017-08-28T16:03:17-07:00
Forum: Developers
Topic: Add png compression to identify -verbose
Replies: 6
Views: 2071

Re: Add png compression to identify -verbose

fmw42 wrote:
2017-08-27T20:34:01-07:00
Identify -verbose does not show that information, now, as far as I can tell.
Right, it doesn't. As I said, you need to use a large toolbox to get everything. For the particular information you wanted,
"pngcheck -vv file.png" provides it. Note that pngcheck is not libpng-based.
by glennrp
2017-08-27T19:45:21-07:00
Forum: Developers
Topic: Add png compression to identify -verbose
Replies: 6
Views: 2071

Re: Add png compression to identify -verbose

Yes, the first tool I usually go to is "pngcheck". If you add enough "v's" it will show you the filter method used for each line pngcheck -vvv file.png (If you add another "v" or two, you'll get every pixel sample, so three is about right for you). The next tool is "od -c" or "xxd" or my own "pngcru...
by glennrp
2017-08-27T19:33:11-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 4594

Re: Linux png compression issue

Perhaps you might discuss this with the others on the libpng development team and see if it makes sense to them to modify libpng to show one or the other. I don't know enough about the filter values to say which is better. I would leave that to you and the PNG team to decide which, if they agree to...
by glennrp
2017-08-26T12:32:41-07:00
Forum: Developers
Topic: Add png compression to identify -verbose
Replies: 6
Views: 2071

Re: Add png compression to identify -verbose

Probably not possible and certainly not easy. The PNG format does not explicitly record the "quality", compression method, or filtering method used in compressing the image. You can make a guess by looking at the filter bytes; if they are all zero or some other constant N, you can guess that the fil...
by glennrp
2017-08-25T15:48:30-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 4594

Re: Linux png compression issue

They probably are using the same ZIP compression and "quality". What would you like -verbose to report? Something like PNG:filters=1600x0; 0x1; 0x2; 0x3; 0x4 PNG:filters=0x0; 1x1; 1x2; 935x3; 663x4 or just PNG:filters=1600, 0, 0, 0, 0 PNG:filters=0, 1, 1, 935, 663 repectively for the two images? It ...
by glennrp
2017-08-24T16:28:14-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 4594

Re: Linux png compression issue

"pngcrush -n -v file.png" shows me that the centos compressor chose the "NONE" (0) filter for every row (note the "count" values): filter[0] defilter time = 0.000420997, count = 1600 filter[1] defilter time = 0.000000000, count = 0 filter[2] defilter time = 0.000000000, count = 0 filter[3] defilter ...
by glennrp
2017-08-24T16:17:39-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 4594

Re: Linux png compression issue

OK my mistake. I had downloaded the dropbox thumbnails. Here's what I get
when I use the DOWNLOAD/Direct Download buttons:

-rw-rw-r-- 1 glennrp glennrp 7027543 Aug 24 19:10 test_res_win.png
-rw-rw-r-- 1 glennrp glennrp 9647753 Aug 24 19:08 test_res_cent.png
by glennrp
2017-08-21T17:38:27-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 4594

Re: Linux png compression issue

Idon't see the differences in filesize that you're talking about:

Code: Select all

-rw-rw-r-- 1 glennrp glennrp 3030102 Aug 21 20:34 test_res_cent.png
-rw-rw-r-- 1 glennrp glennrp 3030102 Aug 21 20:33 test_res_win.png