Search found 1147 matches

by glennrp
2017-08-19T09:07:53-07:00
Forum: Bugs
Topic: "Ignoring invalid time value" when writing PNGs
Replies: 6
Views: 6229

Re: "Ignoring invalid time value" when writing PNGs

There was a problem with timezones east of GMT zone. I was using an unsigned int for "addhours"
but it can be negative. Working on a fix.
by glennrp
2017-08-18T11:31:06-07:00
Forum: Bugs
Topic: Linux png compression issue
Replies: 30
Views: 18526

Re: Linux png compression issue

Could you post your two PNG output files somewhere that we can retrieve them
or if you prefer, run "pngcheck -v file.png" on both and post the result here?
by glennrp
2017-08-14T14:19:16-07:00
Forum: Consulting
Topic: PAID: Extract copyright from comment and annotate image
Replies: 4
Views: 13363

Re: PAID: Extract copyright from comment and annotate image

This does not seem to work with a PNG image that contains a tEXt chunk with copright. The copyright line does show up in the output of identify -verbose as a Copyright property. Properties: Copyright: � 2013,2015 John Cunningham Bowler date:create: 2017-08-14T17:12:35-04:00 but does not show up in t...
by glennrp
2017-08-14T13:12:01-07:00
Forum: Bugs
Topic: "Ignoring invalid time value" when writing PNGs
Replies: 6
Views: 6229

Re: "Ignoring invalid time value" when writing PNGs

It was a temporary glitch, due to some timestamps having the offset from UTC recorded as "Z" instead of "[+-]hh:mm", in IM-7.0.6-6 and 6.9.9-6.
by glennrp
2017-08-03T19:16:20-07:00
Forum: Bugs
Topic: PNG 'tIME' chunk not in UTC
Replies: 2
Views: 3203

Re: PNG 'tIME' chunk not in UTC

Fixed. I added "addhours" and "addminutes" to the scan of "date", and added
that to the existing hours and minutes. Needs more work to handle February
28 on leap years, though.
by glennrp
2017-08-03T16:46:51-07:00
Forum: Bugs
Topic: PNG 'tIME' chunk not in UTC
Replies: 2
Views: 3203

Re: PNG 'tIME' chunk not in UTC

coders/png.c, line 8178, write_tIME_chunk(), gets the time from time_t ttime; time(&ttime); On my Ubuntu platform, "man 2 time" claims that it returns time in UTC. However, I confirm that a PNG image created at 19:54 EDT gets a tIME chunk with 19:54 UTC. The date:create property comes from MagickCor...
by glennrp
2017-07-30T16:53:18-07:00
Forum: Bugs
Topic: "magick nofile output.png" is too verbose
Replies: 1
Views: 2656

"magick nofile output.png" is too verbose

This is a followup to a complaint on the Kudos and Rants Forum. IM7 is too verbose when it can't find a file, as in magick nothing.jpg output.png Im6 only emits 2 lines while im7 seems to get into "property.c" with invalid input, and emits about 3 more error messages. Also, "magick convert nothing.j...
by glennrp
2017-07-30T08:21:12-07:00
Forum: Bugs
Topic: [became suggest/request: write PNG as sRGB by deflt for DynamRng&Compat -edit] image gets darker&darker every round-trip
Replies: 43
Views: 21209

Re: [proposed solution (please respond): write png files as sRGB by default(EDIT)] image gets darker&darker every round-

In the related bug report I've fixed coders/png.c so that pixels survive multiple round trips between HDR and PNG formats.
by glennrp
2017-07-29T18:10:43-07:00
Forum: Bugs
Topic: [glennrp fixd IM7 to git] reading linear png (GAMA=1) sets sRGB (nonlinear colorspace) but should set RGB (linear) instd
Replies: 2
Views: 2853

Re: reading linear png (GAMA=1) sets sRGB (nonlinear colorspace) but it should set RGB (linear) instead

I've pushed a change to the IM7 git repo The "one" demo works nicely; the pixel values survive the round-trip PNG->HDR->PNG->HDR: one: 0,0: (65535,32896,0) #FFFF80800000 srgb(255,128,0) one.hdr: 0,0: (65535,32768,0) #FFFF80000000 rgb(100%,50%,0%) one.hdr.png: 0,0: (65535,32896,0) #FF8000 rgb(255,128...
by glennrp
2017-07-29T17:40:39-07:00
Forum: Bugs
Topic: [glennrp fixd IM7 to git] reading linear png (GAMA=1) sets sRGB (nonlinear colorspace) but should set RGB (linear) instd
Replies: 2
Views: 2853

Re: reading linear png (GAMA=1) sets sRGB (nonlinear colorspace) but it should set RGB (linear) instead

The png reader is setting gamma to1.0 but neglects to reset the image colorspace. That would be a bug that needs to be fixed.
I'm testing a patch now.
by glennrp
2017-07-29T13:32:30-07:00
Forum: Bugs
Topic: [became suggest/request: write PNG as sRGB by deflt for DynamRng&Compat -edit] image gets darker&darker every round-trip
Replies: 43
Views: 21209

Re: [proposed solution (please respond): write png files as sRGB by default(EDIT)] image gets darker&darker every round-

Am I missing something? Wasn't there an issue about IM not doing a round trip correctly? Not reading linear PNG files correctly? Has that been resolved, or is someone investigating? It's still open as far as I am concerned. Incidentally, the one.hdr.png file from my demo does happen to be 16-bit (4...
by glennrp
2017-07-29T05:20:02-07:00
Forum: Bugs
Topic: [became suggest/request: write PNG as sRGB by deflt for DynamRng&Compat -edit] image gets darker&darker every round-trip
Replies: 43
Views: 21209

Re: [proposed solution (please respond): write png files as sRGB by default(EDIT)] image gets darker&darker every round-

... And they recommend exporting images as 8-bit sRGB for use by the world, ... Okay, so, at least if we're writing an 8-bit per sample PNG file would you agree that sRGB should be the default, rather than whatever-colorspace-the-image-just-so-happens-to-already-be-in-for-whatever-reasons? The libp...
by glennrp
2017-07-28T17:27:16-07:00
Forum: Users
Topic: Controlled dithering, 16-bit to 8-bit
Replies: 7
Views: 4541

Re: Controlled dithering, 16-bit to 8-bit

Right, "random-threshold" reduces the image to black and white pixels. I think there's a way to random-dither each channel to get an 8-color image. But no way to get a 256-color image with it.
by glennrp
2017-07-28T17:22:36-07:00
Forum: Users
Topic: Clarification on use of colours and depth in IM
Replies: 12
Views: 5877

Re: Clarification on use of colours and depth in IM

Use -sample instead of -resize if you don't want to add interpolated colors.