Legacy ImageMagick Discussions Archive

Terrific, thanks. (Note to self: As of this writing there is this: ImageMagick-7.0.7-25, 2018-03-04 07:50.)

Here is a slight modification of SetPixel to make a nicely functioning multi-pixel version: SetPixels. It is working for me and is very, very fast compared with repeating calls to SetPixel (or using Fx). Like SetPixel, though, it is only designed for the usual channel families (RGB, etc.). The call ...

Its likely writing the SetPixels() method was a challenge we were not prepared to tackle at the time we developed the GetPixels() method. Would you care to volunteer to write the method and contribute it to the PerlMagick user community? I'd love to, were I only equipped to do so. Not even knowing ...

I'll try then to see if I can grok blobs.

Why, though, is there a GetPixels() method, but no corresponding SetPixels() (only the singular SetPixel())?

Rick

The PerlMagick doc concerning "direct access to pixels" tantalizingly suggests what I need. But I have no clue how to use it. Any "pointers" (heh heh) would be appreciated; a tiny example would be most welcome. GetAuthenticPixels ... return authentic pixels as a C pointer A "C pointer" in Perl ...

I think I'm doing what I'm told in the doc, but I'm getting an error. Doc says, The EvaluateImages() method applies an arithmetic, logical or relational expression to a set of images. For example, $p = $image->EvaluateImages('mean'); averages all the images associated with object $image. But I get ...

Named colours are defined in color.c. They are defined as RGBA components, where RGB are integers 0 to 255, and alpha is floating-point. Almost all named colours have alpha=1. The colours "none" and "transparent" have alpha=0. Something like you describe (an alpha component for each color even if ...

In the Miscellaneous Methods section of the PerlMagick doc is this: Call QueryColor() with no parameters to return a list of known colors names or specify one or more color names to get these attributes: red, green, blue, and opacity value. @colors = $image->QueryColor(); ($red, $green, $blue ...

I'm not getting any traction with this on the PerlMagick board , so let me start fresh here with an extra nudge. Namely, that the array produced by the Statistics() method is unfriendly and likely to cause trouble down the road. It just gives a list of numbers; you're on your own figuring out which ...

Essentially, the MogrifyRegion method does bad things with regions that do not lie wholly within the image. At least if the region strays into negative x or y territory, it works improperly. This is ImageMagick 7.0.7-15 Q16 x86_64 2018-01-17 on Centos 6.9 with perl v5.10.1. My own project produces ...

The doc for -region does not specify any operations that ignore the setting, but -draw certainly seems to. -region geometry Set a region in which subsequent operations apply. Whether or not this is a bug or a feature, it is unfortunate that it isn't mentioned (and even more unfortunate, in my view ...

What should happen? All I expect is setting and then unsetting a region: magick -size 100x100 xc:black -region 40x40+20+20 +region badregion.png Here's what version "7.0.7-15 Q16 x86_64 2018-01-17" thinks of it on Centos 6.9; no image is written: magick: invalid argument for option '+region' '(null ...

You can at least create an image from scratch without reading some external image; below the image 'xc:white' is one of some internal types. (This is probably the same as the "canvas" mentioned earlier".) I don't find this onerous, since I usually want to write on some base color. Maybe there's ...

magick wrote: ↑2018-01-18T17:42:16-07:00 Thanks for the problem report. We can reproduce it and will have a patch to fix it [...]

Excellent. Any thoughts on the main part of the thread (safer access to Statistics array elements)?

Rick

And for the side(tracked) issue ... We cannot reproduce the problem. We're using Perl 5.10.0. The problem was with this, 10 years ago, but it is the same today: Image::Magick->QuantumDepth returns the correct value, but gives a (strict) warning. On my system (Centos 6.9; ImageMagick 7.0.7-15 Q16 x86 ...