ImageMagick

问题 I have the following: ghostscript-fonts-5.50-24 ImageMagick-6.7.2-1 ghostscript-9.02-1 Which I use to create a series of JPGs for each page using: convert -density 175 -colorspace sRGB test.pdf -resize 50% -quality 95 test.jpg When I run this on my windows machine all appears to work ok, but on our linux server we get the black background problem. The resulting JPGs have a black background rendering the image un-readable, what am I missing or is there something I should be doing to correct

问题 I have a captcha image that looks like this: Using a utility called TesserCap from McAfee, I could apply a "chopping" filter to the image. (Before running it, I made sure there were only two colors in the image, white and black.) I was very impressed with the results of using that filter with a value of 2 in the text box. It accurately removed most of the noise but kept the main text, resulting in this: I wanted to implement something like this on one of my own scripts, so I tried to find out

问题 I've been using paperclip to upload and auto-resize photos in my Rails app, and I love it. Only problem is about every other month my crazy manager decides he wants a new size to display the photos in. So I add a new style in my Photo model and all is good for new photos, but the pre-existing photos are now a problem. Now that I'm starting to have more than a few photos to deal with I need a programmatic way to resize existing photos. Perhaps there is some paperclip trick for such a thing? I

问题 I had been using the image resize class written by someone else to resize images or to create the thumbnails, here is the link to the class I had been using. http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php I guess image GD library has some limitations for the resolution or the file size of images, it works fine for low resolution picture resizing(below 1024px) but it does not resize if I try to upload the high resolution jpeg image (i.e 3400px X 2200px) roughly, The

问题 Trying to load a PDF from the local file system and getting a "not authorized" error. "File "/env/local/lib/python3.7/site-packages/wand/image.py", line 4896, in read self.raise_exception() File "/env/local/lib/python3.7/site-packages/wand/resource.py", line 222, in raise_exception raise e wand.exceptions.PolicyError: not authorized `/tmp/tmp_iq12nws' @ error/constitute.c/ReadImage/412 The PDF file is successfully saved to the local 'server' from GCS but won't be loaded by Wand. Loading

问题 I'm working in php, and going through each image pixel-by-pixel to get an average brightness for each image is going to be way to cpu intensive... I've looked through both GD and imagemagick docs, but haven't found a way to return the average brightness of an image... Can this be done quickly either in these libraries, or in another package easily accessible by php? 回答1: Here is an interesting post using ImageMagick for computing the average graylevel of an image. This post also discusses

问题 I set pixel from one jpg. Save it another jpg file. Read a new file again. Get pixel. But it gives me incorrect result. That's my code: use Image::Magick; use Data::Dumper; my $im = new Image::Magick; $im->Read('file1.jpg'); my @pixel = $im->GetPixel(x=>0,y=>0,channel=>'RGB', normalize=>'True'); print Dumper(@pixel); my @color = ('1.0', '0.0', '0.0'); $im->SetPixel(x=>0, y=>0, channel=>'RGB', normalize=>'True', color => \@color); $im->Write('file30.jpg'); @pixel = $im->GetPixel(x=>0,y=>0

问题 First thanks a lot for reading my thread. I am trying to use ImageMagick with VS2012 on Windows 7 64-bit for image rotation. Here is what I did: Download ImageMagick for windows, and unzip it. Go to \ImageMagick-6.8.8\VisualMagick\configure\ folder, open configure.dsw in VS2012, and build it. It was successful. open configure.exe in \ImageMagick-6.8.8\VisualMagick\configure\, and click "next" -> "finish" with default settings. After step 3, an VisualDynamicMT.sln is generated in \ImageMagick

问题 Using the +level ImageMagick operator (https://imagemagick.org/script/command-line-options.php#level) in command line will produce an output image with the channel values of the input image compressed to the range specified. For example, the following ImageMagick command will cause the output pixel intensity values to be present between 45% and 70% of the total pixel value range. magick input.jpg +level 45%,70% output.jpg How do you perform the +level ImageMagick operation in Wand? The wand

问题 Here is my code: #! /usr/bin/env sh # Generate test image. convert -size 100x60 xc:blue -fill blue -stroke black -draw "circle 50,30 55,55" in.png # Make background transparent. convert in.png -fill none -draw 'matte 0,0 floodfill' -flop -draw 'matte 0,0 floodfill' -flop out.png # Replace transparent background with green. mogrify -background green -flatten out.png # The wrong way. convert in.png -transparent blue oops.png mogrify -background green -flatten oops.png It is based on this