All right faggots, it's guide time. Turns out that Windows wasn't very hard to get working, and I got to rediscover Chocolatey's magic while I was at it, so hallelujah for that. Easy to forget how spoiled the Loonix crowd is with package managers.
Prerequisites:- Ruby
⌙ doubleVision (
https://github.com/trishume/doubleVision)- ImageMagick
Step 0: Installing the prerequisitesFor Linux: Install ImageMagick and Ruby from your distro's usual sources, then run
# gem install doubleVision to install doubleVision.
For macOS: Get a package manager such as Macports, Brew, or whatever kludge they use this week, and follow the instructions for Linux. All Linux commands should work exactly the same for macOS.
For Windows (the easy way): Install Chocolatey from (
https://chocolatey.org/install). Once installed, open a command prompt as an administrator and run
> choco install ruby, and
> choco install imagemagick.app -PackageParameters LegacySupport=true. Close the admin command prompt, open a normal non-admin prompt, then run
> gem install doubleVision to install doubleVision.
For Windows (the hard way): Install Ruby for Windows from (
https://rubyinstaller.org/downloads/). Pick the latest Ruby+Devkit installer, and install the defaults. During the MSYS setup phase, accept the defaults.
This step will take around 1 GB of space!Install ImageMagick for Windows from (
https://www.imagemagick.org/script/download.php#windows). Pick the latest recommended installer.
During installation, check the box to install legacy utilities!After everything is installed, open a command prompt and run
> gem install doubleVision to install doubleVision.
All Linux/macOS commands will be shown
like this, and all Windows commands will be shown
like this. Mods, I know NPFchan supports code tags, yet they aren't enabled. Explain yourselves.Step 1: Preparing the imagesWe will need two images: one our fake thumbnail, the 'mask', and the other our real image, the 'secret'. File type won't matter, since we're converting them to PNG files.
Ensure the images are of a similar aspect ratio. We will be resizing these images, so this is important to not distort the end result, particularly our 'secret'.
Copy both your images to a working directory, and open a command prompt there.
Our first step is to resize our 'secret' to a maximum of 600 pixels in either dimension, removing all transparency and replacing it with white.
$ convert <input secret image> -resize 600x600 -background white -flatten secret.png> convert <input secret image> -resize 600x600 -background white -flatten secret.pngMake a note of the dimensions of the output image. In my example, it is 600x338. Our 'mask' image will need to be perfectly resized to this resolution.
$ convert <input mask image> -resize 600x338\\! -background white -flatten mask.png> convert <input mask image> -resize 600x338! -background white -flatten mask.pngDo not omit the \\! or ! in the resize argument. It is needed to resize the mask image perfectly.
You should have two identically sized PNG images.
Adjust parameters to taste.
You can increase the resolution of the images if you wish, but the process of creating our trick image doubles the resolution of our input images, so this will have a negative effect on both filesize and viewability on common resolutions. Don't exceed more than 1000 pixels in any dimension, as an absolute maximum.
Step 2: Creating the trick imageMerge our two images with the doubleVision command.
$ doubleVision secret.png mask.png result.png> doublevision secret.png mask.png result.pngThis should create our trick image. If it fails, ensure that both the secret and mask images are PNG's, have identical resolutions, and try again.
Opening this image in common image viewers and even ImageMagick itself will show our mask image, but opening it in a web browser will show the secret image instead. You'll no doubt notice the thumbnail is also the mask image, too.
Repeat these steps for every image you want to conceal.This trick works because of 4th-dimensional Warp fuckery with PNG gamma settings. If you'd like to learn more, you can read further at
http://thume.ca/projects/2012/11/14/magic-png-files/A warning regarding mobilefags:
these trick images will not work on mobile apps like Clover and Dashchan! They use the internal Android image renderer, which will show only the mask image like any other common image viewer. Mobilefags must use a web browser to see the images for what they are.
All example images and Windows commands were tested on Windows 7. There's no reason they shouldn't work for newer versions.
And thus ends another good night's research and testing! Now that our Windows users aren't left in the dust
and hopefully if I didn't fuck up my formatting again, let's see some good trick images this thread!
You faggots disappointed me last thread, so let's not have a repeat performance.