ImageMagick and RMagick both have a setting/attribute for "density", which is what they call resolution. I can pass it a value of 200 and it should set the resolution to 200x200 when the image is written to either a file or to_blob.
In the Rails console I can load the image, then set the density, and if I check it, it will tell me the density (originally 300x300) is now 200x200, but when I write it out to a file, the resolution is 300x300.
The only way I've successfully been able to change the resolution is by creating a new image of the same width and height, then overlay the original image. This, however, distorts the output, no matter what settings I use (I tried setting the original to fully opaque, the "new" to fully transparent, and even used the CopyCompositeOperation, which should fully replace the "new" image).
I have tried setting density like this:
image.density = "200"
And like this
image.write("test.jpg") {self.density="200"}
And both.
Nothing works... any ideas?
To be clear... I don't want to resize the image, I want to change the print resolution. I want the dimensions to remain the same (i.e. width/height should NOT change).