setting density doesn't appear to work

[dkniffin]

I'm trying to write some code that will take in an svg, resize it up, and output a png.

source svg file

This works fine using imagemagick's convert command:

convert -density 600 -sample 1600x1600 circle.svg out.png

But when I use rmagick to do the same thing:

image = Magick::Image.read("oval.svg"){|a| a.density = "600"}.first
image.sample! 100
image.write("out.png")

I get pixelation problems

I'm pretty sure the root problem here is that rmagick isn't respecting the density attribute properly.

This issue has appeared in a bunch of places around the web, but I've yet to find a solution that works:

• http://stackoverflow.com/questions/6237540/setting-density-upon-image-read-with-rmagick
• https://www.ruby-forum.com/topic/73965
• convert image  #67
• Resolution management #29

[tamagokun]

Also having density issues. Trying to output an image at something other than 72 dpi, and nothing seems to work. I've tried self.density x_resolution y_resolution and resample and none of them changed the output dpi.

[tamagokun]

Need to specify the units beforehand! This bugged the crap out of me for weeks..

Something like this should work..

image = Magick::Image.read("oval.svg") {
  self.units = Magick::PixelsPerInchResolution
  self.density = "600"
}.first

[Watson1978]

If at least one argument is given to the sample method, its value means scale.

 * @overload sample(scale)
 *   @param scale [Numeric] You can use this argument instead of specifying the desired width and
 *     height. The percentage size change. For example, 1.25 makes the new image 125% of the size of
 *     the receiver. The scale factor 0.5 makes the new image 50% of the size of the receiver.

So, image.sample! 100 resize to 10000% size. Looks for me that it is not same with covert command sample.