In configuring PDF to Imagefield in a content type, is the setting: "Density used for rendering PDF". I know what you mean, but it does not refer to a "density". Would be better to rename it, either:

  • Converted PDF image resolution
  • Converted PDF image size

It might also be worth mentioning whether these are absolute values (ie. images will be distorted to fit), or whether the aspect ratio will be preserved, ie. if I chose 100x100, and my PDF is landscape 3:4, then my resultant image would be 75x100.

Comments

dman’s picture

dman commented

You know what I mean? *I* don't!

The terminology is unclear, true, And that's partly because it's unclear to me too.
Whatever 'density' is, it's not image size, and it's something close to 'resolution'.
However ... It's named this because that's what it's actually named by the underlying process.
http://www.imagemagick.org/script/command-line-options.php#density

-density width
-density widthxheight

Set the horizontal and vertical resolution of an image for rendering to devices.
This option specifies the image resolution to store while encoding a raster image or the canvas resolution while rendering (reading) vector formats such as Postscript, PDF, WMF, and SVG into a raster image. Image resolution provides the unit of measure to apply when rendering to an output device or raster image. The default unit of measure is in dots per inch (DPI). The -units option may be used to select dots per centimeter instead.

O_o

So if anyone finds the need to play with these values, I can't do any better than refer to the source documentation and use the same terminology it does.
I didn't want to paraphrase and describe it in a way which may be less clear or less accurate.

I haven't experimented with non-regular proportions, and haven't found a case where that would seem to be a good idea. But if someone wants to, then the only explanation of that will be in the real docs.

iantresman’s picture

iantresman commented

My apologies, I thought represented the resulting image size, but is indeed the device resolution, and there is probably no need to change the default value. The only use would be to affect the final image size, but I guess it is best to let ImageCache sort this out.

Perhaps in addition to noting that "Horizontal and vertical density of the image XxY (e.g. 120x120). Default is 100x100", to also say:

This is the internal device resolution used by ImageMagic, and does not represent the final image size.

dman’s picture

dman commented

Yeah, display size is fully intended to by managed by image size.
This funny setting is exposed only because
A - the convert wouldn't work at all without it, and it didn't seem right to hard-code it if it was actually important.
B - if you're only ever using it to make thumbnails, performance is better if you just use low resolution, but if you want the full pages, you need full res.

But some help text like you suggest is indeed a good idea.
Seeing as I didn't have the link to the docs there in the first case is why it's looked unintuative!

dman’s picture

dman commented
Status: Active » Closed (fixed)