jersmi's picture

Seeking clarification -- why does Vuo use pixels and points for rendered windows and how and when should I use these units of measurement? Google takes me to iOS standards, though text seems to be part of it, too?

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When working with pixels, you

MartinusMagneson's picture
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When working with pixels, you have a set number of "dots" in an array containing the position and color. For images this goes from 0 to max pixels both on the x and y axis. You can think of the pixel space as an absolute space, and it doesn't concern itself with three dimensions.

When you get into 3d space and layers, things change quite a bit. As the objects you generate doesn't get any attributes in terms of pixels until they get rendered, using pixels for placement, size and rotation isn't useful. Instead, the cartesian coordinate system is used. You can think of this as a relative space where you can translate (move), scale and rotate an object.

For more on the cartesian system you can read about it at Wikipedia.

Thanks, Magneson.

jersmi's picture
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Thanks, Magneson.

Sorry, I was trying to sort out units from pixels and points as used in rendering windows. I know Vuo, like QC, uses units to refer to the relative coordinate system. I was wondering, why points as a third unit of measurement? Maybe I should have asked, how many pixels are in a Vuo point?

Also wondering if there was some agreed upon system Vuo is using for points. Out in the world there are (at least) a couple different standards for points as a unit of measurement, both absolute, like printed type (72 points/inch), or the iOS standard of 163 points/inch. Personally, I don't think of pixels as 100% absolute -- is there a standard for pixel size?

Aha, I see. Not too

MartinusMagneson's picture
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Aha, I see. Not too experienced with that, but I think it relates to physical size, just with a different base. Pixels are absolute in the sense that the native resolution of a picture expressed in pixels will span across an equal amount of pixels on any display. If you display an image on two equally sized screens, but with different resolutions, the image will appear smaller on the screen with the higher resolution (more pixels), but it lights up an equal amount of physical pixels.

If I've gotten the point about points, they also have a set physical size, but one that disregards the pixels and use inches instead. For instance, with a 72ppi setting and a 72pt wide image, it should be 1 inch on all devices. When that is said I did some measurements now with a caliper, and it does not retain its size when changing the resolution of the screen, so some clarification on the matter from someone at Team Vuo would be helpful.

Quoting from the vuo.screen

jstrecker's picture
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Quoting from the vuo.screen node set description: "The dimensions of a screen are measured in points. For non-Retina displays, points are equivalent to pixels. For Retina displays, each point is 2 pixels."

[Magneson] Pixels are absolute in the sense that the native resolution of a picture expressed in pixels will span across an equal amount of pixels on any display. If you display an image on two equally sized screens, but with different resolutions, the image will appear smaller on the screen with the higher resolution (more pixels), but it lights up an equal amount of physical pixels.

Yep, that covers what happens if you compare two Retina displays or two non-Retina displays. If you compare a Retina display and a non-Retina display with the same resolution (in points), the image will appear half the physical size on the Retina display as on the non-Retina display.