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- >I agree with Robert's call for the more traditional lower-left-based
- >coordinate system, but feel obliged to point out that the X Window
- >System has 0,0 at the upper left.
-
- Since, this issue doesn't want to die, I vote for staying with "0,0" at the
- top,left. Except for PostScript, that is the common usage within character
- based and bitmap based displays. Diverging from this practice now will
- require extra transformations to the local text and graphics environments.
- PostScript can be confusing sometimes because of the 0,0 at the bottom,
- left. Think about large objects that span pages and arbitrary scaling of
- objects where the "anchor" is typically at the top left of the object, not
- at the bottom left. Even in the simplest cases, where there isn't a "page
- boundary", drawing occurs from the top left, then down the virtual page,
- with scrollbars added if needed. With Hebrew, Arabic, Kanji, etc. which
- read right to left, you still start at the top of the page.
-
- It would be possible to put "0,0" at some arbitrary location within an
- image, like the center of the image so that you have the image overlayed on
- a "normal" cartesian coordinate system. It requires a transformation as
- simple as putting "0,0" at the bottom left, plus defining where you want
- "0,0" and whether you want positive y to go up or down, prior to
- referencing any images.
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- ka
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