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Paths set in /etc/paths are added to the PATH at startup in all shells on Mac OS X. /.bashprofile is just one of several shell scripts run by Bash at startup, and several of these are Bash-specific. Therefore, if you change your shell — Mac OS X also ships tcsh and zsh, for example — changes made to /etc/bashrc don't apply to your new shell. After you have contacted us and have received authorization, please return all items to: Inner Path, 7673 S. Shelby St., Indianapolis, IN. Ship your items back to us in the original unopened packaging, undamaged and unused. Please make sure that your return. For a project I worked on, I had to create a video capture interface. My goal was to make it look and feel as close to the regular iPhone camera app. One of the control that needed to be recreated.
I want to revisit Tuesday’s discussion of clipping; when I wrote that post I was laboring under certain misconceptions related to Core Graphics paths, which I would like to discuss. Asteroids! (schwarzbox) mac os. As a consequence of correcting these misconceptions, I can see that Core Graphics clipping is much easier to work with than I had supposed.
Whoops
My basic mistake was to assume that a Core Graphics path was, essentially, a single closed loop. In fact, a path is a collection of line segments and loops; it is essentially a collection of subpaths, where a subpath corresponds to my original conception of an overall path.
In particular, I misunderstood the purpose of these functions:
I thought that
CGContextBeginPath
and CGContextClosePath
formed a pair, and that a path was defined by Core Graphics calls made between these bookends. In fact, CGContextMoveToPoint
and CGContextClosePath
form the pair; CGContextMoveToPoint
establishes the first point on a subpath to which CGContextClosePath
will connect, if it is called.![InnerPath InnerPath](https://media.s-bol.com/gvw58P57YM9/794x1200.jpg)
Once this misapprehension was corrected, some other issues related to clipping became clear.
Winding vs. Non-Zero
I had been puzzled by this language in the Core Graphics documentation for
CGContextClip
:The function uses the nonzero winding number rule to calculate the intersection of the current path with the current clipping path. Quartz then uses the path resulting from the intersection as the new current clipping path for subsequent painting operations.
and
CGContextEOClip
:The function uses the even-odd rule to calculate the intersection of the current path with the current clipping path. Quartz then uses the path resulting from the intersection as the new current clipping path for subsequent painting operations.
When I was working on clipping to hollow shapes, I first tried this procedure:
- Define the “outer” hull
- Invoke
CGContext*Clip
- Define the “inner” hull
- Invoke
CGContext*Clip
However, no matter which
CGContext*Clip
functions I called at which point, and no matter which winding I used when defining the hulls, I could not get the clipping paths to interact in the way I wanted. I now understand why: These functions effectively apply the “nonzero winding” or “even-odd” rule to the current path (i.e. collection of subpaths), and then take the intersection of the resulting clipping region with the current clipping region.(Incidentally, the difference between the “nonzero winding” and “even-odd” rules is reasonably well explained here; it’s not Apple documentation, but it’s on-point.)
Examples
This function defines a relatively complex clipping region, used to create the image at the top of this post:
Three points:
- This example was hacked together, so some of the arguments to the function don’t make much sense
- The documentation for
CGContextAddArc
states that the final argument (clockwise
) must be 1 on the iPhone to create a CCW arc; this does not appear to be true, although I may be misinterpreting my results - The
CGContextMoveToPoint()s
preceding the arcs are crucial; without them, Core Graphics will insert line segments between the last point of one arc and the first point of another, with undesirable results
With our new understanding of paths and clipping, we can simplify the code that we saw on Tuesday:
I want to revisit Tuesday’s discussion of clipping; when I wrote that post I was laboring under certain misconceptions related to Core Graphics paths, which I would like to discuss. As a consequence of correcting these misconceptions, I can see that Core Graphics clipping is much easier to work with than I had supposed.
Whoops
My basic mistake was to assume that a Core Graphics path was, essentially, a single closed loop. In fact, a path is a collection of line segments and loops; it is essentially a collection of subpaths, where a subpath corresponds to my original conception of an overall path.
In particular, I misunderstood the purpose of these functions:
I thought that
CGContextBeginPath
and CGContextClosePath
formed a pair, and that a path was defined by Core Graphics calls made between these bookends. In fact, CGContextMoveToPoint
and CGContextClosePath
form the pair; CGContextMoveToPoint
establishes the first point on a subpath to which CGContextClosePath
will connect, if it is called.Once this misapprehension was corrected, some other issues related to clipping became clear.
Winding vs. Non-Zero
I had been puzzled by this language in the Core Graphics documentation for
CGContextClip
:The function uses the nonzero winding number rule to calculate the intersection of the current path with the current clipping path. Quartz then uses the path resulting from the intersection as the new current clipping path for subsequent painting operations.
Inner Path Mac Os Download
and
CGContextEOClip
:The function uses the even-odd rule to calculate the intersection of the current path with the current clipping path. Scuffed mac os. Quartz then uses the path resulting from the intersection as the new current clipping path for subsequent painting operations.
Inner Path Mac Os Catalina
When I was working on clipping to hollow shapes, I first tried this procedure:
- Define the “outer” hull
- Invoke
CGContext*Clip
- Define the “inner” hull
- Invoke
CGContext*Clip
However, no matter which
CGContext*Clip
functions I called at which point, and no matter which winding I used when defining the hulls, I could not get the clipping paths to interact in the way I wanted. I now understand why: These functions effectively apply the “nonzero winding” or “even-odd” rule to the current path (i.e. collection of subpaths), and then take the intersection of the resulting clipping region with the current clipping region.Inner Path Mac Os Downloads
(Incidentally, the difference between the “nonzero winding” and “even-odd” rules is reasonably well explained here; it’s not Apple documentation, but it’s on-point.)
Examples
This function defines a relatively complex clipping region, used to create the image at the top of this post:
Inner Path Mac Os X
Three points:
- This example was hacked together, so some of the arguments to the function don’t make much sense
- The documentation for
CGContextAddArc
states that the final argument (clockwise
) must be 1 on the iPhone to create a CCW arc; this does not appear to be true, although I may be misinterpreting my results - The
CGContextMoveToPoint()s
preceding the arcs are crucial; without them, Core Graphics will insert line segments between the last point of one arc and the first point of another, with undesirable results
With our new understanding of paths and clipping, we can simplify the code that we saw on Tuesday: