From: Aaron Jensen <aaronjensen@gmail.com>
To: Alan Third <alan@idiocy.org>,
Aaron Jensen <aaronjensen@gmail.com>,
Kai Ma <justksqsf@gmail.com>,
63187@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>,
Po Lu <luangruo@yahoo.com>
Subject: bug#63187: 30.0.50; Tail of longer lines painted after end of nearby lines on macOS
Date: Sun, 25 Jun 2023 18:33:09 -0400 [thread overview]
Message-ID: <CAHyO48wDPSzbXQJzgRT9sbo88NZvLyJnxrSVM1mxR5QsH5j=7A@mail.gmail.com> (raw)
In-Reply-To: <ZJivG8AKHV47pDzI@idiocy.org>
On Sun, Jun 25, 2023 at 5:18 PM Alan Third <alan@idiocy.org> wrote:
>
> On Sun, Jun 25, 2023 at 03:07:39PM -0400, Aaron Jensen wrote:
> > On Sun, Jun 25, 2023 at 2:17 PM Alan Third <alan@idiocy.org> wrote:
> > > No, you can use [NSGraphicsContext flushGraphics] and CGContextFlush
> > > to force it.
> >
> > OK, that makes sense, but it's hard to find definitive documentation
> > of that (and ChatGPT seems to think that it's not true, but that's
> > likely a hallucination):
> >
> > =====START GPT=====
> > [NSGraphicsContext flushGraphics] (in Cocoa) and CGContextFlush (in
> > Core Graphics) are used to bypass this batching process and force any
> > pending drawing commands to be executed immediately. After calling
> > these methods, you can be sure that all your previously issued drawing
> > commands have been sent to the GPU.
> >
> > However, it's important to understand that while these functions
> > ensure that the commands are sent to the GPU, they don't guarantee
> > that the GPU has finished executing them. The actual rendering work is
> > still done asynchronously by the GPU.
> >
> > So if you need to read back the results of your rendering (e.g., from
> > an IOSurface), there might still be a brief period where the rendering
> > hasn't completed yet, even after calling flushGraphics or
> > CGContextFlush. If you need to ensure that all GPU rendering work is
> > complete before you proceed, you would typically need to use a more
> > low-level API (like Metal or OpenGL) that provides explicit
> > synchronization capabilities.
> >
> > ...
> >
> > Regarding your question about the [NSGraphicsContext flushGraphics]
> > and CGContextFlush, here are the descriptions directly from Apple's
> > documentation:
> >
> > [NSGraphicsContext flushGraphics]: "Forces any buffered drawing
> > commands to be sent to the destination."
> >
> > CGContextFlush: "Forces all drawing operations to be completed in the
> > specified context."
> >
> > It's important to understand these function calls ensure that drawing
> > commands are dispatched, not that they are completed. This is an
> > inference based on understanding of how graphics pipelines generally
> > work. For more detailed behavior and how these calls interact with
> > your specific use-case, you should refer to Apple's documentation and
> > guides, or consider reaching out to Apple's developer support.
> > =====END GPT=====
>
> The GPU isn't involved in this part. We're drawing to an IOSurface,
> which is a buffer in system memory. So when we draw and flush the
> graphics it's all done by the CPU in system memory.
>
> Then we put the IOSurfaceRef in the contents variable of the layer and
> at that point the GPU uses DMA to copy the buffer from system memory
> to GPU memory. While this is happening the IOSurface is locked so we
> know we shouldn't use it.
>
> Once it's in GPU memory, the GPU blits it to the screenbuffer or
> something, but by that time the IOSurface should be unlocked and we
> can start (safely) working on it again.
OK, that's clarifying, thank you.
> > > Set CACHE_MAX_SIZE to 1.
> > >
> > > But on my machine this resulted in unacceptable rendering flaws on
> > > almost all animated gifs as partially drawn buffers were sent to VRAM.
> >
> > What did you see?
> > I tried with this:
> >
> > https://share.cleanshot.com/vJTClHW9
> >
> > And I didn't notice anything drawing related, but I have an M1 with
> > integrated memory.
>
> Lots of white space. I thought that it was being caught either just
> before or as the image was being drawn into the buffer, so some
> portion of the image area was blank.
Interesting. Would:
+ if (context && context != [NSGraphicsContext currentContext])
have impacted that in any way?
Aaron
next prev parent reply other threads:[~2023-06-25 22:33 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <m2fs8histt.fsf@gmail.com>
2023-04-30 10:33 ` bug#63187: 30.0.50; Tail of longer lines painted after end of nearby lines on macOS Eli Zaretskii
2023-04-30 10:46 ` Aaron Jensen
2023-04-30 13:25 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-04-30 14:25 ` Aaron Jensen
2023-04-30 14:42 ` Eli Zaretskii
2023-04-30 14:57 ` Aaron Jensen
2023-04-30 15:26 ` Eli Zaretskii
2023-04-30 16:48 ` Aaron Jensen
2023-04-30 19:04 ` Eli Zaretskii
2023-04-30 23:58 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-05-01 12:40 ` Eli Zaretskii
2023-05-01 13:18 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-05-01 13:25 ` Eli Zaretskii
2023-05-01 13:47 ` Aaron Jensen
2023-05-01 13:52 ` Eli Zaretskii
2023-05-01 13:55 ` Aaron Jensen
2023-05-01 14:06 ` Aaron Jensen
2023-05-09 3:07 ` Aaron Jensen
2023-05-09 5:39 ` Eli Zaretskii
2023-05-13 13:54 ` Eli Zaretskii
2023-05-13 14:23 ` Aaron Jensen
2023-05-18 11:21 ` Eli Zaretskii
2023-05-18 15:59 ` Aaron Jensen
2023-06-08 5:40 ` Kai Ma
2023-06-08 7:33 ` Kai Ma
2023-06-08 12:51 ` Alan Third
2023-06-08 13:42 ` Kai Ma
2023-06-08 14:57 ` Kai Ma
2023-06-08 17:22 ` Alan Third
2023-06-09 2:42 ` Kai Ma
2023-06-09 2:47 ` Aaron Jensen
2023-06-09 3:12 ` Kai Ma
2023-06-09 18:27 ` Alan Third
2023-06-09 18:46 ` Aaron Jensen
2023-06-09 20:00 ` Alan Third
2023-06-12 13:04 ` Aaron Jensen
2023-06-16 2:17 ` Aaron Jensen
2023-06-19 15:46 ` Aaron Jensen
2023-06-24 4:17 ` Kai Ma
2023-06-24 13:34 ` Aaron Jensen
2023-06-24 14:14 ` Alan Third
2023-06-24 14:52 ` Aaron Jensen
2023-06-24 15:08 ` Eli Zaretskii
2023-06-24 15:41 ` Alan Third
2023-06-24 16:05 ` Aaron Jensen
2023-06-24 21:29 ` Alan Third
2023-06-24 21:43 ` Aaron Jensen
2023-06-25 12:46 ` Alan Third
2023-06-25 17:07 ` Aaron Jensen
2023-06-25 18:17 ` Alan Third
2023-06-25 19:07 ` Aaron Jensen
2023-06-25 21:18 ` Alan Third
2023-06-25 22:33 ` Aaron Jensen [this message]
2023-06-26 7:27 ` Kai Ma
2023-06-28 19:53 ` Alan Third
2023-07-21 2:02 ` Aaron Jensen
2023-07-23 11:20 ` Alan Third
2023-07-23 13:01 ` Aaron Jensen
2023-07-25 14:47 ` Aaron Jensen
2023-07-25 15:45 ` Eli Zaretskii
2023-06-23 8:48 ` Alan Third
2023-06-23 11:54 ` Aaron Jensen
2023-05-01 17:26 ` Alan Third
2023-05-01 22:40 ` Aaron Jensen
2023-05-02 10:14 ` Alan Third
2023-05-02 12:21 ` Eli Zaretskii
2023-05-02 22:36 ` Alan Third
2023-05-03 8:11 ` Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-05-03 13:08 ` Eli Zaretskii
2023-05-02 0:07 ` Po Lu via Bug reports for GNU Emacs, the Swiss army knife of text editors
2023-05-02 0:32 ` Aaron Jensen
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