StretchableLayoutResizerBar triggers OpenGL warnings on macOS

MacOSX and iOS
1

Hi,
I’m kind of new around here so I’m not sure whether this is the best place to report potential bugs.

StretchableLayoutResizerBar::paint() directly calls isMouseOver(). When the component is attached to an OpenGL context, paint() is called outside the main thread, and since isMouseOver() maps to a macOS UI call this triggers a warning:

Main Thread Checker: UI API called on a background thread: -[NSView frame]

The fix is seemingly quite simple :
StretchableLayoutResizerBar-avoid-mouse-over-call.diff (2.5 KB)

JUCE Devs, is this worth a pull request? Or what’s the best way to report it?

2

Hi there,
Bumping this because I just found another component suffering from the same issue: ScrollBar::paint() calls isMouseOver() and isMouseButtonDown(). So it triggers the same UI API check warning when attached to a GL context.
Is that a second bug or am I missing something?

3

… and the patch fixing this second instance in ScrollBar:
ScrollBar-avoid-mouse-over-call.diff (2.4 KB)

4

Wouldn’t the issue persist, what with of isMouseButtonDown() still in use in StretchableLayoutResizerBar? In other words, the storing of a isMouseDown bool treatment seems to need to be applied there - based on what you’re saying that is.

5

@jrlanglois yes, that’s precisely what I’m doing in the patches attached.

6

And you’re missing a replacement of the call to isMouseButtonDown in your patches.

7

Oh, right, I see what you meant now. It turns out calling isMouseButtonDown doesn’t trigger the macOS warning, which is why I didn’t replace it in the first patch but you’re right, it would probably be a good idea.

I’ll complete the patch if there’s interest in merging it (still hoping to get feedback from official devs).

8

I’ve put together a solution for this issue. I think it probably makes more sense to address this directly in Component, rather than in each of the individual derived components. I’ll update this thread once the change is merged.

9

Great,thanks @reuk.

10

This should fix the issue:

11

That’s great removing some noise :slight_smile:

btw, also isMinimized can cause similar thing.

    bool isMinimised() const override
    {
        return [window isMiniaturized];
    }
12

Under what circumstances do you see this issue with isMinimised? I wouldn’t expect components to need to check isMinimised during painting, but maybe there’s a use-case I’ve overlooked.

13

Currently when a view is minimized (At least on macOS), the paint callback still triggers.

isMinimised can be used to reduce some painting.
Maybe it’s a corner case but I had this triggered once so thought it’s worth noting. :slight_smile: