[macOS] Ugly drawing of slider's ticks

[hwiesmann]

Description

Compile widgets sample with default compiler options and select the native slider in the tree book. When the ticks are shown it can be seen that the first half of the ticks is slightly centered above the slider's line, the other half is slight centered below the slider's line (see attached screenshot).

The reason for this behavior is the result line 22 in slider_osx.cpp:

 // The dimensions of the different styles of sliders (from Aqua document)

#if wxOSX_USE_COCOA
    #define wxSLIDER_DIMENSIONACROSS_WITHTICKMARKS 28 /* this is the critical line! */
    #define wxSLIDER_DIMENSIONACROSS_ARROW 21
#else
    #define wxSLIDER_DIMENSIONACROSS_WITHTICKMARKS 24
    #define wxSLIDER_DIMENSIONACROSS_ARROW 18
#endif

Whenever the defined preprocessor variable has an even value, the slider's ticks are badly centered, choosing an odd value solves the issue. So, 29 is a good value.

BTW: Aqua is pretty much outdated.

• wxWidgets version you use: latest master built from GitHub
• wxWidgets port you use: macOS 14.4.1

[vadz]

Thanks, let's indeed fix this but I don't know what are the currently recommended values, @csomor would you know this by chance? If we change this to 29 we should probably use the other branch to use 25?

P.S. I've edited the description to use proper code block (triple single quotes).

[csomor]

Actually the 28 is correct for the slider, but the labels calculation lead to a height of 49 when shown, this number leads to the ugly rendering. When neither min max nor value are shown, then IMHO things look fine with 28, so the real fix would be there I think. But unfortunately at the moment I don't have time for it ...

[hwiesmann]

Hi, When the min and max value are not shown but only the value the drawing of the slider’s ticks is as ugly as with the min and max values (I use the widgets sample, see screenshot attached).  Nevertheless, we should change the slider's implementation. Instead of changing one of the constants we can also make sure that the overall height is always an even number.

…

Am 15.05.2024 um 06:43 schrieb Stefan Csomor ***@***.***>: Actually the 28 is correct for the slider, but the labels calculation lead to a height of 49 when shown, this number leads to the ugly rendering. When neither min max nor value are shown, then IMHO things look fine with 28 — Reply to this email directly, view it on GitHub <#24532 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAD6V3HQ4NXRIZWIERAGPR3ZCLRX3AVCNFSM6AAAAABHW4ZQFCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDCMJRGU3TCOJVGI>. You are receiving this because you authored the thread.

[csomor]

When the min and max value are not shown but only the value the drawing of the slider’s ticks is as ugly as with the min and max values (I use the widgets sample, see screenshot attached). 

yes, that's correct, as I wrote when no values and no min max labels are shown, then 28 is correct

Nevertheless, we should change the slider's implementation. Instead of changing one of the constants we can also make sure that the overall height is always an even number.

this would be best IMHO