Add slider menu item, configuring on-screen controls size

[Vankata453]

Adds the ItemSlider menu item. It allows selecting an integer value between a minimum and a maximum value. It can be used with the left mouse button, left/right arrow keys or scroll wheel. The slider step (interval between values when using the arrow keys or scroll wheel) is configurable from "Options" -> "Advanced".

The sound volume, music volume and flash intensity options now utilize a slider. The on-screen controls scale option was added back in "Options" -> "Controls" and utilizes a slider as well.

Supertux.Menu.Sliders-1.mp4

Additionally:

• The on-screen controls toggle has also been re-added in "Options" -> "Controls".
• The on-screen controls configuration values were changed to allow for broader scale customization.

Closes #3010.
Closes #3033.

[MatusGuy]

This is ideal for the volume sliders! Just make sure there's a way to specify the step.

[Vankata453]

Just make sure there's a way to specify the step.

What step?

[MatusGuy]

The step is the interval between values.
For example, if the step is 5, each time you press the right key, instead of increasing by 1 it increases by 5. And when using a cursor it snaps to the right place.

[Vankata453]

Sure, will make an option for it.

[tobbi]

I haven't tested it yet but... Many of the sliders in UI Frameworks have the option of increasing / decreasing when the user hovers over the slider and uses the mouse wheel. Any plans on implementing that?

[Vankata453]

Will do, I forgot they had that.

[Vankata453]

Added customizable slider steps and scroll wheel support.

[Thatstinkyguy]

@Vankata453 Awesome work! Will these features be added to the Android version?

[Vankata453]

Will these features be added to the Android version?

After this is merged, they will.

[tobbi]

/home/runner/work/supertux/supertux/src/gui/item_slider.cpp:90:96: error: implicit conversion from 'int' to 'float' may lose precision [-Werror,-Wimplicit-int-float-conversion]
        *m_value = static_cast<int>(((mouse_pos.x - m_slider_x) / SLIDER_WIDTH) * (m_max_value - m_min_value)) + m_min_value;
                                                                                ~  ~~~~~~~~~~~~^~~~~~~~~~~~~
/home/runner/work/supertux/supertux/src/gui/item_slider.cpp:114:96: error: implicit conversion from 'int' to 'float' may lose precision [-Werror,-Wimplicit-int-float-conversion]
        *m_value = static_cast<int>(((mouse_pos.x - m_slider_x) / SLIDER_WIDTH) * (m_max_value - m_min_value)) + m_min_value;
                                                                                ~  ~~~~~~~~~~~~^~~~~~~~~~~~~
2 errors generated.

[MatusGuy]

Will test this pretty soon.

[MatusGuy]

I really don't like the step option in the config menu. First time mobile port users will be extremely confused when they see the slider going from min to max instantly when using the left/right buttons because they don't know what a "slider step" is (and they're not supposed to).

When using the slider with the mouse on the volume controls, it lags the game. If you want I will investigate this.

I gotta say. I really like how the mouse can be used for precision and the arrows can be used for bringing up quick values. But I think the roles should be switched. When using the mouse, the value should be snapped to the defined step, and the arrow keys should be used for precision values, because if the mouse is somewhat defective, that "precision" is lost.

I'm excited for this!